Effects of Low-Fat, Mediterranean, or Low-Carbohydrate Weight Loss Diets on Serum Urate and Cardiometabolic Risk Factors - A Secondary Analysis of the Dietary Intervention Randomized Controlled Trial (DIRECT)
Research Design and Methods: Secondary study of the Dietary Intervention Randomized Controlled Trial (DIRECT) using stored samples from 235 participants with moderate obesity randomly assigned to low-fat, restricted-calorie (n=85), Mediterranean, restricted-calorie (n=76), or low-carbohydrate, non-restricted-calorie (n=74) diets. We examined SU changes at 6- and 24-months overall, and among those with hyperuricemia (SU³416 μmol/L), a relevant subgroup at risk for gout.
Results: Among all participants, average SU decreases were 48 μmol/L at 6-months and 18 μmol/L at 24-months, with no differences between diets (p>0.05). Body weight, HDL-C, total cholesterol to HDL-C ratio, triglycerides, and insulin concentrations also improved in all three groups (p<0.05 at 6 months). Adjusting for covariates, changes in weight and fasting plasma insulin concentrations remained associated with SU changes (p<0.05). SU reductions among those with hyperuricemia were 113, 119, and 143 μmol/L at 6 months for low-fat, Mediterranean, and low-carbohydrate diets (all p for within-group comparison <0.001; p>0.05 for between-group comparisons), and 65, 77, and 83 μmol/L, respectively, at 24-months (all p for within-group comparison <0.01; p>0.05 for between-group comparisons).
Conclusions: Non-purine-focused weight loss diets may simultaneously improve SU and cardiovascular risk factors, likely mediated by reducing adiposity and insulin resistance. These dietary options could provide personalized pathways to suit patient comorbidity and preferences for adherence.
