L’évolution humaine ayant reposé durant plusieurs millions d’années sur une consommation significative de produits d’origine animale (voir études ici et article ici), il est possible qu’une alimentation trop exclusivement végétale ne parviennent pas toujours à couvrir les besoins nutritionnels d’Homo sapiens. Avec un engouement de plus en plus important pour ces types d’alimentation, des études plus précises et plus nombreuses commencent à être publiées, identifiant certains risques qui avaient possiblement été sous-estimés jusque-là.
D’autres études sont plus favorables, mais il convient de préciser les biais méthodologiques possibles de ces études, qui restent soit des études d’épidémiologie avec un gros risque de mauvais échantillonnage (voir notamment le risque de « biais du survivant »), soit des études d’intervention de courte durée. Il conviendrait en conséquence de rester très prudent quant aux conclusions positives ou négatives concernant les régimes végétariens, et à plus forte raison végétaliens.
1. Avis divers.
2. Dépression, troubles mentaux.
3. Squelette et santé dentaire.
4. Troubles digestifs et troubles associés.
5. Troubles alimentaires.
6. Divers.
7. Adaptations génétiques.
8. Nutriments potentiellement problématiques.
9. Etudes de cas.
10. Soja.
11. Biais possibles.
12. Etudes sur les enfants végétaliens.
13. Etudes sur les adultes.
Méta-analyses et revues systématiques
A Systematic Review of the Association Between Vegan Diets and Risk of Cardiovascular Disease [Texte]
Kaiser et al.
Journal of Nutrition, 2021
Using the Grading of Recommendations Assessment, Development and Evaluation approach, evidence was deemed to be of low to very low strength/quality.
[…] Among the Western populations studied, evidence weakly demonstrates associations between vegan diets and risk of CVDs, with the direction of associations varying with the specific CVD outcome tested. However, more high-quality research on this topic is needed.
–
Meta-analysis of effect of vegetarian diet on ischemic heart disease and all-cause mortality [Texte]
Jabri et al.
American Journal of Preventive Cardiology, 2021
A vegetarian diet, compared with a non-vegetarian diet, was associated with a reduced risk of ischemic heart disease mortality, whereas it had no effect on all-cause and cerebrovascular mortality. However, the results are to be considered with caution considering the low certainty of evidence. Despite recent studies supporting no restriction on animal protein intake gaining wide media attention and public traction, consideration for vegetarianism amongst those with risk factors for coronary artery disease should be contemplated.
–
Méta-analyse de Dinu de 2017, et sa critique.
Vegetarian, vegan diets and multiple health outcomes: A systematic review withmeta-analysis of observational studies [PDF]
Monica Dinu et al.
Critica reiews in food science and nutrition, 2017
Conclusions: This comprehensive meta-analysis reports a significant protective effect of a vegetarian diet versus the incidence and/or mortality from ischemic heart disease (-25%) and incidence from total cancer (-8%). Vegan diet conferred a significant reduced risk (-15%) of incidence from total cancer.
La critique de la méta-analyse :
Plant-based diets do not prevent most chronic diseases
Tanis Fenton & Chelsia Gillis
Critical Reviews in Food Science and Nutrition, 2017
https://www.tandfonline.com/doi/pdf/10.1080/10408398.2017.1389692
We are concerned about the selective reporting, over-stated cause-and-effect statements and lack of mentioning the 10 results of no associations between vegetarian and vegan diets and chronic diseases in the recent paper (Dinu et al. 2017).
Les études sur les adventistes sont plus favorables au végétarisme que les autres. Les études de courte durée sont plus favorables au végétarisme que les études de longue durée (possibilité de carence à long terme ?). Notons que les seuls études US citées sont celles des adventistes. Soit on manque sérieusement d’études, soit la sélection de Dinu est discutable, effectivement :
Remarques personnelles :
Le papier insiste à de nombreuses reprises sur les limitations liées aux études :
the overall analysis in the cohort studies reported no significant association with specific localizations of cancer disease, such as incidence and mortality from breast cancer, as well as incidence of lung, colon-rectum and stomach cancer. This fact can be explained by the low statistical power, due to a low number of studies evaluating this aspect and a low sample size[…]However, data obtained from cross-sectional studies need to be interpreted with caution because of the moderate-to-high risk of bias reported in the vast majority of these studies, and also because of the high degree of heterogeneity evidenced in our overall analysis.
[…]reinforcing the hypothesis that the studies coming from Adventist cohorts present a low degree of generalizability when compared to other cohort
[…]we could not analyze an important datum such as the duration of adherence to the vegetarian or to the vegan patternin the different cohorts. Indeed, only one study explicated this finding that is extremely relevant for understanding the relationship with mortality and incidence of disease. In addition, the definition of the control group, i.e., those following an omnivorous diet was not really well-defined, including in some cases subjects consuming a high intake of meat and meat products and in other cases subjects with a reduced consumption of meat and derivatives. A final potential weakness is the accuracy of the assessment of vegetarian and vegan status. There are several slight differences in the population of vegetarians throughout the world, and the possibility that some studies could have included vegetarians and vegan altogether cannot be ruled.
[…]vegan diet seems to be associated with a lower rate of cancer incidence, but this result must be interpreted with caution, because of the very small sample size and the low number of studies evaluating this aspect
–
Avis divers
Déplacés sur une page dédiée
Squelette et santé dentaire
Déplacé sur une page dédiée.
Troubles digestifs et troubles associés
Association between self-reported vegetarian diet and the irritable bowel syndrome in the French NutriNet cohort
Camille Buscail et al.
Plos one, 2017
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0183039
Among these individuals, 2,264 (5.4%) presented an IBS, and 805 (1.9%) reported a VD. Overall, VD was not associated with IBS or subtypes. A stable VD (i.e. self-declared at least three times) was associated with IBS (aOR 2.60 95%CI [1.37–4.91]), IBS mixed (aOR 2.97 95%CI [1.20–7.36]) and IBS diarrhoea (aOR 2.77 95%CI [1.01–7.59]).
–
Frequency and risk factors of functional gastro-intestinal disorders in a rural Indian population.
Ghoshal UC, Singh R, 2017
https://www.ncbi.nlm.nih.gov/pubmed/27262283
Functional gastrointestinal disorders, particularly dyspepsia-IBS overlap, are common in rural Indian population; the risk factors included chewing tobacco, aerated soft drink, tea/coffee, vegetarian diet, disturbed sleep, anxiety, and dyspepsia predicting occurrence of IBS.
Troubles alimentaires
Orthorexic and restrained eating behaviour in vegans, vegetarians, and individuals on a diet
et al.
Eating and weight disorder, 2018
https://link.springer.com/article/10.1007/s40519-018-0479-0
Conclusion
In general, the results imply that orthorexic eating behaviour varies with the amount of dietary restrictions people display. Food selection strategies like veganism, vegetarianism, and dieting behaviour are accompanied by more pronounced orthorexic eating behaviour, indicating that cognitive control and restrictions of food intake play a role in orthorexia, too. Further research is needed to investigate whether these food selection strategies serve as risk factors regarding the development of orthorexic eating behaviour.
–
Increased prevalence of vegetarianism among women with eating pathology
Kelly L. Zuromski et al.
Eating behaviors, 2015
https://www.sciencedirect.com/science/article/pii/S1471015315000860
Endorsement of vegetarianism was highest among females with severe eating pathology. Future research should use longitudinal data to examine the temporal relationship between these variables, or other underlying factors that may contribute to the co-occurrence of eating pathology and vegetarianism. Clinically, endorsement of vegetarianism may also be an important variable to consider in treatment disordered eating.
–
Cette étude trouve une association entre orthorexie et végétarisme :
Eating and weight disorders, 2014
https://link.springer.com/article/10.1007/s40519-014-0131-6
When we analyzed the differential distribution of orthorexia in our cohort, we only found an association between the ORTO-15 score and vegetarianism (Table 4), i.e., the ORTO-15 score was lower among vegetarians.
The Inter-relationships between Vegetarianism and Eating Disorders among FemalesAnna M. Bardone-Cone et al.
Journal of the Academy of Nutrition and Dietetics, 2012
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3402905/
Compared to controls, individuals with an eating disorder history were significantly more likely to ever have been vegetarian (52% vs. 12%), to be currently vegetarian (24% vs. 6%), and to be primarily motivated by weight-related reasons (42% vs. 0%). The three recovery status groups (fully recovered, partially recovered, active eating disorder) did not differ significantly in percentiles endorsing a history of vegetarianism or weight-related reasons as primary, but they differed significantly in current vegetarianism (33% of active cases, 13% of partially recovered, 5% of fully recovered). Most perceived that their vegetarianism was related to their eating disorder (68%) and emerged after its onset. Results shed light on the vegetarianism-eating disorders relation and suggest intervention considerations for clinicians (e.g., investigating motives for vegetarianism).
Vegetarianism and eating disorders: Association between eating attitudes and other psychological factors among Turkish adolescents.
Bas, M., Karabudak, E., & Kiziltan, G.
Appetite, 2005.
https://www.researchgate.net/publication/7813871_Vegetarianism_and_eating_disorders_Association_between_eating_attitudes_and_other_psychological_factors_among_Turkish_adolescents
As a conclusion, the present study indicated abnormal eating attitudes, low self-esteem, high social physique anxiety, and high trait anxiety in Turkish vegetarian adolescents. The vegetarian adolescents may be more likely to display disordered eating attitudes and behaviors than nonvegetarians.
Hormes, J. M., Catanese, D., Bauer, R, & Rozin, P.
Poster session presented at the annual meeting of the American Psychological Association, 2006.
Self-reported vegetarianism may be a marker for college women at risk for disordered eating.
Klopp, S. A., Heiss, C. J., & Smith, H. S.
Journal of the American Dietetic Association, 2003
Cliquer pour accéder à 02820abdb307fd8e8056e8437fac35e4cb15.pdf
Although many people follow a vege-tarian diet as part of a healthy lifestyle, the results from this study indicate that the practice of vegetarianism may be a marker for college female students at risk for weight preoccupation and eating disorder tendencies. Clinicians need to be aware of subpopulations at increased risk for eating disorder tendencies to aid in the early detection of those with true eating disorders.
