A painful form of arthritis in the foot affects one in six people over 50 - more than previously thought, research suggests.
Experts at Keele University's Arthritis Research UK Primary Care Centre studied more than 5,000 people with painful foot osteoarthritis.
The condition is caused by inflammation in and around the joints, damage to cartilage and swelling. People can suffer a range of symptoms including pain, stiffness and difficulty moving and often have osteoarthritis in other joints, such as hips or knees.
The study found that foot osteoarthritis affects more women than men, while those who have spent a lot of time in manual work are more likely to develop it.
Three quarters of people with the condition reported having difficulty with simple day-to-day activities such as walking, standing, housework and shopping.
Dr Edward Roddy, clinical senior lecturer in rheumatology at Keele University, said the research had focussed on "midfoot" joints, which previous studies have neglected to do.
He said a "substantial proportion of people" with painful foot osteoarthritis have the problem in this area, meaning there has been a previous underestimate in how common it is.
If you’re overweight, losing those excess pounds may take some of the pressure off of your joints. “If I have a patient with RA who’s overweight and loses 10 pounds, every time he takes a forceful step forward, that’s 30 pounds less on weight-bearing joints [such as the hips and knees],” says Dr. Hadler. What’s more, it may also improve quality of life. A 2006 study found that overweight and normal weight people with RA had a higher quality of life than those who were obese. More from Health.com: 10 Ways Rheumatoid Arthritis Affects the Body How RA Differs from Osteoarthritis 10 Ways to Ease Rheumatoid Arthritis Pain
Several studies suggest that people with RA may benefit from fish oil supplements, which contain inflammation-fighting omega-3 fatty acids. RA patients are also at greater risk of cardiovascular disease, and fish oil is thought to be good for the heart too. However, studies suggest that you need to get 3 grams of omega-3 fatty acids per day (a 4-ounce piece of salmon has a little over 2 grams) for 12 weeks, which could get pricey or the diet hard to maintain.
In a 2003 Swedish study, people with RA who ate a Mediterranean diet rich in fruits, vegetable, cereals, legumes, and olive oil for three months experienced improved physical functioning and vitality when compared to RA patients who did not. The effects of the Mediterranean diet on rheumatoid arthritis long-term are still unclear, but including more fruits and vegetables in your diet isn’t a bad idea.
At least one study found that people who ate a vegetarian or vegan diet reported an improvement in RA symptoms, including pain score, morning stiffness, and grip strength compared to those who didn’t. However, because these diets are restrictive, many of the participants were unable to maintain them for the yearlong study period. If you can’t give up meat, then at least try to get a few more greens on your plate. The antioxidants, such as those found in green peas, bell peppers, and broccoli, may protect against tissue damage around the joints caused by free radicals.
Some evidence suggests certain nutrients may help patients with RA. For example, some studies showed that vitamin E supplements reduce RA joint destruction and pain, while others do not. Selenium levels are also thought to be too low in some people with RA. However, only one study has found that selenium reduced swollen joints and stiffness, and it also involved fish oil supplementation, so it’s difficult to determine if selenium can help reduce RA symptoms. In addition, some RA patients take methotrexate to slow disease progression. But the drug also inhibits folic acid metabolism and causes a range of side effects, including mouth sores, says Dr. Hadler. He suggests folic acid supplements to decrease these adverse effects.
Food allergies, especially to dairy and shrimp, may aggravate rheumatoid arthritis. Some people try elimination diets, which involves removing all potential allergens from the diet and slowly adding these foods back to see if they trigger symptoms. Studies have tested whether exposing patients to foods that had previously upset their RA consistently worsened their symptoms. “You get a smidgen of a hint that food aggravates symptoms,” says Dr. Hadler. But he explains that there’s tremendous variation within any individual’s symptoms in a given time period, making it difficult to study the effects of elimination diets.
He added: "Foot osteoarthritis is a more common and disabling problem than we previously thought, making everyday tasks difficult and painful for people affected.
"While it's been known for decades that joints in the foot can be affected by osteoarthritis, much of the previous research has focussed on the hip and knee areas, and research into the foot has concentrated almost entirely on the 'bunion joint' at the base of the big toe.
"However, by looking at the whole foot and the impact on people's lives, it's clear the problem is more widespread than we anticipated.
"Doctors and other healthcare professionals should also be aware of osteoarthritis as a common cause of foot pain in this age group."
According to Arthritis Research UK, 7% of people aged 45 and over have sought treatment for osteoarthritis in the foot or ankle, including 9% of those aged 75 and over.
Professor Anthony Redmond, spokesman for the charity, said: "This is a very important study. We know that foot problems become more much common as we get older but the medical and healthcare community have been guilty in the past of dismissing this as just an inevitable part of ageing.
"The new study tells us that these problems in the midfoot involve some of the same processes that affect arthritic hips and knees: conditions that are taken much more seriously.
"We have long known about some forms of osteoarthritis in the feet such as bunions, which are a common type of osteoarthritic damage affecting the big toe joints and are taken much more seriously, with both non-surgical and surgical treatments widely employed.
"The study tells us that if we want to keep our over-50s active and healthy we should be similarly serious about 'arch' or midfoot pain."
He called for wider use of X-rays to check for signs of the condition.
He added: "While osteoarthritis does not yet have a miracle cure, the associated pain and disability are not inevitable and people with foot pain should be given genuine treatment options - something can always be done."