What is the role of diet in adult acne in adolescents to adults?

• Given the current data, no specific dietary changes are recommended in the management of acne.
• Emerging data suggests that high glycemic index (GI) diets may be associated with acne. 
• Limited evidence suggests that some dairy, particularly skim milk, may influence acne.

Emerging evidence suggests that high glycemic index diets may be associated with acne. In 2007, a randomized controlled trial with 23 Australian males 15 to 25 years of age examined the impact of a low glycemic diet on acne. Those randomized to follow the low glycemic load (LGL) diet had significant improvement in acne severity, a significant reduction in weight and body mass index (BMI), a significant decrease in free androgen index, and improved insulin sensitivity at the end of 12 weeks.¹⁵⁷ The study was limited by its small sample size and the fact that both groups lost weight. In 2012, a 10-week randomized controlled trial was conducted in 32 Korean subjects (24 men and 8 women) 20 to 27 years of age. Those randomized to the LGL diet had a statistically significant improvement in acne severity and no change in weight and BMI. Histologic analyses were conducted, and the authors found that the size of the sebaceous glands were significantly reduced in the LGL group, whereas hematoxylin–eosin stains revealed a decrease in inflammatory cells and additional stains showed a decrease in inflammatory cytokines.¹⁵⁸ Although these 2 studies are the most rigorous to date analyzing the effect of glycemic index diets on acne, a small number of studies further support this association.^159-161,311

While no randomized controlled trials have been conducted to examine the role of dairy consumption and acne, several observational studies suggest that certain dairy products, especially skim milk, may aggravate acne. In 2005, a retrospective study analyzed data from 47,355 adult women who were asked to recall their high school diet. They were also asked to recall if they had “physician-diagnosed acne.” In this study, acne was positively associated with the reported quantity of milk ingestion. The strongest association was noted with skim milk. Specifically, women who consumed ≥2 glasses of skim milk a day had a 44% increased risk of reporting acne.³¹² This study was heavily criticized for its retrospective design, so the same research group conducted 2 follow-up, prospective studies. The first was conducted on a cohort of girls, and found that acne was associated with total milk intake, whole milk, low-fat milk, and skim milk.¹⁶² The second study focused on boys only, and found that acne was associated with the intake of skim milk only.¹⁶³ More recently, a case control study involving 88 Malaysian subjects 18 to 30 years of age found that the frequency of milk and ice cream consumption was significantly higher in patients with acne compared to controls.¹⁶¹ Dermatologist-assessed subjects who consumed milk or ice cream ≥1 time per week had a 4-fold increased risk of having acne. No association was found with cheese or yogurt. Also in 2012, another case control study involving 563 Italian subjects 10 to 24 years of age found that the risk of acne was also increased with milk consumption.¹⁶⁴ The association was more marked with skim milk, and again no association was seen with cheese or yogurt.

Although some small preliminary studies have examined the role of antioxidants (including oral zinc³¹³), probiotics,³¹⁴ and fish oil³¹⁵ on acne, the existing evidence is not strong enough to support any recommendations regarding these dietary factors at this time.

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• Role of diet in acne
• More from the acne guideline