–
Vegetarianism and eating-disordered thinking.
Lindeman, M., Stark, K., & Latvala, K.
Eating Disorders, 2000
https://www.researchgate.net/publication/233482788_Vegetarianism_and_Eating-Disordered_Thinking
The results indicate that vegetarianism and eating disorders are not independent but rather are intertwined phenomena. The potential common links, for example the possibility that vegetarianism is being used as a smokescreen for more severe eating pathology, are discussed.
(PDF) Vegetarianism and Eating-Disordered Thinking. Available from: https://www.researchgate.net/publication/233482788_Vegetarianism_and_Eating-Disordered_Thinking [accessed Dec 07 2018].
–
Adolescent vegetarians. A behavioral profile of a school-based population in Minnesota.
Neumark-Sztainer, D., Story, M., Resnick, M., & Blum, R.
Archives of Pediatrics and Adolescent Medicine, 1997
https://www.ncbi.nlm.nih.gov/pubmed/9265888
Vegetarians were almost twice as likely to report frequent dieting (P < .001), 4 times as likely to report intentional vomiting (P < .001), and 8 times as likely to report laxative use (P < .001) than nonvegetarians. Overall, associations with other health-compromising and health-promoting behaviors were not apparent.
–
Vegetarianism in anorexia nervosa? A review of 116 consecutive cases.
O’Connor, M. A., Touyz, S. W., Dunn, S. M., & Beumont, P. J.
The Medical Journal of Australia, 1987
https://www.researchgate.net/publication/19465975_Vegetarianism_in_anorexia_nervosa_A_review_of_116_consecutive_cases
A retrospective study was carried out of 116 consecutive patients with anorexia nervosa to ascertain the extent and nature of vegetarianism in this population. Sixty-three (54.3%) patients were found to be avoiding red meat. In only four (6.3%) of these did meat avoidance predate the onset of their anorexia nervosa. Of the remaining 59 patients (best termed pseudovegetarians), 25 (42.4%) patients continued to avoid red meat by the end of treatment. Pseudovegetarianism was associated with a longer duration of anorexia nervosa, a lower weight during the course of their illness, and living away from the parental home. The reintroduction of red meat into the diet was more likely if vegetarianism were of a short duration.
Divers
–
Des différences de méthylation de l’ADN entre non végétariens et végans. Hypométhylation chez les végans. Difficile d’évaluer l’importance de cette constatation.
Differences in DNA Methylation Patterns Between Vegans and Non-vegetarians in the AHS-2 Cohort (FS11-06-19)
Miles et al.
Current developpements in nutrition, 2019
https://www.ncbi.nlm.nih.gov/pubmed/31223786?fbclid=IwAR3dxdXbqJyAnN1mbOjKySPIM9z7vq3YVL62ws3p6c1S5j30Qw3l3qkX-vo
Our findings suggest substantial differences in methylation of CpG sites and genes, particularly in regulatory regions, between vegans and non-vegetarians, with a preponderance of hypomethylation among vegans.
–
Factors associated with anemia among female adult vegetarians in Malaysia
Zi Fei Chai et al.
Nutrition research and practice, 2019
https://synapse.koreamed.org/search.php?where=aview&id=10.4162/nrp.2019.13.1.23&code=0161NRP&vmode=FULL
A total of 177 female vegetarians were recruited from a Buddhist and Hindu organization in Selangor, Malaysia.[…]
The findings revealed 28.2% of the participants to be anemic. The age group (AOR = 2.46, 95% CI = 1.19–5.05), marital status (AOR = 2.69, 95% CI = 1.27–5.71), and percentage of energy from protein (AOR = 5.52, 95% CI = 1.41–21.65) were the significant predictors of anemia.
–
Is a vegetarian diet safe to follow during pregnancy? A systematic review and meta-analysis of observational studies
Chang Tan & al.
Critical reviews in food science and nutrition, 2019
https://www.tandfonline.com/doi/abs/10.1080/10408398.2018.1461062?fbclid=IwAR1pAuFe7QoUii8mDCXr2at53ghzddO3bsKRaDNojyAdvq59IuiCRhpm4_M
The overall estimated relation between vegetarian pregnancy and low birth weight (LBW) was marginally significant (1.27 (0.98, 1.65), P = 0.07, I2=0%). Asian (India/Nepal) vegetarian mothers exhibited increased risks to deliver a baby with LBW (1.33 (1.01, 1.76), P = 0.04, I2=0%). However, the WMD of neonatal birth weight in five studies suggested no difference between vegetarians and omnivores. Given the high heterogeneity of the included studies, lack of high-quality evidence, and limited studies included for each category, we failed to reach conclusive results regarding the risks of hypospadias, intrauterine growth retardation, maternal anemia, and gestational diabetes mellitus.
–
Which Is a Good Diet—Veg or Non-veg ? Faith-Based Vegetarianism for Protection From Obesity—a Myth or Actuality ?
Sanjay Borude
Obesity surgery, 2019
https://link.springer.com/article/10.1007/s11695-018-03658-7
In an Asian Indian cohort, we found that vegetarian dietary patterns were associated with a higher incidence of morbid obesity culminating in bariatric surgery. Our study is a myth breaker that all vegetarian diets are healthy diets. Our findings can be utilized to discourage refined and processed food consumption and promote healthy vegetarian food choices.
–
Effect of restriction vegan diet’s on muscle mass, oxidative status, and myocytes differentiation: A pilot study
Daniela Vanacore et al.
Journal of celular physiology, 2018
https://onlinelibrary.wiley.com/doi/full/10.1002/jcp.26427
We enrolled three groups of healthy men (omnivores, vegetarians, and vegans) with similar age, weight and BMI, and we observed a significant decrease in muscle mass index and lean body mass in vegan compared to vegetarian and omnivore groups, and higher serum homocysteine levels in vegetarians and vegans compared to omnivores. We studied whether serum from omnivore, vegetarian, and vegan subjects affected oxidative stress, growth and differentiation of both cardiomyoblast cell line H9c2 and H‐H9c2 (H9c2 treated with H2O2 to induce oxidative damage). We demonstrated that vegan sera treatment of both H9c2 and H‐H9c2 cells induced an increase of TBARS values and cell death and a decrease of free NO2− compared to vegetarian and omnivorous sera. Afterwards, we investigated the protective effects of vegan, vegetarian, and omnivore sera on the morphological changes induced by H2O2 in H9c2 cell line. We showed that the omnivorous sera had major antioxidant and differentiation properties compared to vegetarian and vegan sera. Finally, we evaluated the influence of the three different groups of sera on MAPKs pathway and our data suggested that ERK expression increased in H‐H9c2 cells treated with vegetarian and vegan sera and could promote cell death. The results obtained in this study demonstrated that restrictive vegan diet could not prevent the onset of metabolic and cardiovascular diseases nor protect by oxidative damage.
–
Anthropometric and physiologic characteristics in white and British Indian vegetarians and nonvegetarians in the UK Biobank.
Tong TY et al., 2018
https://www.ncbi.nlm.nih.gov/pubmed/29868910
In white women, after adjustment for age and compared with regular meat eaters, non-red meat eaters had lower adiposity (e.g., 4.5% lower body fat in vegan women) and lower systolic and diastolic blood pressure (-4.2 and -3.3 mm Hg, respectively), and generally lower heel bone mineral density t-score (-0.26). Patterns of differences by diet group were similar in white men. In the Indian population, compared with meat eaters, vegetarian women were shorter (-1.1 cm) and had lower lean mass (-0.5 kg), and both vegetarian women and men had lower grip strength (-1.3 and -1.4 kg, respectively). No significant differences in the other characteristics were observed.
–
When veggies aren’t enough
Yvette van Schie
Professional beauty, 2018
https://search.informit.com.au/documentSummary;dn=562484894378004;res=IELHSS;type=pdf
Etude peu significative, mais sujet à creuser en lien avec les possibles manques de collagènes liés aux alimentations purement végétales.
Although vegetarians and vegan diets are healthy for the body, they can have detrimental effects on the skin, says Yvette van Schie, but supplements can help.
Risk factors for orofacial clefts in India: A case–control study
Sutapa Bandyopadhyay Neogi et al.
Birth defect research, 2017
https://onlinelibrary.wiley.com/doi/full/10.1002/bdr2.1073?fbclid=IwAR00bB0d0WR5BRpNcRiPifzavudWGnRlNIgXY66jJoLu7yGZ8DQu4rmiVMk
–
Vegan diets: practical advice for athletes and exercisers.
Rogerson, D, 2017
https://www.ncbi.nlm.nih.gov/pubmed/28924423
[…] veganism creates challenges that need to be accounted for when designing a nutritious diet. This included the sufficiency of energy and protein; the adequacy of vitamin B12, iron, zinc, calcium, iodine and vitamin D; and the lack of the long-chain n-3 fatty acids EPA and DHA in most plant-based sources. However, via the strategic management of food and appropriate supplementation, it is the contention of this article that a nutritive vegan diet can be designed to achieve the dietary needs of most athletes satisfactorily. Further, it was suggested here that creatine and β-alanine supplementation might be of particular use to vegan athletes, owing to vegetarian diets promoting lower muscle creatine and lower muscle carnosine levels in consumers. Empirical research is needed to examine the effects of vegan diets in athletic populations however, especially if this movement grows in popularity […]
–
Il est ici souligné que l’on a besoin de beaucoup plus de recherche, particulièrement sur la santé à long terme des végans (dont on sait en fait assez peu à ce jour, le recul est faible).
The long-term health of vegetarians and vegans.
Appleby, PN, Key TJ, 2016
https://www.ncbi.nlm.nih.gov/pubmed/26707634
The long-term health of vegetarians appears to be generally good, and for some diseases and medical conditions it may be better than that of comparable omnivores. Much more research is needed, particularly on the long-term health of vegans.
–
Food intake diet and sperm characteristics in a blue zone: a Loma Linda Study.
Eliza M. Orzylowska et al.
