Eating foods lower on the glycemic index scale can lower uric acid concentrations and could be more effective in preventing gout flares than reducing one’s overall carbohydrate intake – which can actually increase uric acid concentrations, a study shows.
The study, published in May in the journal Arthritis and Rheumatology, assesses the effects of carbohydrates on plasma uric acid levels by examining the quantity and intake of foods that are low and high in carbohydrates.
Led by Edgar R. Miller III, M.D., Ph.D., of Johns Hopkins Medical Institutions, researchers conducted a randomized, crossover study comparing the effects of four different diets on 163 overweight or obese adults without cardiovascular disease over the course of five weeks.
The study is based on data from the OmniCarb trial, a low-carbohydrate, higher protein dietary study that examined the impact of carbohydrates intake on cardiovascular disease risk factors. This trial found that consuming low glycemic index foods increased low-density lipoprotein cholesterol level and increased insulin resistance, which is strongly associated with hyperuricemia.
The four OmniCarb diets included: (1) a high glycemic index of >65 with high percentage of carbohydrates (58% kcal); (2) a low glycemic index diet of <45 with a low percentage of carbohydrates (40% kcal); (3) a low glycemic index with a high percentage of carbohydrates; and, (4) a high glycemic index with a low percentage of carbohydrates.
The participants were nearly evenly split: 52% women, 50% whites and 50 % blacks with a mean age of 52.6 years. Their average + SD uric acid level was 4.7 + 1.2 mg/dl, but by reducing the glycemic index, the uric acid levels fell when the percentage of carbohydrates was low (-0.24 mg/dl; P <0.001) or high (- .17 mg/dl; P < 0.001).
Reducing the percentage of carbohydrates marginally increased the uric acid level only when the glycemic index was high (P = .05). The combined effect of lowering the glycemic index and increasing the percentage of carbohydrates was -.27 mg/dl (P < 0.001).
“The greatest difference in uric acid levels was observed when the glycemic index was reduced and the amount of carbohydrates was increased simultaneously, suggesting that adopting a diet rich in low glycemic index carbohydrates may result in the greatest reduction in uric acid levels. However, changing the glycemic index seemed to be more important than changing the carbohydrate proportion with regard to uric acid reduction,” the authors wrote.
The results are encouraging because patients have increasingly shown an interest in adopting both traditional urate lowering therapy with dietary modifications, especially patients with mild gout.
Low glycemic index foods