Reduced Glycemic Index Correlated With Lower Uric Acid Levels

HealthDay News – Glycemic index was found to be more closely tied to uric acid levels as opposed to proportion of carbohydrates consumed among adult patients with body mass indices (BMIs) ≥25 kg/m², according to a study published in Arthritis & Rheumatology.  Reduction in glycemic index resulted in lowered uric acid concentrations.  

Stephen P. Juraschek, MD, PhD, from the Johns Hopkins University School of Medicine in Baltimore, and colleagues conducted a randomized trial of four different diets in 163 overweight or obese adults without cardiovascular disease (ClinicalTrials.gov Identifier NCT00608049). 

Over a five-week period, participants consumed each of four diets: high glycemic index with high percentage of carbohydrates; low glycemic index with low percentage of carbohydrates; low glycemic index with high percentage of carbohydrates; and high glycemic index with low percentage of carbohydrates. The diets were separated by a two-week washout period.

The researchers found that reducing the glycemic index correlated with reduced uric acid levels when the percentage of carbohydrates was low or high (−0.24 mg/dL and −0.17 mg/dL, respectively; both P <.001). The uric acid level was increased marginally with reduction of the percentage of carbohydrates only when the glycemic index was high (P=.05).

Lowering the glycemic index and increasing the percentage of carbohydrates resulted in a combined effect of −0.27 mg/dL (P <.001). The effect persisted even after adjustment for changes in kidney function, insulin sensitivity, and glycolysis products.

“Reducing the glycemic index lowers uric acid levels,” the authors write. “Future studies should examine whether reducing the glycemic index can prevent gout onset or flares.”

Summary and Clinical Applicability

In this cohort of patients, the effects of reducing both glycemic index intake and increasing the proportion of dietary carbohydrates was a reduction in serum uric acid by 0.27 mg/dl.  The apparent relationship between glycemic index and uric acid concentration appeared to be independent of kidney function, insulin sensitivity, and glycolysis byproducts, suggesting that “effects of glycemic index on uric acid are not primarily mediated through changes in kidney function and glucose homeostasis (or insulin sensitivity)”, the authors concluded.

Limitations and Disclosures

This study was limited by the inclusion of only a few patients with hyperuricemia and the absence of baseline gout status.  Patients with common comorbidities such as diabetes, hyperlipidemia, or hypertension were also excluded further limiting generalizability. 

Food for the study was contributed by The Almond Board, the International Tree Nut Council, Olivio Premium Products, and The Peanut Institute.

Reference

Juraschek SP, Mcadams-demarco M, Gelber AC, et al. Effects of Lowering Glycemic Index of Dietary Carbohydrate on Plasma Uric Acid Levels: The OmniCarb Randomized Clinical Trial. Arthritis Rheumatol. 2016;68(5):1281-9.