European journal of obstetrics, gynecology and reproductive biology, 2016
https://www.researchgate.net/publication/303692674_Food_intake_diet_and_sperm_characteristics_in_the_Blue_Zones_a_Loma_Linda_Study
Lacto-ovo vegetarians had lower sperm concentration (50.7±7.4M/mL versus non-vegetarians 69.6±3.2M/mL, mean±S.E.M.). Total motility was lower in the lacto-ovo and vegan groups (33.2±3.8% and 51.8±13.4% respectively) versus non-vegetarians (58.2±1.0%). Vegans had lowest hyperactive motility (0.8±0.7% versus lacto-ovo 5.2±1.2 and non-vegetarians 4.8±0.3%). Sperm strict morphologies were similar for the 3 groups. There were no differences in rapid progression and chromatin integrity. Conclusions: The study showed that the vegetables-based food intake decreased sperm quality. In particular, a reduction in sperm quality in male factor patients would be clinically significant and would require review. Furthermore, inadequate sperm hyperactivation in vegans suggested compromised membrane calcium selective channels. However, the study results are cautiously interpreted and more corroborative studies are needed.
–
Vegetarianism produces subclinical malnutrition, hyperhomocysteinemia and atherogenesis
Ingelbleek & McCully
Nutrition, 2012
https://www.sciencedirect.com/science/article/abs/pii/S0899900711001523
The low dietary intake of protein and sulfur amino acids by a plant-eating population leads to subclinical protein malnutrition, explaining the origin of hyperhomocysteinemia and the increased vulnerability of these vegetarian subjects to cardiovascular diseases.
–
A maternal vegetarian diet in pregnancy is associated with hypospadias
K. North, J. Golding
British Journal of Urology International, 2000, 2008
https://onlinelibrary.wiley.com/doi/full/10.1046/j.1464-410x.2000.00436.x
Adaptations génétiques
Pourquoi c’est important ?
Parce qu’avec l’adoption d’une alimentation végétarienne ou végétalienne, certains nutriments dits non-essentiels, tels que les acides gras à chaîne longue ou le rétinol (vitamine A) devront être convertis à partir de leurs précurseurs (ici acides gras à chaîne courte et pro-vitamines A, principalement béta-carotène). Cette conversion peut être très variable selon les individus, dépendant notamment de leurs adaptations génétiques. Il est possible en conséquence que certains individus ne parviennent pas, dans le cadre d’une alimentation végéta*ienne, à convertir correctement certains nutriments. Dans ce cas, une complémentaiton supplémentaire s’impose, sous réserve que les compléments alimentaires soient correctement absorbés, ce qui n’est pas toujours certain.
–
Conversion des acides gras
Voir aussi page sur la conversion de l’ALA pour les aspects génétiques liés aux gène FADS.
Explication : pour une conversion correcte de l’ALA, oméga 3 à chaine courte à 18 atomes de carbone qu’on trouve dans les végétaux, en DHA, oméga 3 à chaine longue à 22 atomes de carbone (qui est un constituant essentiel de notre cerveau et de notre rétine, notamment), et qu’on ne trouve pas dans les végétaux, il faut une activité suffisante des enzymes Delta5 et Delta6 désaturases. Celles-ci sont codées respectivement par les gènes FADS1 et FADS2 (FADS pour fatty acid desaturase). Selon l’allèle de ces gènes dont nous sommes porteurs, nous produisons plus ou moins de ces enzymes. Or, les populations européennes sont moins porteuses des bons allèles du gène FADS1 et, surtout, du gène FADS2, qui est le plus important, parce que la delta6 désaturase intervient plusieurs fois dans les mécanismes. Seuls 17 à 18% des occidentaux seraient porteurs de l’allèle convertisseur fort du gène FADS2.
Positive Selection on a Regulatory Insertion–Deletion Polymorphism in FADS2 Influences Apparent Endogenous Synthesis of Arachidonic Acid
Kumar S. D. Kothapalli et al., 2016
https://academic.oup.com/mbe/article/33/7/1726/2578764
Analysis using 1000 Genomes Project data confirmed our observation, revealing a global I/I genotype of 70% in South Asians, 53% in Africans, 29% in East Asians, and 17% in Europeans. Tests based on population divergence, site frequency spectrum, and long-range haplotype consistently point to positive selection encompassing rs66698963 in South Asian, African, and some East Asian populations. Basal plasma phospholipid arachidonic acid (ARA) status was 8% greater in I/I compared with D/D individuals. The biochemical pathway product–precursor difference, ARA minus linoleic acid, was 31% and 13% greater for I/I and I/D compared with D/D, respectively. This study is consistent with previous in vitro data suggesting that the insertion allele enhances n-6 LCPUFA synthesis and may confer an adaptive advantage in South Asians because of the traditional plant-based diet practice.
Dietary adaptation of FADS genes in Europe varied across time and geography
Kaixiong Ye et al.
Nature ecology and evolution, 2017
https://www.biorxiv.org/content/biorxiv/early/2017/03/09/111229.full.pdf
Specifically, in pre-Neolithic hunter–gatherers subsisting on animal-
based diets with a substantial aquatic contribution, LCPUFAssynthesis-
diminishing alleles were adaptive. In recent European
farmers subsisting on plant-heavy diets, LCPUFA-synthesisenhancing
alleles were adaptive.
–
Single nucleotide polymorphisms upstream from the β-carotene 15,15′-monoxygenase gene influence provitamin A conversion efficiency in female volunteers.
Lietz G1, Oxley A, Leung W, Hesketh J.
https://www.ncbi.nlm.nih.gov/pubmed/22113863
β-Carotene, the most abundant provitamin A carotenoid in the diet, is converted to retinal by β-carotene 15,15′-monoxygenase (BCMO1). However, β-carotene absorption and conversion into retinal is extremely variable among individuals, with proportions of low responders to dietary β-carotene as high as 45%. Recently, 2 common nonsynonymous single nucleotide polymorphisms (SNPs) within the BCMO1 coding region (R267S; rs12934922 and A379V; rs7501331) revealed reduced catalytic activity, confirming that genetic variations contribute to the low responder phenotype. Because 4 SNPs 5′ upstream from the BCMO1 gene were recently shown to affect circulating carotenoid concentrations, the current study aimed to investigate the effects of these SNPs on β-carotene conversion efficiency. Three of the 4 polymorphisms (rs6420424, rs11645428, and rs6564851) reduced the catalytic activity of BCMO1 in female volunteers by 59, 51, and 48%, respectively. The TG-rich lipoprotein fraction retinyl palmitate:β-carotene ratio was negatively correlated with the G allele of rs11645428 (r = -0.44; P = 0.018), whereas it was positively correlated with the G allele of rs6420424 (r = 0.53; P = 0.004) and the T allele of rs6564851 (r = 0.41; P = 0.028). Furthermore, large inter-ethnic variations in frequency of affected alleles were detected, with frequencies varying from 43 to 84% (rs6420424), 52 to 100% (rs11645428), and 19 to 67% (rs6564851). In summary, a range of SNPs can influence the effectiveness of using plant-based provitamin A carotenoids to increase vitamin A status in at-risk population groups and this effect may vary depending on ethnic origin.
–
Natural selection on HFE in Asian populations contributes to enhanced non-heme iron absorption
Kaixiong Ye et al.
BMC genetics, 2015
https://bmcgenet.biomedcentral.com/articles/10.1186/s12863-015-0223-y
Nutriments potentiellement problématiques
Une première liste de nutriments pouvant être difficiles à trouver dans une alimentation végétale, sans qu’il soit toujours facile d’évaluer le risque pour chacun d’eux (liste en construction) :
La question des protéines est généralement évacuée très vite par les végétariens ou végétaliens : il est généralement affirmé qu’il est possible de trouver sans difficultés dans une alimentation végétale équilibrée l’ensemble des protéines nécessaires. Il semble cependant que cette affirmation puisse être mise en doute pour au moins 3 raisons.
La première raison est que la densité en protéines d’une alimentation végétale est généralement plus faible que celle d’une alimentation omnivore. Or, si les besoins en protéines étaient jusqu’à récemment considérés comme assez faibles (le chiffre généralement donné étant de 0,83g/j/kg, soit chez un adulte de poids normal, entre 40 et 70g par jour, quelque chose de facilement accessible par une alimentation végétale comprenant des légumineuses, notamment, une méthode de mesure plus récente (l’IAAO) et plus précise suggère que cette valeur est nettement sous-évaluée.
La seconde raison est liée à la valeur des acides aminés contenus dans les différents aliments. Là encore, une nouvelle méthode de mesure plus précise (DIAAS) semble donner une moindre valeur aux acides aminés des végétaux. Ainsi, des sources végétales qui étaient jusque-là considérées comme bonnes ne le sont plus. Frédéric Leroy explique cette question ici.
La troisième raison est liée au fait que certains acides aminés considérés comme non essentiels, et dont, par conséquent, on ne se soucie pas quand on devient végéta*ien, pourraient en fait nécessiter des besoins significatifs en apports alimentaires. Si ces acides aminés sont peu présents dans les végétaux, il y a risque. Voir étude sur la glycine ci-dessous.
– Sur les besoins globaux en protéines :
Variable Intensity Exercise Increases Protein Requirements in Active Male and Female Adolescents as Determined by the Indicator Amino Acid Oxidation (IAAO) Technique
Jahmal C Brooks et al., 2017
https://www.fasebj.org/doi/abs/10.1096/fasebj.31.1_supplement.652.11
–
Recent developments in understanding protein needs – How much and what kind should we eat?
Pencharz, Paul B. et al., 2016
Cliquer pour accéder à apnm-2015-0549.pdf
Using IAAO we have shown that minimum protein requirements have been under estimated by 30-50%. The National Academy of Sciences have for macro-nutrients proposed “Acceptable Macronutrient Distribution Ranges”, which for protein is 10 to 35% of total energy. In practice, we suggest 1.5-2.2 g/kg/d of a variety of high-quality proteins.
–
Protein: A nutrient in focus
Arentson-Lantz et al.
