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    Professor claims diet does, after all, affect acne

    A report from a University of Colorado professor has dermatologists scratching their heads and pondering more than 30 years of medical teaching and patient advice. Does diet, or more specifically the wrong diet, lead to the sebaceous secretions that cause acne vulgaris?

    Loren Cordain, Ph.D., studied eating habits in Paraguay and Papua New Guinea, where hunting, fishing and gathering fruits and vegetables are common practice. His report, published in the December 2002 issue of Archives of Dermatology, throws to the breeze a previously upheld landmark study by Gerd Plewig, M.D., who in 1970 conducted a double-blinded study showing no causal link between chocolate and incidences of acne.

    Dr. Cordain's work suggests a traditional Western diet, high in refined carbohydrates, permanently boosts insulin. This elevates growth and hormone levels, stimulating the sebaceous secretions that lead to clogged pores, bacteria growth and acne vulgaris.

    "The importance of this study is that we are defining the underlying etiology of acne –– why acne occurs," Dr. Cordain said. "It's a black box right now, isn't it? Everybody gets it, it usually goes away by the end of your teenage years. I think we've been able to define for the first time that the environment indeed underlies acne, and in all likelihood it's the high-glycemic load of the typical Western diet."

    Reaction in the dermatology community is mixed. Some dermatologists long have suspected a link between diet and acne. Others are skeptical, preferring to rely on Dr. Plewig's long-held theories.

    "I have treated acne for many years and each patient who notes a dietary connection has a different food that flares acne," said Zoe Diana Draelos, M.D., clinical associate professor of dermatology, Wake Forest University School of Medicine, Winston-Salem, N.C. "The most commonly mentioned connection is between soft drinks and acne. I personally believe that acne is related to hormonal changes, which ultimately influences sebum production that is essential to adolescent acne. I think there are many diseases called 'acne,' but the etiology of each disease is different. Adolescent acne is clearly different from acne in women ages 40 to 50 years."

    Dr. Cordain's study examined the Kitvian Islanders of Papua New Guinea and the Ache hunter-gatherers of Paraguay. Their diets included no breads, sugars, soft drinks, or potato chips. The civilizations had no incidence of acne vulgaris.

    The unrelated populations and acne incidence couldn't be explained by genetics, Dr. Cordain said, and they had fundamentally different diets. So, essentially, he studied as much as what they did not eat as much as what they did eat.

    Results in Debate Dr. Cordain concluded that high-glycemic foods such as breads, cakes, sugars and sodas "contribute to the acne suffered by 95 percent of Westernized teenagers."

    The figures, impressively high, are not accepted by all dermatologists.

    "It's theoretically possible," said Norman Levine, M.D., professor and chief of dermatology, University of Arizona. "But right now it's an observation without data. I don't think this represents a paradigm shift and shouldn't change anything. It's an observation that they essentially worked backward on. It's very premature, based on [only] this observation."

    Dr. Cordain's work included an examination of Dr. Plewig's methodology and isolated what Dr. Cordain called "a fatal flaw." Dr. Plewig compared two groups, one being given chocolate and the other placebo, noticing no difference in acne outbreak. The flaw came in that the placebo and the chocolate actually had identical glycemic loads [equal amounts of sugar] –– and this recently was pointed out to Dr. Plewig.

    "Gerd Plewig was one of the reviewers of our paper," Dr. Cordain said. "Plewig admitted –– he is a good scientist –– he admitted that was a fatal flaw in his study, and literally it set the entire discipline down the wrong track for 30 years."

    Dr. Cordain has outlined an acne-friendly diet, and scientific papers related to it can be downloaded at thepaleodiet.com. Although it does focus on carbohydrate intake, the diet shouldn't be mistaken for another program popularized by Robert C. Atkins, M.D.

    "The Atkins diet is a high saturated fat diet," Dr. Cordain said. "The diet we recommend gets less than 10 percent of its energy from saturated fats."

    Even dermatologists open-minded to a link between diet and acne have reservations. "I have just as many patients who clearly have a diet connection to their acne and as to others who don't," said Tina S. Alster, M.D., clinical assistant professor of dermatology and pediatrics, Georgetown University Medical Center.

    "Arguing against it, at least from a practical standpoint, are the numerous patients that I have had whose acne worsens when they travel abroad –– and their diet actually is lower in carbohydrates. I always thought that the worsening was related to travel-induced stress," she said.

    PCOS and Causal Information Dr. Cordain clarified his study. "This is a descriptive study, not a causal study," he said. "However, there is some causal information that supports the theory, and that comes from dietary interventions with women who have Polycystic Ovary Syndrome [a condition affecting about 10 percent of American women involving metabolism, insulin resistance and acne]. If you take women who have PCOS and intervene with low-glycemic-load carbohydrates, it moves all the endocrine function in the manner that is predicted by our model."

    Dermatologists maintain that many factors always will play into the treatment and prevention of acne vulgaris. Isolating one factor above another will be tough.

    "The bottom line is that acne remains a multifactorial disease with variables affecting its severity including genetics, diet, stress, general health and topical exposure," Dr. Alster said.

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