According to the study of more than 32 thousand women in Sweden, regular weekly consumption of the oily fish, such as mackerel or salmon cuts the risk of developing rheumatoid arthritis almost in half.
In fact, one regular serving of oily fish per week is enough to achieve such health benefits. The essential omega-3 fatty acid abundant in oily fish is needed by human body to function normally, and since it can not be synthesized internally, we can get it only through our diet.
Omega-3 fatty acid appears to be an efficient anti-inflammatory agent, which would explain how it might combat arthritis, say researchers in the journal Annals of the Rheumatic Diseases.
Rheumatoid arthritis affects more than 580,000 people in England and Wales. As the disease progresses, the immune system attacks the joints, making them stiff, swollen and painful.
For the purpose of the Swedish study, which lasted for a decade, women who consistently ate any type of fish at least once a week cut their risk of developing rheumatoid arthritis by nearly a third.
And those who ate at least one portion of oily fish or four servings of other fish each week halved their risk. Medical director of Arthritis Research UK, Professor Alan Silman commented: "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".
He said the study suggests that taking high levels of fish oils can prevent inflammation from starting in the joint. "One of the challenges is that this can mean quite substantial changes in people's diets".
Includes mackerel, herring, salmon, trout, pilchard, sardine, and fresh tuna.
Rich in long-chain omega-3 fatty acids and vitamin D.
Some white fish and shellfish also contain omega-3 but not as much as oily fish.
A healthy diet should include at least two portions of fish a week, including one of oily fish.
A portion of oily fish is around 140g when cooked.
Pregnant women and those who want to conceive in the future should eat no more than two portions of oily fish a week because it can contain low levels of pollutants that can build up in the body.
Source: NHS Choices