NRC research press, 2015
https://www.nrcresearchpress.com/doi/full/10.1139/apnm-2014-0530#.XmPb_krjJEY
–
Amino Acid Metabolism and Protein Requirements in Active, Trained Adult Males Using the Indicator Amino Acid Oxidation (IAAO) Technique
Packer, Jeffrey Ethan, 2015
Cliquer pour accéder à Packer_Jeffrey_E_201511_MSc_thesis.pdf
–
Protein dietary reference intakes may be inadequate for vegetarians if low amounts of animal protein are consumed
Kniskern & Johnston
Nutrition, 2011
https://www.sciencedirect.com/science/article/abs/pii/S0899900710003059?via%3Dihub
This research suggests that the protein DRI for vegetarians consuming less than the expected amounts of animal protein (45% to 50% of total protein) may need to be adjusted from 0.8 to about 1.0 g/kg to account for decreased protein bioavailability.
–
Sur la valeur des diverses protéines en fonction de leur proportion en acides aminés :
Can the digestible indispensable amino acid score methodology decrease protein malnutrition
Hannah H. Baylay & Hans H. Stein
Animal Frontiers, 2019
https://academic.oup.com/af/article/9/4/18/5575466/?fbclid=IwAR3uZMJFWnkErlQLn_Cdhv6SgdIyb7iwB2HUZ3Os1HPXkLh7OJLTtcVfGB0
Wheat has a DIAAS value of 45 (Mathai et al., 2017); however, when wheat is processed in the form of a breakfast cereal, it may only have a DIAAS value of 1 (Rutherfurd et al., 2015). In contrast, milk has a DIAAS value of 118 (Rutherfurd et al., 2015). The calculated DIAAS value of a mixed meal of 60% milk and 40% breakfast cereal is 107 (Rutherfurd et al., 2015), demonstrating the ability of milk to complement wheat resulting in a balanced meal that meet the requirement for all indispensable AA. Likewise, it was recently demonstrated that milk and eggs are efficient in complementing low-quality plant proteins to improve the DIAAS value (Shivakumar et al., 2019). Although legumes generally have a greater DIAAS value than cereal grains, they are limiting in methionine and may contain antinutritional factors that often reduce the absorption of amino acids or micronutrients (Rutherfurd et al., 2015, Shivakumar et al., 2019). Consequently, animal proteins are more effective in increasing the protein quality of mixed meals and meeting human amino acid requirements than proteins from legumes.
–
Potential impact of the digestible indispensable amino acid score as a measure of protein quality on dietary regulations and health
Christopher P.F. Marinangeli and James D. House
Nutrition reviews, 2017
Cliquer pour accéder à nux025.pdf
Un exemple d’acide aminé considéré comme non essentiel, car partiellement synthétisable, mais dont l’apport par la nutrition est nécessaire :
A weak link in metabolism: the metabolic capacity for glycine biosynthesis does not satisfy the need for collagen synthesis.
Melendez-Hevia et al.
Journal of biosciences, 2009
https://www.researchgate.net/publication/41111844_A_weak_link_in_metabolism_the_metabolic_capacity_for_glycine_biosynthesis_does_not_satisfy_the_need_for_collagen_synthesis
–
Pour la carnosine, un peptide considéré lui aussi comme non essentiel, il semble que les capacités de synthèse soient réduites. On en retrouve moins chez les végétariens que dans la population générale.
Vegetarianism, female gender and increasing age, but not CNDP1 genotype, are associated with reduced muscle carnosine levels in humans
Evereaert et al.
Amino acids, 2011
https://link.springer.com/article/10.1007/s00726-010-0749-2?fbclid=IwAR2ri_UTx7kD_RgTOqU6FzhM-GMgf0Egemo0C0NUpX8iIoGcuulkA1gmxa0
Vegetarians have a lower carnosine content of 26% in gastrocnemius compared to omnivores.
–
Il serait donc judicieux de se demander si les autres acides aminés et peptides non essentiels manquant dans une alimentation végétale sont correctement synthétisés.
Composition of polyamines and amino acids in plant-source foods for human consumption
Hou et al.
Amino acids, 2019
https://link.springer.com/article/10.1007/s00726-019-02751-0?fbclid=IwAR2J9ebl1cQZbAw4wT5A-RL9qlr2upcuZu19z1ugpizO_KXK_oMC8uA8X_k
All of the analyzed plant-source foods lacked taurine, creatine, carnosine and anserine (antioxidants that are abundant in meats and also present in milk), and contained little 4-hydroxyproline. Proper proportions of plant- and animal-source products are likely most desirable for optimizing human nutrition and health.
–
Des différences très importantes de statut en DHA des enfants nourris au sein par des véganes et des omnivores, chez Sanders.
The influence of a vegetarian diet on the fatty acid composition of human milk and the essential fatty acid status of the infant
TAB Sanders, Sheela Reddy
The journal of pediatrics, 1992
https://www.sciencedirect.com/science/article/pii/S0022347605812399
The proportion of DHA in erythrocyte total lipids of infants breast-fed by vegans was 1.9% compared with 3.7% in infants fed a milk formula containing butterfat as the sole source of fat and 6.2% in infants breastfed by omnivores at 14 weeks postpartum. The ratio of linoleic/α-linolenic acid in the diet was predictive of the proportion of elcosapentaenoic acid but not that of DHA in infant red blood cell lipids. It is concluded that the intakes of linoleic acid and DHA are the major determinants of the proportion of DHA in plasma and red blood cell lipids.
–
De même que chez des enfants végans.
Studies of vegans: the fatty acid composition of plasma choline phosphoglycerides,
erythrocytes, adipose tissue, and breast milk, and some indicators of susceptibility to ischemic heart disease in vegans and omnivore controls
Sanders et al.
American Journal of clinical nutrition, 1978
Cliquer pour accéder à 1e071c2a6505622eeb07c6a461560170eac6.pdf
Etudes de cas
Recognising the return of nutritional deficiencies: a modern pellagra puzzle
Ng & Neff
British medical journal, 2018
https://www.ncbi.nlm.nih.gov/pubmed/30567139
Dietetic consultation led to the diagnosis of severe protein-energy malnutrition, consequent to a severely restricted, primarily vegan, diet. Analysis of the patient’s reported diet with nutritional software revealed grossly suboptimal caloric intake with risk of inadequacy for most micronutrients, vitamins and minerals, including niacin. Oral thiamine, multivitamin, iron supplementation and vitamin B complex were started, and a single intramuscular vitamin B12 dose was administered. Marked improvement was seen after 6 weeks, with near-complete resolution of skin changes. These findings supported a diagnosis of pellagra.
–
Veganism as a cause of iodine deficient hypothyroidism.
Yelosof & Silverman
Journal of pediatric endocrinology and metabolism, 2018
–
B12 Deficiency in a Breastfed Infant Due to Maternal B12 Deficiency: A Case Report.
Kamath et al.
Journal of Clinical & Diagnostic Research, 2018
https://web.a.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=0973709X&AN=128099144&h=MnooFTQzvrwBvRPC9RAfTc9javlCHnbZmtsobuSj1gw1bhLSM6M05ENQggfeaLIleziPIi3VFOU%2fMJunTftufg%3d%3d&crl=c&resultNs=AdminWebAuth&resultLocal=ErrCrlNotAuth&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d0973709X%26AN%3d128099144
–
Impact of iodine deficiency on thyroid function in vegan siblings
Agnieszka Brandt, Michal Ajzensztejn, Sophia Sakka, Moira Cheung & Tony Hulse, 2018
https://www.endocrine-abstracts.org/ea/0058/ea0058p042
–
Toddler’s Paralysis: An Acute Case of Leg Stiffening in a Previously Healthy 2-Year-Old
Kahne, Kimberly Renee, MD; Tay, Ee Tein, MD, 2018
https://journals.lww.com/pec-online/Abstract/2018/06000/Toddler_s_Paralysis__An_Acute_Case_of_Leg.22.aspx?fbclid=IwAR2M661HV2Al024a4SNpnLw9dZw0JvJCJSZehQ0JMO5fNRElw-sxSnyVChQ
We describe a case of a 2-year-old previously healthy child consuming a vegan diet who presented to the pediatric emergency department with an acute inability to move her legs. Ionized calcium was found to be 0.89 mmol/L, and symptoms completely resolved within 2 hours of calcium gluconate infusion.
–
Acute small bowel obstruction in a child with a strict raw vegan diet
Stefano Amoroso et al., 2018
https://adc.bmj.com/content/early/2018/05/13/archdischild-2018-314910
–
Unusual cause of glomerular deposition disease: Collagenofibrotic glomerulopathy
S. Nimmagadda
Indian journal of nephrology, 2017
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5255993/
A 63-year-old man, hypertensive for ten years, nondiabetic, a vegan, and with no significant past or family history,
–
Reticulate pigmentation associated with vitamin B12 deficiency
Amanjot K. Arora et al., 2016
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4886604/
–
Rare association of thin corpus callosum with infantile tremor syndrome in a 5.5-month-old infant
Chandra Madhur Sharma et al, 2015
[url]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4611903/[/url]
Among various theories, the nutritional theory is the most accepted. Vitamin B12 deficiency has been found to be associated with ITS in many studies.[1] It is usually seen in children who are exclusively breast-fed for prolonged periods by vegetarian mothers.
–
Neuroregression in an infant: A rare cause
P Subramani, CG Saranya, GM Chand, RS Narayani, S James, PN Vinoth, 2015
https://www.ajol.info/index.php/sajchh/article/view/120204
Neuroregression in infants has diverse aetiologies, and vitamin B12 deficiency is a rare one. Infantile vitamin B12 deficiency is usually secondary to maternal pernicious anaemia or maternal vegetarian diet. We report a 10-month-old infant with developmental regression secondary to vitamin B12 deficiency. Her mother was a strict vegetarian and the patient was exclusively breastfed. Clinical symptoms normalised after vitamin B12 supplementation.
–
Case Series of Megaloblastic Anemia due to Vitamin B12 Deficiency in Exclusively Breastfed Infants Born to Vegan Mothers in a Rural Area.
