Preliminary research suggests a possible association between foods rich in beta-caretene and a reduced risk of rheumatoid arthritis. Rheumatoid arthritis is a disease in which the body's immune system engages in battle against its own tissues. That results in inflammation, which in turn triggers the release of chemicals into the synovium, or joint lining. These chemicals cause synovial thickening and subsequent joint damage that makes it hard to manipulate areas such as the knuckles and knees. 

For more than 2 decades arthritis experts have known that the products of free radical, or oxidative, damage are present in synovial fluid, with the amount increased in joints inflamed by rheumatoid arthritis. Related research has shown that patients with rheumatoid arthritis have lower blood levels than others of beta-carotene, which in its antioxidant capacity fights free radicals. 

Now a study from Johns Hopkins University suggests that a low level of beta-carotene in the blood may actually increase a person's risk of getting rheumatoid arthritis in the first place. Looking at the levels of various antioxidants in blood samples drawn and frozen from more than 20,000 people in Maryland's Washington County in 1974, the Johns Hopkins scientists traced who among the blood donors developed rheumatoid arthritis up to 15 years later. Among people who had not fallen victim to arthritis, the pre-disease beta-carotene blood levels were 29 percent higher. 

"People should interpret the results to mean that they should eat more fruits and vegetables," says Head Researcher George Comstock, M.D.. Previous research linked beta-carotene supplements with an increased risk of lung cancer in certain populations.

Beta-carotene is found in high concentrations in carrots, apricots, cantaloupe, sweet potatoes, pumpkin, and dark green vegetables.