WAIKOLOA, HAWAII -- Most physicians, taught that diet is unrelated to the pathogenesis of acne vulgaris, dismiss as folklore the frequent questions posed by patients and family members as to whether eating greasy foods or chocolate or other sweets is what causes their skin problem.

The

diet issue, however, has gained renewed vitality of late in the dermatology literature, with various studies implicating milk, high-glucose-load diets, and low fiber/high saturated fat intake, Dr. Anthony J. Mancini said at the annual Hawaii dermatology seminar sponsored by Skin Disease Education Foundation.

"From all these studies, what's clear is [that] questions are again being raised and people are paying attention to the influence of diet in acne vulgaris. There are not a lot of answers yet. I have a lot of questions myself. But I think this is still a very ripe area for investigation. Stay tuned," urged Dr. Mancini, head of pediatric dermatology at Children's Memorial Hospital, Chicago.

The link between milk consumption and acne has been extensively pursued by investigators at the Harvard School of Public Health, Boston, he said.

In their prospective cohort study of 6,094 girls aged 9-15 years who were children of Nurses' Health Study II participants, self-reported greater consumption of milk--whether whole, low-fat, or skim--on food frequency questionnaires was independently associated with acne severity in a multivariate analysis.

Those girls who drank two or more servings of milk per day during the 2-year study period were roughly 20% more likely to have acne than were girls who drank less than one serving per week.

The results weren't significantly altered by excluding girls using contraceptives or restricting the analysis to those who were less than 11 years old at baseline (Dermatol. Online J. 2006; 12:1).

In a similarly designed study that was conducted recently with 4,273 teenage boys, the Harvard group once again found a positive association between milk intake and acne. This time, though, the relationship with acne was significant only for skim milk consumption (J. Am. Acad. Dermatol. 2008 [Epub doi: 10.1016/j..2007.08.049]).

The Harvard investigators' hypothesis is that bovine hormones and other bioactive agents contained in milk products have effects on acne.

In an editorial accompanying an earlier study by the group, Dr. F. William Danby, a dermatologist at Dartmouth University, Hanover, N.H., noted that 75%-90% of all milk reaching the marketplace comes from pregnant cows.

This milk contains progesterone, other dihydrotestosterone precursors, somatostatin, prolactin, insulin, growth factor releasing hormone, insulinlike growth factors 1 and 2, and numerous other substances that could stimulate pilosebaceous activity (J. Am. Acad. Dermatol. 2005; 52:360-2).

Dr. Mancini noted that the link between acne and a high-glycemic-load diet that is rich in processed carbohydrates was made by Loren Cordain, Ph.D., and coworkers at Colorado State University, Fort Collins.

In contrast to the near-universal prevalence of acne in adolescents in modern developed countries, they reported a rate of essentially zero in two non-Western ized populations: the Ache hunter gatherers of Paraguay and the Kitavan Islanders of Papua New Guinea.

These subjects also had low serum insulin and high insulin sensitivity.

Genetic factors were unlikely to be the sole explanation, the investigators said.

They highlighted the subjects' strikingly non-Western diets, which consisted of minimally processed plant and animal foods (Arch. Dermatol. 2002; 138: 1584-90).

In pursuit of the hypothesis that lowglycemic-load diets may diminish acne, investigators at RMIT University in Melbourne conducted a 12-week randomized trial involving a low-glycemic-load diet and a carbohydrate-dense control diet in 43 male acne patients aged 15-25 years, Dr. Mancini said.

Both acne severity and insulin sensitivity improved on the low-glycemic-load diet, but the subjects also lost weight on the diet and the investigators couldn't rule out the possibility that this weight loss played a role in the observed benefits (J. Am. Acad. Dermatol. 2007; 57: 247-56).

The Australian study prompted a response from Alan C. Logan, a researcher in Yonkers, N.Y., who, in a letter to the editor, offered an alternative explanation for the study diet's favorable effects: the low-glycemic-load diet contained nearly 30% more fiber than the control diet, as well as substantially more polyunsaturated fats, both of which can decrease androgen levels (J. Am. Acad. Dermatol. 2007; 57: 1092-3).

SDEF and this news organization are wholly owned subsidiaries of Elsevier.

BY BRUCE JANCIN

Denver Bureau