How Fat Affects Gout
Adding pounds raises uric acid levels and increases risk for flares.
Painful gout attacks are caused by an excess of uric acid in the body that leads to the buildup of flare-triggering uric acid crystals around joints. The more you weigh, the less efficient your body is at removing uric acid, says Hyon Choi, MD, PhD, professor of medicine and director of the Gout and Crystal Arthropathy Center at Harvard Medical School in Boston.
Carrying extra weight slows down the removal of uric acid by the kidneys. Elevated levels of this acid are the primary culprit in the development of gout and its disabling attacks.
“There’s a very tight association between excess weight and the risk of developing gout and gout flares. It’s a dose-response relationship, meaning the more you weigh, the higher your risk, and the more likely you are to have recurrent attacks,” Dr. Choi says.
Insulin resistance, a state in which insulin levels remain abnormally high because the body has reduced sensitivity to the hormone, is likely the major player in the increased risk of gout linked to body fat.
More Fat, More Uric Acid
When people are overweight or obese, their bodies produce more insulin. “Higher levels of insulin circulating throughout the body inhibit uric acid elimination by the kidneys. This excess uric acid can lead to gout and gout attacks,” says Dr. Choi.
Because uric acid level is dynamic, like blood pressure, many factors can move it up or down, says rheumatologist Puja Khanna, MD, MPH, assistant professor of medicine at the University of Michigan in Ann Arbor.
“Stress, dehydration and certain medications, such as diuretics, can cause a jump in uric acid, as can weight gain,” she says. “One study found that just gaining 10 pounds over four months was associated with an increased incidence of gout.”
Belly Fat and Gout Risk
Numbers like overall weight and body mass index (BMI) may not tell the whole story, according to recent research looking at gout and visceral fat – the fat that builds up inside the abdomen. Too much visceral fat is linked to insulin resistance and development of type 2 diabetes – and gout.
A 2015 Arthritis Research & Therapy study found that people who were not obese as measured by BMI, but who had high levels of visceral fat, were more likely to have gout than their smaller-bellied counterparts (47.4% versus 27.3%). Gout patients with normal BMIs but high abdominal fat were also more likely than people without it (31.7% versus 13.2%) to have metabolic syndrome. The cluster of factors that make up this syndrome, which include abnormal cholesterol levels and high blood sugar, together increase the risk of heart disease, stroke and diabetes more than any one factor alone.
“Gout is not just an arthritis, but also a metabolic disease in which the primary metabolic problem is high uric acid,” says Dr. Khanna. “Like obesity and diabetes, high uric acid is a direct risk factor for cardiovascular disease and cardiac events.”
Gout is Long-Term Disease
Another common misunderstanding about gout, she says, is that while attacks may make the condition seem like something that comes and goes, it is a chronic disease.
“Keeping uric acid low to prevent flares and reduce future complications requires long-term treatment with uric acid-lowering therapy,” she says. “Lifestyle changes can also edge down uric acid levels, and should be seen as an additional treatment – but not a replacement – to medication.”
Improving diet, including avoiding sugary soda, exercising and keeping your weight closer to a healthy number can help lower uric acid. Drs. Khanna and Choi also note that these lifestyle changes lower the risk factors for heart disease, stroke and diabetes that are common among people with gout. A 2015 European study of 3,079 gout patients, for example, found 68% had high blood pressure, 59% had high cholesterol and 24.2% had type 2 diabetes.
“The goal of gout management is to stop both attacks of gout and its complications,” says Dr. Khanna. “This requires uric acid-lowering medication, but weight loss can help. For example, one small trial found patients with gout who lost about sixteen pounds dropped uric acid levels about three points.”
Dr. Choi, who says diet and lifestyle changes are cornerstones of his gout management plan, advises choosing sustainable diets that are shown to improve cardiovascular and metabolic risk factors, such as the DASH (dietary approach to stop hypertension) diet and those plans modeled on Mediterranean eating patterns.