A recent study by US researchers has identified a link between a high-salt diet and lower blood levels of uric acid, a condition recognised to trigger gout, but sodium could also worsen blood pressure.

The study, the findings of which have been published in Arthritis & Rheumatology, a journal produced by the American College of Rheumatology, found that a high sodium intake, typical of a normal American diet, led to lower levels of uric acid.

Researchers started from the base of the original DASH (Dietary Approaches to Stop Hypertension) diet, results of which were published in 1997, designed to tackle high blood pressure, which emphasises reduced salt, whole grains, fruits, vegetables, low-fat dairy products and a reduced intake in red meats, sweets and saturated fats. This followed 412 participants eating either the DASH diet or a typical American diet for three months. For each month of the study, participants’ diets provided a different level of sodium in random order, including low (1.2g per day), medium 2.3g per day and high (3.4g per day). The high sodium level was comparable to the average daily intake in a typical American diet.

While this had a marked positive improvement on blood pressure and cholesterol, researchers in the new study revisited blood samples taken at the time, to determine whether and how each intervention affected uric acid blood concentrations. They found that the DASH diet led to a 0.35mg per decilitre decrease in uric acid concentrations, but the higher the level of sodium intake, the more dramatic the decrease in uric acid levels, up to 1.3mg per decilitre

In some study participants, the effect was so strong that it was nearly comparable to that achieved with drugs specifically prescribed to treat gout.

However, while researchers concluded that there might be an effective, safe and sustainable dietary approach to the treatment of gout, as a result of the study, they were careful not to advocate a high level of sodium consumption. Stephen P Juraschek, research and clinical fellow in general internal medicine at the John Hopkins University School of Medicine and a lead author on the study, said: “More than 70% of people with gout have high blood pressure. If one was to consume more sodium to improve uric acid, it could worsen blood pressure.”

The researchers also cautioned that further studies were needed to directly explore whether the DASH diet might reduce or prevent gout flare-ups.

Edgar R Miller, professor of medicine at the John Hopkins University School of Medicine, concluded: “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.”

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