Arthritis and nutrition
Researchers have been exploring potential links between diet and arthritis for many decades, but apart from the effect of diets rich in purine on gout, there is still no agreement on the results of many of these nutritional studies.
There is little scientific evidence that taking expensive food supplements or eating elaborate diets is beneficial. Rather, the same results can be obtained by eating balanced meals that keep your weight down while providing all the vitamins and minerals you need.
For this reason you should try to eat a diet that:
- contains plenty of cereal foods, vegetables and fruits;
- is low in fat; and
- includes only moderate amounts of sugar, salt and alcohol.
The weight factor
Your weight is the single most important link between diet and arthritis, as being overweight puts an additional burden on your hips, knees, ankles and feet. If you are unable to exercise as much because of your arthritis, you should reduce your calorie intake. This will prevent excess energy from the food you eat being stored in your body as fat. However, you should continue to eat foods that have lots of vitamins and minerals such as fruit and vegetables and wholemeal, starchy foods, and cut down on fats and sugars.
Excess body weight is a problem for many people with arthritis, particularly those whose condition restricts them to a more sedentary lifestyle. People with rheumatoid arthritis who are taking corticosteroids may also have weight gain as a side effect of the steroid treatment.
Sometimes people with rheumatoid arthritis have a poor nutritional status as a result of weight loss. It can also be difficult for people with arthritis to increase their food intake if they experience pain when trying to prepare meals or go shopping, or if they are taking other medicines that cause gastritis or peptic ulcers.
Vitamins and minerals
People with rheumatoid arthritis may experience the following vitamin and mineral deficiencies: folate, vitamin C, vitamin D, vitamin B6, vitamin B12, vitamin E, calcium, magnesium, zinc and selenium.
Taking vitamin supplements may help redress a deficiency, but increasing their intake has not been shown conclusively to slow the progression of arthritis, or alleviate its symptoms.
Folate, found in green leafy vegetables and wholegrain cereals, is important for people with rheumatoid arthritis who have been prescribed methotrexate, since it can help reduce some of the oral and gastrointestinal side effects of the medicine. Folic acid is the manufactured version of folate.
Calcium and vitamin D
Making sure you get enough calcium (found in dairy products and vegetables such as broccoli, Brussels sprouts and cabbage) and vitamin D (from sunlight and fortified dairy products) is recommended to counter the effects of long-term therapy with steroid medicines such as prednisolone, which can contribute to osteoporosis.
It has also been suggested that increased intake of antioxidants such as selenium and vitamin E may decrease free-radical damage to the linings of the joints, although this has not been clinically proven.
Many people with arthritis are anaemic, but this is not always helped by iron. The anaemia may be due to blood loss associated with bleeding ulcers if you are taking non-steroidal anti-inflammatory drugs (NSAIDs). Your doctor will advise you if you need more iron.
Omega-3 fatty acids
In recent years, researchers have become increasingly interested in the benefits of Omega-3 fatty acids which are found in fish oils. These essential fatty acids (EFAs) appear to have an effect on the inflammatory process.
Some studies have shown that taking Omega-3 fatty acid supplements can relieve joint pain and stiffness in people with rheumatoid arthritis, however, the doses used in these studies may be more than people would take when buying supplements themselves. Benefits from fish oils are modest, and may take months to appear.
As well as possibly helping rheumatoid arthritis, Omega-3 fatty acids help reduce blood clotting and protect against heart disease. It’s important not to confuse fish oils with fish liver oils (such as cod liver oil). Fish liver oils contain a lot of vitamin A, which can be dangerous in large amounts and should not be taken by pregnant women as it may harm the baby.
Glucosamine and chondroitin
Glucosamine has also become popular as a treatment for osteoarthritis. There is some evidence that it may help control pain, and may even slow cartilage deterioration. However, a Cochrane analysis of clinical trials examining the usefulness of glucosamine suggests its effect on pain may be less than first thought. More trials are needed to assess its possible effect of slowing deterioration.
Chondroitin is another commonly used treatment, but currently there is limited scientific evidence to support a significant benefit in treating osteoarthritis.
Elimination diets are a way of trying to identify the foods that may cause hypersensitivity in people. On an elimination diet, you would stop eating foods that may be causing your arthritis symptoms and then bring foods back into your diet one at a time. Elimination diets should be followed only under the guidance of a doctor to make sure you are still obtaining necessary nutrients. It is still very difficult to isolate foods because many foods are hidden ingredients in other foods. The usefulness of elimination diets in arthritis is probably questionable, as only a tiny percentage of people truly suffer from food allergies.
The evidence for foods causing arthritis or making it worse is very controversial and the list of the foods that have been implicated in causing flare-ups in arthritis is quite substantial, including milk and dairy products, food colouring, additives and preservatives, chocolate, red meats, salt, sugar, coffee and nightshade vegetables (such as potatoes, tomatoes and eggplant).
Some studies have looked at the relationship between inflammation of the gut and inflammation of the joints. Researchers have looked at lectins, food substances found in cereal grains such as wheat, rye, barley, oats and corn, or legumes such as peas and beans, which it has been suggested may promote the development of rheumatoid arthritis in genetically susceptible individuals. Lectins are said to cause the walls of the digestive tract to become leaky. Researchers propose that material normally kept inside the gut may leak into the body, prompting an immune reaction that leads to inflammation in the joints.
It can be quite difficult to determine accurately whether a particular type of food adversely affects your arthritis. The power of suggestion can be very strong, and some foods used in cooking may be eaten without you realising. Further complicating the issue is that arthritis is not constant — it flares up in an attack and then may calm down.
Each individual is different and there is no one food reported to cause symptoms in everyone. There are many books that recommend all sorts of exclusion diets and claim miraculous results, but these are controversial and may deprive your body of essential nutrients.
In the absence of concrete evidence, it is best to avoid unproven nutritional practices. If you have concerns about the adequacy of your diet, talk to your doctor.
2. Towheed T, Maxwell L, Anastassiades TP, et al. Glucosamine therapy for treating osteoarthritis. Cochrane Database of Systematic Reviews 2005, Issue 2. Art. No.: CD002946. DOI: 10.1002/14651858.CD002946.pub2. Available at: http://www.cochrane.org/reviews/en/ab002946.html (Accessed 2009, Dec 17)
3. Hagen KB, Byfuglien MG, Falzon L, Olsen SU, Smedslund G. Dietary interventions for rheumatoid arthritis. Cochrane Database of Systematic Reviews 2009, Issue 1. Art. No.: CD006400. DOI: 10.1002/14651858.CD006400.pub2. Available at: http://www.cochrane.org/reviews/en/ab006400.html (Accessed 2009, Dec 17)