"Good" Fats Trim Body Fat in Diabetic Women

The study (of 35 older women with Type 2 diabetes) found that supplements containing two types of fats -- conjugated linoleic acid (CLA) or safflower oil -- led to healthy changes in body composition over four months.

With CLA, the women saw a dip in body mass index (BMI) -- a measure of weight in relation to height -- and in their total level of body fat.

With safflower oil, the women's BMI did not change, but they typically shed a couple pounds of fat from the trunk area; they also showed improvements in their blood sugar levels, which signals better diabetes control.

CLA is an unsaturated fatty acid found in beef, lamb and dairy products. Animal research has found that CLA can help melt away body fat, and some studies have suggested the same may hold true in humans.

Safflower oil is rich in omega-6 polyunsaturated fats, but exactly how it might affect body fat and blood sugar is unknown, said Dr. Martha Belury, an author of the study and a professor of nutrition at Ohio State University in Columbus.

She explained that she and her colleagues were simply using safflower oil as a comparison substance to gauge the effects of CLA. The former, it turned out, had its own unique benefits.

Belury stated that it is too soon to recommend that overweight women with diabetes buy CLA or safflower oil supplements. But they can try to fit more polyunsaturated fats into their diet.

"Don't get rid of the healthy fats in your diet when you get rid of the bad ones," she advised.

The study, included 35 obese women with an average age of 60. Each took either 8 grams of the safflower oil supplement or 8 grams of the CLA supplement every day for 16 weeks; after a one-month break, the women then switched to the other supplement.

Overall, Belury's team found, the women showed a small decline in BMI and shed a couple pounds of body fat while on CLA. There was no change in their blood sugar levels or muscle mass.

In contrast, while on safflower oil, the women lost body fat in the trunk area and gained some muscle mass, while their blood sugar levels showed a general decline.

"These fats seem to work very differently from each other," Belury said.

More research is needed to understand why that is, according to the researchers. Studies suggest that CLA affects enzymes involved in body-fat storage, which may explain its benefits for body composition -- but its potential effects on diabetes are unclear. The supplement did not affect blood-sugar control in this study, and a previous study of diabetic adults found that CLA actually raised blood-sugar levels.

For now, Belury recommended that people try to work polyunsaturated oils into their diets -- eating salads with oil-and-vinegar dressing, for instance, or cooking vegetables with the oils instead of butter.

She noted that the amount of safflower oil used in this study was equivalent to just under two teaspoons a day, which is easy to get through food. A number of other oils, like sunflower and corn oils, are also high in omega-6 polyunsaturated fats.

On the other hand, the amount of CLA used in the study would be tough to get through the diet. A liter of full-fat milk, for example, contains only about 1 gram of CLA.

American Journal of Clinical Nutrition, Oct. 2009