Type 2 Diabetes Risk Linked to Fish
If you think you already know all the risk factors for type 2 diabetes, this one may be new to you. A study from Indiana University School of Public Health reports that exposure to mercury in fish can significantly increase type 2 diabetes risk among young adults.
Isn’t fish good for you?
The findings of this latest study on the risk of type 2 diabetes, which was conducted by a research team headed by epidemiologist Ka He, may have many people scratching their heads, because fish is often touted as a healthy food. Indeed, the American Diabetes Association (ADA) website asks and answers the question “Why is seafood such a great choice for diabetes?” and urges individuals to include at least two fish meals per week.
But previous research has suggested that exposure to mercury, which is present in most fish and other seafood to some degree, may cause dysfunction of islet beta cells, which are the cells in the pancreas that produce insulin. As the current authors noted, few human studies have examined the association between exposure to mercury and diabetes.
He and his team studied 3,875 American adults who participated in CARDIA—the Coronary Artery Risk Development in Young Adults study—who were followed for 18 years. The researchers took into consideration the subjects’ lifestyle habits, including dietary factors such as consumption of omega-3 fatty acids (which are found in abundance in fish) and magnesium, two elements that can help protect against the damaging effects of mercury.
Results of their analysis revealed a link between mercury levels and the risk of type 2 diabetes, making this study the first to establish such an association in humans. Specifically, they found that higher levels of exposure to mercury in young adults (ages 20 to 32 in this study) increased the risk for type 2 diabetes later in life by 65 percent.
Ironically, the researchers also found that the individuals who had the highest levels of mercury also engaged in more exercise and had lower body mass indexes than other people in the study. They also ate more fish.
Should you stop eating fish?
The findings led He to stress that individuals should choose fish known to have low levels of mercury. The ADA notes that such fish include anchovies, Atlantic and Pacific mackerel, herring, Pacific oysters, salmon, sardines, trout, and tuna (light canned).
These recommended fish are also high in omega-3 fatty acids, which can help reduce the risk of heart disease, high blood pressure, and arrhythmias. Individuals with diabetes are also at risk for heart disease.
Examples of fish high in mercury are king mackerel, shark, swordfish, and tilefish. The ADA notes that eating a variety of seafood can help minimize exposure to mercury. Young children pregnant women, and women of childbearing age should be especially mindful of eating fish that are low in mercury. The Food and Drug Administration offers consumers information on mercury and fish consumption as well.
The study’s authors concluded that their findings are consistent with previous laboratory studies and indicate that “people with high mercury exposure in young adulthood may have elevated risk of diabetes later in life.”
American Diabetes Association
He K et al. Mercury exposure in young adulthood and incidence of diabetes later in life: the CARDIA trace element study. Diabetes Care 2013; doi: 10.2337/dc12-1842