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Reducing carbohydrate consumption, not glycemic index, lowers glycemia in adults
Reducing carbohydrate content in the diet may lead to greater success in lowering glycemia in adults at risk for diabetes compared with reducing glycemic index of foods, according to study findings recently published in BMJ Open Diabetes Research & Care.
Stephen P. Juraschek, MD, PhD, research and clinical fellow in general internal medicine at the Johns Hopkins University School of Medicine, and colleagues evaluated data from OmniCarb trial on 163 adults (mean age, 53 years) with overweight or obesity (mean BMI, 32 kg/m2) to determine the effects of glycemic index and carbohydrate content on glucose homeostasis and inflammation. All participants consumed four diets in random order that varied by glycemic index ( 65 vs. 45) and carbohydrate amount (40% vs. 58% kcal): high carbohydrate and high glycemic index; high carbohydrate and low glycemic index; low carbohydrate and high glycemic index; or low carbohydrate and low glycemic index. Each of the four diets were consumed for 5 weeks with 2-week washout periods.
Glycated albumin and fructosamine were not affected by reducing glycemic index, regardless of carbohydrate content. Fasting glucose was increased in the low glycemic index and low carbohydrate diet compared with the high glycemic index and low carbohydrate diet (P = .02). Fasting insulin was not affected by reducing glycemic index.
Glycated albumin was decreased in the high glycemic index and low carbohydrate diet (P = .03), and fructosamine was reduced in the low glycemic index and low carbohydrate diet (P = .003). Glycated albumin (P = .04) and fructosamine (P = .01) were decreased when dietary carbohydrate was reduced and glycemic index was simultaneously increased.
“We found that reducing [glycemic index] increased fasting glucose, particularly in the setting of a low-carbohydrate diet. However, these increases in fasting glucose had little influence on markers of 2- to 3-week glycemia, glycated albumin and fructosamine, likely because of the opposite direction of effects conferred by reducing postprandial glycemia from the reduced [glycemic index] diet,” the researchers wrote. “In contrast, reducing the amount of dietary carbohydrate generally reduced glycated albumin and fructosamine, suggesting that reducing dietary carbohydrate may represent a more effective strategy than reducing [glycemic index] for lowering glycemia in overweight or obese adults.” – by Amber Cox
Disclosure: The researchers report no relevant financial disclosures.