Everyone has heard the recommendations to eat fish for the health benefits. Fish is a high source of omega 3 fatty acids, is low in saturated fats, and high in many vitamins and minerals. However, certain fish are also high in mercury, a known neurotoxin.
There are certain populations that are cautioned against eating fish, especially those known to be high in mercury. Pregnant women and children should not eat high amounts of fish because of the mercury.
A recent study published in the International Journal of Obstetrics and Gynecology measured the levels of mercury in pregnant women living in Taiwan. Most of these women consume high amounts of fish, usually at least 3 servings a week. A total of 65 women were in the study. Levels of mercury were measured in their blood, the umbilical blood, and in the placental tissue.
Mercury levels in the blood were nearly double the recommended levels in 89% of the women. The levels in the umbilical blood were slightly higher and concentrations in the placental were also high.
Mercury is a known neurotoxin. It can cause damage to the nerves, brain, and kidneys in developing fetuses. Some reports suggest it may also stunt growth.
The fish with the highest levels of mercury tend to be large ocean fish such as tuna, shark, swordfish, and mackerel. Freshwater fish and smaller fish tend to have less mercury. Canned tuna is often the greatest source of mercury in pregnant women and children and in most cases should be consumed in only small amounts.
Posted by Dr. Christina Gutierrez on December 29, 2006 03:17 PM
