People who take certain cholesterol-lowering drugs would still do well to eat a heart-healthy diet, according to a study published recently in the Journal of the American Medical Association.

While dietary changes are not enough to significantly lower cholesterol in some people, the study results show that a combination of eating a heart-healthy diet and taking cholesterol-lowering drugs is more effective than either one alone.

Complementing drugs with diet

Finnish researchers studied 120 men aged 35-64 who had high cholesterol levels but had not been previously treated. The men were randomly divided into two groups of 60 each, with the men in one group instructed to eat their normal diets and those in the other group instructed to eat a "Mediterranean-type" diet that contained no more than 10% of calories from saturated and trans fat, and no more than 250 milligrams of cholesterol a day. The diet was also to be high in sources of omega-3 fatty acids, such as fish, and in sources of fiber, such as oat bran, fruits, and vegetables.

The men following the Mediterranean diet were advised to choose lean cuts of meat and poultry and low-fat or fat-free dairy products, to eat fish once or twice a week and to substitute canola oil margarine (a monounsaturated fat) for butter.

Within each group of 60, half the men received simvastatin (Zocor®) and the other half a placebo. Neither the researchers nor the study participants knew which they were receiving. After 12 weeks, the men taking simvastatin were switched to a placebo and vice-versa for another period of 12 weeks.

An "additive" effect

Treatment with simvastatin lowered total cholesterol levels by 21%, whereas diet alone lowered them by almost 8%. But the effects of each, according to the researchers, were "independent and additive," meaning that the treatment together lowered total cholesterol by nearly 29%.

Treatment with both simvastatin and diet lowered LDL-cholesterol (the "bad" cholesterol) levels by 41%, whereas simvastatin alone lowered LDL by 30% and diet alone lowered LDL by 11%.

Other benefits of diet

In addition to adding to the drug's cholesterol-lowering effect, the diet may have counteracted some potentially negative side effects of the drug, say the researchers. Treatment with simvastatin lowered blood concentrations of some antioxidant nutrients, but this problem was much less evident in those who consumed a produce-rich Mediterranean diet.

In the meantime, if you take simvastatin or another "statin" drug for cholesterol-lowering purposes, and have not made any changes in your diet, you may want to talk to your doctor or a dietitian about adopting a heart-healthy diet low in saturated and trans fat, and high in monounsaturated fat, omega-3 fatty acids, and fiber.