Rather, they assumed that low folic acid levels were caused by inadequate diatary intake. Victor Herbert, M.D., a leading expert on B12 metabolism, has pointed out that the low folic acid levels among the experimental subjects could have been caused by decreased B12 absorption related to getting older. Lowering the serum concentration of homocysteine has been proven to reduce the risk of adverse cardiovascular events among people with homocystinuria. Screening for elevated homocysteine levels is advisable for individuals who manifest coronary artery disease that is out of proportion to their traditional risk factors or who have a family history of premature atherosclerotic disease. The effect of supplementation is usually apparent within a month.
Some physicians recommend that all patients with atherosclerotic disease be screened.
Since folic acid is nontoxic, it seems prudent to treat elevated homocysteine levels based on current knowledge. The process should be supervised by a well-informed physician. B12 deficiency leads to anemia and, if not corrected in time, will permanently damage the nervous system. For this reason, people over 50 who take folic acid supplements should also take at least 25 micrograms of vitamin B12 per day, a dose large enough to enable adequate amounts to be absorbed. Dr. Herbert believes that everyone over age 50 should take B12 supplements anyway, because gastric atrophy is common as people age.