Just one serving of fish can lower RA risk by 30%
Rheumatoid arthritis is a chronic inflammatory disorder that typically affects the small joints in your hands and feet. Although rheumatoid arthritis can occur at any age, it usually begins after age 40. The disorder is much more common in women than in men. It has been estimated 13 million people in the United States have RA. There are nearly three times as many women with RA compared to men.
There have been at least 17 randomized controlled clinical trials that examined the effects of omega 3 fatty acids supplements in RA. The results suggest that omega 3 fatty acids in conjunction with conventional therapies may joint pain associated to the disease.
In a new cohort studies led by Alicja Wolk, DrMedSci, head of The Institute of Environmental Medicine (IMM), a department at Karolinska Institute and colleagues examined the association between dietary long-chain n-3 polyunsaturated fatty acids (PUFAs) and incidence of rheumatoid arthritis (RA) in middle-aged and older women from the Swedish Mammography Cohort, a population-based prospective study.
According to researchers fish oil supplementation is the only source of long-chain n-3 PUFAs consistently associated with a reduced risk of RA. Studies of dietary sources of n-3 PUFAs have shown mixed results.
In this large prospective cohort of middle-aged and older women data had been collected from the Swedish Mammography Cohort in 1987 and 1997 among women who were born between 1914 and 1948 and resided in two Swedish counties along with a self-administered food-frequency questionnaire.
The first survey obtained information on diet, height, weight, parity and education. The second questionnaire extended to questions concerning physical activity, smoking history, use of aspirin and dietary supplements.
Among the32, 232 women in the study, 205 cases of RA were reported during the mean follow-up of 7.5 years.
An intake of dietary long-chain n-3 PUFAs of more than 0.21 grams a day was linked to a 35% reduced risk of developing RA. An intake of more than 0.21 grams a day was linked to a 52% decreased risk of RA. Long-term consumption of fish at more than once a week compared to less than one serving a week was linked to a 29% decreased risk. According to the researchers these results remained even after taking lifestyle factors such as smoking and alcohol consumption into account.
The researchers concluded “This prospective study of women supports the hypothesis that dietary intake of long-chain n-3 PUFAs may play a role in aetiology (cause of) of RA.
Taking fish oil supplements in lieu of eating fish did not appear to help prevent RA. However, Wolk said this could be due to the fact so few people were taking supplements making it difficult to come to any definitive conclusion.
The results of this study are reported online in Annals of Rheumatic Diseases.