Homocysteine is a substance found in the blood. Some evidence suggests that high levels of homocysteine might be an important risk factor for heart disease. Since homocysteine levels can be reduced without drugs—adequate intake of folate , vitamin B12 , and vitamin B6 will suffice—in the late 1990s some public health researchers seized on the homocysteine hypothesis as a possible way to prevent major killers through simple nutritional supplementation.
Numerous large studies were designed and conducted to determine whether homocysteine reduction can reduce heart disease, strokes, and other cardiovascular diseases. Unfortunately, the results thus far have been disappointing. The results of completed trials suggest that homocysteine reduction does not have a marked effect on heart disease and related conditions.
However, some these large studies have, in passing, noted unexpected benefits among those given homocysteine-reducing supplements.
One of these possible “positive side-effects” is discussed in an article published in 2007 by the prestigious journal Lancet . Researchers in this article analyzed results of a study that enrolled 818 people with high homocysteine. Participants in this study were given either folate (800 mcg daily) or placebo for a total of three years. All were given a great number of medical tests as the study progressed, some of which involved evaluation of mental function. The results of the mental function tests indicated that those who were given folate showed improvement in areas of cognitive function that typically decline with age; in comparison, those given placebo did not improve.
This finding suggests that use of folate may help enhance mental function in seniors. Note, however, that these apparently promising results must be taken with a grain of salt. The study referenced above was not designed to look at effects on mental function. The laws of probability ensure that if enough variables are measured, some will come out better in the treatment group of a double-blind study, just by chance. Only if repeat studies designed in advance to evaluate folate’s effect on mental function show benefit, will we have reliable evidence that it actually works.