A diet rich in fruits, vegetables, low-fat dairy and reduced in fats and saturated fats (the DASH diet), designed decades ago to reduce high blood pressure, also appears to significantly lower uric acid, the causative agent of gout.
Further, the effect was so strong in some participants that it was nearly comparable to that achieved with drugs specifically prescribed to treat gout, a new study led by Johns Hopkins researchers shows.
The findings – derived from a randomized clinical trial – could offer an effective, safe and sustainable dietary approach to lower uric acid and possibly prevent gout flare-ups in those with mild to moderate disease and who can’t or don’t want to take gout drugs.
Dietary excesses, such as consuming a lot of red meat and alcohol, have long been associated with gout, a disease marked by high levels of uric acid in the blood and whose causes remain somewhat of an enigma despite centuries of investigation.
The Hopkins researchers noted that while symptoms of gout outbreaks – severe inflammation and sharp pain in the joints, particularly the base of the big toe – have been linked to elevated uric acid, it’s been unclear exactly what type of diet might lower uric acid and decrease the risk of flare-ups.
In an effort to find out, Stephen P. Juraschek, M.D., Ph.D., research and clinical fellow in general internal medicine at the Johns Hopkins University School of Medicine, and his colleagues used data from the DASH (Dietary Approaches to Stop Hypertension) clinical trial, a widely popular and often-cited study whose results were first published in 1997.
These results showed that the DASH diet – which emphasizes reduced salt, whole grains, fruits, vegetables, low-fat dairy products and reduced intake of red meats, sweets and saturated fats – had a marked positive improvement on blood pressure and cholesterol.
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, the participants’ diets provided a different level of sodium in a random order, including low (1.2 grams per day or about half a teaspoon), medium (2.3 grams per day or about one teaspoon), and a high level (3.4 grams per day or about 1.5 teaspoons). The high sodium level was comparable to the average daily intake in a typical American diet.
At baseline and at the end of each sodium intake period, the researchers conducting the original study also took blood samples, which were analyzed for a variety of blood markers, including uric acid.
In this new study, Juraschek and his colleagues examined these data to determine whether and how each intervention affected uric acid blood concentrations. They found that the DASH diet led to a modest 0.35 milligrams per deciliter decrease in uric acid concentrations overall. However, the higher participants’ baseline uric acid levels, the more dramatic the decrease.
In the context of what is known about levels of uric acid linked to gout flare-up risk, “That’s a large reduction in uric acid,” explains Juraschek. Gout-treating medications, such as allopurinol, often reduce patients’ blood uric acid concentrations about 2 milligrams per deciliter.
Juraschek noted that the effect of sodium on uric acid concentrations was small, but significant and quite the opposite of what the researchers expected. Specifically, during the part of the DASH trial in which participants were given the least sodium, their uric acid concentrations were the highest, with slight decreases achieved during the medium and high sodium portions of the trial.
Although high sodium levels appear to slightly decrease uric acid concentrations, Juraschek cautions against jumping to the conclusion that to reduce blood uric acid it’s a good idea to purposely consume lots of sodium. “More than 70 percent of people with gout have high blood pressure,” Juraschek says. “If one was to consume more sodium to improve uric acid, it could worsen blood pressure.”