B Vitamins and Heart Disease
Can B vitamins keep your heart healthy?
Sadly, the death of two young children who had died of massive strokes were the catalyst for a 1968 investigation. The Boston pathologist who investigated the death of the children found that they had extraordinarily high levels of a protein breakdown product in their blood. Both children’s arteries were blocked by cholesterol as well, resembling more closely the arteries of a middle-aged unhealthy person than those of a young child. These discoveries led to the hypothesis that elevated levels of this breakdown product (know as homocysteine) had contributed to the process of hardening of the arteries. This condition is called atherosclerosis. So, what is the connection between B vitamins and heart health?
Folate, vitamin B6 and vitamin B12 are instrumental in the body’s ability to convert homocysteine into methionine. Methionine is one of the 20 substances that help the body to build new proteins. Insufficient levels of any or all of these B vitamins can hamper the conversion process, driving homocysteine levels up. Sufficient levels of these vitamisn, on the other hand, can help to keep homocysteine at a safe level.
Many studies over the last few decades have shown that high levels of homocysteine can be associated with an increase in the risk of heart disease and stroke. Some studies have also shown that there is a causal relationship between high intakes of folate and the lower incidence of cardiovascular disease, hypertension and strokes. There cannot be a direct link made, however, between higher homocysteine levels and lower folate levels to an increased risk of heart disease. In other words, it cannot be definitely stated that lower homocysteine levels by taking more folic acid and other B vitamins will lower one’s risk of having a heart attack, stroke or other heart-related condition.
There have been several randomized trials involving B vitamins and heart health, but they have not conclusively shown any relationship between the two. In the studies adutl participants who had a history of heart conditions or who were in the upper risk categories for heart disease were given either a placebo or a pill that contained high doses of vitamins B6, B12 and folic acid. The result of the study was that taking the high doses of the three B vitamins did lower the levels of homocysteine present in the body, but that that reduction did not lead to a reduction in the number of cardiac events in the participants. There is some suggestion that the participants in this study were already too far gone in terms of heart health for the B vitamins to have an effect.
Recently, analysis of several studies seems to suggest that taking folic acid supplements can reduce the likelihood of a stroke in a person who had never before suffered a stroke. The risk reduction does not occur, however, in people who have already had a stroke. Further, folic acid was most effective in promoting heart health when combined with vitamins B6 and B12 as opposed to when it is consumed in isolation.
In the United States and in Canada, since the governments in those countries have mandated that certain products such as bread and pasta be fortified with folic acid, the rate of death from stroke has fallen dramatically. In the UK, where folic acid fortification is not yet mandated, there has been no significant change in the rate of death from strokes.
The long and the short of it is this: Folic acid supplementation may reduce the risk of heart disease in people who have lower levels of folate in their systems. This will typically include those people living in countries where folic acid fortification of food is not yet the rule. In countries where people already get adequate levels of folic acid from their food, further supplementation, even levels that are much higher than can be found in a standard multivitamin, has not been sufficiently shown to be of any significant benefit and, actually, may cause harm.
Currently, what constitutes a sufficient daily intake of B vitamins isn’t clearly defined. The definition would likely change over time anyway, as more data are collected from randomized trials. Currently in the United States, folic acid fortification of food has led to an increase in the percentage of adults who have adequate levels of folate in their systems. Still, only a small percentage of American adults currently get the recommended daily intake of all B vitamins derived just from their diets alone.