VANCOUVER, B.C. – Mounting evidence suggests that consuming a low glycemic index diet can substantially improve acne, according to Dr. Hyuck Hoon Kwon.
The approach has held up in several small-scale randomized clinical trials, earning it a grade of 1B last year from the American Academy of Dermatology, noted Dr. Kwon of Seoul National University in South Korea.
“Dermatologists can recommend dietary modification to patients, and can advise them to avoid foods that they believe worsen their acne,” Dr. Kwon said at the World Congress of Dermatology. He said he has seen clinically meaningful reductions in acne lesions as soon as 4 weeks after patients cut their intake of refined carbohydrates and other high glycemic index (GI) foods, although results can take up to 12 weeks, and more studies of time to effect are needed.
Scientists and clinicians have long debated the role of diet in the pathogenesis of acne, and until recently, there were no randomized, controlled trials or meta-analyses of the topic. But observational studies have repeatedly documented “astonishingly” low rates of acne in cultures with “traditional” diets that are lower in refined carbohydrates and fat than typical Western fare, said Dr. Kwon.
In one study of 1,285 individuals in Korea, those who did not have acne reported consuming significantly higher amounts of fish and yellow, leafy green, and cruciferous vegetables, while those with acne ate significantly more instant noodles, processed cheeses, and “junk” foods, he noted (Eur. J. Dermatol. 2010;20:768-72).
In another trial, Dr. Kwon and colleagues randomized 32 individuals with mild to moderate acne to either a low-GI diet that emphasized beans, barley, vegetables, fish, and whole-grain breads, or to a high-GI control diet (Acta Derm. Venereol. 2012;92:241-6). The low-GI group ate more protein to replace calories lost from cutting carbohydrates. At 10 weeks, the groups had similar mean calorie intakes and body mass indices, but the low-GI group had reduced its dietary glycemic load from baseline and had significantly fewer inflammatory and noninflammatory acne lesions compared with baseline and with the high-GI group, Dr. Kwon said. The low-GI group also had significant decreases in total average area of sebaceous glands, and decreased expression of sterol response element-binding protein-1 (SREBP-1), which stimulates lipogenesis in sebocytes.
Most recently, scientists have explored the molecular mechanisms linking diet to acne, Dr. Kwon noted. High GI diets trigger chronic hyperinsulinemia, which impairs the ability of FoxO1 transcription factor to mediate androgen receptor signaling, oxidative stress, lipogenesis, and sebaceous gland homeostasis. Importantly, FoxO1 inhibition also is associated with activation of mTORC1, which promotes lipid and protein synthesis, sebaceous gland hyperplasia, and sebaceous lipogenesis, he said.
Dr. Kwon reported having no relevant conflicts of interest.