Does Dairy Fat Reduce Type 2 Risk?

Harvard School of Public Health scientists, along with colleagues from other institutions, have discovered a natural substance in dairy fat that could reduce the risk of type 2 diabetes. The substance, a fatty acid that's present in butter, cheese, and milk, is called trans-palmitoleic acid.

The scientists described their findings in the Annals of Internal Medicine, noting that trans-palmitoleic acid could be behind other studies that found that diets rich in diary products are associated with a lower risk of type 2 diabetes. The substance, which is not made by the body, can only be obtained by consuming foods that contain it. Trans-palmitoleic acid is not the same as commercially produced trans fats, which have been linked to cardiovascular disease.

Investigators tracked the nearly 4,000 study participants' insulin levels, blood sugar levels and blood fatty acid levels. They learned that those with higher levels of trans-palmitoleic acid ran a substantially lower chance of getting type 2 diabetes.

"This type of observational finding requires confirmation in additional observational studies and controlled trials, but the magnitude of this association is striking," noted Harvard professor Dariush Mozaffarian. "This represents an almost three-fold difference in risk of developing diabetes among individuals with the highest blood levels of this fatty acid."

But don't rush out and lay in a supply of super-premium ice cream and butter just yet. While it's an interesting study, it's too early to start telling people to increase their intake of full-fat dairy products as a way to reduce their type 2 diabetes risk, experts say.

"It's one study based on one survey," says Suzanne Steinbaum, MD, of Lenox Hill Hospital in New York City. "I don't think the conclusion was based on enough data and at this point, based on this trial, we can't recommend eating dairy foods as a way to prevent diabetes."

What's needed next, says Leonid Poretsky, MD, director of the Friedman Diabetes Institute at Beth Israel Medical Center in New York City, is an interventional prospective study. "In this type of study, you would give people the substance over a period of time and then observe whether there are indeed fewer cases of diabetes," he says. "This study was just an association study. It doesn't prove cause and effect."

Full fat dairy products contain saturated fat, long considered a no-no for those concerned about heart health. Drinking whole milk and eating full-fat cheeses can contribute to obesity, which is one of the proven risk factors for type 2 diabetes.

"If you want to prevent type 2 diabetes, lose weight and exercise," Steinbaum recommends. "As for diet, we've found that one high in fruits and vegetables, such as the Mediterranean diet, has been the most successful in preventing type 2 diabetes."


Natural Dairy Fat Component Reduces Diabetes Type 2 Risk. 22 December 2010. Medical News Today."

Diabetes Risk May Be Reduced by Component in Common Dairy Foods. 21 Deccember 2010."