Homocysteine is an amino acid and its existence has been known for many years; more recently it has been advocated as a risk factor for heart disease. There are a number of coronary risk factors and the three most prominent are smoking, high blood pressure and high cholesterol levels.
In 1968 Dr. Kilmer McCully was a young pathologist at the very well known hospital in Boston, Massachusetts General. He studied a two month old boy who had died of homcysteinuria, which is a rare genetic disease characterized by very high levels of homocysteine in the urine and blood. When he examined the infants arteries he found that they were hardened and clogged, much like a person in his 60s, 70s or even 80s. As a result of this and one other reported case, Dr. McCully though that homocysteine might in some way be linked to heart disease. Other researchers at that time thought that his theory was rather far-fetched. He had great promise and he doggedly held to his hypothesis, even in the face of considerable skepticism from the rest of the medical community. In 1978 his colleagues thought his work so unorthodox that he was asked to find a position in another hospital.
As pointed out in the Harvard Health Letter (Vol. 22, No. 11, September 1997) he was, in effect, vindicated by very important findings from the Physicians Health Study. In this study it was found that of some 300 doctors who had had a heart attack, many had a three fold increase in homocysteine levels. So, some thought that this was a risk factor on par with, for example, a high cholesterol level. Other studies suggested much the same results, including the prominent Framingham Heart Study. Framingham is a town in Massachusetts and which has had a long term study of the population ongoing over the past four decades. In their study they also found some low blood levels of vitamin B-6, B-12, and folate, and, therefore, the authors thought that these nutrients might play a role in breaking down homocysteine in the body. And their attention was directed to the therapeutic possibility of patients taking a diet high in B complex vitamins, or else taking supplements of vitamin B. Some of the nutriments that are high in B complex vitamins are orange juice, bananas, strawberries, asparagus, Brussels sprouts, broccoli, baked potatoes, chicken and tuna fish. While this theory seems plausible, thus far there have been no long term studies to show that it works, although such studies are underway at the present time.
Advocates for this hypothesis think that homocysteine may be a risk factor not only for heart attacks, but also for strokes, blood clots in the legs, and, in general, arterial damage throughout the body.
The situation is not altogether clear as yet, since about thirty percent of the people who do have high homocysteine levels also have fairly normal vitamin levels. In such patients, nutritional intervention may have no value. Still, it is unclear as to how high homocysteine levels need to be before it signals danger. Many experts view it as a continuum in that the higher the homocysteine level is, the greater the risk is for having arterial damage or having a heart attack.
At the present time it might prove worthwhile to study patients, especially young patients, who have had heart attacks but do not have the usual risk factors. Such individuals may be studied for homocysteine, vitamin B complex levels, etc. to see if these are causative factors. Those who do have a high homocysteine level probably should be sure that their nutritional intake of vitamin B complex is sufficient, or perhaps even take vitamin supplements containing B complex. It is interesting that the government is entering the fray and in January, 1998 the U.S. Food and Drug Administration is mandating folate fortification in certain foods. The original reason for this was to reduce the risk of certain types of birth defects, but it may prove to be a bonus in that such folate fortification may help further decrease the incidence of heart disease. If one opts to take vitamin supplementation, then the standard amounts of vitamin B-6 (2 milligrams), B-12 (6 micrograms), and folate (400 micrograms) are the recommended dosages. These are standard amounts and vitamin preparations list the exact contents on the bottle. Most research that has been done to date suggests that RDA levels of these nutriments are all that is required to keep homocysteine levels within a normal range in most people. Interesting results should be forthcoming from the various current studies in the next two to three years.
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