Diet and Acne Redux

The science of nutrition has produced dramatic findings over the past few decades. Of particular note is the expansion of knowledge about essential fatty acids during the 1980s. Also, profound changes in the concept of daily nutritional requirements find the United States replacing "recommended daily allowances" with "dietary reference intakes." This reflects the consideration of optimal nutrient levels rather than minimum daily requirements. The vitamin paradigm changed forever when neural tube defects declined radically with folic acid supplementation.¹ No longer do we think only of preventing nutritional deficiency diseases. Now we are learning to provide optimal nutrient intake for optimal function.

Cardiologists have embraced this concept and now prescribe vitamin B₁₂, vitamin B₆, and folate to bring down elevated homocysteine levels in patients at risk for stroke and myocardial infarction.² Although causality has not been proved, study findings are highly suggestive, and supplementation carries few risks. The American Heart Association also acknowledges the benefit of daily fish oil supplementation for some patients.³ However, few physicians in other fields seem to take advantage of recent discoveries in nutrition and apply them clinically.

Dermatology has been particularly tied to older nutrition dogma with regard to acne and diet. The article by Cordain et al⁴ in a recent issue of ARCHIVES should serve to awaken us to the relevance of nutrition to skin disease and stir us to review the dogma. The major textbooks of dermatology tend to view diet as irrelevant to the treatment of acne. The primary references to which the texts refer are both more than 30 years old.^{5 - 6}

In 1971, Anderson⁵ observed 27 college students on a "typical high-carbohydrate dorm diet." The students believed that specific foods caused inflammatory flares within 3 days of ingestion. They received the culprit foods on a daily basis and returned daily for facial mapping of lesions. None flared. While the uniformity of response was impressive, the study had a few glaring flaws. The sample size was fairly limited. The study was neither controlled nor blinded. The article was not peer reviewed by dermatologists (published in the American Family Physician). Most importantly, given the effects of chronically elevated insulin posited by Cordain et al,⁴ the baseline diet may have obscured the findings.

In 1969, Fulton et al⁶ explored the effect of chocolate on acne by using "pseudo-chocolate" bars made with 28% partially hydrogenated vegetable oil as the control. With our 2002 lens, we can see that the high proportion of trans fats in the control bar limits the usefulness of the study. Trans fats compete with essential fatty acids in the production of prostaglandins and appear to significantly contribute to inflammation.⁷

In the nutrition literature, evidence supporting dietary effects on health continues to mount, and dermatology is no exception. Many of our patients' skin conditions are affected by what they eat. It may be time for us to open our minds and our nutrition textbooks.