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Research into diet and arthritis
There are some scientific reasons to think that diet affects arthritis.
Diet may serve as a risk factor by increasing your chances for developing certain kinds of arthritis. Diet may also change the way the body's defenses--the immune system react in certain kinds of arthritis that involve inflammation. Inflammation is a part of the body's defense system. It can cause the swelling, redness, warmth and tenderness that come with some kinds of arthritis.
How diet affects the response of the immune system is a central question in several research studies. These studies are looking at the role of diet in worsening or lessening symptoms in certain types of arthritis.
Some very early studies in animals or in small numbers of people with certain types of arthritis suggest, but do not prove, that changes in diet may help. The results of these studies are experimental. They need to be studied further in large numbers of people. So, there is not enough scientific evidence to recommend to people with arthritis any of the dietary changes described below, except for weight control.
Weight and osteoarthritis
Being very overweight or obese increases your risk for developing osteoarthritis in the knees. People who are very overweight tend to develop osteoarthritis in the knees at an earlier age than people with ideal weights for their heights. Weight is only one of several factors that increase your chances for osteoarthritis in the knees.
Food allergies and/or reactions
Reactions to certain foods by the immune system may lead to or worsen symptoms in certain kinds of arthritis. Researchers think it is possible that a small number of otherwise healthy people develop temporary symptoms of arthritis from an allergic reaction to food. In a few people who already have arthritis, reactions to certain foods may worsen symptoms. However, available observations suggest that for most people who thought their arthritis symptoms were related to food, a connection between food and the arthritis symptoms could not be confirmed.
Fasting, low calorie or low fat diets
The immune system may work to lessen symptoms in response to other factors in our diet. For example, several researchers have observed that fasting and low calorie/low fat/low protein diets slightly reduce some symptoms of rheumatoid arthritis in humans or lupus in animals. Scientists do not yet understand why this happens or if certain changes in diet, such as short-term fasts, help.
Fatty acids and/or fish oils
Another example of the possible effect of diet on arthritis is the role of certain fatty acids in the chemical chain reaction that causes inflammation. For instance, oils from some cold water fish and plants block the body from making certain chemicals. These chemicals cause painful inflammation in rheumatoid arthritis. More studies are needed to see if these oils are an effective and safe way to block inflammation.
How is diet researched?
Researchers test the role of diet in arthritis in certain ways. They accept that there is a connection between diet and arthritis only after a number of studies show the same results.
To test what effect a diet may have on arthritis, researchers will have one group of people with arthritis try a test diet. The foods in this diet are those thought to make arthritis better or worse. A second group of people stays on a diet that does not contain the foods being tested. Neither the researchers nor the people in the study are told who is in which group.
Both groups are alike. There are an equal number of men and women. The people are similar in their ages as well as in the kind of arthritis they have. People in both groups continue to follow their diets for a number of weeks. In addition, the people in both groups usually stay on their regular medical treatment programs during the study.
Researchers measure the amount of improvement--such as the amount of swelling in each joint--in each person by several different ways. Then, they compare the total improvement between the two groups to see if the test diet made a difference. Other researchers repeat the study at least three or four times in other groups of people with arthritis to see if they get the same results. Only then, do researchers accept the treatment as effective.
Health frauds or diets under study?
Some people claim that special diets, foods or supplements cause or cure arthritis.
These claims usually appear in magazine articles, books and on talk shows. Most claims for such diets have not been scientifically tested to prove that they work and are safe.
Some claims for special diets for arthritis are health frauds. There is no scientific basis for the claims. Other findings, like those described earlier in the section on research, are still under study. Still other claims have never been studied. All diets are considered unproven until repeated studies show they work and are safe.
When you hear about diet claims in the treatment of arthritis, ask the following questions:
- Does the diet eliminate any group of foods?
- Does it stress only a few foods or eliminate others?
If you can answer yes to either question, you are probably looking at an unproven diet.
Trying a change in diet
Most claims for special diets that help arthritis are unproven. But surveys show that many people believe that diet is linked to arthritis and try changes in their diets anyway. If you think something in your diet makes your arthritis either better or worse, talk with your doctor. And continue your regular medical care for arthritis even if you decide to try a diet change.
Healthy diets are important
Researchers are looking with increased interest at several roles diet may play in arthritis.
There is not yet enough scientific evidence to tell if and how people with certain kinds of arthritis should change their diet. For this reason, any claims for a special diet for arthritis are unproven. However, researchers stress the importance of a healthy diet for people with arthritis.
There are three major ways to change to a healthier diet, including:
- maintain ideal weight
- add variety fiber & starch
- reduce salt, fat & cholesterol, sugar, and alcohol
More information
There are many sources for answers to your questions about diet. A place to start is with your doctor. Your doctor can refer you to experts in diet and nutrition for help.
Cooperative Extension Services can help answer your questions about meal planning. Look in the "Government Offices" section of your phone book under "Cooperative Extension Service."
Credits
Some of this material may also be available in an Arthritis Foundation brochure. Contact the Washington/Alaska Chapter Helpline: (800) 542-0295. If dialing from outside of WA and AK, contact the National Helpline: (800) 283-7800.
Adapted from a pamphlet originally prepared for the Arthritis Foundation. This material is protected by copyright.
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