Osteoarthritis (OA) is a degenerative disease that leads to pain, stiffness, swelling of joints and is a leading cause of disability around the world. Genetics, overweight, age, injury, overuse of joints, as well as certain underlying diseases and medical conditions, can all cause the cartilage between the bones of the joints to break down. Without this shock-absorbing cartilage cushion, the bones grate against each other causing the swelling and other symptoms of osteoarthritis.

There is no specific treatment or cure for OA, but exercise, medications and surgery are all used to manage its painful symtoms. One of the major goals of research into OA is the prevention of joint and cartilage changes and trying to find ways to slow down the progression of disease and disability in those who already show symptoms.

Losing weight is helpful for two reasons: It can decrease the physical load on joints, and it reduces the presence of inflammatory compounds within the joints.

Researchers at the University of Surrey reviewed the last ten years of osteoarthritis literature to try to come up with recommendations for measures that individuals could take to help prevent or slow down the disease.

What they found and what they recommend will give you a game plan for avoiding the pain of OA and remaining mobile in the years to come.

Overweight and obesity put extra wear and tear on bones and joints, making it more likely that overweight individuals will develop osteoarthritis and at an earlier age than people who weigh less. Obese individuals are also more likely to need joint surgery because of OA. But studies of osteoarthritis in the hands of obese individuals make clear that there is also another mechanism at play — inflammation.

Obesity is associated with a generalized low-grade inflammation with higher levels of inflammatory compounds circulating throughout the body. Their presence changes the metabolic balance within the joints and can lead to OA, making weight management potentially effective for two reasons. First, losing weight can decrease the physical load on joints. And second, weight loss reduces the presence of inflammatory compounds within the joints.

Based on the studies they reviewed, the researchers recommend that people with OA who are overweight should aim for a 10 percent weight loss and a BMI (body mass index) within the normal range. People with OA who cut back on calories need to be sure they are not compromising the intake of essential nutrients and vitamins, the researchers warn, and recommend that dieting be done in conjunction with exercise, strengthening and mobility programs that are tailored to the capabilities of the individual.

Western diets, which are higher in omega six fatty acids relative to omega three fatty acids, can also contribute to inflammation within joints. Fish oil, high in omega three fatty acids, can help reduce both pain and inflammation. This appears to be the case with symptoms of OA as well, the University of Surrey team found. More studies are needed, but the available data show that there is some improvement in OA symptoms and progression when fish oil is used as a daily supplement of one to two capsules of 1000 mg per day. They also recommend that people with OA reduce their intake of omega 6 fatty acids by substituting oils that are rich in monounsaturates such as rapeseed, canola and olive oils to help correct the imbalance between omega six and omega 3 fatty acids.

Serum cholesterol is another risk factor for OA, the review study found. In women, moderately elevated serum cholesterol is associated with a significant risk of OA of the knee joint. It is postulated that cholesterol accumulates in the joint and is a pro-inflammatory compound that leads to OA pathology. Therefore, the researchers recommend dietary management of cholesterol and lipids. This includes decreasing total calories, reducing saturated fats to 11% of calories, using soluble fiber (such as oats) to lower cholesterol, and considering adding soy protein, plant stanols and sterols such as broccoli, cauliflower, brussel sprouts, dill, apples, avocados and tomatoes. One recommended option is to increase consumption of tree nuts which provide sources of unsaturated fats, phyto-sterols and soluble fiber, all of which have been shown to decrease cholesterol levels.

There has been considerable interest in the role antioxidant vitamins A, C, E can play in preventing or slowing the progression of osteoarthritis, but none of the research offered conclusive evidence for a positive role of any of these vitamins. The authors recommend they be included as part of a healthy diet, but not specifically supplemented for OA.

Vitamin D plays a primary role in bone health, and when it is too low, bone may not be able to protect itself from osteoarthritis. Some studies have shown an association between low vitamin D and the loss of cartilage and progression of OA, but studies on vitamin D supplements to prevent or slow OA have not been uniformly positive. Vitamin D deficiency has not been clearly shown to cause OA, but, the researchers note, when vitamin D levels are adequate, muscles are stronger and would more effectively surround and support the joint, a good reason for OA patients to make sure their vitamin D levels are adequate. Dietary sources of vitamin D include eggs, fatty fish, fortified food and beef liver.

So what can you do? There is enough evidence to make several recommendations to help prevent and delay the progression of osteoarthritis, even if the precise causes are not yet clear. It's important to take an active approach toward maintaining your joint and bone health. The recommended steps are essentially risk-free strategies that are good for general metabolic health and well-being, and which can also reduce your risk of osteoarthritis: Lose weight if you need to; get more exercise; lower your lipid intake and dietary cholesterol; eat foods that will supply the micronutrients and vitamin D that will help prevent inflammation and joint damage.

The study is published in Rheumatology.