A low glycemic index (GI) and glycemic load (GL) diet decreases IGF-1 concentrations, a well-established risk factor in the pathogenesis of acne pathogenesis, research published in the Journal of the Academy of Nutrition and Dietetics has found, indicating that such diets have the potential to reduce the impact of acne.
“Further research of a longer duration should examine whether a low GI and GL diet would result in a clinically meaningful difference in IGF-1 concentrations leading to a reduction in acne,” the researchers concluded.
As a high glycemic index (GI) and glycemic load (GL) diet is believed to stimulate acne pathways by influencing biochemical factors associated with acne, U.S. researchers set out to examine changes in biochemical factors associated with acne among adults with moderate to severe acne after following a low GI and GL diet for two weeks compared with those who continued to follow their usual diet.
A total of 66 patients were randomly allocated to the low glycemic index and glycemic load diet (34 patients) or usual eating plan (32 patients).
After two weeks, IGF-1 concentrations had decreased significantly among patients who followed a low GI and GL diet, falling from 267.3±85.6 ng/mL to 244.5±78.7 ng/mL) (P=0.049). However, there were no differences in changes in glucose, insulin, or IGFBP-3 concentrations or insulin resistance between the two groups. Carbohydrate (P=0.019), available carbohydrate (P<0.001), percent energy from carbohydrate (P<0.001), GI (P<0.001), and GL (P<0.001) decreased significantly among participants following a low GI/GL diet over the same period, but there were no differences in changes in body composition between the two groups.
Researcher Jennifer Burris, of the Department of Nutrition and Food Studies, New York University, said that this short-term randomised controlled trial found that a low glycemic index and glycemic load diet decreased IGF-1 concentrations among male and female adults with moderate to severe acne after two weeks, demonstrating the important effects a low GI and GL diet had on factors related to acne and the potential for nutrition therapy to influence acne pathogenesis.
“Our results…suggest medical nutrition therapy may be a viable treatment option for patients with acne, due to the diet-induced endocrine effects on acne-promoting pathways,” she said and “may aid researchers in designing future interventions focused on improving acne.”
Glycemic xinde and glycemic load are believed to play a role in the pathophysiology of acne predominately by influencing insulin metabolism. “Studies have suggested that hyperinsulinemia increases IGF-1 concentrations, which simultaneously increase androgen production and inhibit IGFBP-3 concentrations,” Dr. Burris said.
IGF-1 is a mediator of cellular growth and may amplify acne by stimulating androgen synthesis, sebocyte growth, and lipogenesis of sebaceous glands. Androgen hormones are well-established factors in acne development, stimulating keratinocyte proliferation, sebum production, and sebaceous gland growth. Suppressing IGFBP-3 may increase the bioavailability of IGF-1, amplifying acne development.
“Treatment with IGF-1 provokes acne development, and polymorphisms of IGF-1 are linked to a predisposition to acne, possibly due to higher circulating IGF-1 concentrations,” Dr. Burris added.
More recently it has been suggested that diet-induced hyperinsulinemia may promote acne at the cellular level by stimulating IGF-1 concentrations and activating the phosphoinositide-3-kinase/Atk pathway, which may reduce the nuclear localization of the forkhead Fox-O1 transcription factor.
Reduced forkhead Fox-O1 increases the activity of the androgen receptor and decreases the activity of the nutrient-sensitive kinase mammalian target of rapamycin complex and sterol regulatory element-binding protein. “Therefore, dietary GI and GL may aggravate acne development by activating mammalian target of rapamycin complex and stimulating keratinocyte proliferation and differentiation, androgen signaling, and lipid synthesis,” she said.
Decreased sterol regulatory element-binding protein concentrations may additionally influence acne by amplifying sebocyte growth and inducing sebaceous lipogenesis.
“In addition to confirming our findings, future research should consider including a longer duration to examine the effect of a low GI and GL diet on biochemical factors associated with acne and acne development, including the number of acne lesions and acne severity,” she said.
Burris J, Shikany JM, Rietkerk W, Woolf K. A low glycemic index and glycemic load diet decreases insulin-like growth factor-1 among adults with moderate and severe acne: a short-duration, 2-week randomized controlled trial. J Acad Nutr Diet. doi: 10.1016/j.jand.2018.02.009