Eating fish to prevent arthritis
Women who have diets high in omega-3 fatty acid derived from fish are less likely to develop rheumatoid arthritis than those who skimp on fish, new research suggests.
Researchers surveyed Swedish women about their diets and found over the course of more than seven years, long-term consumption of more than one serving of fatty fish each week was tied to a lower risk of developing the condition.
Ms Daniela Di Giuseppe, a doctoral student at the Karolinska Institute in Stockholm and lead author of the study, said: “This study is the first to attribute the protective effect of fish against rheumatoid arthritis to its content of omega-3 fatty acid.”
Rheumatoid arthritis is an autoimmune disease which causes joint inflammation, deformities and disability. Patients also have a higher risk of heart disease, some infections, anxiety, depression and blood cancer such as leukaemia.
The American College of Rheumatology said between 0.5 and 1 per cent of the population in the United States has rheumatoid arthritis. Women are two to three times more likely than men to develop the disease, which most commonly starts affecting people in their 60s.
Ms Di Giuseppe and her colleagues followed more than 32,000 women born between 1914 and 1948 who were part of the Swedish Mammography Cohort. Information about fish consumption was gathered from questionnaires sent to women in 1987 and 1997.
National registries were used to identify new diagnoses of rheumatoid arthritis between 2003 and 2010.
The researchers separated the women into five groups based on the amount of fish-based omega-3 fatty acid in their diet, ranging from 0.21g or less per day to at least 0.5g daily.
Eating 0.21g per day of omega-3 fatty acid equates to about one serving per week of salmon (above) and other fatty fish, or four servings per week of lean fish such as cod.
During the follow-up period, 205 women developed rheumatoid arthritis, the researchers reported in Annals Of The Rheumatic Diseases.
Women who reported getting more than 0.21g of omega-3 fatty acid derived from fish per day both in 1987 and 1997 had a 52 per cent decreased risk of developing the disease, compared with those who ate the least.
The researchers found a threshold effect, suggesting more omega-3 fatty acid may not always be better. Below 0.35g per day, the risk of rheumatoid arthritis decreased, but above it, the benefits seemed to taper off.
The results are consistent with other studies that have found threshold effects, and with recommendations from the US Department of Agriculture and the Department of Health and Human Services, which advise eating at least two servings of fish per week.
The researchers concluded that “moderate consumption of fish is sufficient to reduce risk of diseases”.
Omega-3 fatty acid is used by the body to make molecules, which help regulate inflammation called eicosanoids. The current thinking is that eicosanoids derived from essential fatty acid in meat promote more inflammation than that from omega-3 fatty acid in fish, researchers said.
Genes and lifestyle may both play a role in rheumatoid arthritis.
Dr Simon Helfgott, a rheumatoid arthritis researcher at Harvard Medical School in Boston who was not involved in the new research, said people can prevent the disease by not smoking, avoiding gum disease by having good oral hygiene and improving their diet by eating fish.
Source: Reuters
