Recent studies have shown that certain fish that are high in omega-3 fatty acids can help prevent osteoarthritis, the age-related form of arthritis that limits joint mobility and causes pain. But new research published in the journal Annals of the Rheumatic Diseases details a large study that showed weekly meals of high-fat fish such as salmon, mackerel, herring, sardines, or trout significantly reduced the risk of the autoimmune disease called rheumatoid arthritis (RA), where the immune system mistakenly attacks the joints.

The Swedish study examined over 32,232 women born between 1914 and 1948 and found that consumption of fatty fish led to a significant decrease in the incidence of the autoimmune disease. The researchers found that eating as little as one portion of fish once a week for 10 years reduced the overall risk of the disease by 29 percent, compared to eating other less fatty fish.

Which fish were the best?

The researchers found that the fish with the highest fat content and the greatest concentration of omega-3 fatty acids had the greatest benefit. Salmon and mackerel had the greatest effect, reducing the risk of developing the disease by up to 52 percent, essentially halving a person’s risk if eaten more than once a week.

Those who had the oily fish at portions of just about once a week had a 29 percent reduced risk of developing the disease.

The study asked the women what they ate at two different time points, in 1987 and 1997. During the study period, 205 of the women in the study developed the autoimmune disease.

Understanding The RA And Omega-3 Connection

Rheumatoid arthritis is an autoimmune disease where the body’s immune system is activated and begins attacking the cartilage in joints. This causes severe destruction of the joints, along with inflammation pain. People affected by the disease often lose function in their joints, usually in their hands and feet. Current treatments for rheumatoid arthritis include antibody therapies such as Humera and Remicade, which block an inflammatory factor, TNFalpha, that is released by the wayward immune cells.

Omega-3 fatty acids are thought to act on the immune system by enabling it to regulate itself better and reduce inflammation. Many scientists now believe that, in some people, the disease can be stopped before it begins by using omega-3 fatty acids to reduce inflammation before the disease sets in or by stopping some initiating factor.

Omega-3 fatty acids are also extremely good for heart health and have been shown time and time again to prevent the risk of cardiac disease and heart attacks. Another recent study has even shown that the fatty acids can inhibit cancer metastasis, the spread of cancerous cells through the body, and tumor growth because a chemical the body makes after proccessing the fatty acid can limit blood vessel growth, which tumors induce to grow and spread.

Source: Di Giuseppe D, Wallin A, Bottai M, Askling J, Wolk A. Long-term intake of dietary long-chain n-3 polyunsaturated fatty acids and risk of rheumatoid arthritis: a prospective cohort study of women. Annals of the Rheumatic Diseases. 2013.