If you’ve thought your joints felt achy after a meal, only to doubt yourself after hearing that no evidence links food allergies and rheumatoid arthritis (RA), you are not alone. Until now there has been little evidence of foods that cause inflammation. Evidence suggests it may be time to consider a rheumatoid arthritis diet.

Most studies have focused on antibodies (proteins that attack and destroy foreign substances) in the blood, but that focus may have been wrong. Food-related antibodies may show up in the gut – rather than the blood – of people with RA, and that’s just where researchers at the University of Oslo, Norway, looked in a 2006 study.

They found that, in test tubes at least, the intestinal fluid of people with RA had higher levels of antibodies to proteins from cow’s milk, cereal, hen’s eggs, codfish and pork than that of people without RA.

How Food Allergies Occur and Cause Inflammation

“The gut is the first site of exposure to food, and the immune system in the gut is the first to recognize potential allergens,” says Jonathan Brostoff, DM, professor of allergy and environmental health at Kings College London.

Food allergies occur when your immune system mistakenly believes that something you ate is harmful. To protect you, the immune system produces immunoglobulin E – also called IgE antibodies – against that food. The antibodies set off a chain reaction that causes symptoms. 

In some people, the antibodies and proteins bind together and form immune complexes in the intestine. These immune complexes then circulate and get into every nook and cranny of the body, including the joints, where they may contribute to inflammation, says Dr. Brostoff.  Once antibodies are made against a particular food, the body instantly recognizes that food the next time it is consumed, and the cycle begins again.

So what should you do if you think certain foods cause inflammation and make your RA worse? Keep in mind that this study is preliminary, and it looked at results only in test tubes. The researchers withdrew intestinal fluid from the participants and then added the proteins to the fluid in the lab; participants didn’t actually eat the suspect foods. So unknowns remain.