Antioxidants may protect against knee arthritis

NEW YORK (Reuters Health) - People who have plenty of foods with antioxidants in their diets may be protecting themselves from bone changes associated with knee arthritis, according to a new study.

Australian researchers found that middle-aged adults with higher dietary levels of vitamin C were less likely to develop certain bone abnormalities that contribute to knee arthritis.

The findings "highlight the potential of diet to modify the risk of osteoarthritis," they report in the online journal Arthritis Research & Therapy. Dr. Yuanyuan Wang of Monash University in Melbourne led the research.

The subjects were 293 men and women who were middle-aged, healthy and free of knee pain at the start of the study. At that time, they completed detailed questionnaires on their diets; 10 years later, their knee tissue was examined using MRI scans. All of the nutrients were obtained through food, rather than from supplements.

In general, Wang's team found, the higher a person's dietary levels of vitamin C at the start of the study, the lower the risk of certain bone changes 10 years on. The same was true when the researchers looked at overall consumption of fruit, a prime source of vitamin C.

Certain carotenoids, such as the lutein and zeaxanthin found in green vegetables, were also related to a lower risk of cartilage defects in the knee.

Antioxidants protect cells throughout the body from accumulating oxidative damage, which has been shown to play a role in osteoarthritis. Some research has shown the vitamin C boosts bone density, which may explain the benefits seen in this study, the researchers note.

According to experts, the best way to get the full gamut of antioxidants in your diet is to eat a variety of fruits and vegetables every day.

SOURCE: Arthritis Research & Therapy, online July 6, 2007.