Research
Micronutrients & recovery
Vegetarian and vegan diets are associated with suboptimal Vitamin B12 status and elevated homocysteine levels, requiring careful monitoring and supplementation to avoid potential health risks.
If you follow a vegetarian or vegan diet, you must monitor your Vitamin B12 levels. Relying on plant sources like seaweed is unreliable. Use fortified foods or supplements to maintain adequate B12 status and keep homocysteine levels low.
GoodQualifiesHIGH confidence
Recent research using more sensitive indicators of vitamin B12 status... has shown that substantial proportions of vegans and even of vegetarians have suboptimal vitamin B12 status... Recent work shows that vegetarians must be careful to ensure that they do consume adequate amounts of vitamin B12.
Why this rating
Based on multiple studies using sensitive biomarkers (methylmalonic acid, homocysteine) across diverse populations.
Source
Health effects of vegetarian and vegan diets
Timothy J. Key et al. · Proceedings of The Nutrition Society · 2006
DOI 10.1079/pns2005481
narrative_reviewCited 406×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Adopting a vegetarian or vegan diet is associated with a moderate reduction in mortality from ischemic heart disease (IHD) compared to non-vegetarian diets, primarily driven by lower plasma cholesterol levels and lower body mass index (BMI).Good
- Vegetarian and vegan diets are consistently associated with a lower Body Mass Index (BMI) and slower weight gain over time compared to non-vegetarian diets, although obesity prevalence can still be high in specific subgroups.Good
- Vegetarian and vegan diets do not show clear differences in total mortality, stroke mortality, or cancer rates (colorectal, breast, prostate) compared to non-vegetarians, although IHD mortality is lower.Good
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