Effects of Dietary Patterns on Serum Urate: Results From a Randomized Trial of the Effects of Diet on Hypertension

Objective: To determine whether the Dietary Approaches to Stop Hypertension (DASH) diet or an alternative, simplified diet, emphasizing high-fiber fruits and vegetables (the FV diet), lowers serum urate levels. Methods: We conducted a secondary study of the DASH feeding study, a 3-arm, parallel-design, randomized trial of 459 adults with systolic blood pressure (BP) of <160 mm Hg and diastolic BP of 80–95 mm Hg, who were not receiving BP medications. Participants were randomized to receive 8 weeks of monitored feeding and ate 1 of 3 diets: 1) a typical American diet (control), 2) the FV diet, a diet rich in fruits and vegetables but otherwise similar to the control diet, or 3) the DASH diet, which was rich in fruits, vegetables, and low-fat dairy products, and reduced in fat, saturated fat, and cholesterol. Body weight was kept constant throughout the study. Serum urate levels were measured at baseline and after 8 weeks of feeding. Results: For the 327 participants with available specimens (mean ± SD age 45.4 ± 11.0 years, 47% women, 50% African American), the mean ± SD baseline serum urate level was 5.7 ± 1.5 mg/dl. Compared to the control diet, the FV diet reduced the mean serum urate level by 0.17 mg/dl (95% confidence interval [95% CI] −0.34, 0.00; P = 0.051) and the DASH diet reduced the mean serum urate level by 0.25 mg/dl (95% CI −0.43, −0.08; P = 0.004). These effects increased with increasing baseline serum urate levels (<5, 5–5.9, 6–6.9, 7–7.9, and ≥8 mg/dl) for those receiving the DASH diet (a reduction of 0.08, 0.12, 0.42, 0.44, and 0.73 mg/dl, respectively; P for trend = 0.04), but not for those receiving the FV diet. Conclusion: Our findings indicate that the DASH diet reduces serum urate levels, particularly among those with hyperuricemia. These findings support the growing need for a dedicated trial to test the DASH diet among patients with hyperuricemia and gout.