The incidence of osteoarthritis (OA) is rising around the world due to both increasing levels of obesity, poor diet and ageing populations.
OA is a chronic disease of the joints, usually affecting the hips, knees, spine or fingers. It is caused by a breakdown of cartilage that surrounds the joints. This can cause the bone at the edge of the joint to thicken and spur forming osteophytes which can lead to inflammation. Symptoms include severe pain and decreased mobility and function.
Genetics, old age and general wear and tear play a role in developing OA; however new research has demonstrated that there is a link between OA and diet.
The journal, Arthritis Research & Therapy, recently linked an increased intake of antioxidants to a reduced risk of osteoarthritis and improved bone and joint health. Click here to see an abstract from the original research paper.
So let us take a look at how diet can help with both the reduction in symptoms and the prevention of OA:
Antioxidants
Antioxidants are substances that protect cells from the damage caused by unstable molecules known as free radicals. Free radicals are molecules that can damage cells, causing inflammation and pain. They are made in all combustion processes which include smoking, radiation, frying, barbecuing, meat smoking and curing. Sun exposure, stress, alcohol, exhaust fumes and even breathing create free radicals; therefore it is important for the body to be well equipped against these potentially harmful molecules.
Vitamins A, C and E are the primary antioxidant vitamins, found in fresh fruit, vegetables, whole grains and legumes that can neutralise free radicals. Vitamin C is especially crucial for cartilage growth and repair. Good sources of vitamin C are found in kiwi fruit, peppers, watercress, cabbage, broccoli and strawberries.
"Bad" Oils and Fats
Hydrogenated or trans fats (found in certain biscuits, chocolate, pastries and some margarines or created by shallow frying and deep frying) are to be avoided. When these fats are incorporated into normally very fluid cell membranes, they pack very tightly because of their structure. Thus, essential nutrients are unable to get into the cell, making the cell less healthy and more prone to injury. In contrast, poly-unsaturated fats are beneficial to cells because they prevent the tight packing of fatty acids in the membrane. Unsaturated fatty acids (found in nuts, seeds, cold compressed oils (flax, hemp, borage oils) and oily fish) have gaps in their chains and these gaps allow for a certain amount of "fluidity” and therefore improved function of the cell. Saturated fats found in processed foods and animal products such as red meat causes inflammation in the body so these fats are best kept to a minimum in the diet.
Anti-inflammatory foods
Alcohol, refined sugars, and coffee are likely to cause more inflammation in the body and intake should be reduced. Foods that may reduce inflammation tend to be fruit and vegetables and foods containing essential fatty acids from oily fish, nuts and seeds. It must be noted that certain foods such as citrus fruit or foods from the “nightshade family” such as aubergines, potatoes, tomatoes and peppers can sometimes aggravate joint pain and swelling so are best avoided if there is a noticeable worsening of symptoms.
Healthy Bones are Important Too
Where there is low bone mineral density, there may be an increased risk for OA, therefore adequate bone nutrients in the diet can help to maintain bone density and strength.
The most important bone nutrients are calcium, magnesium and boron, although recent research suggests that vitamin D is just as important as calcium in maintaining bone health.
Research presented this month (Nov 2007) at the American College of Rheumatology Annual Scientific Meeting highlighted the importance of vitamin D in joint health. They presented several research papers highlighting the link between low levels of vitamin D and higher incidence of knee pain and decreased mobility amongst OA patients. Vitamin D aids the uptake of calcium from the gut but also helps retain calcium in the bone.
Foods rich in vitamin D are cold water fish such as mackerel and herring, liver, cottage cheese and egg yolk. Exposure to sunlight allows the body to produce its own supply of vitamin D.
What about exercise?
Maintaining normal body weight through diet and exercise is an important part of treating OA. Research has found that obesity increases the risk of OA and excess weight puts increased stress on weight-bearing joints. Weight-bearing exercise is crucial for maintaining healthy bones and joints. This includes brisk walking, jogging, and aerobics. Exercise such as yoga, swimming, tai chi and cycling are gentler on the joints and good for strengthening the muscles, ligaments and tendons around the joint but should be combined with weight-bearing exercise in order to maintain optimum bone health.
Amanda Michie is a Urbod Nutritionist working in the City and Canary Wharf.
