Soy In Diet Reduces
Cholesterol Levels
WASHINGTON - Replacing meat with soy substitutes and fresh fruits and vegetables can significantly lower blood cholesterol levels, Canadian researchers said Wednesday.
They said they were able to reduce the levels of "bad" low density lipoprotein (LDL) cholesterol in healthy middle-aged men and women by replacing the meat in their diets with soy substitutes, vegetables and beans over two one-month periods.
"We're only beginning to understand the potentially powerful health benefits of soy," David Jenkins, a professor of nutritional sciences at the University of Toronto, who led the study, said in a statement.
"These findings demonstrate the power of certain foods in the fight against cholesterol and may explain why heart disease is so rare in East Asian countries where soy consumption is much higher."
The 31 men and women who the researchers studied all had high blood cholesterol, which has been linked to heart disease. Some were overweight and some were not.
Jenkins' team gave the subjects ready-made meals containing soy instead of meat, as well as soy "cold cuts," which are widely available at health food stores. The subjects also were given extra servings of oats, barley and legumes such as lentils or beans.
They were asked not to change their exercise patterns.
Half the volunteers received this special diet, while half were put on a low-fat diet that matched current recommendations for lowering cholesterol but which included meat and no extra soy. Then the two groups were switched.
Adding soy and legumes to the low-fat diet produced measurable effects, Jenkins reported in the journal Metabolism.
"Significant blood lipid (fat) reductions were seen by two weeks," the researchers wrote in their report.
Members of the soy group had their overall cholesterol lowered, on average, by 6 percent, with LDL reduced by 6.7 percent on top of any reductions seen in the low-fat diet.
"Good" or high-density lipoprotein (HDL) cholesterol levels remained at their previous levels.
The researchers said adding soy and legumes greatly boosted the amount of soluble fiber in the diet " something doctors long have recommended.
"Vegetable proteins in general tend to result in lower serum (blood) cholesterol levels compared to animal proteins," they wrote.
In a second study, presented last weekend at the Canadian Federation of Biological Societies meeting in Winnipeg, Jenkins said he found that smaller amounts of the same soy food prevented oxidation of the LDL in his volunteers.
Oxidation, the same process that leads to rust on metal, causes fats to harden and helps them form the blockages that damage arteries.