Diet and arthritis: what the evidence shows

It is worth saying plainly: no food, diet or supplement cures arthritis. What diet can do depends a great deal on which type you have. In osteoarthritis, the wear-related type, diet works mainly through weight. In inflammatory arthritis such as rheumatoid arthritis, the disease is driven by the immune system and needs medication to control it, with diet playing a supporting role. The sections below take each in turn.

This is where diet has its strongest evidence. In osteoarthritis, particularly of the knee, losing excess weight reduces pain and improves how well the joint works, and UK guidance from NICE recommends it for anyone who is overweight. The effect is mechanical as well as chemical: carrying less weight means less load through the joint with every step, and trials combining a healthy diet with exercise have shown reduced strain and inflammation around the knee. A balanced, calorie-appropriate diet that helps you reach and hold a healthy weight is the most useful dietary change you can make for osteoarthritis.

For rheumatoid and other inflammatory arthritis, a Mediterranean-style way of eating, with plenty of vegetables, fruit, wholegrains, olive oil and oily fish and less red and processed meat, may modestly ease symptoms such as pain and stiffness. Omega-3 from oily fish, or fish-oil supplements, may help a little too. The honest position is that the evidence is limited and not conclusive, so think of this as a healthy, supportive measure rather than a treatment. It does not replace your disease-modifying medication (DMARDs), which remains essential to control the disease and protect the joints, so keep taking it as prescribed.

A great deal of popular diet advice for arthritis has no good evidence behind it:

• Nightshades are fine. There is no evidence that tomatoes, peppers, aubergines or potatoes cause inflammation or make arthritis worse.
• Do not cut out whole food groups. Elimination diets, or going gluten-free without coeliac disease, are not recommended and can lead to nutritional deficiencies. The risks usually outweigh any benefit.
• Glucosamine and chondroitin supplements do not have good evidence of benefit.
• Be wary of miracle cures. Expensive anti-inflammatory diets and supplements that promise to cure arthritis rarely deliver. If a claim sounds too good to be true, it usually is.

Even where the direct effect on the joints is modest, eating well matters. People with inflammatory arthritis have a higher risk of heart disease, so a balanced, Mediterranean-style diet and a healthy weight protect your heart, your energy and your overall wellbeing. A good diet is worth it for the whole of you, not only your joints.

The most useful step is to know exactly what you are dealing with, because the right diet for osteoarthritis is not the same as for rheumatoid arthritis. Our guides to osteoarthritis and rheumatoid arthritis explain each in more detail. Discuss any major dietary change with your team, and never stop prescribed treatment in favour of a diet.

Can diet cure my arthritis?

No. No diet or supplement cures arthritis. For inflammatory types such as rheumatoid arthritis, medication is essential to control the disease; diet is a supportive measure, most powerfully through weight management in osteoarthritis.

What is the single most effective dietary change?

For osteoarthritis, losing excess weight. It has strong evidence for reducing pain and improving how the joint works, especially in the knees, because it lowers the load going through the joint.

Should I avoid nightshade vegetables like tomatoes and peppers?

There is no evidence that nightshades cause inflammation or make arthritis worse. Cutting out healthy food groups is not advised and can do more harm than good through nutritional deficiencies.

Do omega-3 or fish oil supplements help?

A Mediterranean-style diet with oily fish, or omega-3 supplements, may modestly help symptoms in inflammatory arthritis, but the evidence is limited. They are a reasonable support alongside, not instead of, your treatment.

Should I try an elimination or anti-inflammatory diet?

Be cautious. Cutting out whole food groups risks nutritional deficiencies and rarely helps. A balanced, Mediterranean-style diet is a safer, evidence-based choice. Discuss any major change with your team and never stop prescribed treatment in its favour.