The Dietary Approaches to Stop Hypertension (DASH) diet, designed to reduce high blood pressure, also appears to significantly lower serum uric acid (SUA), the etiologic precursor of gout, according to a study published online August 15, 2016 in the journal Arthritis and Rheumatology.
In some study participants, the DASH diet worked so well that it nearly equaled the effect of drugs for treating gout. Indeed, a dietary approach should be considered as first-line therapy to prevent gout, the researchers concluded.
Even though diet has long been known as an important factor in the production of uric acid, most clinical trials that investigated reducing SUA have focused on drug therapy. Because of the lack of randomized clinical trials of dietary interventions for gout, these researchers sought to determine whether a healthy diet might effectively lower SUA.
The DASH diet emphasizes whole grains, poultry, fish, fruits, vegetables, and low-fat dairy products along with reduced intake of sodium, red meats, sweets, and saturated fats than the typical American diet.
In the original DASH-Sodium trial, 412 participants ate either the DASH diet or a typical American diet for three months. For each month of the study, participants consumed a different level of sodium in a random order, including low (1.2 g per day), medium (2.3 g per day), and high level (3.4 g per day). The results, first published in 1997, showed that the DASH diet had a significant positive improvement on hypertension and cholesterol.
As part of the trial, the original DASH researchers took participants’ serum samples at baseline and at the end of each sodium intake period. These were analyzed for a variety of blood markers, including uric acid.
For this new study, researchers at the Johns Hopkins University School of Medicine, in Baltimore, MD, performed a secondary analysis of the original DASH study data. They found that the DASH diet led to a modest 0.35 mg/dL decrease in SUA overall.
However, the higher the participants’ baseline uric acid levels, the greater the decrease. For those with baseline SUA of more than 7 mg/dL—among the highest of all participants—the decrease was as large as 7 mg/dL.
“That’s a large reduction in uric acid,” said lead author Stephen P. Juraschek, MD, PhD, clinical fellow in the Division of General Internal Medicine at Johns Hopkins. “When you get as high as the reduction we believe occurred with the original DASH diet in this study, the effect starts being comparable with gout medications.”
The gout medication allopurinol, for comparison, often reduces patients’ SUA by about 2 mg/dL, the researchers noted.
Sodium provided a small but significant increase on SUA levels—which was the opposite of what the researchers expected. When participants were given the least amount of sodium, their SUA levels were at the highest. But during the medium and high sodium portions of the trial, participants had slight decreases in SUA.
Although high sodium levels appear to slightly decrease uric acid concentrations, Dr. Juraschek advised against purposely consuming sodium to reduce SUA. “More than 70% of people with gout have high blood pressure,” he said. “If one was to consume more sodium to improve uric acid, it could worsen blood pressure.”
Senior author Edgar R. Miller III, MD, PhD, Professor of Medicine at Johns Hopkins, said, “Results of this trial are good news to patients with high blood levels of uric acid or those at risk for gout. A dietary approach to prevent gout should be considered first-line therapy.”
“This study suggests that standard dietary advice for uric acid reduction, which is to reduce alcohol and protein intake, should now include advice to adopt the DASH diet,” concluded Dr. Miller.