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AMSTERDAM, THE NETHERLANDS. A high blood level of homocysteine (a
sulfur-containing amino acid derived from methionine) has been
associated with the development of atherosclerosis. High
homocysteine levels can be reduced by supplementation with folic
acid; however, it is still uncertain whether this reduction
actually lowers the risk of atherosclerosis. Now researchers at
the University Hospital Vrije Universiteit report evidence that
supplementation with folic acid and vitamin B6 is associated with
a decreased occurrence of abnormal exercise electrocardiographs -
important markers for atherosclerosis. The study involved 158
siblings of 167 patients with premature atherothrombotic disease.
The study participants (siblings) had no signs of arterial disease
when entering the study, but were obviously at greater risk of
developing atherosclerosis than normal. The participants
underwent a methionine-loading test at the start of the study and
were subsequently divided into two groups. One group of 104 had
high homocysteine levels after the methionine-loading test while
the second group of 54 siblings had normal levels. Each group was
subsequently randomized to receive either 5 mg folic acid plus 250
mg vitamin B6 daily for a two-year period while the other group
received a placebo.
At the end of two years all participants had an electrocardiogram,
an ultrasound measurement of the carotid and femoral arteries, and
a determination of their ankle-brachial pressure index at rest and
after exercise. As expected, the vitamin treatment was associated
with a significant drop in both fasting homocysteine concentration
and postmethionine homocysteine concentration. Blood plasma
content of folic acid increased 13-fold and that of vitamin-B6 9-
fold in the supplement group. There was no apparent effect of
vitamin treatment on ankle-brachial pressure indices or ultrasound
measurements; however, the incidence of new abnormal exercise
electrocardiograms was much lower in the vitamin group (6 versus
14 in the placebo group). The researchers conclude that vitamin
therapy lowers the risk of an abnormal exercise electrocardiogram
by 60 per cent independent of other risk factors such as age, sex,
baseline level of postmethionine homocysteine, cholesterol levels,
smoking habits, and the presence of hypertension or diabetes.
Although the trial involved participants at high risk for
atherosclerosis the researchers see no reason why the results
should not be applicable to healthy individuals.
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