Monday, April 30, 2007

Trans-Fat Alternative Fares Poorly In Study

Trans-fat, like saturated fat and dietary cholesterol, has been found to raise LDL cholesterol, increasing risk for heart disease. Trans-fats may also increase insulin resistance in people with diabetes. (See Trans Fatty Acids And Insulin Resistance.)

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) recommends that people with diabetes limit intake of foods with trans-fat, such as snack foods and commercially baked goods.

But how healthy are the fats being used to replace trans-fats?

A study that appeared in the January 15th issue of Nutrition & Metabolism tested the effects of interesterified fats (IE fats), one of the leading contenders to replace trans-fats. Thirty participants consumed diets that were either rich in palm olein*, trans-fat, or IE fat. After 4 weeks:
  • Those on the trans-fat and IE fat diets had higher LDL/HDL cholesterol ratios than those on the palm olein diet.
  • Those on the trans-fat and IE fat diets had higher fasting plasma glucose than those on the palm olein diet. (Those eating trans-fat had a BG increase of about 5.2 mg/dl after 4 weeks, those eating IE fat had a BG increase of about 18.9 mg/dl.)
Manufacturers are still working to find a good replacement for trans-fats. What this study tells us is that not all apparently healthy alternatives to trans-fats are good ones.

*Palm olein is the fraction of palm oil that is liquid at room temperature. Palm olein is approximately 45% saturated fat and 55% unsaturated fat. (American Palm Oil Council)


For the study (full free access):
Stearic Acid-Rich Interesterified Fat And Trans-Rich Fat Raise The LDL/HDL Ratio And Plasma Glucose Relative To Palm Olein In Humans