Diet, nutrition and arthritis

Key points

From research findings so far, we recommend that you should:

• Lose weight by changing your eating habits and by taking exercise.
• Eat less sugar.
• Eat more fruit and vegetables, especially the brightly coloured varieties that contain antioxidants.
• Eat plenty of calcium- and iron-rich foods.
• Eat less saturated fat – these are mostly animal fats and for most people the main source of them is dairy products: milk, cheese yoghurt etc (use monounsaturated oils such as olive oil and rapeseed oil instead if need be).
• Try to incorporate 'good fats' such as omega-3 oils (fish oil) into your diet.
• Try to eat oily fish at least twice a week (unless you have gout).
• If you have inflammatory arthritis (other than gout) consider further increasing your intake of oily fish and/or fish oil supplements
• Get your vitamin and minerals from the food you eat rather than from supplements – a well balanced diet is the best way to give your body what it needs.
• Getting out in the sun regularly can boost your vitamin D levels.

Because of the way joints work, the pressure in your knee joints is 5–6 times your body weight when you walk so even a small weight loss can make a big difference if you have arthritis.

Having too much body fat may also increase inflammation in the body, making your joints more painful. Evidence shows that achieving a healthier weight can reduce inflammation. This can be seen in blood test results for inflammation such as CRP (C-reactive protein) and ESR (erythrocyte sedimentation rate).

Your body needs food to supply energy and a variety of vitamins and minerals to stay healthy. If your diet contains more energy than you use, your body will convert the surplus to fat, and you will put on weight. Conversely, if your food contains less energy than you are using, you will lose weight.

If you have arthritis you may find it hard to get as much exercise as you did before. If you are burning less energy you are likely to put on weight unless you also reduce your calorie intake. If you eat fewer calories, it's important not to lose out on vitamins and minerals. Foods such as fruit and vegetables are high in vitamins and minerals but low in calories.

Cut down on fat

Fat has twice as many calories as the same weight of starch or protein and most people eat far more fat than they need for health. Eating 30 g (about 1 oz) less fat each day saves 270 calories.

There are three kinds of fats in foods:

Saturates – These are mostly of animal origin and are found in:

• full-fat dairy products
• processed foods like biscuits, cakes and pastry
• chips (if fried in animal fat)
• Asian foods, especially meals cooked using ghee (clarified butter).

Some vegetable oils, such as palm oil and coconut oil, also contain a lot of saturates. Saturated fats are the most important kind of fat to reduce since they can increase the pain and inflammation in the body.

Monounsaturates – as found in olive and rapeseed oil. These are 'neutral' fats in that they do not worsen inflammation, but they contain just as many calories as saturated fats, so limiting them is still important to lose weight.

Polyunsaturates – Softer fats and oils from corn or sunflower sources are high in what are called omega-6 polyunsaturates and these can also increase general inflammation in the body.

To eat less fat:

• Avoid 'invisible' fats in foods like biscuits, cakes, chocolate, pastry and savoury snacks – check the labels.
• Choose lean cuts of meat, which don't contain much saturated fat, and always trim off excess fat.
• Choose fish and poultry more often.
• Use skimmed or semi-skimmed milk.
• Use low- or reduced-fat dairy products (e.g. yogurt, low-fat cheese).
• Use low-fat, olive-oil-based or soya margarines.
• Grill instead of frying.
• Use a small amount of olive oil or rapeseed oil (rather than sunflower oil) when needed.
• Fill up on wholegrain breads, cereals, fruits and vegetables.
• Look for snacks that are naturally low in fat, such as fruit, vegetable sticks or plain popcorn. Small quantities of nuts and seeds provide beneficial fats but do not appear to cause weight gain.

Cut down on sugar

Sugar contains only calories and has no other food value so it can be cut without any loss of nourishment. Eating 30 g (about 1 oz) less sugar each day saves 120 calories. Dried fruit like raisins can be used to sweeten cereals and puddings; unlike sugar and artificial sweeteners, they also provide vitamins and minerals.

