Many causative dietary factors have been studied for their role in acne. These include glycemic index, dairy consumption, high and low carbohydrate diets, gluten-free diets, high protein diets, candida elimination diets, probiotics, multivitamins, chocolate, and more. Currently, the greatest body of evidence in the study of a clear skin diet exists in the role of a low glycemic index and a low dairy diet.
What’s the Glycemic Index?
Glycemic index (GI) is a scale that measures the rise in blood sugar as triggered by any particularly carbohydrate found in various foods and drinks. Further, researchers have refined the glycemic index as the glycemic load (GL), which takes into account the changes in blood sugar with a typical serving of a given food. A high GI food raises blood sugar quickly while a low GI food raises blood sugar slowly.
Low GI foods
- Green vegetables
- Raw carrots
- Bran cereals
Medium GI foods
- Multigrain bread
High GI foods
- White bread
How does the Glycemic Index affect the skin?
With respect to acne and particularly hormonal acne, there are many studies that have established a connection between GI and the severity of acne. High GI/GL diets lead to elevated levels of insulin, which the body secretes in response to sugar in the blood. As a result, this leads to increased levels of insulin-like growth factor (IGF-1). These molecules have been shown to increase oil production and shedding of skin cells, which leads to the plugging of the oil glands. They also increase the production of acne-causing hormones and their receptors, leading to increased hormonal activation of acne.
In clinical studies, it has been shown that patients on a low GI/GL diet have lower levels of acne-causing hormones, lower levels of oil production, and less clinically apparent acne. Additional studies have shown that many patients on low GI/GL diets are able to reduce their usage of oral and topical acne medications as well. Further, patients on specific diets such as the South Beach Diet and Mediterranean diet, both of which utilize low GI/GL principles, have had reduced acne.
Milk consumption has also been linked to acne pathogenesis. Similar to carbohydrates in other foods, carbohydrates in milk elevate insulin and IGF-1. Consequently, this increases acne formation through increased oil production, inflammation of the follicle, and increased acne hormones. Additionally, milk contains bovine IGF-1, which is identical to human IGF-1 and acts in a similar fashion.
Milk also contains several hormonal triggers of acne as well. Clinical studies have supported this connection. There are two large studies showing that all types of milk cause acne and one study showing that only skim milk causes acne. Importantly, whey protein in milk and in supplements have recently been shown to contribute to acne as well.
Treatment with vitamins and supplements
Lastly, there have also been small studies that suggest a role for certain vitamins and supplements in the treatment of acne. In one small study, the intake of omega 3 fatty acids resulted in acne improvement. In another study, the use of probiotics along with routine antibiotic treatment for acne resulted in lower acne lesion counts. Zinc, vitamin A, and vitamin D have also been studied, but the role of these vitamins in acne remains unclear. Nicotinamide, a derivative of vitamin B3, has also been used as a supplement to improve acne. There are several studies that support its use, though the studies are small and mainly observational. There is an FDA-approved combination of nicotinamide that contains folic acid, zinc, and copper and is purported to improve acne. However, caution must be taken with these supplements, as there have also been side effects reported with high dose supplementation.
Clear skin diet
At this time, the role of diet in acne treatment continues to be elucidated. There is increasing interest in specific dietary changes and the need for topical and oral medications. Further research remains to be done on specific subsets of acne, such as hormonal acne in adult women, and the role of diet on the microbiome and acne.
The greatest body of evidence exists for low GI/GL diets and some evidence exists for low dairy diets. Both interventions are considered an integral part of an approach to acne treatment. A clear skin diet may not treat all types of acne or may not be sufficient to treat moderate to severe acne. Further research is likely to reveal causative factors that can be implemented for integrative long term acne management. An experienced dermatologist can assess the severity of acne and tailor an approach that combines oral and topical therapies along with diet and lifestyle management.