WASHINGTON — People who ate a diet rich in foods that lower cholesterol, such as nuts, soy, avocado, olive oil and oats, saw a bigger drop in cholesterol than people on a low-fat diet, said a US study on Tuesday.

After six months of eating a diet that specifically included foods that lower LDL cholesterol, the randomized trial showed people experienced a 13 percent drop in low-density lipoprotein (LDL, or "bad" cholesterol).

Those on a diet that just emphasized low-fat foods, including high-fiber options and whole grains, saw a three percent drop in LDL, said the report in the Journal of the American Medical Association.

"This study indicated the potential value of using recognized cholesterol-lowering foods in combination," said the study.

The trial took place at four different sites in Canada -- Quebec City, Toronto, Winnipeg, and Vancouver -- and included 351 participants with elevated cholesterol levels.

Those on the concentrated cholesterol-lowering regime were divided into two groups -- one which had two nutritional counseling sessions and the other which had seven clinic visits over six months -- but both saw very similar results.

The trial did not restrict calories or provide subjects with food. All the subjects lost a similar amount of weight -- between 1.2-1.7 kilograms (2.6-3.7 pounds) -- during the study.

Foods included in the cholesterol-lowering group were drawn from a list of US Food and Drug Administration approved suggestions for better heart health, including the use of olive oil instead of butter, and margarine products fortified with plant sterols that help block absorption of cholesterol.

Other such foods included avocado, oatmeal, soy, tofu, beans, lentils, almonds, hazelnuts, peanuts, pecans, pistachio nuts and walnuts.

The study had a high overall dropout rate -- 22.6 percent -- though it noted "this attrition rate is common to dietary studies provided at these levels of intensity."

Another drawback was that it included mainly white subjects of moderate weight with low heart disease risk, so it was "unknown" if similar effects would be seen in "higher-risk, more overweight, or obese patient populations."