While the list of foods that could harm or even kill a baby continues to grow and make one wonder how earlier generations ever survived, another no-no has been added to the list: water.

Thirsty babies under six months of age should not be given water. Due to the dangerous combination of a strong sucking reflex, and immature kidneys, it's easy for an infant to take in too much water and throw off the body's sodium level enough to affect brain activity.

To make matters even worse, the first signs of water intoxication in infants are the same as a baby just having a cranky day: irritability, drowsiness and other mental changes. Other symptoms include low body temperature (generally 97 degrees or less), puffiness or swelling in the face, and seizures. Because the early signs are easily overlooked, seizures are generally a parent's first real indication something is wrong. However with prompt medical attention, they should not cause lasting damage.

As a cost-cutting measure, it might be tempting dilute formula in order to make those expensive cans last longer, but that short changes the child of necessary calories and nutrients and increases water intake.

I wondered if swimming lessons could also cause water intoxication in babies. I took my sons to the beginner Red Cross classes, which were really more of a water playgroup than actual lessons. Parents held the baby in the pool and we sang songs and splashed their little hands and feet and tried not to die of embarrassment from showing our post partum bodies in swimsuits, but it does seem like a quick dunk underwater was involved. (However, the embarrassment over the bathing suit issue is clouding my memory.)

According to The American Academy of Pediatrics, if you're willing to squeeze into that suit, baby swim lessons are fine. The AAP policy on swimming and infants is:

Until more clear-cut scientific evidence exists on the effects of infant and toddler aquatic programs, the AAP recommends the following:

1. Children are generally not developmentally ready for formal swimming lessons until after their fourth birthday.
2. Aquatic programs for infants and toddlers should not be promoted as a way to decrease the risk of drowning.
3. Parents should not feel secure that their child is safe in water or safe from drowning after participation in such programs.
4. Whenever infants and toddlers are in or around water, an adult should be within an arm's length, providing "touch supervision."
5. All aquatic programs should include information on the cognitive and motor limitations of infants and toddlers, the inherent risks of water, the strategies for prevention of drowning, and the role of adults in supervising and monitoring the safety of children in and around water.
6. Hypothermia, water intoxication, and communicable diseases can be prevented by following existing medical guidelines and do not preclude infants and toddlers from participating in otherwise appropriate aquatic experience programs.
7. Pediatricians should support data collection, drowning prevention research, and legislation aimed at reducing the risk of drowning in young children in and around water