A new paper published in the Journal of Nutrition has once again shown that vegetarians have higher homocysteine levels than evenly matched omnivores. Homocysteine is a near proven cause of heart disease. Homocysteine is a toxic amino acid derived from the essential amino acid methionine. Its levels are controlled and held in check by adequate levels of vitamins B6, B12, and folic acid. Since B6 and B12 are mostly found in animal foods, it is difficult for vegetarians and vegans to get enough of these two nutrients in their daily diets unless supplements are employed. Folic acid is present in legumes and dark leafy green vegetables, but is also plentiful in liver.
Not surprisingly, the study showed that the Taiwanese vegetarians in the study had adequate levels of folic acid in their blood, but inadequate levels of B6 and B12. Compared with the Taiwanese omnivores, vegetarians also had significantly lower serum levels of the amino acids valine, leucine, lysine, alanine and arginine, but higher levels of glycine.
The study provides yet one more reason to include at least a minimum of animal foods in your diet. Raw milk and raw milk cheeses are fair sources of B6 and B12. Of course, liver is the best source of all three nutrients. Many vegetarians and vegans believe that they can get B12 from algae products like spirulina. Not so. True B12 is only found in animal foods.
Source: Plasma Homocysteine Levels in Taiwanese Vegetarians Are Higher than Those of Omnivores.
J. Nutr. 132:152-158, 2002