Diet and Acne

A Q&A with renowned acne expert Dr. Whitney Bowe

Advances in acne treatments have been few and far between over the years, leaving more than 50 million people in the U.S. suffering from the condition. Is it time we began approaching treatment from a new perspective? Our 3-part conversation with dermatologist and acne expert Whitney Bowe, M.D., sheds light on very new findings regarding this persistent skin condition. In Part 1 of our Q&A with Dr. Bowe we look at underlying causes of acne.

What are some of the most common misconceptions about the causes of acne?

Myths surrounding acne are almost as ubiquitous as the skin problem itself.  Many people think that dirt causes acne, which leads them to use abrasive cleansing techniques that make the condition worse.  Another common misconception is that acne is contagious; you can’t “catch” acne by getting close to someone with acne or using her makeup brushes.  Yet another myth is that wearing makeup or moisturizer causes or exacerbates acne, but that’s definitely not true!  You just have to select the right products (I tell my patients to look for words like non-comedogenic, non-acnegenic).

What role does diet play in the cause and treatment of acne?

Although initially considered controversial, recent studies have prompted dermatologists to revisit the link between diet and acne.  The strongest evidence to date suggests that foods with a high Glycemic Index (GI) can exacerbate acne.  Certain dairy products, particularly skim milk, are also linked with acne.  Some smaller, preliminary studies suggest a possible role for probiotics, certain types of fish oil, and antioxidants in the treatment of acne as well.  Although dietary modifications can make a difference in an individual’s acne, they are only a small part of the treatment plan and meant to be used in conjunction with tried and true therapies.

Tell me more about Glycemic Index and how it factors into acne.

Diets that include many foods that are high on the Glycemic Index (GI) appear to exacerbate acne.  The GI has to do with a food’s potential to increase blood glucose and insulin.  Ingestion of high-GI foods triggers a cascade of endocrine responses that may promote acne through androgens, growth hormones and cell signaling pathways.  Foods with a GI of less than 55 are Low – I encourage patients with acne to consider adding these foods to their diet.  Foods with a GI of more than 70 are High—I recommend avoiding these foods when possible.

How can dairy affect acne?

Certain dairy products may make acne worse, especially skim milk. Although the mechanism remains unclear, hormones and/or growth factors in dairy products might be the culprit.  Ingestion of milk, and skim milk in particular, is associated with high blood levels of a growth hormone called insulin-like growth factor 1 (IGF-1).  If a patient believes that certain dairy products might be aggravating his or her acne, I encourage that person to try some dairy-free alternatives that also have a low GI.  Almond milk has a low GI (30), is low calorie and cholesterol-free. In my patients who choose to eliminate dairy altogether, I make sure they supplement with calcium and vitamin D.

If diet is indeed linked to acne, how might gut flora relate to acne?

There appears to be enough supportive evidence to suggest that gut microbes, and the integrity of the gastrointestinal tract itself, are contributing factors in the acne process and the maintenance of healthy skin. Here are some steps that are involved in what I like to call the “gut-brain-skin axis:”

• Psychological distress alone, or in combination with processed foods devoid of fiber, can slow gut motility and alter the GI flora.  This has been shown to lead to increased intestinal permeability (a “leaky gut”).
• An unhealthy or leaky gut results in a cascade of events that affects the skin.  Not only are markers of systemic inflammation increased, but substance P (a molecule that leads to inflammation and oil production) is also elevated, and insulin sensitivity is decreased.
• This cascade is thought to exacerbate acne and result in irritated, inflamed skin.

How can probiotics help acne?

Probiotics help restore the normal intestinal barrier, decreasing inflammation and halting that detrimental cascade of events described above.  Probiotics and their metabolites also interact with what’s called the Gut Associated Lymphoid Tissue, or GALT.  This lymphoid tissue makes up 70 percent of the body’s immune system. That interaction is critical in how the immune system responds to pathogens, allergens or commensal bacteria in the future.  Oral probiotics have been shown to regulate the release of inflammatory molecules (cytokines) within the skin, particularly IL-1 alpha (interleukin 1 alpha).  Oral probiotics have also been shown to reduce insulin resistance, which we now know plays a role in acne.