Eat more fruit and vegetables

The World Health Organisation recommends at least five portions of fruit and vegetables every day. This is to make sure the body receives the important nutrients – particularly vitamins, minerals and antioxidants – that it needs to maintain good health and to protect it during the stress of disease.

For people with arthritis this is even more important because:

• Antioxidants help to protect joints.
• Antioxidants reduce inflammation by 'mopping up' some of the body chemicals that cause inflammation.
• Research has shown that people who eat plenty of fresh fruit and vegetables, especially those containing vitamin C, seem to have a lower risk of developing inflammatory arthritis.

Top tip: Brightly coloured vegetable and fruits are richer in antioxidants!

Exercise regularly

Not only does exercise burn calories that would otherwise end up as fat, but it also increases your strength and suppleness. Of course, arthritis can make exercise difficult and painful. So it’s important to find something you enjoy and so do it regularly.

Vitamin C

Poor vitamin C intake has been linked with arthritis but if you follow the '5 fruit and vegetables per day' advice, you shouldn't have a problem with vitamin C, and we don't recommend supplements.

Calcium

Calcium is important for maintaining healthy bones. Calcium deficiency increases the risk of osteoporosis (brittle bones), which is quite common in women after the menopause. Many people with arthritis have a risk of developing osteoporosis.

The richest sources of calcium are:

• milk (skimmed or semi-skimmed milk contains more calcium than full-fat milk)
• cheese
• yoghurt
• fish that are eaten with the bones (such as sardines)
• calcium-enriched soya milk.

We recommend a daily intake of calcium of 1,000 milligrams (mg) or 1,500 mg if you are over 60. 

Vitamin D

Vitamin D is needed for the body to absorb calcium and there's some evidence that arthritis progresses faster in people who are low in it.

Vitamin D is produced by the body when the skin is exposed to sunlight, so a slight deficiency is quite common in winter. It can also be obtained from the diet (especially from oily fish) or from supplements such as fish liver oil. However, it is important not to take too much fish liver oil.

If you are over 60, dark skinned or don't expose your skin much to the sun,  it may be helpful to take a supplement containing 10–20 micrograms (µg) of vitamin D. (See Osteomalacia for more information on vitamin D and vitamin D deficiency.)

Iron

Iron is important to prevent anaemia. Many people with arthritis are anaemic. The anaemia can be due to different causes. NSAIDs (non-steroidal anti-inflammatory drugs) such as aspirin, ibuprofen and diclofenac help the pain and stiffness of arthritis but may cause bleeding and stomach ulcers in some people, leading to anaemia. The other main cause of anaemia in arthritis is 'anaemia of chronic disease', which often occurs with rheumatoid arthritis and similar conditions, and doesn't improve with iron supplements. If you are anaemic your doctor can tell you if more iron is likely to help.

Good sources of iron:

• red meat
• oily fish e.g. sardines
• pulses e.g. lentils and haricot beans
• dark green vegetables e.g. spinach, kale and watercress.

Iron is absorbed better if there is also vitamin C in the meal, so have a good portion of fruit or vegetables with your meal. Avoid drinking tea with your meal as this reduces the amount of iron that your body can absorb.

Selenium

Mild selenium deficiency is quite common in the UK and may be associated with more rapid progression of arthritis. The richest natural source of selenium is Brazil nuts, but meat and fish also contain some. Selenium is nearly always included in antioxidant vitamin and mineral supplements which you can buy in chemists and health food shops.

What are fatty acids?

When the fats and oils we eat are broken down by the digestive system they break down into fatty acids. The nature of the fat or oil depends on the type of fatty acid it is made of. Some fatty acids can be made by the body from other compounds. But some cannot be made and must be obtained from food – these are called essential fatty acids (EFAs). Polyunsaturated fatty acids are divided into two main groups – omega-3 and omega-6.

