Acne and Diet: Does Carb Intake Play a Role?
Acne is often a concern among adolescents, teenagers and, increasingly, adults — particularly women. While this chronic inflammatory condition associated with oily skin may not last a lifetime, acne pustules and cysts can leave red marks and mild to deep pitting that, unless treated, can be carried into old age.
A Historical Look
While acne sufferers in the past were advised they’d “grow out of it,” modern dermatology has several effective therapies, ranging from topical medications that target sebum or the bacteria that colonize or infect the skin, to hormonal therapies such as oral contraceptives. For stubborn cases, isotretinoin (Accutane), an orally administered vitamin A derivative, is very effective at reducing the production of sebum that leads to acne but has side effects that can be severe, including an elevated risk of birth defects if used by pregnant women.
During the 1960s and 1970s, the consumption of chocolate and greasy foods was believed to contribute to acne. It was subsequently determined that acne has a genetic cause and the possibility of any relationship of diet to the disease was prematurely discarded.
“The prevalence of adult acne in the US appears to be increasing over the last few decades,” Shereen. N. Mahmood, MD, and Whitney. P. Bowe, MD, observe in a recent review. “We are well aware that genetics can strongly influence a patient's risk of developing acne. However, significant changes in germline genetic variants are unlikely to have occurred over the last 20 years.”1
Although acne in one’s teens is usually at its worst among males as opposed to females (which is blamed on the onset of high levels of androgenic hormones that play a strong role in the disease), acne often continues into adulthood in women, or can make its first appearance then.2
Acne and Carbohydrate Metabolism
While a condition characterized by polycystic ovaries and infertility in women was described in 1935 by Irving F. Stein, Sr. and Michael L. Leventhal, formal diagnostic criteria for the condition now known as polycystic ovary syndrome (PCOS) were not proposed until the 1990s at a National Institute of Health sponsored conference. “It is now accepted that it is multifactorial, partly genetic; however, a number of candidate genes have been postulated,” write Dorota Szydlarska and colleagues in 2017. “Insulin resistance has been noted consistently among many women with PCOS, especially in those with hyperandrogenism, but it is not included in any of the diagnostic criteria. Now there is strong evidence that cardiovascular disease risk factors and disturbances in carbohydrate metabolism are all increased in patients with PCOS compared to the healthy population.”3
Polycystic ovary syndrome is characterized by multiple ovarian cysts, irregular menstrual periods, infertility, obesity, insulin resistance, hirsutism, scalp hair loss, acanthosis nigricans, and acne. However, PCOS may be a misnomer. A significant percentage of women who appear to have the condition have normal-looking ovaries. And while obesity has been hypothesized as a driver of the condition, lean women also have PCOS. Nevertheless, obesity and/or insulin resistance are closely involved with the condition, although researchers aren’t sure whether they are a cause or an effect.
In an article titled, “Acne vulgaris: The metabolic syndrome of the pilosebaceous follicle,” B. C. Melnik notes that acne vulgaris is primarily a disease of wealthy countries and is more prevalent in developed than in developing countries. The article states that “No acne has been found in non-Westernized populations still living under Paleolithic dietary conditions constraining hyperglycemic carbohydrates, milk, and dairy products”. It further explains that Western diets over-activate mTORC1, “the key conductor of metabolism”, and that increased mTORC1 signaling is a “characteristic feature of insulin resistance, obesity, type 2 diabetes mellitus, cancer, and neurodegenerative diseases”.4
In 2007, a trial reported in the American Journal of Clinical Nutrition reported a reduction in total acne lesion counts and improved insulin sensitivity among male acne sufferers assigned to low glycemic load diets for 12 weeks days in comparison with participants who were assigned to consume carbohydrate-dense foods.5 And in a study involving 64 New York residents among whom half had moderate to severe acne, it was found that acne patients had a greater total carbohydrate, available carbohydrate, percent energy from carbohydrate and glycemic load intake compared to those without the disease.6 The acne group also had higher insulin and insulin-like growth factor-1 levels, and increased insulin resistance.
The increase in glucose and consequent rise in insulin among individuals who consume high amounts of carbohydrates can increase the production of testosterone in the ovaries, which causes acne and other PCOS symptoms. In addition to avoiding the consumption of excessive carbohydrates by following a low glycemic index diet, acne sufferers may also wish to avoid foods that contain significant amounts of testosterone or its metabolite dihydrotestosterone. According to dermatologist Norman Orentreich, MD, these include wheat germ, peanut and corn oils.
In 137 women with PCOS who had menstrual abnormalities and/or acne and/or mild hirsutism and insulin resistance, supplementation with myo-inositol or D-chiro-inositol helped regulate their menstrual cycles and improved acne, endocrine and metabolic parameters, and insulin resistance.7 Another trial, which investigated the effects of daily chromium supplementation in women with PCOS, found a significant decrease in the prevalence of acne and other PCOS characteristics in women who received the mineral compared with a placebo group.8 And in a 10-week randomized trial involving 45 participants with mild to moderate acne, there was a reduction in inflammatory and noninflammatory acne lesions in association with supplementation with the omega 3 fatty acids EPA and DHA, as well as the omega 6 fatty acid GLA, in comparison with a control group.9
Although iodine is an essential mineral, prolonged intake of high doses can result in acne in those who are predisposed. Acne sufferers are advised to stick to the current recommended daily allowance of iodine if they find that higher amounts aggravate their condition.
Diet and Acne
“Does diet really affect acne?” H. R. Ferdowsian and S. Levin ask in a recent view. “Prospective studies, including randomized controlled trials, demonstrated a positive association between a high-glycemic-load diet, hormonal mediators, and acne risk. Based on these findings, there exists convincing data supporting the role of dairy products and high-glycemic-index foods in influencing hormonal and inflammatory factors, which can increase acne prevalence and severity.”10
While we can’t do anything (yet) about genetic predispositions, following a low glycemic index diet designed to minimize spikes in glucose and insulin could go a long way toward reducing acne as well as overweight and obesity, hypoglycemia and diabetes, and other conditions associated with insulin resistance.