Dataset Information

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).

ABSTRACT:

Objective

Weight loss diets may reduce serum urate (SU) by lowering insulin resistance while providing cardiometabolic benefits, something urate-lowering drugs have not shown in trials. We aimed to examine the effects of weight loss diets on SU and cardiometabolic risk factors.

Research design and methods

This secondary study of the Dietary Intervention Randomized Controlled Trial (DIRECT) used 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 (SU ≥416 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 cholesterol (HDL-C), total cholesterol: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

Nonpurine-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.

SUBMITTER: Yokose C

PROVIDER: S-EPMC7576420 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundReduced calorie, low fat diet is currently recommended diet for overweight and obese adults. Prior data suggest that low carbohydrate diets may also be a viable option for those who are overweight and obese.PurposeCompare the effects of low carbohydrate versus low fats diet on weight and atherosclerotic cardiovascular disease risk in overweight and obese patients.Data sourcesSystematic literature review via PubMed (1966-2014).Study selectionRandomized controlled trials with ≥8 weeks follow up, comparing low carbohydrate (≤120gm carbohydrates/day) and low fat diet (≤30% energy from fat/day).Data extractionData were extracted and prepared for analysis using double data entry. Prior to identification of candidate publications, the outcomes of change in weight and metabolic factors were selected as defined by Cochrane Collaboration. Assessment of the effects of diets on predicted risk of atherosclerotic cardiovascular disease risk was added during the data collection phase.Data synthesis1797 patients were included from 17 trials with <1 year follow up in 12. Compared with low fat diet, low carbohydrate was associated with significantly greater reduction in weight (Δ = -2.0 kg, 95% CI: -3.1, -0.9) and significantly lower predicted risk of atherosclerotic cardiovascular disease events (p<0.03). Frequentist and Bayesian results were concordant. The probability of greater weight loss associated with low carbohydrate was >99% while the reduction in predicted risk favoring low carbohydrate was >98%.LimitationsLack of patient-level data and heterogeneity in dropout rates and outcomes reported.ConclusionsThis trial-level meta-analysis of randomized controlled trials comparing LoCHO diets with LoFAT diets in strictly adherent populations demonstrates that each diet was associated with significant weight loss and reduction in predicted risk of ASCVD events. However, LoCHO diet was associated with modest but significantly greater improvements in weight loss and predicted ASCVD risk in studies from 8 weeks to 24 months in duration. These results suggest that future evaluations of dietary guidelines should consider low carbohydrate diets as effective and safe intervention for weight management in the overweight and obese, although long-term effects require further investigation.

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