Studies question the usefulness of raising HDL cholesterol with niacin
Many Americans take high does of niacin (vitamin B3) to improve their cholesterol levels in the hopes of guarding against heart attacks. However, several recent studies cast doubt on whether niacin actually protects the cardiovascular system. In 2011, Health After 50 reported that a major study had failed to find any evidence that, in people who take statins, niacin pills reduce the risk for heart attacks, strokes and other cardiovascular events. Now, a second large study has reached a similar conclusion.
Does this spell the end for niacin as a heart medication? The study hasn't persuaded all doctors to stop prescribing niacin, but it's led to a growing discussion among cardiologists about the drug's role in preventing and managing heart disease.
Previously, the biggest known downside to niacin was that it could cause intense facial flushing (uncomfortable but harmless skin reddening and burning), gastrointestinal bleeding and gout. These most recent studies have linked high doses of niacin to other serious health concerns.
An HDL cholesterol booster
For most people, the diet supplies enough niacin to meet its requirement as a vitamin; dairy, eggs, meats, nuts and many other foods contain niacin. However, much larger doses of niacin, administered as a pill, are needed to lower low-density lipoprotein (LDL) cholesterol and raise high-density lipoprotein (HDL) cholesterol.
LDL cholesterol enters artery walls, while HDL removes excess cholesterol from the arteries and ferries it to the liver for elimination from the body. Population studies have shown that men and women who have low levels of HDL cholesterol are at a heightened risk for coronary artery disease and heart attacks.
Doctors have long thought that boosting HDL cholesterol promotes heart health. A 2-gram dose of niacin increases HDL cholesterol levels by about 20 percent. Niacin is available by prescription under various brand names, such as Niaspan and Niacor, and sold over the counter.
The advent of statin drugs, starting with lovastatin (Mevacor) in the 1980s, provided doctors with a more potent drug than niacin for lowering LDL cholesterol. However, researchers wanted to know whether patients taking statinswhich include simvastatin (Zocor), atorvastatin (Lipitor) and rosuvastatin (Crestor)gain further heart protection by using niacin, too.
Simeon Margolis, MD, Professor of Medicine & Biological Chemistry, Johns Hopkins University School of Medicine
Because reviews and meta-analyses aren't as meaningful as well-controlled studies, I'd tend to discount the review of niacin studies published earlier in 2013 in the Journal of the American College of Cardiology, which suggests that taking niacin or a niacin-statin combination lowers the risk of cardiovascular events.
But I hasten to add that, personally, I've always questioned the use of niacin because of (1) its side effects and (2) the lack of meaningful evidence that niacin prevents cardiovascular events or delays mortality. Moreover, the genetic study questions whether raising HDL cholesterol will diminish cardiovascular events.
Source: Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50