What to Know About Rheumatoid Arthritis and Food Allergies/Sensitivities

Medically Reviewed by David Zelman, MD on May 26, 2024
5 min read

If you notice more joint pain and swelling when you grab a burger or polish off a pint of ice cream, you’re not alone. One-third of people with rheumatoid arthritis (RA) say certain foods worsen their symptoms. There’s plenty of evidence to back this up. For example, red meat and dairy are known to trigger inflammation.

Some research suggests food allergies or sensitivities (also called intolerances) may play a role, too. An elimination diet to pinpoint problem foods is a great place to start. That’s when you stop eating a certain food and then slowly reintroduce it to see if it’s causing problems.

Inflammation is the driving force in RA. These foods are linked to inflammation:

  • Red and processed meats
  • Sugar, especially sugary beverages like sodas, energy and sports drinks, and lattes
  • Saturated fat
  • Dairy products like milk, cheese, and ice cream
  • Gluten, even if you don’t have celiac disease
  • Trans fats (the FDA banned them, but they still lurk in many fast foods and processed foods)
  • Vegetable oils including corn, sunflower, canola, and safflower oil (all contain inflammatory omega-6 fatty acids)
  • Refined or “white” carbs, such as white flour products, white pasta, and white potatoes
  • Alcohol

Nightshade vegetables like potatoes, eggplant, tomatoes, and peppers sometimes trigger inflammation as well.

Study after study shows that symptoms improve when people limit or stop foods linked to inflammation. In one survey, nearly half of patients with RA reported less pain and stiffness when they switched to a plant-based or Mediterranean-style diet. Both are rich in fruits, veggies, nuts, and olive oil. In another survey, patients with RA said blueberries and spinach improved their symptoms while sugar made them worse.

Food allergies are when the immune system mistakes a protein in food as harmful. To fight the perceived threat, it releases antibodies called immunoglobulin E (IgE). The next time you eat the food, these antibodies trigger the release of histamine, a powerful chemical that causes allergy symptoms. These can range from belly pain, hives, or tingling in your mouth to a life-threatening reaction called anaphylaxis. Symptoms usually appear right after eating.

Food allergies are much more common in infants and children than adults. About 1 percent of adults have food allergies compared to 7 percent of kids, though the number of kids with allergies is on the rise. And while food allergies usually start early in life, you can form one when you’re older.

These nine foods cause most food allergies:

  • Eggs
  • Milk
  • Fish
  • Shellfish (shrimp, scallops, and crab)
  • Peanuts
  • Tree nuts (walnuts, pecans)
  • Wheat
  • Soy
  • Sesame

Experts aren’t sure. We do know that both are the result of an overactive immune system. With a food allergy, your immune system attacks certain foods. In RA, it attacks your joints and other healthy tissues.

One study done in animals found high levels of milk and egg antibodies in rodents with RA. In a small human study, people with RA had far more cross-reactive food antibodies in their gut than normal. Cross-reactive antibodies react to more than one allergen. This might lead to joint inflammation and other RA symptoms.

Leaky gut may play a role in both food allergies and RA. Leaky gut is when inflammation damages the lining of the intestine. This can cause food allergens to “leak” into the bloodstream. Immune cells see the food allergens as a threat and go on the defense. This can lead to more inflammation that may harm joints.

Food allergies and RA seem to be much more common in people who have low levels of vitamin D. Symptoms may improve when vitamin D levels return to normal. For people with RA, the goal is a 25-hydroxy vitamin D blood level of 35 to 45 ng/mL.

Food sensitivities involve your digestive system. They usually happen when you can’t break down or absorb something you eat.

They’re much more common than food allergies. They’re also harder to track, since symptoms such as cramps, bloating, and diarrhea may not show up right away.

You can react to almost any food. Lactose, a sugar in milk and other dairy products, is common one. Millions of people, especially of Asian descent, lack the enzyme (lactase) needed to digest it. You can also be sensitive to:

  • Artificial colors and flavors
  • Preservatives
  • Sulfites in wine and beer
  • Alcohol
  • Aspirin

Then there’s a big group of foods called FODMAPs, which is short for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. These are carbs found in many healthy foods that some people can’t digest.

Research suggests that people who are sensitive to some items in a food group may be fine with others. For example, you may not be able to drink milk, but yogurt and hard cheese might be OK. It also depends on how much of a problem food you eat. Unlike food allergies, most people can handle small amounts of foods they’re sensitive to. Low-FODMAP diets describe exactly how much of each food you can safely eat.

It’s hard to miss a food allergy. Symptoms are sudden and often severe. Sensitivities are harder to track and may involve some trial and error. Your doctor may ask you to keep a food diary, where you note what you eat and when you have symptoms. This can help you spot the foods you might need to avoid. It’s also the first step in another approach called an elimination diet.

With this diet, you stop eating all sensitive foods for at least 2 weeks. If your symptoms don’t improve, you follow the diet for another 2 weeks. Once you go 5 days without symptoms, you start to add problem foods back into your diet, one at a time. If your symptoms flare, you limit or cut out the food completely. You may be sensitive to more than one food. An elimination diet can show you which ones. Then you can work with your doctor to make a long-term eating plan you enjoy and can stick to.

The elimination diet isn’t perfect and doesn’t work for everyone. Still, it’s a good way to zero in on foods that affect you. Thirty to 40% of people with RA feel much better when they cut sensitive foods from their diet. Some have even been able to stop their medications.