Prudent Diet Reduces Risk of RA and Gout Save

The 2015 ACR meeting in San Francisco highlighted several studies wherein dietary patterns predicted a reduced risk of both rheumatoid arthritis (RA) and gout.

The first abstract #1213 by Lu et al from the Brigham and Women’s Hospital and Harvard Medical School found that a typical Western diet (a "Big Mac" diet) may increase the risk of RA.

Using data from from the NHS II Survey, they examined 93,859 women (without RA) and their dietary patterns from 1991 to 2011. Diets were categorized as prudent (diet high in fruits, vegetables, legumes, whole grains, poultry and fish) or Western diets (high in red and processed meat, refined grains, fried food, high-fat dairy and sweets).  

With over 1.5 million patient-years of followup they identified 626 incident cases of RA. In the multivariable adjusted model, those with a Prudent dietary pattern noted a reduced risk of RA, such that those in the highest two quartiles had a 19% - 29% reduced risk.

At the same time, those on a Western diet were at increased risk for RA, but after adjustment for BMI these findings were attenuated. This indicates that the effects of the two dietary patterns on RA risk may be partially through BMI, and the clear mechanism is still unknown.

Therefore, adherence to a healthy diet may be a way to RA prevention, especially for high risk individuals.

Another study from Choi et al (Abstract # 2095) examined the benefits of the DASH diet. The DASH diet is commonly employed as a dietary means of controlling hypertension.  Like the Prudent diet, the DASH diet has no or low animal protein, but plenty of fruits, vegetables, and low fat dairy products. They compared the incidence of gout in those adhering to either a DASH diet or Western diet and used dietary "scores" to indicate the degree of adherence to either. 

They enrolled 78906 women from Nurses Health Study beginning in 1984. With 22 years of followup, there were 778 incident gout cases (meeting old ACR criteria for gout). Those patients in the upper 2 quintiles of DASH dietary scores had 33-40% lower risk of developing gout. Conversely, the Western Diet had a 37-68% higher risk in 4-5th quintiles.

These studies indicate an important role for diet in the development of inflammatory arthritis - both gout and rheumatoid arthritis. It is unknown if these findings are applicable to "at risk" populations (i.e., those with preclinical RA or gout).  It is also interesting to speculate the role of an altered microbiome in the genesis of abberant immune responses leading to chronic inflammatory states.