Vitamin B12 deficiency in vegetarians
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Prevalence of Vitamin B12 Deficiency in Vegetarians
Vitamin B12 deficiency is common among vegetarians, with studies consistently showing higher rates of deficiency compared to non-vegetarians due to the lack of animal-based foods in their diets 23568910. The prevalence varies by age, gender, and type of vegetarian diet. For example, deficiency rates among vegetarians have been reported as 62% in pregnant women, 25–86% in children, 21–41% in adolescents, and 11–90% in the elderly 25. Vegans, who avoid all animal products, are at even higher risk than lacto-ovo-vegetarians 2568910.
Risk Factors and Demographic Considerations
Vegetarians of all ages and backgrounds are at risk for vitamin B12 deficiency, regardless of where they live or their specific type of vegetarian diet 2579. Pregnant and lactating women, infants, children, and the elderly are particularly vulnerable due to increased nutritional needs or decreased absorption 2579. Those who have followed a vegetarian diet since birth are more likely to be deficient than those who adopted the diet later in life .
Clinical Manifestations and Biomarkers
Vitamin B12 is essential for DNA synthesis, red blood cell formation, and nervous system health. Deficiency can lead to a range of symptoms, some of which may be severe or irreversible, such as neurological issues and anemia 58. Subclinical deficiency is also common, where individuals have abnormal biomarkers but no obvious symptoms 159. Reliable assessment of B12 status includes measuring serum B12, holotranscobalamin (holo-TC), and homocysteine levels, as total serum B12 alone may not reflect true status 19.
Health Consequences: Cardiovascular Disease and Beyond
Vitamin B12 deficiency in vegetarians is linked to elevated homocysteine levels, which increase the risk of cardiovascular diseases such as coronary artery disease, stroke, and other circulatory problems 145. Macrocytosis, another consequence of deficiency, is also associated with higher rates of heart disease . These risks may offset some of the cardiovascular benefits typically associated with vegetarian diets .
Prevention and Supplementation Strategies
Because plant foods contain little or no vitamin B12, vegetarians are advised to take regular B12 supplements or consume fortified foods to prevent deficiency 23568910. Supplementation is especially important for vegans and those at higher risk, such as pregnant women and the elderly 257910. Studies show that regular supplementation significantly reduces deficiency rates among vegetarians and vegans 910. A daily dose of 50 to 100 micrograms is commonly recommended .
Screening and Awareness
Routine screening for vitamin B12 deficiency is recommended for vegetarians, especially those in high-risk groups 3579. Increased awareness about the lack of B12 in plant foods and the health risks of deficiency is crucial for prevention 36810.
Conclusion
Vitamin B12 deficiency is a significant concern for vegetarians, particularly vegans and those in vulnerable life stages. Regular supplementation and routine screening are essential to prevent deficiency and its associated health risks. Increased education and awareness can help ensure vegetarians maintain adequate vitamin B12 status and enjoy the full health benefits of their dietary choices.
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