A good diet is essential for health, and many complementary and alternative therapists advise on diet. Dietary changes can help many people with arthritis, both inflammatory types and osteoarthritis.
As well as having a healthy, balanced diet, getting additional nutrients from food supplements may help if you have arthritis.
Omega-3 fatty acids for inflammatory arthritis
Omega-3 polyunsaturated fatty acids EPA and DHA (found naturally in oily fish) can be helpful if you have inflammatory arthritis (including rheumatoid arthritis, reactive arthritis, psoriatic arthritis and ankylosing spondylitis, but not gout). Quite large amounts of omega-3 are needed for the best effects, so a concentrated fish oil supplement providing 3 g of EPA and DHA (i.e. total EPA + DHA) is available.
Fish oils act quite slowly, so you may want to try them for 3 months to see if you notice any benefit.
Some people find high doses of fish oils upset their stomach. If this is a problem you could try taking two or three smaller doses during the day. Or try eating oily fish instead – at least twice a week, but not more than four times a week. However, if you have gout, ily fish is generally best avoided.
If you’re vegetarian, or fish oil disagrees with you, you can get other types of omega-3 fatty acids from flaxseed oil, rapeseed oil and walnuts, but we don’t know whether they’re as beneficial as the EPA and DHA found in fish oil.
It's important not to confuse fish oil with fish liver oil. Lots of people take cod liver oil for osteoarthritis, but there’s no evidence to show that it makes a difference to the condition. Also, large doses of fish liver oil could potentially result in an overdose of vitamin A – this is particularly dangerous in women who are pregnant or might become pregnant because too much vitamin A could be harmful to an unborn baby. If you want to increase your intake of omega-3 fatty acids, we recommend taking pure fish oil rather than fish liver oil.
There’s some evidence to suggest that vitamin E can play a role in the treatment of arthritis by preventing damage in the cells of your bones and joints. It may also have anti-inflammatory properties.
It’s important to include vitamin E in your diet, especially if you’re taking a lot of fish oil, but you should avoid doses of more than 400 mg a day of vitamin E. The following foods are rich in vitamin E:
- plant oils (including soya, wheat and olive)
- sunflower seeds
Mild selenium deficiency is quite common and it has been suggested that deficiency may result in your arthritis progressing more quickly, although there’s doubt about this. Selenium is usually derived from yeast for medicinal purposes. It’s available as part of most vitamin or mineral supplements or on its own in the form of capsules.
We get most of our vitamin D from the action of sunlight on our skin, particularly during the summer. From June to August, 15 minutes a day in the sun with your arms exposed to the elbows is enough. Darker skin needs more, and more exposure is needed in winter.
Slight vitamin D deficiency is quite common, especially in winter in the UK. A lack of vitamin D can lead to the development of osteomalacia (soft bones) and osteoporosis. The effect of vitamin D supplements on the progression and pain of knee osteoarthritis is currently being evaluated.
The vitamin D content of most foods is low, but the best sources are eggs and oily fish, particularly herrings (grilled), salmon (fresh and tinned) and mackerel. Some foods are fortified with vitamin D such as margarine, various breakfast cereals and powdered milk.
Glucosamine sulphate and chondroitin for osteoarthritis
Many people take glucosamine sulphate tablets with or without added chondroitin for osteoarthritis. Cartilage contains substances related to glucosamine and chondroitin, and taking supplements of these natural ingredients may nourish damaged cartilage. Research results are mixed but suggest that some people will benefit from this therapy.
Research suggests glucosamine sulphate is more likely to be helpful than glucosamine hydrochloride. If you're thinking of trying glucosamine we suggest taking 1500 mg per day of glucosamine sulphate. You may want to try glucosamine and chondroitin supplements for 3 months, and if your joint pain improves you can choose to continue with them.
If you’re allergic to shellfish, there are vegetarian or shellfish-free forms of glucosamine available.
Glucosamine can increase the level of sugar in the blood, so if you have diabetes it would be useful to discuss glucosamine with your doctor before you start to take it. You should also speak with your doctor if your blood sugars seem to be rising after starting glucosamine.
If you’re taking warfarin your blood-thinning control (international normalised ratio or INR) may be affected, so make sure you have your regular blood checks and discuss using glucosamine with your doctor.
Some people find that certain foods aggravate their arthritis and avoid these foods. The only way to be sure that you have a food intolerance is by dietary 'exclusion and challenge' where you leave out a certain food for several weeks. This is followed by a 'challenge', where you reintroduce the food to see if it causes a reaction. If your arthritis is related to a food allergy you'll notice a flare-up of your symptoms within a few days. It's important to cut out each food you're testing completely and re-introduce them one at a time.
It's better, if possible, to eat a balanced diet, rather than relying on nutritional supplements. For instance, for most people dairy products (milk,cheese, yogurt) are important sources of calcium, which is essential for strong bones. If you don't eat dairy products you will need to think about other sources of calcium.
Are they safe?
For more information on the above and many more supplements and alternative medicines, see our authoritative report. This report has a detailed safety and effectiveness scoring system for each product.
Read more about complementary and alternative medicines for the treatment of rheumatoid arthritis, osteoarthritis and fibromyalgia.
Read more about diet and arthritis.