Omega-3 (or 'n-3') fatty acids exist in two forms:

• ‘long-chain’ forms such as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) – found in high levels in oily fish such as pilchards, sardines, mackerel, kippers and salmon
• ‘short-chain’ forms, such as ALA (alpha-linoleic acid) – found in  rapeseed oil, hemp oil, flaxseed oil and walnuts

Omega-6 (or 'n-6') fatty acids are found mostly in plant seed oils such as sunflower and corn oil.

The body uses both these types of fatty acids to make chemicals called prostaglandins and leukotrienes; the right balance of these helps to control inflammation in the body.

How do I increase my intake of fatty acids?

There’s good evidence that high doses of fish oil benefit inflammatory arthritis. The active ingredients are the long-chain fatty acids DHA and EPA, and research suggests you need at least 2.7 g (2,700 mg) per day. You can buy supplements from health food shops and some chemists. The capsules are usually 1 g (1,000 mg) but aren’t pure DHA and EPA. Even with ‘high strength’ preparations you may need 4–5 capsules per day. Fish oils are also available in liquid forms. Fish oils are quite slow-acting so we recommend you give them at least 3 months’ trial. There’s no particular advantage in splitting the dose over the course of the day, although some people find this helps to avoid minor digestive problems.

Research to find out whether fish oils can be helpful for osteoarthritis has so far been inconclusive.

It’s possible that short-chain omega-3 essential fatty acids may be converted within the body into the long-chain forms which benefit arthritis, but it’s not certain that they are as beneficial as the long-chain omega-3 fatty acids found in fish oil. Omega-3s also help protect against heart disease.

Read more on fish oil and fish liver oil, from our authoritative report.

What about omega-6 polyunsaturated fatty acids?

Omega-6 (also called ‘n-6’) polyunsaturated fatty acids aren’t thought to be of benefit in arthritis and in fact they may increase inflammation by competing in the metabolism with omega-3 polyunsaturated fatty acids.

In the UK, most people have diets that already contain more omega-6 than is needed, so it may help to cut down on the amount of omega-6 in your diet (such as sunflower oil, corn oil, and products made from these such as sunflower margarines).

Are there any possible side-effects of polyunsaturated fatty acids?

In theory, polyunsaturated fatty acids can generate harmful substances called free radicals in the body. Free radicals can be eliminated by antioxidants. Vitamin E is an effective antioxidant for omega-3 fatty acids, especially those found in fish oil. If you are taking a lot of fish oil (2 grams a day or more), you should eat plenty of fresh fruit and vegetables and include foods with good levels of vitamin E – for example:

• sunflower seeds
• nuts, especially almonds
• avocado
• spinach
• breakfast cereals that have extra vitamin E added.

Combined preparations of antioxidant vitamins and minerals, which contain vitamin E, selenium and other antioxidants, can be found in chemists and health food shops.

Glucosamine sulphate and chondroitin for osteoarthritis

Osteoarthritis is often regarded as a mechanical or 'wear and tear' form of arthritis. It particularly affects the weight-bearing joints of the legs and back. Changes to the cartilage affect the ability of the bones to glide over each other and to absorb shocks.

Many people try glucosamine, sometimes combined with chondroitin. The reason behind their use is that joint cartilage contains substances related to glucosamine and chondroitin and taking supplements of these natural ingredients may help improve the health of damaged osteoarthritic cartilage.

The research findings are conflicting; some recent studies have not shown a beneficial effect. Many people, however, report them to be effective. If you are thinking of trying glucosamine we suggest taking 1,500 mg per day. If you notice an improvement in your joint pain after three months you may wish to continue with this. There doesn’t seem to be much extra benefit in taking glucosamine combined with chondroitin.

You should bear in mind the following:

• Glucosamine can increase the level of sugar in the blood, so if you have diabetes be sure to check your blood sugar and discuss with your doctor if your blood sugars seem to be higher.
• If you are taking warfarin your blood-thinning control (international normalised ratio, or INR) may be affected, so make sure you have your regular blood checks and again discuss this with your doctor.
• Glucosamine is often made from shellfish. If you are allergic to shellfish make sure you take a vegetarian or shellfish-free variety.

