Losing Weight on a Low-Calorie Diet Can Improve Psoriatic Arthritis Disease Activity and Heart Disease Risk Factors

The inflammatory conditions psoriasis and psoriatic arthritis seem to go hand in hand with being overweight or obese. But while research has shown that weight loss can improve psoriasis symptoms and decrease disease activity, there’s less information on whether the same is true for psoriatic arthritis (PsA).

Now a study in the journal Arthritis Research & Therapy suggests that this may indeed be the case. Obese adults with PsA who lost weight with a low-calorie liquid diet had fewer symptoms and less disease activity, the authors report.

Though the study was small, the findings are still compelling, writes George Martin, MD, in a perspective article in Healio Psoriatic Disease. “[A]s little as 7 percent to 16 percent sustained weight loss improves disease outcome measures, lending further support for our mantra of ‘diet and exercise’ in patients with obesity and PsA in order to reduce disease activity,” he wrote.

In an earlier study, the study authors, based in Sweden, investigated the effect of a Very Low Energy Liquid Diet (VLED) on 41 obese adults with psoriatic arthritis. The VLED provided a total of about 640 calories daily (in powder formula to be stirred with hot or cold water) for 12  weeks or 16 weeks. Over the following 12 weeks, participants slowly reintroduced food with an emphasis on typically healthy items such as fruits, vegetables, fish, poultry or lean meat, and whole grains. They were also encouraged to exercise at least 150 minutes a week.

Thirty-nine participants, all of whom had started the study with a body mass index (BMI) or 33 or more, stayed with the study for the full year. They had a median weight loss of 16 percent and nearly 40 percent reported having minimal disease activity compared with 28 percent when the study began.

Minimal disease activity is an overall measure of how psoriatic arthritis is affecting your health. It includes assessments of swollen and tender joints, sites of enthesitis (where ligaments and tendons connect to bones, such as at the Achilles heel), how much of your skin is affecting by psoriasis plaques, and patient surveys about pain and daily function.

The current study followed 35 of the original participants out to 24 months. All of the participants gained back some weight in the intervening year, but still maintained a median weight loss of 7.4 percent. (That’s the equivalent of a 150-pound person losing about 11 pounds or a 200-pound person losing about 15 pounds.)

The number of patients with minimal disease activity jumped to nearly 46 percent.

The researchers also noted decreases in blood pressure, blood glucose levels, and cholesterol, which is particularly good news given that both psoriasis and psoriatic arthritis can increase the risk of dying from cardiovascular disease.

Participants also saw lowered uric acid levels, which may indicate a lower risk for gout, although it’s not clear if this result was due to weight loss or better eating habits and drinking less alcohol.

Besides a small sample size, the study had several limitations, which the authors acknowledge. Perhaps the biggest was lack of a control group of people with PsA, although the researchers did include a control group of individuals without PsA who were matched for sex, age, and body weight. Another drawback: Participants were allowed to change their medications six months into the study, which means the authors can’t rule out that medical treatments contributed to the improvements.

Still, the findings give credence to the idea that a mantra of “diet and exercise,” as Dr. Martin said in his article, can guide people with PsA to a better quality of life.

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