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Interviewee: Historically, dietary advice was a very standard part of acne therapy and all the dermatology textbooks used to teach dermatologists to discourage chocolates, fats, sweets, carbonated beverages in our acne population.

However, recently, in the last few decades, we have a lot of evidence supporting the link between diet and acne. And specifically with regards to high glycemic index foods, dairy, and anti-oxidants. So, as far as the high glycemic index foods goes, foods that have a high glycemic index, for example, white bread, white rice, white pasta, corn flakes, chips, white french fries, things like that, are thought to stimulate and make acne worse. Thought to exasperate acne.

Whereas low glycemic index foods are thought to be protective against acne. Dairy has also been correlated with acne. In specific, actually in particular, skim milk has been shown to influence acne. And lastly anti-oxidants have been shown to be somewhat protective against acne. There are very few small, preliminary studies that show encouraging results that using anti-oxidants either topically, or through oral supplementation, through pills, or through our diet can actually protect against the inflammation that's linked with acne.

Interviewer: Can you give me more details about anti-oxidant.

Interviewee: So, with the anti-oxidants, there's some studies supporting some stable vitamin C precursors. One example is something called sodium ascorbyl phosphate. Green Tea, Lycopene is found in tomatoes. And zinc and nicotinamide are two nutrients that have been shown to support anti-oxidant pathways. Those are the anti-oxidants that have been studied to give us some insight into the fact that their supplementation might actually benefit acne.

Interviewer: Okay. What is the making of this antioxidant?

Interviewee: So, reactive oxygen species, free radicals, and oxidative stress is thought to play a role in the initiation of acne. And patients with acne actually have higher levels of the kind of markers of inflammation. Whereas they actually have lower levels of antioxidant enzymes, and antioxidant vitamins like A and E in their blood, if you detect it in acne patients.

So, there appears to be an oxidative burden in acne that's significant. So, by trying to replenish that store of anti-oxidants we might be kind of quelling some of that inflammation that's predisposing to acne. There are three critical studies, really, analyzing the link between dairy and acne.

So, the first one was a retrospective study, in which over 47,000 adult women in the nurse's health study were examined and they found that women who consumed two or more glasses of skim milk a day, actually had a 44% increased risk of having acne. Now that study was criticized for its retrospective design.

So, that group actually set out to uphold their studies using prospective studies designs. So, they did two follow up studies, one in girls and one in boys. And they found that in one of the studies, acne was associated with all forms of milk ingestion. Whereas in one of the other studies, acne was associated with only with the ingestion of skim milk in particular.

Now, we don't fully understand the mechanism behind that association, but hormones might play a role. Milk is known to contain both testosterone and dihydrotestosterone precursors. And insulin like growth factor, and growth factors might also be at play. The ingestion of milk, and actually skim milk in particular, has been correlated with increased levels of insulin like growth factor one, which is actually thought to promote acne through, promote sebaceous gland secretion, and promote keratinization that leads to acne.

I consider that the best evidence to date, linking glycemic index and acne. It was an Australian study, in which acne, males who had acne, I think they were around 15 to 25 years old, they followed a very strict low-glycemic load diet for a period of twelve weeks. And after that twelve week period, the authors noted significant improvement in their acne severity.

They had improvement in their insulin sensitivity, they had a decrease in their free androgen index, and they also had a decrease in their weight and their body mass index, their BMI. And that was a very well-designed study. They had a randomized control trial design. The authors took multiple measures to ensure compliance, with that kind of dietary regiment. It was a very well-done study with very interesting results.

Interviewer: Okay. To finish what is your message for dermatologists.

Interviewee: Yes, I think the take home message at this point is that we can no longer look our patients in the eye and say that diet has no effect on acne. Clearly, what we're learning is that diet does play a role. At this point, we can steer our patients towards a low-glycemic load diet and try to steer them away from skim milk, but other than that, I think there's a lot that remains to be learned.

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Does Diet Influence Acne?

Dr. Whitney Bowe discusses the effects diet may have on acne.