Singh, V.; Nigwekar, P.; Dhyabar, A.; Garg, A.; Vaidya, S.; Lonare, N., 2015
http://eds.b.ebscohost.com/abstract?site=eds&scope=site&jrnl=09750533&AN=103581342&h=zDqMwa3ZaL%2bRa6FHp%2fMvVE4p5%2flX8e5wn9FEGQcXvGYnkNEDSTk31iI7nebTyQlMJzWlKCjhagg5EY0xY9ifjQ%3d%3d&crl=c&resultLocal=ErrCrlNoResults&resultNs=Ehost&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d09750533%26AN%3d103581342
–
Cerebral Atrophy in a Vitamin B12-deficient Infant of a Vegetarian Mother
Celebi Kocaoglu et al., 2014
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4216972/
–
Hematological and neurological compromise due to vitamin B12 deficit in infant of a vegetarian mother: case report
PJ Bravo et al., 2014
https://europepmc.org/abstract/med/25697251
–
Vitamin B12 deficiency with intrinsic factor antibodies in an infant with poor growth and developmental delay
Kathleen McNeil et al., 2014
https://academic.oup.com/pch/article/19/2/84/2647189
–
A Case of Nutritional Osteomalacia in Young Adult Male
Choong-Kyun Noh et al., 2013
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3780826/?fbclid=IwAR2xC7QucZMiMIebDXfDnTLjxKzdDRniveKN6lTmPLtaXGGuSFsrYdypp7E
Vitamin D is an important hormone that can be a role of bone and calcium metabolism in the human organ. Thus, vitamin D deficiency could contribute to the severity of metabolic bone disease. The osteomalacia, one of the metabolic bone diseases, is the softening of the bones caused by defective bone mineralization secondary to inadequate amounts of available phosphorus and calcium. We experienced a case of osteomalacia presented with walking disturbance, 30 year-old young aged man, caused by vitamin D deficiency due to strict vegetarian diet and lack of sunlight exposures.
–
Vitamin B12 deficiency presenting as acute ataxia
Crawford JR1, Say D.
BMJ, 2013
https://www.ncbi.nlm.nih.gov/pubmed/23536622
A dietary history revealed the child subscribed to a restrictive vegan diet with little to no intake of animal products or other fortified foods.
–
Severe vitamin B12 deficiency in an exclusively breastfed 5-month-old Italian infant born to a mother receiving multivitamin supplementation during pregnancy
Sophie Guezet al.
BMC Pediatrics, 2012
https://doi.org/10.1186/1471-2431-12-85
–
Herpetic keratouveitis mixed with bilateral Pseudomonascorneal ulcers in vitamin A deficiency
Hung-Yuan Hsu et al.
Cliquer pour accéder à 82420420.pdf
A systemic review on the patient showed malnutrition due to her dietary pref-erence and vegetarianism. […] Although rare in Taiwan, vitamin A deficiency should be kept in mind when conjunctival and corneal xerosis occurred. Vitamin A supplements are suggested because of the increased susceptibility to infection in patients with this clinical status.
–
Consequences of exclusive breast-feeding in vegan mother newborn–case report
Mariani et al.
Archives de pédiatrie, 2009
https://europepmc.org/abstract/med/19748244
We report on the case of an infant who was hospitalized because of failure to thrive, megaloblastic anemia, and delayed psychomotor development. He was 10 months old and had been exclusively breast-fed by his vegan mother. Investigations showed vitamin B(12) deficiency with hematocytopenia and pervasive developmental disorders as well as vitamin K and vitamin D deficiencies. The infant’s mother presented the same deficiencies. Introduction of vitamin supplementation normalized the biological disorders, and the infant showed weight gain and neurological improvement. This case highlights that a vegan diet during pregnancy followed by exclusive breast-feeding can induce nutritional deficiencies in the newborn, with clinical consequences. Detecting mother and child vitamin deficiencies and preventing them is essential.
–
Irreversible subacute sclerotic combined degeneration of the spinal cord in a vegan subject
Filippo Brocadello et al., 2007
https://www.sciencedirect.com/science/article/pii/S089990070700175X
Despite rehabilitative treatment, the patient developed spastic hypertonia with mild improvement of paresthesias. Six months later, vitamin B12 plasma levels and hematological analysis were normal. One year later, spastic paraplegia was still present and the patient was unable to walk despite improvement on magnetic resonance imaging.
–
Floppy baby with macrocytic anemia and vegan mother
Schlapbach LJ et al, 2007
https://www.ncbi.nlm.nih.gov/pubmed/18293883
We report the case of a 7 month-old girl that presented with acute anemia, generalized muscular hypotonia and failure to thrive. Laboratory evaluation revealed cobalamin deficiency, due to a vegan diet of the mother. The clinical triad of an acquired floppy baby syndrome with megaloblastic anemia and failure to thrive is pathognomic for infantile cobalamin deficiency. Neurological abnormalities are often irreversible and may be associated with delayed myelinization in the MRI. A normal cobalamin level in maternal serum and absence of anemia do not exclude subclinical deficiency. If cobalamin deficiency is suspected, e.g. in pregnant women on vegan diet, urinary methylmalonic acid excretion and plasma homocysteine levels should be determined and cobalamin substitution should be started at an early stage to avoid potentially irreversible damage of the fetus.
–
Severe nutritional vitamin deficiency in a breast-fed infant of a vegan mother
Baatenburg de Jong et al.
European journal of pediatrics, 2005
https://link.springer.com/article/10.1007/s00431-004-1613-8
Failure to thrive combined with severe anaemia can be a sign of nutritional vitamin deficiency. Here, we report a case of severe nutritional vitamin deficiency in a breast-fed infant of a strict vegan mother.
–
Coma and respiratory failure in a child with severe vitamin B(12) deficiency
Codazzi D, Sala F, Parini R, Langer M., 2005
The baby had been exclusively breast-fed, but his mother had been a strict vegan for 10 yrs. Chronic dietary vitamin B(12) deprivation was confirmed by blood and urinary samples. Treatment with vitamin B(12) led in 2 wks to rapid and complete hematological improvement and to partial regression of neurologic symptoms. During the following 3 yrs the boy had normal vitamin intake and underwent intensive rehabilitative treatment. The brain atrophy regressed, but linguistic and psychomotor delay persisted.
–
Breastfeeding and vegan diet
Wagnon et al.
Journal de gynécologie, obstétrique et biologie de la reproduction, 2005
https://europepmc.org/abstract/med/16208206
Vegan diet in lactating women can induce vitamin B12 deficiency for their children with risk of an impaired neurological development. A 9.5-month-old girl presented with impaired growth and severe hypotonia. She had a macrocytic anemia secondary to vitamin B12 deficiency. MRI showed cerebral atrophy. She was exclusively breastfed. Her mother was also vitamin B12 deficient, secondary to a vegan diet. She had a macrocytic anemia when discharged from the maternity. Vegan diet is a totally inadequate regimen for pregnant and lactating women, especially for their children. Prevention is based on screening, information and vitamin supplementation.
–
Metabolic complications and neurologic manifestations of vitamin B12 deficiency in children of vegetarian mothers
Smolka, V et al., 2001
https://www.ncbi.nlm.nih.gov/pubmed/11787236?fbclid=IwAR0X-IlECNhMy1U-Cn_JV-_PhSlKFq4uVXOPN0niRPLNjWizh2wV0yqK-aU
The mother of the first child was a strict vegetarian. She had an elevated urinary methylmalonic acid level and a low concentration of serum vitamin B12. Her 13-month-old daughter was exclusively breast-fed until the age of 9 month and then she was fed only vegetables. Physical examination revealed psychomotoric retardation, apathy, muscular hypotonia, abnormal movements and failure to thrive. Laboratory analysis showed a megaloblastic anaemia, a low level of vitamin B12 and methylmalonic aciduria. MRI of the brain revealed diffuse frontotemporoparietal atrophy and retardation of myelination. After treatment with vitamin B12 supplements, abnormal movements disappeared and development improved, but a mild generalised hypotonia continued. A cranial MRI 9 months after treatment still showed signs of retardation of myelination. The second patient, an 8 month-old male, son of a strict vegetarian mother too, was referred for investigation of psychomotoric retardation, hypotonia, dyskinesia, failure to thrive and microcephaly. He was breast-fed and from 6 month of age he had also received fruit juices. Laboratory analysis revealed megaloblastic anaemia, high methylmalonic aciduria and homocystinuria. The patient’s and his mother’s serum level of vitamin B12 were low. After treatment with vitamin B12 supplements, biochemical and metabolic markers of disease were normal but there continued a generalised hypotonia, microcephaly and language delay.
–
Reversible Subacute Combined Degeneration of the Spinal Cord in a 14-Year-Old Due to a Strict Vegan Diet
https://journals.sagepub.com/doi/pdf/10.1177/000992280104000710?casa_token=mP3L_YJhEzEAAAAA:f-Y73Rd-izvDSOq4fHnq61cR_K748oBNFOf5vTfmB9LRTUio4QwZpRnvaz5njEXB96feunpP9xk-
R Chiron et al., 2001
https://www.sciencedirect.com/science/article/pii/S0929693X00001688
Anemia and limping in a vegetarian adolescent
Chiron, R et al.
Archives de pédiatrie, 2001
https://europepmc.org/abstract/med/11218586
A 15-year-old adolescent was hospitalized because of lameness and pallor. The lameness was explained by femoral epiphysiolysis caused by rickets with severe hypocalcemia. The pallor, jaundice and splenomegalia were due to cobalamin-deficiency megaloblastic anemia. A prolonged supplemental diet with calcium, vitamins D and B12 as well as orthopedic treatment stabilized the bone lesions. The megaloblastic anemia was cured by parenteral cobalamin. The adolescent and his brother were victims of a diet imposed by a cult and a lack of care due to their parents refusing that a vegan diet was the cause of the deficient pathology. Penal proceedings led to the incarceration of the parents and to the placement of the children.
–
Blindness in a strict vegan
Dan Milea et al.
