Higher levels of mercury exposure in young adults can increase their risk of developing type 2 diabetes by 65 per cent, later in life, a new study has warned.
The research, led by Indiana University School of Public Health- Bloomington epidemiologist Ka He, is the first to establish the link between mercury and diabetes in humans.
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, that make them important to a healthy diet.
In the study, published in the journal Diabetes Care, 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. 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, He said, 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.
"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," the authors wrote.
"In the current study, the association between mercury exposure and diabetes incidence was substantially strengthened after controlling for intake of LCn-3PUFAs (omega-3) and magnesium," they said.