Diet may trigger acne after all

For years it was widely believed that certain foods, such as chocolate and French fries, made acne worse. Then dermatologists said food didn’t cause pimples. Now, get ready for another about-face.

According to a study in the December issue of the Archives of Dermatology, our Western diet may be a reason 79% to 95% of American teenagers have acne. Researchers spent seven weeks examining the skin and lifestyle of village people on Kitava Island, Papua New Guinea. No acne was found in the more than 1,200 people studied, including 300 15- to 25-year olds.

Unlike typical American teenagers, Kitava islanders are physically active and eat a low-fat (20%), high-carbohydrate (70%) diet of mostly roots, fruits and vegetables, which keeps their insulin levels low. The researchers found no acne in a group of 115 Ache people in Paraguay either. They also eat a low-glycemic diet, but they do eat animal protein.

Studies have shown that when insulin levels in the blood peak, a series of hormonal events increases production of testosterone and several potent growth factors. Testosterone stimulates sebum, or oil, production in the pores. The growth factors cause an overgrowth of cells lining the pores, which creates a plug, keeping the oil in.

“It’s like a balloon with no outlet that then becomes infected and causes acne,” says Loren Cordain, a coauthor of the study and a specialist in evolutionary medicine at Colorado State University.

High-glycemic foods that increase insulin and are implicated in acne include white flour, sugar and potatoes -- ubiquitous in the West, says Cordain. And about that chocolate and French fries? He says it’s not the fat that’s the problem, it’s the sugar.