A joint is where two or more bones are joined together. Joints can be rigid, like the joints between the bones in your skull, or movable, like knees, hips and shoulders. Many joints have cartilage where the bones come together. Healthy cartilage helps you move by allowing bones to glide over one another. Cartilage also protects bones by preventing them from rubbing against each other.
Many people take over-the-counter dietary supplements, such as glucosamine and chondroitin, for joint health. Current research shows that these supplements seem to help reduce osteoarthritis pain in some, but not all, people. However, there is no evidence that they can prevent any form of arthritis.
Scientists are also researching the effects of other dietary supplements, such as green tea and certain vitamins, to see if they can help keep joints healthy. Check with your doctor before taking dietary supplements.
Sources: National Institute of Arthritis and Musculoskeletal and Skin Diseases; the National Institutes of Health