Vitamin B6 appears to offer protection against
heart disease, according to researchers. But their study also
casts doubt on the theory that high levels of homocysteine in
the blood increases heart risk.
Much attention has recently been drawn to the potential
role of homocysteine in heart disease. Some researchers have
reported that high blood levels of the chemical can help
identify individuals at increased risk of heart disease, while
others have proposed that elevated homocysteine may in fact
cause heart disease.
But a report published in the July 21st issue of the
journal Circulation suggests that elevated homocysteine levels
"may be a consequence, not a cause" of heart disease. Dr.
Aaron R. Folsom of the University of Minnesota in Minneapolis
and colleagues at multiple sites also report that their study
indicates that high blood levels of vitamin B6 may protect
against heart disease.
The researchers measured levels of homocysteine and vitamin
B6 in 769 individuals, aged 45 to 64 years, enrolled in the
Atherosclerosis Risk in Communities (ARIC) study. An average
of 3.3 years later, they followed-up the patients and recorded
new diagnoses of heart disease and stroke in these patients
during the period.
After accounting for a variety of risk factors for coronary
heart disease, Folsom and others found that only vitamin B6
was independently associated with the risk of heart disease.
In fact, the risk of heart disease was 70% lower in study
subjects with the highest blood levels of vitamin B6 at the
start of the study compared with those with the lowest
levels.
In contrast, homocysteine levels were not independently
associated with the risk of heart disease, according to the
investigators.
"I believe that homocysteine isn't as important as some
previous research suggests and that more studies are needed to
clarify how homocysteine, B vitamins and heart disease are
linked," said Folsom in a statement issued by the publishers
of Circulation, the journal of the American Heart Association.
Folsom further stressed the importance of follow-up clinical
trials in an interview with Reuters Health, noting that people
should not assume that vitamin B supplements will lower their
risk of heart disease. "We need first of all for people to be
aware of the main risk factors -- high blood pressure,
cholesterol and smoking," he said.
SOURCE: Circulation 1998;98:204-210.
NEW YORK,
Jul 20 (Reuters) –
