If you see adolescents and young adults in your practice, you are managing complaints about acne. Acne pathogenesis is related to sebum production, occlusion of skin follicles, bacteria (Propionibacterium acnes), and inflammation. The social impact of this condition can be profound.
I would be fascinated to hear how my clinical practice colleagues address the issue of diet. One would envision that it ranges from avoiding the topic altogether to a "diet is everything" counseling session.
So who is right?
Registered dietitian Jennifer Burris and her colleagues recently published a brilliant systematic review on this topic (J. Acad. Nutr. Diet. 2013;113:416-30), providing luminescence to a debate plagued with more heat than light.
They remind us that the earliest research in the field pointed to an association between acne and chocolate, sugar, and fat. Causality was hypothesized to be related to the effect of these foods on skin oil production. Food restriction was, therefore, part of treatment approaches.
This was subsequently challenged in the 1960s by two studies that suffered from significant methodologic limitations. Shockingly, these studies became highly cited and profoundly influenced our medical culture. The relationship between acne and diet was not studied for another 40 years!
But now we have new and stronger data on the topic. Recent studies have observed an association between milk consumption and acne. Other studies have suggested a link between acne and food with a high glycemic index (GI) or glycemic load (GL).
Recall that the GI is a measure of how quickly blood sugar level rises after eating a particular type of food. The GL takes into account the actual amount of carbohydrate consumed by multiplying the GI by the carbohydrate content of the actual serving. Low-GL diets reduce hyperinsulinemia and have been associated with decreased total and inflammatory acne lesions. Online tools are available to determine the GI/GL of foods.
The authors conclude that epidemiologic, observational, and experimental evidence suggests an association between diet and acne. The link between dairy and acne remains unclear and may be due to milk, milk protein, or the effect of milk on insulin levels. The link between GI/GL appears to be stronger. Importantly, diet appears to affect the severity of acne rather than cause it.
So, if we are not doing so already, it now seems reasonable and evidence-based to counsel our patients on medical nutrition therapy to reduce the severity of acne. Many of our patients might be highly motivated to do so to treat this condition.
This column, "What Matters," appears regularly in Internal Medicine News. Dr. Ebbert is professor of medicine and a primary care clinician at the Mayo Clinic in Rochester, Minn. He reported having no relevant financial conflicts. The opinions expressed are those of the author.