Mercury damages children's immune systems and kidneys, but its toxicity to the developing brain is worse. The July 2001 policy statement of the American Academy of Pediatrics (AAP) warns that minimizing mercury exposure is "essential to optimal child health". The most important sources of mercury exposure are fish eaten by pregnant or breastfeeding mothers and fish eaten directly by children. In March 2001, the FDA recommended that pregnant women and women of childbearing age should completely avoid consumption of shark, mackerel, swordfish, and tilefish. For tuna, the FDA has advised that children and pregnant women consume less than 12 ounces (one large can of tuna) per week. The AAP cautions, "These guidelines are not a "bright line" above which levels are dangerous and below which they are safe." I agree with restricting fish intake, though this saddens me. Tuna can be an excellent source of nutrients, especially for developing brains. I would prefer stricter guidelines on industrial emissions (the source of the mercury in the fish), rather than depriving women and children of foods ideally suited to stimulate brain growth.