Research into complementary therapies is continuing all the time. Read our detailed authoritative report covering therapies for rheumatoid arthritis, osteoarthritis and fibromyalgia.

• Some foods tend to produce substances that may aggravate arthritis. This is the case, for instance, with gout. However, in this case the effects of losing weight and reducing the amount of alcohol you drink are more significant than the effect of cutting out particular foods.
• Fasting can have a temporary effect on rheumatoid arthritis. However, it is not recommended as a treatment for arthritis. If you do want to fast this should only be done under specialist supervision.
• Vegetarian diets have been shown to be helpful in the long term to some people with rheumatoid arthritis. Some studies have shown that people who eat a lot of red meat seem to have a higher risk of developing inflammatory arthritis.
• A vegan diet (i.e. no meat, fish, or other animal products such as eggs, milk, cheese or other dairy-based foods) may also be helpful. If you eat a vegan diet you’ll need to take special care to make sure you get all the nutrients you need, particularly calcium, vitamin B12, vitamin D and selenium. Some soy milks and vegetable margarines have added vitamin D, although moderate exposure to sunlight is probably a better source if you are pale-skinned. If you are darker-skinned or prefer to keep your skin covered you may need to consider taking a vitamin D supplement. Some breads have added calcium. Yeast extract is a good source of vitamin B12 and Brazil nuts are rich in selenium.
• Some people believe certain foods are bad for arthritis. These include acidic fruit (e.g. oranges, lemons and grapefruit) and vegetables from the so-called nightshade family (solanaceous plants) including potatoes, tomatoes, aubergines, chillies and peppers.

There’s no scientific evidence that leaving out any of these foods helps arthritis, and doing so may reduce the beneficial antioxidants in the diet.

What about food allergies?

Research has shown that some people can have an improvement in their symptoms by excluding some foods, although the reasons for this aren’t yet clear. Non-steroidal anti-inflammatory drugs (NSAIDs), which are commonly used for arthritis, increase the permeability of the gut, causing it to become ‘leaky’. This allows larger molecules of food to pass through than would normally be the case, causing food sensitivity. So if you are able to reduce your NSAIDs, you may become less food-sensitive.

Finding out whether you really are sensitive to a particular food can be quite a difficult process. The only way to be sure that you have a food allergy is an elimination (or exclusion) diet where you leave out a certain food from your diet, for a period of 3–4 weeks, followed by a ‘challenge’, where you reintroduce the food to see if it causes a reaction. If you think you have food sensitivities it’s worth consulting a dietician who can make sure you are excluding foods correctly and check that your diet is providing enough nutrients.

Labels on pre-packaged foods now have to make it clear if the food contains certain ingredients (e.g. milk or wheat) that people may be allergic to.

Are there any diets or food supplements that research has shown not to be beneficial?

• There’s no scientific evidence to demonstrate that cider vinegar and honey – often recommended for arthritis – is helpful.
• MSM (methylsulphonylmethane) is a sulphur-containing substance that has been recommended for various health problems, including arthritis. However, there’s no strong evidence to support the effectiveness of MSM for treating arthritis symptoms.
• CMO (cetylmyristoleate) is a waxy substance made from beef fat, which it is claimed can help arthritis. Again, there’s little scientific evidence that it does so.

In fact, if you are, there’s even more reason to eat a good diet as it can help to protect the body against some potential side-effects of drugs. For example steroids, such as prednisolone, can cause osteoporosis over a period of time. Plenty of calcium in your diet will help to reduce this risk.

In addition, some of the changes we recommend can help to reduce the need for drug treatments – losing weight, eating a healthy diet, perhaps excluding some foods, and increasing your omega-3 polyunsaturated fatty acid intake, either through foods or supplements or both.