Design and methodology of a randomized crossover trial to test the effect of low and high dAGE diets on metabolic risk factors and inflammatory markers among overweight and centrally obese Asian Indian adults

Abstract

Background: Heat processing of foods accelerates the formation of advanced glycation end products (AGEs). Dietary AGEs (dAGEs) could exacerbate the risk for diabetes, by adversely affecting glucose metabolism. Asian Indian diets have not been evaluated for AGEs and their effect on metabolic risk factors. Objective: As a proof of concept, we report the dAGE content of Indian foods to further plan the design and methodology of a study that would evaluate the effect of high and low dAGE diets on metabolic risk factors such as insulin resistance, glycemia, lipid profile, and inflammatory markers in overweight and centrally obese Indian adults without diabetes. Materials and Methods: This randomized crossover trial includes 50 overweight and centrally obese adults aged 25–45 years with body mass index (BMI) ≥23\u2009kg/m2 and waist circumference (WC) ≥90cm in men and ≥80cm in women. Participants will be provided 12 weeks each of low and high dAGE diets (with the dAGE content being measured by enzyme-linked immunosorbent assay), matched for calories and macronutrients with a 2-week washout period in between the two diets. Low dAGE diets use steaming, boiling, and pressure cooking compared to deep frying, stir frying, and roasting in high dAGE diets. Biochemical measures will be assessed both at baseline and the end of each diet using standard protocols. The difference in outcome measures will be evaluated (analysis of variance and paired t test) using SAS (version 9.2). Results: The dAGE content was found to be 49709 ± 5239 vs. 26178 ± 4327\u2009mg/day (mean ± standard deviation [SD]) in high and low dAGE diets, respectively (P < 0.001). Baseline demographic and biochemical characteristics did not differ between low and high dAGE diet interventions. Conclusion: The study trial will throw light on the effect of high and low dAGE diets on metabolic risk factors in overweight and centrally obese Indian adults, potentially leading to a novel dietary strategy to prevent diabetes in this population.