Although gout has been studied for centuries, there are still many questions unanswered.
Gout is a rheumatic condition caused by a buildup of uric acid in the joints, known as hyperuricemia.
It is the most common form of inflammatory arthritis in men. Gout normally strikes in the base joint of the big toe and can be debilitatingly painful.
Flare-ups can last for days or even weeks, causing an individual significant discomfort.
Although the exact mechanisms that lead to a gout event are not fully understood, some risk factors are known; these include alcohol intake, hypertension (high blood pressure), insulin resistance, and a diet rich in red meat and seafood.
According to the Centers for Disease Control and Prevention (CDC), in 2007-2008, 3.9 percent of all American adults and 5.9 percent of men (6.1 million individuals) had gout.
They also report that overall incidence of gout has risen 1.2 percent over the previous 20 years.
Although the dietary factors mentioned above are known to play a role in elevating levels of uric acid in the blood, the exact causes remain a mystery. Researchers from Johns Hopkins University School of Medicine, MD, recently set out to investigate the influence of diet on gout in more detail.
A fresh look at gout
Dr. Stephen P. Juraschek and his colleagues reopened data from a clinical trial carried out in 1997 called DASH (Dietary Approaches to Stop Hypertension). The landmark study demonstrated that the DASH diet - reduction in salt, an increase in whole grains, fruits, and vegetables, low-fat dairy products, and less red meat, sweets, and saturated fats - significantly improved blood pressure and cholesterol.
In the DASH-Sodium experiment, more than 400 participants were given either a DASH diet or a typical American diet for 3 months. Each month, participants were given differing amounts of sodium - 1.2 grams (low), 2.3 grams (medium), or 3.4 grams (high). The higher figure equates to a standard American diet.
Before the trial began and after each month, the researchers analyzed the participants' blood for various chemical markers; these included uric acid.
Dr. Juraschek and his team recently reopened the data set and analyzed the effects of each of the salt interventions on uric acid concentration.
Overall, the DASH diet led to a uric acid decrease of 0.35 milligrams per deciliter. Although that is only a moderate decrease, the team found that the change was greater for individuals who had the highest levels of uric acid at baseline. Participants with a reading of 7 milligrams per deciliter at the start of the study showed a reduction of 1.3 milligrams per deciliter.
To put that figure into perspective, drugs designed to treat gout, such as allopurinol, generally lower uric acid levels by 2 milligrams per deciliter.
"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."
Dr. Stephen P. Juraschek
Sodium and uric acid levels
When the team examined the interaction between sodium levels and uric acid, the findings surprised them - they were the opposite to expectations. During the low salt phase of the DASH diet, uric acid levels were at their highest; during the medium and high sodium diets, levels were reduced.
These changes due to salt intake were small but significant.
The authors, however, do not recommend that people with gout start adding salt to their diet. "More than 70 percent of people with gout have high blood pressure," says Dr. Juraschek. "If one was to consume more sodium to improve uric acid, it could worsen blood pressure."
The results of the analysis are published this week in the journal Arthritis and Rheumatology. Although further studies will be necessary to confirm the findings, the researchers are optimistic. If the DASH diet can prevent or at least minimize gout flare-ups, it would be of substantial benefit for gout sufferers.
Gout currently costs the healthcare system of America around $7.7 billion. A dietary change that controls gout while simultaneously controlling hypertension and cholesterol levels could make a significant difference to millions of lives.