A researcher might rewrite the books on acne with his findings that candy, carbohydrates and cola play an important role in the skin disease after all.
Professor Loren Cordain of Colorado State University studied thousands of hunters, gatherers and farmers in Paraguay and Papua New Guinea whose diets contained no bread, cake, sugar, soft drinks, potato chips or pizza, and he didn't find a single case of acne.
His research, which will appear in this month's Archives of Dermatology, has caused a sensation in the medical community. For years, Americans have been told overactive glands and genes -- not diet -- caused acne.
Cordain led a study that looked at the Kitvian Islanders of Papua New Guinea and the Ache hunter-gatherers of Paraguay.
The perfect skin of the two unrelated groups on opposite sides of the globe couldn't be explained by genetics, he said. People who lived nearby and who looked very much like them had their share of acne. They also ate very different foods. So the researchers zeroed in on the diet.
The Kitvian Islanders eat mostly fruit, fish, yams and sweet potatoes.
"They have no grains, sugars or oils, no breakfast cereals, white bread, doughnuts, pasta, pizza," Cordain said. "They only have what you can grow in the garden or catch in the ocean."
The Ache people eat wild game, peanuts and a native root, sweet manioc, plus a tiny amount of Western foods. Cordain concluded that high-glycemic foods such as bread, cakes, sugars and soft drinks "may contribute to the acne suffered by 95 percent of Westernized teenagers."
Cordain and researchers from Australia, Sweden and New Mexico believe Western diets permanently boost insulin. Insulin elevates growth and hormones, stimulating an overproduction of oil and skin cells in pores. Those clogged pores feed bacteria that form blemishes.
The researchers believe switching to a more natural diet might help reduce acne by better regulating the metabolism of insulin.
The theory flies in the face of 30 years of medical advice. The American Academy of Dermatology has long called the diet-acne connection a myth, blaming the skin disease on overactive sebaceous glands, which are particularly busy during the teen years. Heredity and hormones also play big roles, the AAD says.
Ironically, it turns out what's old may be new. Baby boomers and World War II teens remember their mothers' scoldings that greasy food and chocolate caused pimples.
What happened to change that advice?
Cordain says dermatologists relied too heavily on a study by Gerd Plewig in 1970. Plewig gave one group chocolate and another group a placebo.
"There was no difference in the incidence of acne in the two groups," Cordain said. "But 30 years later, we pointed out to him that it was fatally flawed because the placebo had the same identical glycemic [sugar] load as the chocolate."
Plewig sat on the team that reviewed Cordain's report.
"He's a good scientist, he ate humble pie and admitted his mistake," when the flaw in the 1970 study was pointed out, Cordain said.
E-mail this story 
