Sept. 25, 2000 -- Those who have survived years of school lunches may get weak in the knees at the prospect of having to eat still more gelatin. But a new study reported at a meeting of the American Academy of Family Physicians in Dallas last week suggests that adding a special gelatin supplement to the diet could provide some relief to people with mild osteoarthritis of the knee.

Osteoarthritis is the most common form of arthritis, or inflammation and swelling of the joints. It occurs as a consequence of aging and the thousand natural shocks that weight-bearing joints or frequently used joints -- such as the knees, fingers, and wrists -- are exposed to. Just as the knees in a favorite pair of jeans wear out over time, wear-and-tear on cartilage, the tissue that coats and helps to lubricate the ends of bones where they meet in joints, can eventually cause osteoarthritis. Symptoms of the condition include pain, stiffness, and limited mobility of the affected joint.

In the study, 175 patients with osteoarthritis of the knee were randomly assigned to receive either a daily gelatin supplement or a placebo. Those who ate a supplement containing 10 grams of gelatin plus calcium and vitamin C had significant improvements across the board in pain, stiffness, and mobility measures.

"This suggests that gelatin supplementation has the potential to improve knee function during activities that cause high amounts of stress on the joint," according to Sean S. McCarthy, MS, from the Center for Clinical and Lifestyle Research in Shrewsbury, Mass.

But before you hobble out to the grocery store to stock up on some gelatin, you should know that gelatin could be getting the credit for a job done by good old vitamin C. "If gelatin was protective, there'd be less osteoarthritis in this country and not more, because it's widely contained in foods," says Timothy McAlindon, MD, MPH, associate professor of medicine at Boston University School of Medicine and a staff member in the Arthritis Center at Boston University Medical Center.

McAlindon, who treats patients with osteoarthritis, previously conducted a study looking at the role of diet in people with osteoarthritis of the knee, "and found an apparent strong protective effect of high vitamin C intake on knee osteoarthritis progression. So vitamin C might play a role: It is an antioxidant and has other effects which might be considered beneficial," he tells WebMD.