The new england journal of medicine, 2000
https://www.nejm.org/doi/full/10.1056/NEJM200003233421217
The optic neuropathy in our patient was apparently related to deficiencies of vitamins B12 and B1, but other associated deficiencies mtaiway have had a role. Vitamin supplementation is essential in persons who adhere to a strict vegetarian diet, especially because vitamin deficiencies may cause severe, irreversible optic neuropathy.
–
Maternal vegan diet causing a serious infantile neurological disorder due to vitamin B12 deficiency
T. Kühne, R. Bubl, R. Baumgartner, 1991
https://link.springer.com/article/10.1007/BF01963568
–
Nutritional Vitamin B12 Deficiency in a Breast-fed Infant of a Vegan-diet Mother
Ronald Sklar.
Clinical pediatrics, 1986
https://journals.sagepub.com/doi/abs/10.1177/000992288602500409?casa_token=gCaZbK0e1UgAAAAA:cNiicQObveO_xJYcpIGu87Dc0KSsRSSE3872odpAo8fb8Kdsx03V8srkn3C6nys4_O7gDywsaGv1
–
Nutritional rickets in vegetarian children
Curtis et al.
Journal of canadian medical association, 1983
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1874810/
We report 3 children in whom rickets developped after prolonged periods of strict vegetarian diet.
–
–
Megaloblastic Anemia in an Adult Vegan
John D. Hines.
The american journal of clinical nutrition , 1966
https://academic.oup.com/ajcn/article-abstract/19/4/260/4787636
Risques liés aux supplémentations
Des cas d’allergies ou de problèmes cutanés liés à certaines supplémentations en vitamine B12 sont rapportés. Difficile d’évaluer leur fréquence, et si ces problèmes sont associés à une utilisation normale des suppléments ou à des utilisations marginales. La vitamine B12 modifie l’expression d’un certain nombre de gènes liés au diabète, sans qu’il soit possible de dire si ces modification peuvent être délétères en cas de surdosage.
–
Vitamin B12 supplementation influences methylation of genes associated with Type 2 diabetes and its intermediate traits
Dilip K. Yadav et al.
Future medicine, 2017
B12 supplementation influences regulation of several metabolically important Type 2 diabetes-associated genes through methylation of miR21. Hence, our study provides novel epigenetic explanation for the association between disordered one carbon metabolism and risk of adiposity, insulin resistance and diabetes and has translational potential.
–
P484 Cobalt as the culprit: vitamin B12 supplementation as a trigger for chronic pruritis
S. Vakaljan, J. Ohayon
Annals of allergy, asthma and immunology, 2017
https://www.annallergy.org/article/S1081-1206(17)31045-1/pdf?fbclid=IwAR0go61fhvaXXW6oZ6sAq8EyNqLXqdoQ2-m5aKYt6T28k1WbgVX171dMi0o
–
Acneiform eruptions caused by vitamin B12: A report of five cases and review of the literature
Stefano Veraldi et al.
Journal of cosmetic dermatology
https://onlinelibrary.wiley.com/doi/abs/10.1111/jocd.12360
We describe five cases of acneiform eruption caused by vitamin B12 in five females aged 37, 32, 62, 29, and 21 years, respectively. The eruption appeared from 1 week to 5 months after the beginning of the therapy with i.m. or oral vitamin B12.
–
Cobalt-Induced Contact Urticaria Presenting as Chronic Urticaria Due to Intramuscular Vitamin B12 Injections
–
Vitamin B12 modulates the transcriptome of the skin microbiota in acne pathogenesis
Dezhi Kang et al.
Science Translational Medicine, 2015
https://stm.sciencemag.org/content/7/293/293ra103.short
Vitamin B12 supplements have been shown to lead to acne development, but the mechanism behind this effect has remained unexplored. Now, Kang et al. show that transcriptional changes in the skin microbiota contribute to vitamin B12–induced acne. Supplementing patients with vitamin B12 reduced the expression of vitamin B12 synthesis genes in Propionibacterium acnes and altered the transcriptome of the skin microbiota, resulting in the production of inflammation-inducing porphyrins. These studies demonstrate a clear link between changes in the skin microbiome and disease pathology.
–
A Review of Vitamin B12 in Dermatology
several dermatologic conditions, including vitiligo, aphthous stomatitis, atopic dermatitis, and acne are related to cobalamin excess or deficiency. The cutaneous complications of cobalamin therapy include acne, rosacea, and allergic site reactions, or anaphylaxis with cobalamin injections. As cobalt is a component of cobalamin, patients with cobalt sensitivity have been reported to have cutaneous manifestations when receiving cobalamin replacement therapy.
–
Hypervitaminémie B 12 : implications cliniques et prise en charge
Monica Cosma Rochat et al.
Revue médicale suisse, 2012.
https://www.revmed.ch/RMS/2012/RMS-360/Hypervitaminemie-B-12-implications-cliniques-et-prise-en-charge
Alors que le déficit en vitamine B12 est largement connu et recherché, l’hypervitaminémie B12, souvent trouvée fortuitement, est une anomalie fréquente. Les maladies associées et la prise en charge de l’hypervitaminémie B12 sont moins connues.
–
Le risque peut être lié aussi à une supplémentation insuffisante, ou inexistante. Bien que la nécessité d’une prise de vitamine B12 soit régulièrement rappelée pour les végétaliens, il est important d’envisager une telle supplémentation aussi pour les végétariens, voire pour toute personne ne consommant que des quantités modérées de produits animaux, et notamment pas d’abats (rappelé notamment sur la page Facebook « Vive la B12 », notamment).
La question reste posée, au moins pour certaines personnes, des besoins en complémentation en divers nutriments tels qu’iode, zinc, DHA, rétinol, vitamine D, etc. Notons que le complément recommandé par la page « Vive la B12 », le Veg1, élaboré par la Vegan Society, contient vitamine B12, iode, vitamine D, vitamine B2, vitamine B6, acide folique et sélénium.
–
On trouve des carences en vitamine B12 assez importantes chez les végétariens et végétaliens. Il est certain qu’une part de ces carences est liée à de mauvaises supplémentations ou des supplémentations inexistantes. Il est plus difficile de déterminer s’il existe des carences malgré une supplémentation adéquate. De plus, une supplémentations en vitamine B12 est souvent nécessaire pour les végétariens, alors que seuls les végétaliens sont systématiquement avisés de se supplémenter.
Serious neurological compromise due to vitamin B12 deficiency in infants of vegan and vegetarian mothers
Aguire et al.
Archivos de pediatria argentina, 2019
Cliquer pour accéder à v117n4a29.pdf
B12 deficiency is not usually suspected by the pediatrician in healthy infants with neurological symptoms. The manifestations are nonspecific: apathy, rejection of food and loss of maturational patterns. A nutritional history of the mother, mainly if she is vegetarian, to estimate her reserves is fundamental to detect risk of deficiency of this vitamin in the small child.
–
How prevalent is vitamin B12 deficiency among vegetarians?
Roman Pawlak et al.
Nutrition review, 2013
https://academic.oup.com/nutritionreviews/article-abstract/71/2/110/1940320
The deficiency rates reported for specific populations were as follows: 62% among pregnant women, between 25% and almost 86% among children, 21–41% among adolescents, and 11–90% among the elderly. Higher rates of deficiency were reported among vegans compared with vegetarians and among individuals who had adhered to a vegetarian diet since birth compared with those who had adopted such a diet later in life.
Soja
Parmi les aliments retrouvés de manière importante dans les alimentations végétales, le soja a été soupçonné de pouvoir induire des perturbations hormonales. Si peu des risques supposés semblent être supportés par des études, il en existe tout de même quelques-unes associant notamment un allaitement avec des formules à base de soja et des troubles survenant beaucoup plus tard, à l’âge adulte. Une question de dose ? Remplacer les laits animaux par des boissons au soja pourrait par ailleurs causer déminéralisation des dents et caries.
–
Effects of soy and bovine milk beverages on enamel mineral content in a randomized, double-blind in situ clinical study.
Chen et al.
Journal of dentistry, 2019
CONCLUSIONS:
In this randomized, double-blind in situ clinical trial consumption of a soy beverage demineralized enamel whereas bovine milk produced remineralization.
CLINICAL SIGNIFICANCE:
Although soy beverages are promoted as healthy alternatives to bovine milk the added sugar and low calcium bioavailability of the soy drink makes frequent consumption a caries risk.
–
Soy-based infant formula feeding and menstrual pain in a cohort of women aged 23–35 years
Kristen Upson et al.
Human reproduction, 2018
https://academic.oup.com/humrep/advance-article/doi/10.1093/humrep/dey303/5146638
Women ever fed soy formula as infants were more likely than unexposed women to report ever use of hormonal contraception for menstrual pain (RR 1.4, CI: 1.1–1.9) and moderate/severe menstrual discomfort/pain with ‘most periods’, but not ‘every period’, during early adulthood (ages 18–22 when not using hormonal contraception) (RR 1.5, CI: 1.1–2.0).
–
Soy-based infant formula feeding and ultrasound-detected uterine fibroids among young african-american women with no prior clinical diagnosis of fibroids
Kristen Upson et al.
Environmental health perspective, 2018
https://ehp.niehs.nih.gov/doi/abs/10.1289/ehp.1510082
Results:
We did not observe an association between soy formula feeding and fibroid prevalence [adjusted prevalence ratio (aPR) 0.9, 95% CI: 0.7, 1.3]. Nor were exposed women with fibroids more likely to have ≥ 2 tumors than unexposed women with fibroids (aPR 1.0, 95% CI: 0.7, 1.6). However, exposed women with fibroids had significantly larger fibroids than unexposed women with fibroids. On average, soy formula feeding was associated with a 32% increase in the diameter of the largest fibroid (95% CI: 6%, 65%) and a 127% increase in total tumor volume (95% CI: 12%, 358%).
Conclusions:
Our observation that women fed soy formula as infants have larger fibroids than unexposed women provides further support for persistent effects of early life phytoestrogen exposure on the uterus.
–
The effects of dietary levels of genistein on ovarian follicle number and gene expression
Payel Kundu et al.
