A recent study has shown that being exposed to mercury whilst still in the womb can be linked to the subsequent development of Attention Deficit Hyperactivity Disorder (ADHD). As some fish carry low levels of mercury, does this mean that pregnant women should avoid eating fish?
The answer is, surprisingly, quite the opposite. This same study also showed that women who did eat fish during pregnancy actually had lower incidences of ADHD in their children. The disorder is one of the most common types of neurodevelopmental disorder, affecting between eight and 12 percent of children. Typical symptoms are impulsive behaviour, lack of attention, inability to concentrate and extreme hyperactivity. The study was conducted by testing hair samples of women who had just given birth, to assess the levels of mercury present in the woman’s system. The children resulting from the pregnancies were then monitored to assess which ones developed ADHD, and whether the was a link between higher levels of mercury and higher incidences of ADHD – which there was.
Exposure to methylmercury comes primarily from consuming fish. Whilst some types of fish, such as tuna, swordfish, marlin, shark and king mackerel carry higher levels of mercury and should be avoided altogether, pregnant women should bear in mind for family wellness that fish also contains some very important nutrients for developing foetuses.
Pregnant women who are concerned about the wellbeing of their unborn children should continue to eat two six-ounce servings of lower-mercury fish (such as herring, salmon, plaice and anchovies) per week to keep up their intake of important nutrients like the omega-3 fatty acids contained in these types of fish, while keeping their mercury exposure low. This serving-size recommendation comes from the U.S. Food and Drug Administration, which has issued the guidance to help protect women, following the studies that show links between mercury and ADHD.