The homocysteine connection

This is not however the end of the story. Most vegans show adequate B12 levels to make clinical deficiency unlikely but nonetheless show restricted activity of B12 related enzymes, leading to elevated homocysteine levels. Strong evidence has been gathered over the past decade that even slightly elevated homocysteine levels increase risk of heart disease and stroke and pregnancy complications. Homocysteine levels are also affected by other nutrients, most notably folate. General recommendations for increased intakes of folate are aimed at reducing levels of homocysteine and avoiding these risks. Vegan intakes of folate are generally good, particularly if plenty of green vegetables are eaten. However, repeated observations of elevated homocysteine in vegans, and to a lesser extent in other vegetarians, show conclusively that B12 intake needs to be adequate as well to avoid unnecessary risk.