Reproductive toxicology, 2018
The present study investigated the effects of adult genistein exposure on follicle number and gene expression in the ovaries of CD-1 mice. We found that exposure to genistein had no effect on follicle number, but it did affect the expression of apoptotic regulatory genes (Bax, Bcl-2, Bid, and Dffa) in the ovary.
–
Une étude laissant penser qu’effectivement, ce pourrait être la dose le problème, même s’il faut la prendre avec précautions.
A J-shaped association between soy food intake and depressivesymptoms in Chinese adults
Bin Yu et al.
Clinical nutrition, 2018
Cliquer pour accéder à 553a12f3-ba1f-4043-a8d3-20310a91267d.pdf
–
Soy-based infant formula feeding and heavy menstrual bleeding among young African American women
Kristen Upson et al.
Epidemiology, 2016.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5425950/
We observed associations between soy formula feeding and variables indicating a history of heavy menstrual bleeding, including ever experiencing heavy, gushing-type bleeding (RR 1.2, 95% CI: 1.0-1.4), ever use of non-steroidal anti-inflammatory drugs for heavy bleeding (RR 1.3, 95% CI: 1.0-1.6), and ever use of a contraceptive method for heavy bleeding (RR 1.2, 95% CI: 0.9-1.6).
–
Early-life factors and endometriosis risk
Kristen Upson et al.
Fertility and sterility, volume 101, Issue 4, 2015
https://www.sciencedirect.com/science/article/pii/S0015028215004690
We observed that women who were regularly fed soy formula as infants had more than twice the risk of endometriosis compared with unexposed women (aOR 2.4, 95% CI 1.2–4.9). Our data also suggested increased endometriosis risk with prematurity (aOR 1.7, 95% CI 0.9–3.1) and maternal use of DES (OR 2.0, 95% CI 0.8–4.9, adjusting only for frequency matching variables), although these confidence intervals included the null.
–
Un doute sur cette étude publiée dans une revue open acces. Serait à évaluer.
Soy Infant Formula may be Associated with Autistic Behaviors
Cara J. Westmark; 2013
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4229689/?fbclid=IwAR0Eoc0JK63SK7Y0k8lS5RAworClb6K3drxUZQKCE-urnOkf55McEs_dDX0
This study provides preliminary data that the use of soy-based infant formula may be associated with specific autistic behaviors.
–
Acidogenic potential of soy and bovine milk beverages.
Dashper et al.
Journal of dentistry.
https://www.ncbi.nlm.nih.gov/pubmed/22609610?fbclid=IwAR1BmieyDM0BkcgXRl3rCD9RO1vnFOrRkyQfirJSaRPmH8wJQQ_8y0lVtVI
CONCLUSIONS:
Soy beverages have a higher potential acidogenicity than bovine milk beverages.
CLINICAL SIGNIFICANCE STATEMENT:
Patients consider soy beverages to be a healthy, low cariogenic alternative to other beverages, including bovine milk. This study shows that soy beverages have a higher potential acidogenicity than bovine milk and therefore may have a greater potential cariogenicity.
–
Hypogonadism and erectile dysfunction associated with soy product consumption
Timo Siepman et al.
Nutrition, 2011
https://www.sciencedirect.com/science/article/pii/S089990071000359X
This case indicates that soy product consumption is related to hypogonadism and erectile dysfunction. To the best of our knowledge, this is the first report of a combination of decreased free testosterone and increased DHEA blood concentrations after consuming a soy-rich diet. Hence, this case emphasizes the impact of isoflavones in the regulation of sex hormones and associated physical alterations.
–
From one womb to another : early estrogenic exposures and later fibroid risk
M. Nathaniel Mead
Environmental health perspective, 2010
https://ehp.niehs.nih.gov/doi/full/10.1289/ehp.118-a131a
The authors report a 25% increase in early fibroid diagnoses for women who had been fed soy formula compared with those who had not. Although the authors postulated the first 2 months of life may include a period more sensitive to isoflavone exposure, they were unable to demonstrate an association with soy formula intake during this time period specifically.
–
Soy infant formula and phytoestrogens
PG Tuohy
Journal of paediatrics and child health, 2003
https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1440-1754.2003.00178.x
Against this generally positive view there is an increasing number of recent reports that suggest that in experimental animals, phytoestrogens have adverse effects with respect to carcinogenesis, reproductive function, immune function, and thyroid disease. Despite the absence of adequate scientific research that quantifies the level of risk to infants, most would argue for a precautionary approach to be taken in situations where there are potential developmental effects from the consumption of pharmacologically active compounds in infancy and childhood.
–
Soy Diets Containing Varying Amounts of Genistein Stimulate Growth of Estrogen-dependent (MCF-7) Tumors in a Dose-dependent Manner
Soy protein diets containing varying amounts of genistein increased estrogen-dependent tumor growth in a dose-dependent manner. Cell proliferation was greatest in tumors of animals given estrogen or dietary genistein (150 and 300 ppm). Expression of pS2 was increased in tumors from animals consuming dietary genistein (150 and 300 ppm). Here we present new information that soy protein isolates containing increasing concentrations of genistein stimulate the growth of estrogen-dependent breast cancer cells in vivo in a dose-dependent manner.
–
Les taux d’oestrogènes auxquels sont exposés les enfants nourris avec des préparations à base de soja semblent très importants, et sans commune mesure avec ceux auxquels sont exposés les adultes.
Exposure of infants to phyto-oestrogens from soy-based infant formula
Setchell et al.
The Lancet, 1997
https://www.sciencedirect.com/science/article/pii/S0140673696094809
The daily exposure of infants to isoflavones in soy infant-formulas is 6–11 fold higher on a bodyweight basis than the dose that has hormonal effects in adults consuming soy foods. Circulating concentrations of isoflavones in the seven infants fed soy-based formula were 13 000–22 000 times higher than plasma oestradiol concentrations in early life, and may be sufficient to exert biological effects, whereas the contribution of isoflavones from breast-milk and cow-milk is negligible.
Biais possibles des études de nutrition en général et des études sur les végétariens et les végans en particulier
Etudes sur les enfants végétaliens
Vegan diet in young children remodels metabolism and challenges the statuses of essential nutrients
Hovinen et al.
EMBO. Molecular medicine, 2021
https://www.embopress.org/doi/full/10.15252/emmm.202013492
We recruited 40 Finnish children with a median age 3.5 years—vegans, vegetarians, or omnivores from same daycare centers—for a cross‐sectional study. They enjoyed nutritionist‐planned vegan or omnivore meals in daycare, and the full diets were analyzed with questionnaires and food records. Detailed analysis of serum metabolomics and biomarkers indicated vitamin A insufficiency and border‐line sufficient vitamin D in all vegan participants. Their serum total, HDL and LDL cholesterol, essential amino acid, and docosahexaenoic n‐3 fatty acid (DHA) levels were markedly low and primary bile acid biosynthesis, and phospholipid balance was distinct from omnivores. Possible combination of low vitamin A and DHA status raise concern for their visual health. Our evidence indicates that (i) vitamin A and D status of vegan children requires special attention; (ii) dietary recommendations for children cannot be extrapolated from adult vegan studies; and (iii) longitudinal studies on infant‐onset vegan diets are warranted.
Due to the lack of current, large-scale studies examining their dietary intake and health, there are concerns about vegetarian (VG) and vegan (VN) diets in childhood. Therefore, the Vegetarian and Vegan Children Study (VeChi Diet Study) examined the energy and macronutrient intake as well as the anthropometrics of 430 VG, VN, and omnivorous (OM) children (1–3 years) in Germany. A 3-day weighed dietary record assessed dietary intake, and an online questionnaire assessed lifestyle, body weight (BW), and height. Average dietary intakes and anthropometrics were compared between groups using ANCOVA. There were no significant differences in energy intake or density and anthropometrics between the study groups. OM children had the highest adjusted median intakes of protein (OM: 2.7, VG: 2.3, VN: 2.4 g/kg BW, p < 0.0001), fat (OM: 36.0, VG: 33.5, VN: 31.2%E, p < 0.0001), and added sugars (OM: 5.3, VG: 4.5, VN: 3.8%E, p = 0.002), whereas VN children had the highest adjusted intakes of carbohydrates (OM: 50.1, VG: 54.1, VN: 56.2%E, p < 0.0001) and fiber (OM: 12.2, VG: 16.5, VN: 21.8 g/1,000 kcal, p < 0.0001). Therefore, a VG and VN diet in early childhood can provide the same amount of energy and macronutrients, leading to a normal growth in comparison to OM children.
Schürmann S, Kersting M, Alexy U, 2017
https://link.springer.com/article/10.1007/s00394-017-1416-0
This review demonstrates that the available data do not allow firm conclusions to be drawn on the benefits or risks of present-day vegetarian-type diets with respect to nutritional or health status of infants, children, and ado-lescents. Apart from the scarcity and heterogeneity of the studies, in general, there has in particular not yet been any long-term follow-up.
[…]Increased health risks of vegetarian diets were particularly reported for iron status. Studies in children on vegan diets are scarce and the two studies identified in this review did not analyse biomarkers.
L’étude Farm
Growth of Vegetarian Children: The Farm Study
https://pediatrics.aappublications.org/content/84/3/475?download=true
(il est possible de trouver l’étude complète via Sci-Hub)
Growth of vegetarian children. Farm study, O’Connel 1989
Porte sur une communauté très particulière, suivie de 1980 à 1983, qui prend pas mal de compléments alimentaires (Vitamine B12, A et D, plus d’autres vitamines et minéraux, dit la publi), qui est d’un excellent niveau de compétence nutritionnelle, qui produit elle-même une part de sa nourriture. L’étude n’investigue rien d’autre que la taille et le poids des enfants, ne fait aucune recherche supplémentaire. Elle trouve une taille et un poids un peu inférieurs à la normale, mais sans que ce soit significatif.
Une telle étude ne peut en aucun cas être extrapolée aux personnes se supplémentant uniquement en B12, à la population générale moins compétente en nutrition, aux personnes consommant une nourriture industrielle. Elle ne conclut par ailleurs rien sur d’éventuels autres aspects que le poids et la taille, et ne peut en aucun cas conclure à une absence de problèmes sanitaires des enfants étudiés, puisqu’elle ne les investigue pas. Difficile de conclure aussi sur les éventuelles conséquences à long terme d’une telle alimentation à partir d’un suivi de 3 ans seulement.
