‘Quality of carbohydrate matters’ in lowering diabetes risk
High-quality carbohydrates, particularly whole grains, lowered the risk for type 2 diabetes, according to data presented at Nutrition 2020 Live Online.
“Previous studies have examined associations between carbohydrate intake and type 2 diabetes risk,” Shilpa N. Bhupathiraju, research scientist at Harvard T.H. Chan School of Public Health, told Healio Primary Care. “We wanted to specifically examine if the association between carbohydrate intake and type 2 diabetes risk differed by the quality of the carbohydrate and by the nutrient it replaced in the diet.”
Researchers analyzed dietary data from more than 200,727 participants who were enrolled the Nurses’ Health Study, Nurses’ Health Study II and Health Professionals Follow-up Study. Collectively, their analysis represented almost 4 million years of follow-up.
Bhupathiraju and colleagues identified 11,872 documented cases of type 2 diabetes in their analysis. They found that replacing 5% of energy from saturated fat with 5% of energy from low-quality carbohydrates — refined grains, sugary foods, and potatoes — was associated with a higher type 2 diabetes risk (HR = 1.05; 95% CI, 1-1.09). However, substituting 5% of energy from saturated fat with high- quality carbohydrates, such as whole grain bread, brown rice, rye, barley and quinoa, was associated with a lower type 2 diabetes risk (HR = 0.93; 95% CI, 0.87-0.99).
Further, isocaloric substitution of other macronutrients with low-quality carbohydrates was not associated with type 2 diabetes risk. Conversely, isocaloric substitution of high-quality carbohydrates was associated with lower type 2 diabetes risk when the replacement nutrient was monounsaturated fat (HR = 0.88; 95% CI, 0.83-0.94), animal protein (HR = 0.88; 95% CI, 0.83-0.93), vegetable protein (HR = 0.9; 95% CI, 0.84-0.96), trans fat (HR = 0.9; 95% CI, 0.85-0.97) and polyunsaturated fat (HR = 0.92; 95% CI, 0.86-0.98).
“When individuals consume a low fat diet, the replacement nutrient is almost always low quality or refined carbohydrates that our study shows to be associated with a higher risk for type 2 diabetes,” Bhupathiraju said. “The quality of carbohydrate matters.”
In a press release, study co-author Kim Braun, PhD, of Erasmus University Medical Center and Harvard T.H. Chan School of Public Health, encouraged similar studies in people with various socioeconomic backgrounds, ethnicities and age to “provide insight into how applicable these findings are for other groups.”