Pregnant women have long been warned to avoid eating fish high in mercury, such as tilefish, king mackerel or swordfish. That is because methylmercury can interfere with nervous system development in the fetus.
A new study shows that even women who are not pregnant have a reason to avoid high-mercury fish. Based on data from more than 1,300 women in the National Health and Nutrition Examination Survey (NHANES), the researchers identified mercury as an important factor in raising the risk of autoimmune disease such as inflammatory bowel disease, lupus, multiple sclerosis or rheumatoid arthritis.
Women with higher body burdens of mercury had higher levels of autoantibodies. Although autoantibodies may sometimes appear without an autoimmune disease, there is a correlation. Sometimes autoantibodies become elevated, and years later the autoimmune disease becomes apparent.
Around 50 million Americans have an autoimmune disease, and the majority are women. The most alarming finding of the study is that autoantibodies begin to rise even at levels of mercury that have been considered safe up until now.