15 May 2017

DASH off for gout

Aged Care Clinical

Dietary interventions for gout may do more harm than good, a leading Australian rheumatologist says.

Despite publicity around a new study suggesting the DASH diet, which emphasises fruits and vegetables, whole grains and low-fat dairy products, lowered the risk of gout, Associate Professor Neil McGill said that the evidence was not strong enough.

“It is sensible to be really cautious, and not be tempted to say this should be recommended as a treatment for people who have been found to have gout,” the University of Sydney rheumatologist said. “Because it leads them away from treatments which have been shown to be useful.”

Drug therapy to bring urate levels down below saturation, either to a target of less than 0.36 mmol/L for ordinary gout or lower for tophaceous gout, is proven to provide long-term benefit, he said.

“What we don’t have, unfortunately, is a study showing that if you recommend dietary modification to people, that you end up with long-term benefit.”

This new prospective cohort study of more than 44,000 healthy men with no baseline history of gout found that over the 26-year follow-up, the risk of incident gout was significantly lower in men who had a higher DASH diet score compared to those eating more of a Western diet.

The benefits remained even after accounting for common risk factors such as alcohol and coffee consumption, high blood pressure, BMI and age.

Compared to other Western diets, the DASH diet consists of less red and processed meats, chips, refined grains, sweets and desserts. As well as being recommended for reducing high blood pressure and cardiovascular disease risk, research has suggested the diet reduces levels of serum uric acid in patients with hyperuricemia.

“The conventional approach of a diet low in purine for gout [prevention] offers limited efficacy, palatability and sustainability,” the authors said, pointing to the tendency for people on the low-protein diet to increase refined carbohydrate intake.

This increased intake was linked to insulin resistance, increasing plasma glucose levels, triglycerides, and LDL cholesterol, all of which are problematic for patients already at an increased risk of cardiovascular metabolic comorbidities.

But while the authors of the study concluded that the findings may make the diet “an attractive preventive dietary approach for men at risk of gout”, Professor McGill urged caution.

Previous studies had also shown links to meat and seafood intake and serum urate or incident gout, but none had been able to show benefits in a prospective, randomised trial, he said.

“No one has actually implemented that advice and demonstrated any benefit,” Professor McGill said.

“My own advice is that if they are overweight there is a good reason for them to lose weight for their general health. If they drink too much alcohol it’s a good idea for them to cut back on their alcohol because there is a range of health harms,” he said.

“And losing weight and reducing their alcohol will be of some assistance in terms of reducing their urate level, unfortunately it is exceptionally rare for people who have proven gout to be able to reduce their urate level to below saturation, to a level that will actually allow the crystals to start dissolving, through dietary modification.”

BMJ 2017; online 9 May