Carbohydrate Quality Is Independently Associated with Cardiometabolic Risk in Chinese Individuals with Impaired Glucose Tolerance

Background/Objectives: Dietary manipulation with carbohydrate restriction has been extensively investigated in diabetes prevention programmes. Carbohydrate (CHO) quality, rather than quantity, is associated with various metabolic outcomes. Few studies examined the fibre/CHO ratio on lipid profiles, liver fat and insulin resistance in individuals with impaired glucose tolerance (IGT). Methods: In this comprehensive cross-sectional study, we evaluated the association of carbohydrate-related nutritional factors with metabolic parameters in a cohort of 177 Hong Kong Chinese with impaired glucose tolerance (IGT). The subjects underwent a 75 g oral glucose tolerance test (OGTT) with measurement of plasma C-peptide and lipid profiles, body composition, transient elastography, and three-day food records. The fibre/CHO ratio is calculated by dividing fibre intake by total carbohydrate intake (in grams). Results: The median (IQR) age of the study cohort was 60 (54-62) with a mean ± SD BMI of 26.7 ± 3.9 kg/m2, and 40.7% were female. A higher carbohydrate quality, measured as fibre/CHO ratio, was inversely correlated with triglycerides (r = -0.305, p < 0.001) and positively correlated with High-density lipoproteins cholesterol (HDL-C) (r = 0.354, p < 0.001). These associations remained significant after adjusting for age, gender, lipid-lowering drugs, total calorie, macronutrient and sugar intake, physical activity and sodium/potassium ratio. Blood pressure, liver fat and insulin resistance were also associated with the fibre/CHO ratio after the adjustment of these confounding factors. Consuming more than 5.5 g of fibre per 100 g carbohydrate was associated with lower serum triglycerides. Conclusions: Our results highlight the potential for using the fibre/CHO ratio as a metric for daily carbohydrate quality and the importance of addressing both carbohydrate quality and quantity in designing dietary interventions to reduce cardiometabolic risk.