People on vegetarian or vegan diets have a lower risk of cardiovascular disease and a higher risk of nutritional deficiencies than omnivores.  Vitamin B-12 is found naturally in animal products and in artificially fortified foods (breakfast cereals, plant-based milks, soy products and yeast extracts).  Vitamin B-12 deficiency is defined as a blood level below 118 nmol/liter; folate deficiency is defined by a blood level below 6.3 nmol/liter.

The present study of men was extracted from a study of 65,000 people from 1993 to 1999.  Omnivores ate at least 3 servings of meat per week.  Lacto-ovo vegetarians used soy milk and soy products.  Vegans ate no animal products.  Blood levels of vitamin B-12, folate, and homocysteine, etc., were drawn on enrollment in the study and the vegan men were retested in 2001.

Of the omnivores, 4% took supplements with B-12; 19% of vegetarians and vegans took supplements.  Of those not taking supplemental B-12, the dietary intake of B-12 in omnivores was 5 times that of vegetarians and 36 times that of vegans.  Vegans not taking a folic acid (folate) supplement had a higher intake of folate than vegetarians and omnivores.  The dietary intake of folate in omnivores, vegetarians and vegans was above the lowest accepted level by 96%, 99%, and 98%, respectively.  All vitamin users had folate levels above the accepted level.  Vegetarians who took folate supplements had higher folate levels than those who did not and age did not seem to be a factor in the blood levels.

Serum B-12 of vegans was 33% lower in vegetarians and 57% lower than in omnivores.  Fifty-two percent of vegans and 7% of vegetarians were B-12 deficient.  “There was no significant difference in mean serum concentration of vitamin B-12 between men who reported taking a vitamin B-12 supplement compared to non-users of supplements in any of the diet groups.”  Only a few men in all groups were folate deficient.

Men on a vegetarian diet are at risk of being B-12 deficient in this study.  When B-12 is restricted, the blood level of B-12 seems to drop rapidly within months.  Some plant-based vitamin B-12 supplements are reported to be inactive.  Neurological damage can result from B-12 deficiency, such as degeneration of the spinal cord with difficulty in the arms and legs.

CONCLUSION:  Vegans and vegetarians have lower levels of B-12 and higher levels of folate than omnivores.  Vegans and vegetarians should take either fortified foods or supplements.

NOTE:  Folate can mask anemia seen in B-12 deficiency, but does not prevent spinal cord injury from B-12 deficiency (pernicious anemia).  According to this study, note that supplementation with B-12 does not always make up for deficiency in the diet.

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NOTE: Read about folic acid and foods which contain it.

PMID: 20648045.

Summary #585.