Washington: Young adults who consume high levels of mercury increase their risks for type 2 diabetes later in life by 65 percent, a new study has found.
The study, led by Indiana University School of Public Health-Bloomington epidemiologist Ka He, paints a complicated nutritional picture because the main source of mercury in humans comes from the consumption of fish and shellfish, nearly all of which contain traces of mercury.
Fish and shellfish also contain lean protein and other nutrients, such as magnesium and omega-3 polyunsaturated fatty acids, which make them important to a healthy diet.
In the study, the people with the highest levels of mercury also appeared to have healthier lifestyles-lower body mass indexes and smaller waist circumferences, more exercise-than other study participants. They also ate more fish, which is a possible marker of healthy diet or higher social economic status. Risk factors for type 2 diabetes include being overweight.
The study, which involved 3,875 men and women, established the link between mercury levels and type 2 diabetes risk after controlling for lifestyle and other dietary factors such as magnesium and omega-3 polyunsaturated fatty acids, which could counter the effects of the mercury.
These findings, said He, point to the importance of selecting fish known to have low levels of mercury, such as shrimp, salmon and catfish, and avoiding fish with higher levels, such as swordfish and shark. FDA and EPA guidelines for fish consumption highlight this, particularly for women who are pregnant or of childbearing age and for young children.
"It is likely that the overall health impact of fish consumption may reflect the interactions of nutrients and contaminants in fish. Thus, studying any of these nutrients and contaminants such as mercury should consider confounding from other components in fish," he and the authors wrote in the study.
The study will be published in the journal Diabetes Care.