TAB Sanders
Pediatric Clinics, 1995.
TAB Sanders and Sheela Red
American journal of clinical nutrition, 1994.
The growth and development of vegan children
Sanders & Manning
Journal of human nutrition and dietetics, 1992
https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-277X.1992.tb00129.x
The growth and development of the children were normal but they tended to be lighter in weight and exceptionally lean compared with standards.[…]
The results of this study show that children can be successfully reared on a vegan diet providing sufficient care is taken to avoid the known pitfalls of a bulky diet and vitamin B12 deficiency.
Thomas AB Sanders
American journal of clinical nutrition, 1988
https://academic.oup.com/ajcn/article-abstract/48/3/822/4716540?redirectedFrom=PDF
Sanders & Purves
Journal of human nutrition, 1981
https://www.ncbi.nlm.nih.gov/pubmed/7288184
The nutritional status of 23 vegan children between one and five years was assessed using anthropometric and dietary criteria. All of the children had been breastfed for at least the first six months of life and in most cases well into the second year. The majority of the children were growing normally but they did tend to be smaller in stature and lighter in weight when compared with standards. Energy, calcium and vitamin D intakes were usually below those recommended. Their diets, however, were generally adequate but a few children had low intakes of riboflavin and vitamin B12. It is concluded that, provided sufficient care is taken, a vegan diet can meet the nutritional requirements of the preschool child.
–
Dans celle-ci, on trouve des taux d’EPA et de DHA très bas chez les enfants végans, et un rapport oméga/6 sur oméga 3 très élevé. A l’époque, Sanders considère ça comme peu important, et du fait que le cholestérol est plus bas chez les végans, considère que le profil lipidique est meilleur chez les végans. Pas sûr qu’avec les connaissances actuelles, on puisse arriver aux mêmes conclusions :
Studies of vegans: the fatty acid composition of plasma choline phosphoglycerides,
erythrocytes, adipose tissue, and breast milk, and some indicators of susceptibility to ischemic heart disease in vegans and omnivore controls
Sanders et al.
American Journal of clinical nutrition, 1978
Cliquer pour accéder à 1e071c2a6505622eeb07c6a461560170eac6.pdf
Etudes sur les adultes végétariens et végétaliens
Mortality in vegetarians and comparable nonvegetarians in the United Kingdom
Appleby et al.
American journal of clinical nutrition, 2016
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4691673/
United Kingdom–based vegetarians and comparable nonvegetarians have similar all-cause mortality. Differences found for specific causes of death merit further investigation.
Les végans ont un taux de mortalité globale plus élevé, mais le résultat n’est pas statistiquement significatif (de peu) : RR 1,14 (0,97, 1,35) par rapport aux gros mangeurs de viande.
La différence deviendrait probablement significative si on les comparait avec les groupes « low meat eaters » et « fish eaters » qui ont des RR de 0,93 et 0,96.
L’échantillon végan étant faible (n=2228), les résultats sont hétérogènes et non significatifs pour les différentes causes de décès : RR 1,14 pour les cancers, 0,85 pour le cardiaque non ischémique, 1,63 pour le cérébrovasculaire, 1,57 pour les maladies respiratoires. La durée de suivie n’est pas donnée séparément pour les végans : « Two-thirds of the vegetarians and vegans had followed their diet for more than 5 y ».
Les études sont sur du déclaratif simple, ne précisent pas la consommation réelle (les végétariens et végans sont crus sur parole, on n’essaie pas de vérifier ce qu’ils mangent réellement, comme dans Nutrinet, par exemple). L’article est une synthèse de 2 études (Oxford et OVS) et certains participants ont été dans les deux. Il est intéressant de noter que près d’un tiers d’entre eux ne déclare pas le même régime d’une étude à l’autre, avec 13 ans entre les deux recrutements, ce qui est considéré pourtant comme une bonne adhésion aux différents régimes : « Of the 2708 persons who participated in both the OVS and EPIC-Oxford study, 1839 (68%) were allocated to the same diet group […] at recruitment to both studies, with an average 13 y gap between recruitment dates, indicating a high degree of consistency in diet group ».
(exemple : supposons que sur 100 personnes qui tentent d’être véganes, 50 aient un avantage à l’être, et 50 aient de gros problèmes. Sur les premières années, les 100 personnes sont véganes, mais sur les 50 pour lesquelles le régime est défavorable, on observe donc des problèmes, et même des décès. On a donc plus de décès dans le groupe végan durant les premières années. Au bout d’un certain nombre d’années, les survivants parmi ces 50 abandonnent parce que le régime les rend malades. Les autres continuent parce que ça leur convient bien : le taux de décès diminue, et est plus faible pour ceux qui ont gardé le régime. Le régime est donc globalement mauvais pour l’ensemble de la population, mais bon pour une fraction de la population, et on trouve de meilleurs résultats à long terme qu’à court terme : biais du survivant)
Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies
Key et al.
American journal of clinical nutrition, 1999
https://academic.oup.com/ajcn/article/70/3/516s/4714974
Remarques.
Echantillon des végans : 753 participants et seulement 68 décès répertoriés au total.
En conséquence, le détail des décès par cause est extrêmement hétérogène pour les végans, et rien n’est statistiquement significatif, du fait du faible échantillon. RR 2,18 pour le cancer de l’estomac, 0,83 pour le cancer colorectal, 2,79 pour le cancer du poumon, 0,74 pour le cardiaque ischémique, 1,33 pour les autres causes…
Il est par ailleurs signalé une « hétérogénéité significative entre les études ».
De fait, 2 études sur 5 portent sur les adventistes, et leurs résultats sont plus favorables aux végétariens et végétaliens que les autres, voire contradictoires. RR pour la mortalité globale de 0,83 et 0,80 pour les adventistes, 1,11, 1,17 et 1,00 pour les 3 autres études, pour les deux dernières, le RR n’est pas statistiquement significatif.
La durée moyenne de suivi est d’une dizaine d’années, les participants aux études ont entre 16 et 89 ans au moment du recrutement. Pas d’enfants, donc.
Le type d’alimentation suivi est simplement déclaratif et très sommaire (je mange de la viande ou du poisson/je n’en mange pas, avec juste une précision sur la fréquence de viande, plus ou moins d’1 fois par semaine). Il ne semble pas y avoir de contrôle. La durée de suivi est partagée entre moins de 5 ans et plus de 5 ans, sans autre précision, végétariens et végétaliens confondus, on ne connaît pas les durées moyenne et médiane d’adhésion à l’alimentation.
Il ne semble pas y avoir de données sur les taux d’abandon spécifiques des végétariens et végétaliens. C’est problématique pour détecter un éventuel biais du survivant. Il est constaté une surmortalité significative chez les végétariens et végétaliens confondus ayant suivi cette alimentation depuis moins de 5 ans au moment du décès => possible que ça ne convienne pas à certains ?
Le résultat mis en avant dans l’abstract pour les végans, sur la mortalité cardiovasculaire ischémique porte seulement sur 17 décès chez les végans, non significatif statistiquement (intervalle de confiance : 0,46-1,21). C’est surprenant de mettre en avant un tel résultat.
Dans le tableau 3, la mortalité relative des végétariens/tous omnivores est de 0,95. La mortalité relative des végétariens/mangeurs de viande réguliers est de 0,84 dans le tableau 7, où l’on exclut par ailleurs l’étude Health food shoppers, ce qui est favorable aux végétariens. La mortalité des végétariens est alors grosso-modo équivalente à celle des petits mangeurs de viande et des mangeurs de poisson.
Si on fait abstraction de la faiblesse de l’échantillon et de l’étude manquante, les végétaliens ont la même mortalité globale que les mangeurs de viande réguliers, mais ils ont une mortalité significativement plus élevée que celle des petits mangeurs de viande, des mangeurs de poisson et des végétariens (courbe en U / exclusion de produits animaux).
Comme l’échantillon est faible, l’analyse réintègre l’étude précédemment supprimée, ce qui augmente le nombre de végans à 1146. On passe alors de 68 décès/753 (9%) à 165/1146 (14,4%), soit 60% d’augmentation. Curieusement, le hazard ratio annoncé augmente seulement de 6%. Je ne comprends pas ce résultat.
Les populations étudiées sont par ailleurs très différentes de la population générale : la mortalité globale, tous groupes confondus, y est inférieure d’environ 50% à la mortalité générale.
Conclusions :
La faiblesse de l’échantillon ne permet pas de tirer de conclusions sur les végétaliens.
Les populations étudiées sont adultes, et le suivi d’une dizaine d’années en moyenne ne permet pas de tirer de conclusions sur l’ensemble d’une durée de vie, y compris pour les végétariens.
L’absence de suivi des abandons et la mortalité accrue dans les premières années ne permet pas d’exclure un biais du survivant prononcé chez les végétariens et végétaliens.
En revanche, l’importante diminution de la mortalité globale par rapport à la population générale, pour toutes les catégories étudiées, semble plaider, au moins pour une fraction de la population, pour la possibilité de suivre une alimentation végétalienne sans risque, au moins durant une ou deux décennies, à l’âge adulte.
Cherry-Picking
Les études portant sur le végétarisme sont parfois positives, et parfois négatives. Dans de nombreux avis favorables aux végéta*ismes, les études négatives, comme celles citées sur cette page, sont purement et simplement oubliées.
Une association comme L214 reprend sur ses sites les avis favorables au végétalisme « à tous les âges », mais oublie tous les avis plus mitigés, voire négatifs, sur la question. L’honnêteté commanderait de signaler, comme je le fais moi-même, qu’il n’y a pas consensus sur la question.
Is There a Lack of Support for Whole-Food, Plant-Based Diets in the Medical Community?
Maximilian Andreas Storz, MD
The permanente journal, 2019
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6307547/
https://twitter.com/fleroy1974/status/1036366992654184453
https://twitter.com/fleroy1974/status/1037456501596725249
Anthropogoniques 