Red Meat Increases Risk of Rheumatoid Arthritis
December 13, 2004
By: Laurie Edwards for Knee1
A new study released by England’s University of Manchester suggests that consuming large amounts of red meat may be a contributing risk factor in developing rheumatoid arthritis. Patients in the study, published in the December issue of Arthritis and Rheumatism, were twice as likely to develop the autoimmune disease as their less carnivorous counterparts.
Rheumatoid arthritis (RA) is a chronic disease that attacks the joints and surrounding tissues in the body, causing pain and inflammation that can lead to the permanent degeneration of joints and cartilage. Typical symptoms include painful swelling of the joints, especially hands, wrists, hips and ankles, as well as morning stiffness, general fatigue and in more severe flare-ups, difficulty walking or completing other daily tasks.
An estimated 2.1 million people—or roughly 1 percent of the country’s population—suffer from RA, the majority of them women.
RA is characterized by an immune response in which certain cells are mistakenly classified by the body as foreign entities and are attacked as such. Researchers point to a host of possible risk factors for the disease: a viral or bacterial infection, family history of autoimmune disorders, genetic defects, obesity and smoking. Females and people of Native American ethnicity are also more heavily predisposed towards developing RA.
The University of Manchester study followed 88 patients recently diagnosed with RA in at least two joints and 176 control subjects. Participants in the study were asked to complete a seven-day food diary, and after adjusting the results for smoking and other possible dietary factors contributing to the disease, researchers discovered that those who ate meat every day doubled their risk, while those who at it less regularly, around twice a week, did not. People who consumed red meat with other meat products faced comparable risk.
While consumption of protein from a variety of dietary sources was attributed to an increased risk of developing RA, higher levels of fat, including saturated fat, were not.
Researchers caution that it is only people who have an existing predisposition for RA who consume large quantities of meat that face this increased risk.
Like many of the potential risk factors for RA, researchers are not yet certain as to the exact mechanism that causes red meat to increase a person’s likelihood of developing the chronic illness. “A high level of red meat consumption may present a novel risk factor for inflammatory arthritis or may act as a marker for a group of persons with an increased risk from other lifestyle causes. It is unclear whether the association is a causative one.”
Researchers speculate that it could be that the iron from meat accumulates in membranes and causes tissue damage, or that the collagen in meat triggers this faulty immune response.
“It may be that the high collagen of meat leads to collagen sensitization and consequent production of anti-collagen antibodies, most likely in a subgroup of susceptible individuals. Meat consumption may be linked to either additives or even infectious agents, but again, there is no evidence as to what might be important in relation to RA,” said the authors.
Studies of people in Mediterranean countries, where red meat makes up a much smaller component of a typical diet, found lower incidences of RA among participants. In addition, vegetarian or vegan diets have been found to reduce the risk of RA.