Science / Medicine : Clues Found for Fish Oil’s Role

Scientists report they have evidence that might explain why fish oil would be effective for treating diseases in which the immune system malfunctions, like rheumatoid arthritis.

A fatty acid found in fish oil appears to suppress key immune system hormones, perhaps preventing the immune system from attacking the joints and other parts of the body in autoimmune diseases, the researchers found.

“We think we have the mechanism as to why this may work,” said Dr. Charles Dinarello, a professor of medicine at Tufts University School of Medicine who headed the research.

In addition to apparently reducing the risk of heart disease, previous studies have suggested that substances in fish oil known as n-3 or omega-3 fatty acids appear effective in treating a variety of autoimmune diseases. In autoimmune diseases, such as rheumatoid arthritis and psoriasis, the immune system apparently malfunctions, attacking the joints and skin respectively.

In a new study published in the New England Journal of Medicine, Dinarello and his colleagues gave nine healthy volunteers commercially available fish oil concentrate for six weeks and measured the blood levels of substances known as interleukin-1 and tumor necrosis factor. The levels of the two substances, which are important hormones involved in causing inflammations, dropped sharply for up to 10 weeks after the supplementation, a finding the researchers called “striking.”