DASH Diet Significantly Improves Serum Urate Levels Among Patients with Hyperuricemia

Patients with higher urate at baseline prescribed the Dietary Approaches to Stop Hypertension (DASH) diet demonstrated significantly decreased serum urate, particularly in younger adults, according to a study published in The Journal of Clinical Hypertension.¹ Investigators urge future research to assess these interventions in patients with gout or hyperuricemia.

Noelle Castilla-Ojo, MD

Credit: Doximity

The DASH diet is a well-established dietary intervention used to lower blood pressure and serum urate, especially patients with hyperuricemia. Further, losartan also has uricosuric effects, albeit their effects on serum urate have not been fully confirmed. The combination of the DASH diet and losartan may, therefore, demonstrate greater efficacy on serum urate, although the impact is unknown.²

“Hypertension is a particularly common comorbidity, present among over 70% of adults with gout,” wrote lead investigator, Noelle Castilla-Ojo, MD, associated with Harvard Medical School, and colleagues. “The co-occurrence of hypertension and gout has driven interest in identifying lifestyle and pharmacologic strategies that might benefit both hypertension and hyperuricemia. However, prior dietary recommendations (eg, a low purine diet) may worsen hypertension, while some antihypertensive agents (eg, thiazide diuretics and beta blockers), may worsen hyperuricemia and gout.”

A post hoc analysis of the DASH-Losartan trial, an investigator-initiated, multi-center trial conducted in 3 clinical centers between September 1994 and March 1996, was performed to analyze the effects, either alone or combined, of the DASH diet compared with a control diet or 50 mg/day of losartan compared with placebo on serum urate levels during an 8-week study period. The DASH diet consisted of higher proportions of fruit and vegetables, low-fat dairy products, fish, poultry, nuts, whole grains, and lower levels of cholesterol and total and saturated fats.

Serum urate was assessed at baseline, week 4, and week 8. At the 4-week mark, patients were switched in a crossover fashion from losartan to placebo and vice versa. Diets were formatted to maintain the patient’s weight. The effects of the DASH diet and/or losartan were evaluated both overall and among patients with a baseline serum urate ≥6 mg/dL.

Of the 55 subjects included in the analysis, the mean age was 52 years, 58% were women, and 64% were Black. Patients had a mean serum urate of 5.2±1.2 mg/dL and a mean baseline systolic blood pressure/ diastolic blood pressure (SBP/DBP) of 146±12/91±9.

Although the dietary intervention did not significantly reduce overall urate levels, (mean difference −.05 mg/dL; 95% confidence interval [CI]: −.39, .28), it did decrease levels among those with baseline hyperuricemia (−.33 mg/dL; 95% CI: −.87, .21; P = .007). Losartan significantly reduced serum urate levels (−.23 mg/dL; 95% CI: −.40, −.05), with the greatest effects demonstrated among adults aged <60 years compared with adults aged ≥60 years (−.33 mg/dL vs .16 mg/dL, P = .003).

Investigators noted the study design, coupled with high follow-up rates and standardized data collection, as strengths of the study. The study also purposely included a group of clinically relevant patients with hypertension at a higher risk of developing gout. Further, the effects of sublimation and long-term storage were minimized as the measurement of serum urate was performed within 6 months of collection.

However, the study sample was relatively small, the study duration was relatively short, and most patients had normal serum urate levels. Therefore, investigators were unable to determine the long-term effects of these interventions on serum urate levels.

“These findings add to the growing evidence that the DASH diet and losartan lower serum urate,” investigators concluded. “However, replication among adults with hyperuricemia and gout is needed.”

References

1. ^{Castilla-Ojo N, Turkson-Ocran RA, Conlin PR, Appel LJ, Miller ER 3rd, Juraschek SP. Effects of the DASH diet and losartan on serum urate among adults with hypertension: Results of a randomized trial [published online ahead of print, 2023 Sep 11]. J Clin Hypertens (Greenwich). 2023;10.1111/jch.14721. doi:10.1111/jch.14721}
2. ^{Hamada T, Ichida K, Hosoyamada M, et al. Uricosuric action of losartan via the inhibition of urate transporter 1 (URAT 1) in hypertensive patients. Am J Hypert. 2008; 21(10): 1157-1162. doi:10.1038/ajh.2008.245}