John McDougall, M.D., wrote an article called “Acne Is Caused by Diet, Especially Dairy Products” in his March 2011 newsletter. Although it has long been debated whether or not diet plays a role in acne, Dr. McDougall wrote about two studies that clearly show the connection. The typical Western diet does aggravate acne.
A study published in November 2010 in the European Journal of Dermatology examined the diets of 783 Koreans with acne to see if their outbreaks were aggravated by certain foods. Researchers concluded “A high glycemic load diet, dairy food intake, high fat diet, and iodine in Korean foods appear to play a role in acne exacerbation.”
It seems that avoiding pizza and chocolate bars was sage advice after all.
Why is this? The answer may be in an article published by B.C. Melnik and G. Schmidt, which Dr. McDougall referenced in his e-letter. These researchers explained the systemic changes which result from eating high-glycemic foods as well as foods containing dairy.
When you eat a diet high in sugar, it causes your insulin levels to rise. These foods include highly processed foods, including junk food, which convert to sugar and cause surges of insulin in the blood stream. High levels of insulin create inflammation throughout the body. Since acne is an inflammatory disease of the skin, anything that increases inflammation should be avoided.
These same highly processed foods (sometimes called refined carbohydrates) cause an increase in the growth hormone “insulin-like growth factor-1 (IGF-1).” An increase in IGF-1 has also been shown to encourage acne growth.
Dairy products affect hormones in two ways that contribute to skin problems. First, dairy contains a milk protein that causes IGF-1 to rise. Fat is not to blame, because studies show there are increases in insulin-like growth factor regardless of whether you drink whole milk or a low-fat version.
The same milk protein promotes a rise in androgen levels. Although a male hormone, androgens are present in women and men (girls and boys). Androgens cause an increase in oils and sebum (a greasy substance in the pores)—a perfect environment for bacteria growth, which often leads to breakouts and acne.
If you are concerned about your skin, particularly if you are plagued by teen or adult acne, consider removing dairy from your diet. Know that if you are eating a Western diet, which is high in fat, sugar, meat, dairy, and junk food, its inflammatory properties are likely affecting the condition of your skin.
1. Jung JY, Yoon MY, Min SU, Hong JS, Choi YS, Suh DH. The influence of dietary patterns on acne vulgaris in Koreans. Eur J Dermatol. 2010 Nov-Dec;20(6):768-72.
2. Melnik BC, Schmitz G. Role of insulin, insulin-like growth factor-1, hyperglycaemic food and milk consumption in the pathogenesis of acne vulgaris. Exp Dermatol. 2009 Oct;18(10):833-41.