Many
people take over-the-counter niacin as a replacement
for, or complement to, cholesterol-lowering drugs. A
new survey shows that these products do not always contain
the amount of niacin, or nicotinic acid (vitamin B 3
) described on the label. The survey found broad variations
in the products, ranging from no available niacin to
toxic levels of niacin. The inconsistencies are attributed
to the fact that niacin is classified by the FDA as
a dietary supplement. This means that the product is
entirely unregulated; therefore, the manufacturers do
not have to prove quality, safety, or efficacy.
The
survey of niacin products was conducted by C. Daniel
Meyers, MD, Veterans Affairs Medical Center, Long Beach,
CA, and colleagues, who acknowledged that niacin is
one of the first agents found to raise the level of
good cholesterol (HDL) and lower the level of bad cholesterol
(LDL) and triglycerides when taken in daily doses of
1,000-4,000 mg. The worst side effect is “niacin flushing,”
that is, redness, itching, burning, which starts within
10-15 minutes after swallowing the tablet and can last
up to an hour.
Dr.
Meyers and colleagues looked at 29 commonly used over-the-counter
niacin products (500-mg tablets or capsules) from three
categories: Immediate-release, sustained-release, and
“no-flush.” They calculated the monthly cost for each
product purchased in pharmacies, health-food stores
or over the Internet. Ironically, the no-flush preparations,
the most expensive ($21.70) of all, do not contain free*
nicotinic acid. Some brands of the sustained-release
preparations contain amounts of niacin so high as to
be toxic to the liver.
In
yet another ironic twist, the best products are the
least expensive ($7.10). They are the immediate-release
preparations, which contain, according to Dr. Meyers
and colleagues, “the full amount of free nicotinic acid
used safely for more than 40 years” and “shown to prevent
cardiovascular disease and death.” The cheapest brands
in this category are Rugby, Bartell's, Natural Factors—all
are under $5.19 for a one-month supply (Annals of Internal
Medicine, 12/16/03). In most people, the niacin flushing
becomes less pronounced with time, according to Dr.
Meyers and colleagues, who wrote, “Both the frequency
and severity of flushing episodes decrease with repeated
doses…Some trials, however, show that 40% of the people
stopped taking niacin because of this side effect.”
The
biggest irony of all regarding niacin is the likelihood
that it is safer and just as effective as statin drugs—for
men, that is. In the introduction to this survey, Dr.
Meyers and colleagues cite the Coronary Drug Project,
which followed 3,908 men taking a placebo or niacin
therapy. After nine years of follow-up, the men in the
latter group had not only a lower rate of non-fatal
heart attacks but also an 11% lower rate of all-cause
mortality than the men in the placebo group. Statin
drugs lower cholesterol and reduce the rate of non-fatal
heart attacks in men, but they do not reduce the rate
of cardiovascular or overall death (See
Statin Drugs: How Safe? How Effective?).
*The
full amount, as designated on the label.
January
2004
