Hi, I’m Dr Kathleen Potter. I’m a medical researcher from the University of Western Australia. I joined the Editorial Advisory Board of the Virtual Cardiac Centre three years ago and today I’m going to share with you some insights on homocysteine, B vitamins and cardiovascular disease.
Homocysteine is an amino acid that circulates in the blood stream. Its levels can be measured in a blood sample in the same way that cholesterol can. And a lot of evidence shows that homocysteine levels are linked to cardiovascular disease.
This evidence shows that the higher a person’s blood homocysteine level, the more likely it is that the person will have a heart attack or a stroke. Now this much is well known and is not controversial. However what is less clear is whether or not homocysteine actually causes cardiovascular disease.
The best way to test whether or not homocysteine causes cardiovascular disease is to find out whether reducing the homocysteine levels actually reduces the number of people who have a heart attack or a stroke. And fortunately it’s very easy to reduce homocysteine in most people, simply by giving them a B vitamin supplement. A combination of folic acid and vitamin B12 reduces homocysteine by about 25%.
Recently several studies have tested the effects of B vitamin treatment on cardiovascular disease. These studies have enrolled large numbers of people, about 17,000 in total. And they have randomly allocated people to one of two groups, either treatment with B vitamins or treatment with a placebo tablet that had no effect on the homocysteine levels. After several years people taking the vitamins had much lower homocysteine than people who had been taking the placebo tablet. However when the results from all of the trials were put together, there didn’t seem to be any difference between the two groups in the number of people having heart attacks or strokes.
Now these results suggest that homocysteine probably doesn’t cause atherosclerosis and may just be a marker for the disease that is already there. It seems that reducing homocysteine may simply reduce the marker, and not actually change the cardiovascular disease risk. However the case is not completely closed.
Most of the studies were conducted in people who had already had a stroke or a heart attack. And some people think that B vitamins might be more effective if used in healthy people, before they actually develop the cardiovascular disease. And there’s definitely some evidence that reducing homocysteine might have more effect on strokes than on heart attacks, with at least one of the big studies showing a reduction in the number of strokes in the people taking the B vitamins.
However the same studies showed that the people taking the B vitamins were actually slightly more likely to have a serious angina attack. Fortunately there is several large trials still going on at the moment. So when the results from these trials come in, hopefully the picture will become a bit clearer. However at the moment there is certainly no good evidence that using B vitamins to reduce homocysteine will prevent cardiovascular disease.
Thanks for watching and have a great day.
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