Benefits of 'B's' Unsettled
The study began in 1993 with nearly 750 patients who had some evidence of heart disease that occurred before they were 56 years old. The researchers then sought out the siblings of these individuals, and screened them for high levels of homocysteine. A total of 450 siblings were screened for this protein, but the final study sample was much smaller -- 80 joined the placebo group and 78 were placed in the treatment group. The treatment group received 250 mg of vitamin B6 and 5 mg of folic acid daily for two years.
At the end of the two years, those in the treatment group were 60% less likely than those in the placebo group to have abnormal tests during stressful exercise. There was no change in other tests that measure heart function.
In his editorial, Bostom said the study size was too small to be significant and called the use of stress exercise tests questionable. Bostom says studies underway in the U.S. and Europe will indicate whether lowering homocysteine levels with B vitamins actually results in fewer heart problems. Until then, he advises "watching and waiting" and does not recommend that people take higher than recommended doses of B6 and folic acid.
Stehouwer, in contrast, says he sees little peril in suggesting that people who are at increased risk of heart disease consume B6 and folic acid, a practice he says his hospital has adopted. If results from future studies indicate little value, the vitamins can easily be stopped, he says. "What we used were a bit higher than what it the common dose. We believe the chances of doing harm are fairly remote."
But another researcher currently studying this issue feels there is some danger from this study. Charles Hennekens, MD, tells WebMD he fears such studies will prompt people to abandon the more difficult -- but proven -- lifestyle changes they should be making to reduce their risk of heart disease.
"It is premature to begin to tell people to take folic acid [and vitamin B6] to prevent heart disease, but we can't sweep suggestions that high levels of homocysteine are correlated to heart disease," says Hennekens, a visiting professor in the department of epidemiology and public health at the University of Miami. "But these are research questions, not public policy questions. We have a population in the U.S. that prefers prescription of drugs, rather than proscription of lifestyle modifications. If people, hearing the news, relax their efforts at reducing cigarette smoking, reducing obesity, reducing physical inactivity ... that could do damage."