So what is the relationship between what, and how, we eat and arthritis?
Studies are difficult to do, because controlling people’s diet is difficult, and because it is often harder to fund studies of adequate size to really answer the questions.
Studies have been looking into this question for decades. One study from 1983 found no benefit from 10 weeks of a diet free of additives, preservatives, fruit, red meat, herbs, and dairy product.
Another small study published back in 1991, compared 27 patients who were in a health farm on a 7-10 day subtotal fast and then on a gluten free vegan diet for 3.5 months and compared them to 26 other patients who also stayed on a health farm but had a normal diet.
They found that the diet group had improvements not only in pain and stiffness, but in blood tests for inflammatory markers, the number of swollen joints and their general health by questionnaire. Remarkably, the health benefits were still there a year later.
The Mediterranean diet
The Mediterranean diet consists of plenty of plant foods such as unrefined cereals, fruit, vegetables, legumes and extra-virgin olive oil, moderate consumption of poultry, dairy products and eggs and low consumption of sweets and red meat. This diet is thought to be rich in antioxidants and anti-inflammatory nutrients so it has been explored in rheumatoid arthritis.
What about fish?
There has been a lot of interest in omega-3 fish oils. There are suggestions that patients taking these supplements are more likely to respond to traditional treatments of rheumatoid arthritis. Also, in a questionnaire of patients with rheumatoid arthritis (RA), those who ate fish more frequently were likely to have milder disease.
The American College of Rheumatology warns: “Fish oils that contain omega-3 fatty acids have been reported to relieve pain and joint tenderness in patients with rheumatoid arthritis. The benefits are modest and may take several months to appear. Side effects may include gastrointestinal distress and a fishy odour to the breath. Those who consider fish oil supplements should be aware that some fish oil supplements may contain high levels of mercury or vitamin A, which could be toxic.
A review of all the published trials in 2009 concluded that it was uncertain whether there were benefits from various diets including: vegetarian, Mediterranean, elemental and elimination diets for patients with rheumatoid arthritis. A more recent study did find an association between eating a Mediterranean diet and a lower risk of rheumatoid arthritis but, perplexingly, only in men!
A survey was conducted of 217 patients with rheumatoid arthritis. 24% reported that foods affect their rheumatoid arthritis symptoms, with 15% reporting improvement and 19% reporting worsening.
Blueberries and spinach were the foods most often reported to improve RA symptoms, while soda with sugar and desserts were those most often reported to worsen RA symptoms.
I’m confused! Please summarise!
There’s no really great conclusive evidence out there yet. It is possible that a Mediterranean diet is somewhat helpful, and it might be that having a few more fish is helpful too, but the effects are fairly small. It is probably best to stick to a sensible healthy well-balanced diet, and that’s about all we can say with confidence.