Foods high in folic acid include green, leafy vegetables, citrus fruits and tomatoes. Since 1998, wheat flour has been fortified with folic acid to add an estimated 100 micrograms per day to the average diet. Folic acid supplements should be used to lower homocysteine levels when the diet doesn't provide enough.

Recent findings suggest that laboratory testing for plasma homocysteine levels can improve the assessment of risk. It may be particularly useful in patients with a personal or family history of cardiovascular disease, but in whom the well-established risk factors (smoking, high blood cholesterol, high blood pressure) do not exist. Folic acid and B-vitamin supplementation can reduce the need to test homocysteine levels.

Vegetarians and vegans are at increased risk for elevated levels of homocysteine, since it's virtually impossible to have enough B12 in your diet without consuming an omnivorous diet.