Research on the role of diet in acne has gone back and forth, said Dr Linda F. Stein Gold, MD, FAAD, at the beginning of her presentation. In the 1940s and 1950s, diet was considered really important in influencing acne. However, some small studies, conducted later, that showed no association and changed the entire mindset of the field. It was not that long ago, said Dr Stein Gold, that the role of diet in acne was considered a myth. Now research is coming back around, and diet and acne really might have something to do with each other, she added.
Dr Stein Gold reviewed the current acne treatment guidelines, which stated that given the current data there is no specific dietary recommendation that can be made for acne, but there is emerging data that high glycemic diets and dairy, particularly skim milk, may influence acne.
One of the studies that changed the minds of investigators was the examination of 2 non-westernized civilizations that had a very strict healthy diet, low glycemic diet, with no consumption of dairy, alcohol, caffeine, or sweets, who did not have acne. At first it was thought that maybe something they ate influenced the low incidence of acne, but there are other factors that could have influenced why they did not have acne, said Dr Gold Stein.
One factor is glycemic index of foods. Glycemic index is based on sugar load in the system, measured by its effects on blood glucose levels. Foods that are high glycemic raise glucose. However, milk is not a high glycemic index food, suggesting there are other reasons it influences acne.
Consuming high glycemic food increases both glucose and insulin growth factor type 1 (IGF-1). Why do we care? asked Dr Stein Gold, because IGF-1 increases androgens and sebum production.
A study from Australia found eating a low glycemic diet showed statically significant improvement in acne, but also found participants lost weight, had less IGF-1, and decreased inflammation in terms of acne in images before and after initiating the diet. A small Korean study showed low glycemic diet improved the acne and sebaceous gland size was starting to decrease in biopsies, said Dr Stein Gold. She also discussed a Cochrane review that assessed the quality of the data. Overall, the data is not that good, she said, but there is limited evidence that a healthy diet improves acne.
There is conflicting data on the effects of dairy on acne, said Dr Stein Gold. She discussed the results from a nursing study that included about 47,000 women who completed food questionnaires. The study showed strong associations between acne and certain dairy products, specifically milk and skim milk.
A meta-analysis also found an association between dairy and acne in low-quality studies. Dairy overall influenced acne, skim milk, and total milk had positive associations, along with low fat milk, she said. In addition, there was a dose-response relationship. What is the bottom line? Dairy seems to, milk seems to, but what does not have an association are yogurt and cheese, said Dr Stein Gold, which suggests “we cannot make a blanket statement regarding dairy and acne.”
According to Dr Stein Gold, there are hormonal mediators added to milk, specifically IGF-1 and whey protein. Case reports showed 5 men who were body builders developed acne while using whey protein supplement. Another showed young men with acne did not experience reduction in acne until stopping whey protein supplementation. A study in Brazil showed rapid acne development in 30 young athletes with whey protein use.
When talking to patients, Dr Stein Gold does not recommend telling adolescents to stay away from milk because the data is not strong enough. However, she does recommend patients eat a healthy diet and avoid foods that appear to exacerbate acne.
Stein Gold LF. Diet and acne. Presented at: the 2019 American Academy of Dermatology Summer Meeting; July 25-28, 2019; New York, NY.