A low-fat vegan diet may relieve rheumatoid arthritis

April 25, 2022 – Pain from rheumatoid arthritis appears to be linked to what we eat, but researchers haven’t been able to develop an ideal diet for patients.

Now, a new study in women suggests that adopting a low-fat vegan diet and then eliminating trigger foods may provide relief within months, possibly helping patients lose weight quickly.

The study’s unusual design and small size make it impossible to know whether the diet — or any part of it — actually works. Still, the diet is “a life-changing experience for people,” says lead author Neal D. Barnard, MD, an internal medicine specialist and chair of the Physicians Committee for Responsible Medicine. “Doctors should know that and they should try it themselves.”

The study was published April 3 in the American Journal of Lifestyle Management.

About 1 in 200 people (more than 1.6 million people) in the United States have rheumatoid arthritis, which is caused when the immune system goes haywire and attacks the joints of the body. It is more common in women and causes symptoms such as swelling, stiffness and pain.

Doctors have linked rheumatoid arthritis to diet for decades, and a 2017 survey of 217 patients with the disease, 19% said certain foods, such as sugary sodas and sweets, made their symptoms worse. But there’s no consensus on the best diet for relief.

A 2021 research report found positive results for the Mediterranean diet, high doses of omega-3 fatty acids (found in fish oil), vitamin D supplements, and salt removal. Other approaches, such as fasting and vegan diets, have had inconclusive results.

For the new study, the researchers wanted to explore the possible benefits of a “convenient, easy-to-prescribe diet” with no calorie limits, Barnard says.

The researchers randomly assigned 44 women (mean age 57, 66% Caucasian and 16% Black) to one of two diets for 16 weeks. The women then took a 4-week break and followed the other diet for 16 weeks. This “crossover” approach means that the 32 people who completed the study were exposed to each diet.

One diet was low fat and vegan. After 4 weeks, those on the diet did not use common rheumatoid arthritis trigger foods such as cereals containing gluten, nuts, citrus fruits and chocolate. After week 7, the women added the trigger foods back one at a time, keeping them in their diets if they didn’t seem to be causing symptoms.

People on the other regimen took a placebo.

After the participants followed the low-fat vegan diet for 16 weeks, their average swollen joint count dropped from 7 to just over 3, and they reported better symptoms overall.

Average body weight dropped 14 pounds among those in the diet group, while those in the placebo group gained an average of almost 2 pounds.

It’s unclear whether weight loss is more responsible for the diet’s benefits than actual food, says Harvard Medical School rheumatologist Daniel Solomon, MD, who reviewed the study results for WebMD. Another possibility is that parts of the regime — not the entire regime — were responsible, he says.

“I’m sure motivated patients could follow such a diet,” he says, “but first we need to determine if the specific diet was the key issue or if the weight loss was more important.”

Barnard, the study’s lead author, says the patients tolerated the diet well. “It’s convenient for everyday life” and cheaper than meat- and dairy-based diets, he says.

He encourages patients to try changing their eating habits before turning to medication.

“It’s a good idea for anyone to have the chance to try diet change,” he says. “You will know in a few weeks if it will work.”