Adding monounsaturated fats to a diet low in saturated fat may improve cholesterol levels

Lowering cholesterol is a concern of many people, some of whom turn to statins to do the job. But a new study finds that adding monounsaturated fats to an already low-cholesterol diet may improve cholesterol levels as well.

The small study included 24 men and women with cholesterol levels that were mildly to moderately high who were on a month-long monitored diet low in saturated fat. After that, some were randomly assigned for a second month to a vegetarian diet -- also monitored -- that was either high or low in monounsaturated fats. Monounsaturated fats are fatty acids that are thought to lower LDL “bad” cholesterol and raise HDL “good” cholesterol. Foods containing monounsaturated fats include avocados, walnuts and olive oil.

In the high-monounsaturated-fat diet, 13% of carbohydrate calories were replaced with monounsaturated fats in the form of sunflower oil (test subjects could exchange some of that for avocado oil).

After four weeks HDL cholesterol increased by 12.5% in the high-monounsaturated fat group, while HDL levels in the low-monounsaturated group did not change. Both groups also lowered LDL cholesterol by 35% over the two months. Average weight loss was small and about the same for both groups.

Because the diets were monitored, the authors suggest that further study may be needed to see if the positive effects of a high-monounsaturated-fat diet still hold when people are left to their own devices as far as diets and motivation are concerned.

The study was published this week in the Canadian Medical Assn. Journal.