The Link Between Sugar and Rheumatoid Arthritis

Medically Reviewed by Michael W. Smith, MD on December 10, 2020
4 min read

If you have rheumatoid arthritis (RA), you’re no stranger to joint pain and swelling. But you may have noticed that your symptoms are worse a day or two after you drink a giant soda or binge on homemade chocolate brownies. You’re not imagining it. There’s a reason: added sugars.

“My patients often report flares in their RA when they eat sugary foods like desserts and soft drinks, and note that they notice an improvement when they cut them out,” says Betty Hsiao, MD, a rheumatologist at Yale Medicine in New Haven, CT.

A 2017 survey of people with RA found that the foods most often linked to worse symptoms were sugary ones, specifically desserts and sodas. One reason may simply be that people who cut out added sugar end up losing weight, which can improve RA symptoms, explains survey co-author Sara Tedeschi, MD, MPH, assistant professor of medicine at Harvard Medical School. “It’s hard to separate the effect of dietary change from the effect of weight loss.”

The tie between sugar and RA is nothing new. Many people assume that the autoimmune disorder started happening only recently. But it was first seen by Western doctors in the late 19th century, when sugar became more widely available to the public. “At the same time as we started seeing tooth decay and gum disease, we started seeing RA,” explains Avram Goldberg, MD, clinical director of NYU Langone Rheumatology Associates in Lake Success, NY. “We think that the sugar caused a change in bacteria in the mouth, which in turn made some people more susceptible to the condition.”

Also, many people with RA have proteins in their body called anti-citrullinated protein antibodies (ACPA), Hsiao explains. These cause the inflammation that triggers the disease. Experts think sugar triggers your body to make more ACPA, she says, which can make your symptoms worse.

Sugar can affect your gut microbiome, the balance of good and bad bacteria in your digestive tract. “Sugar encourages the growth of bad bacteria, and some research already suggests that patients with RA already have gut microbiomes that are out of whack,” explains Melissa Ann Prest, a Chicago nutritionist and spokesperson for the Academy of Nutrition and Dietetics. The more off-kilter your gut bacteria are, the more likely you are to have inflammation that can worsen your RA symptoms, she says.

If you have RA, you don’t have to skip the sweet stuff entirely. “All the studies show an association between sugar in your diet and RA. We can’t definitively say the two are connected,” Goldberg says. “But if you do find that sugary foods seem to make your RA symptoms worse, then you should keep them to an absolute minimum.”

Here are some ways to do it:

Skip the sugary drinks. They’re already the biggest contributors of sugar in the American diet, Prest says. Women who drank at least one sugar-sweetened soda a day were about 60% more likely to get RA than women who drank less than one a month, according to a 2014 study in the Journal of Clinical Nutrition.

Read food labels carefully. Seemingly non-sugary foods like cereals, yogurts, frozen meals, and even condiments like ketchup may have a lot more added sugar than you may realize. If you have RA, it’s a good idea to keep your added sugar intake to less than 5% of your total daily calories, Prest says. Check the nutrition label, which is now required to list added sugars in grams and as a percent of Daily Value.

You should also do a quick scan of the ingredient list for common names for sugar, such as sucrose, high-fructose corn syrup, barley malt, dextrose, maltose, and rice syrup, Hsiao says. If one of those is among the first three ingredients, chances are, it’s a high-sugar product.

Substitute fruit for refined sugar. Fruit is naturally sweet but is also rich in antioxidants, which help reduce inflammation, Hsiao says. In fact, the 2017 survey found that berries such as blueberries and strawberries were linked to improved RA symptoms. Ways to eat more fruit include:

  • Put fruit on your toast instead of jam, or sprinkle it on your cereal instead of sugar.
  • Make “ice cream” by freezing ripe bananas and then tossing them into a blender. “It gets creamy and a little gooey,” Prest says. (You can add peanut butter for more creaminess and texture.)
  • Warm berries in a saucepan with a splash of orange or cranberry juice. This makes a great topping for whole-grain waffles or plain yogurt, Prest says.
  • Puree or mash your favorite fruit and let it freeze overnight in ice pop molds for frozen fruit bars. If you don’t have the time and patience to do that, put some grapes in the freezer instead, Prest says.