MONDAY, April 30 (HealthDay News) -- Green tea, already touted for its cardiovascular and anticancer benefits, may also help ease the inflammation and pain of rheumatoid arthritis, a new study suggests.
The study was conducted in the laboratory, and its findings are preliminary, stressed lead researcher Salah-uddin Ahmed, an investigator at the University of Michigan Health System, in Ann Arbor.
"It's too early" to fully recommend green tea to ease rheumatoid arthritis, he said, but the study "is a starting point."
Ahmed was scheduled to present the research Sunday at the Experimental Biology meeting, in Washington, D.C.
For the study, Ahmed isolated cells called synovial fibroblasts from the joints of patients with rheumatoid arthritis. These cells form a lining of tissue surrounding the capsule of the joints.
In patients with rheumatoid arthritis, this lining is inflamed, leading to long-term joint damage and chronic pain. About 2.1 million Americans have rheumatoid arthritis, according to the Arthritis Foundation.
Ahmed's team next cultured these cells and exposed them to the active ingredient in green tea, a compound named epigallocatechin-3-gallate (EGCG). Next, the cells were stimulated with a protein of the immune system known to play a role in causing joint degradation in rheumatoid arthritis. The protein is called cytokine interleukin-1 beta or IL-1B.
"IL-1B is a major player in mediating cartilage degradation," Ahmed explained.
In an earlier study, Ahmed's team found that fibroblasts pretreated with EGCG and then stimulated with cytokine IL-1B were better able to block IL-1B's ability to produce damaging proteins and enzymes. Those proteins and enzymes can infiltrate the joints and cause the cartilage breakdown seen in people with rheumatoid arthritis.
In the more recent study, the researchers focused on whether EGCG had the ability to block the activity of two potent molecules, IL-6 and cyclooxygenase-2 (Cox-2), which also play a role in breaking down bone in an RA joint.
The two molecules were suppressed by the EGCG, Ahmed's team found. While he said it is difficult to quantify exactly the effect of the suppression, the EGCG "blocked them significantly," he said.
EGCG also blocked the production of prostaglandin E2, another compound that can cause joint inflammation.
One expert said the new green tea study was intriguing. "This study is very specific," said Stephen Hsu, an associate professor of dentistry, molecular medicine and genetics at the medical College of Georgia in Augusta.
In his own research, Hsu has found that green tea may help protect against certain autoimmune diseases, in which the body triggers an immune response, basically attacking its own cells. Hsu studied EGCG's effect in helping to inhibit an autoimmune disorder known as Sjogren's syndrome, in which the salivary glands are affected, and in lupus, in which the skin is affected.
The new research by Ahmed is one of the first to focus on rheumatoid arthritis and green tea, Hsu said. If it bears out, it could be good news for rheumatoid arthritis patients, perhaps offering them a non-drug option to keep pain under control, he said.
Ahmed cautioned that it's too soon to advise rheumatoid arthritis patients to drink green tea. On the other hand, drinking green tea certainly wouldn't hurt, he said, since it is known to have many health benefits and no known side effects.