If you're worried about developing rheumatoid arthritis, you may want to start eating oily fish once a week, as a new Swedish study has uncovered special benefits to consuming salmon, cod and mackerel, the Daily Mail reports.

Published in the Annals of the Rheumatic Diseases journal, the Swedish study involved 32,000 women born between 1914 and 1948, and had them complete weekly food surveys on what they ate during the years 1987 and 1997. During this period, 205 women developed rheumatoid arthritis, and factors such as smoking, alcohol intake and age were adjusted for.

Researchers from the Institute of Environmental Medicine at the Karolinska Institute in Stockholm found that women who had a consistently high weekly or daily intake of oily fish omega-3 in both 1987 and 1997 had a 52 percent lower risk of developing rheumatoid arthritis as well. The researchers attributed their findings to the womens' consumption of omega-3 fatty acids, which block our body's response to inflammation.

Oily fish in particular contain high levels of omega-3s, considered diet essentials that protect the heart and brain and found in abundance in mackerel, herring, salmon, sardines and trout.

"We've known for some time that there is good evidence that, in people with active arthritis, taking fish oils can reduce the level of inflammation," Alan Silman, medical director of Arthritis Research UK, told the BBC. "One of the challenges is that this can mean quite substantial changes in people's diets."

In addition to oily fish, some scientists also believe that sunshine may reduce the risk of rheumatoid arthritis, as a similar study published in February in the Annals of the Rhuematic Diseases journal suggested a link between UV-B light and preventing the disease. However, not all are convinced that vitamin D plays a role.

"Studies that have been undertaken have not shown, thus far, that vitamin D is a useful treatment for rheumatoid arthritis," Silman told BBC News at the time. "We know that many people with arthritis have low levels of vitamin D and this can have a powerful effect on the types of immune cells which may cause this condition. We're currently doing research to find out how this happens and are performing lab studies to find out whether vitamin D can alter the aggressive immune response found in rheumatoid arthritis and turn it into a less harmful or even a protective one."