How Water Affects Babies.... from the New York Times

Is It Safe for Babies to Drink Water?
By The New York Times


A. Is it safe for babies to drink water? I heard there’s a 1 percent chance they could get encephalitis.
D.J., New York, N.Y.

Dr. Alan Greene responds:

Even though water may be the safest and healthiest everyday beverage for older children and adults, water can be dangerous for young babies.

During the months before starting solid foods, the amount of water already present in breast milk or formula usually provides all of the water that healthy babies need both to grow and to replace the water they normally lose through their urine, stool, skin and lungs.
Dr. Alan GreeneDr. Alan Greene. (Tami DeSellier)

Water intoxication

Too much water can cause water intoxication in babies. Each time a baby pees, he or she loses not only water but sodium and other electrolytes. But unlike with adults, who tend to get too much sodium in our diets, babies usually get just the electrolytes they need from breast milk or formula. Too much water and they lose too much sodium. The sodium levels in their blood can plummet and cause irritability, brain swelling, unresponsiveness and seizures. (Note: Water intoxication also involves other factors, but that’s more detail than I can go into here.)

The risk of water intoxication is especially high if the baby is losing both water and electrolytes from diarrhea. Fluid losses should be replaced with breast milk, formula or perhaps a rehydration solution. Don’t give plain water for rehydration.

The risk is also high if formula is diluted with too much water in a misguided effort to save a little money.

What about hot weather?

In very hot weather, when babies may be losing extra water without urinating more, it can be O.K. to offer a bottle-fed baby a small (2 to 4 ounce) bottle of water between formula feedings – but there is no need to force this. Most will do well with just a little extra formula if they seem thirsty. Breast-fed babies are even less likely to need extra water.

What about dehydration?

If you are concerned that your baby is getting dehydrated, contact your health care provider. We expect babies to pee at least once in the first 24 hours of life, at least twice in the second 24 hours, and at least three times every day thereafter.

What about encephalitis?

Encephalitis is inflammation of the brain. It’s closely related to meningitis, or inflammation of the tissues protecting the brain, and the two often go together. Infections are a major cause of encephalitis.

When people think of encephalitis infections, they often think of mosquito-borne infections like West Nile Virus. But waterborne encephalitis infections are also possible, though they are quite rare in the United States.

All tap water from public water systems in the United States must adhere to Environmental Protection Agency safety standards and is usually free from infection-causing organisms. Nevertheless, infections sometimes occur and are especially likely during a natural disaster like a flood or earthquake, when public and private water supplies may become contaminated.

For those with strong, healthy immune systems, infections from drinking water are usually minor and are often limited to the digestive tract, causing symptoms like diarrhea. In young babies younger than a month or two and in those who are immunocompromised, the infections are more likely spread to other parts of the body, including the brain.

What about parasites and other organisms in drinking water?

The tiny Cryptosporidium parasite is one of the most common causes of drinking water infections in the United States. Cryptosporidium is not killed by chlorine but is killed by boiling. Advisories to boil water should blanket the local news whenever there is an outbreak in a public water supply, but there may be a delay. The biggest known outbreak occurred in Milwaukee’s city drinking water in 1993, when more than 400,000 people became ill with diarrhea, and it took two weeks to figure out that drinking water was the source.

Most, but not all, home water filters will remove Cryptosporidium and other parasites. Look for filters that have an absolute pore size (not a nominal pore size) of 1 micron or less, or that are reverse osmosis filters, or that have the NSF trademark plus the words “cyst removal.”

The Centers for Disease Control and Prevention did a two year survey from 1993 to 1994 to measure the scope of all illnesses from drinking water. They found a total of 30 outbreaks in 17 states that sickened 2,366 people (not counting the huge Cryptosporidium outbreak) – a very small slice of the overall population. One child died from waterborne meningo-encephalitis (from a different parasite — amoebas), but he had been swimming in a waste-water holding pond and in a river that were both contaminated with the organism.

Of the 30 drinking water outbreaks, 20 occurred from well water; one was from commercially bottled water. A median of 33 people were affected in each outbreak. Giardia (another parasite) was the second most common organism, followed by Campylobacter. And Shigella, Salmonella and cholera were responsible for one outbreak each. For the other five outbreaks, the cause was never determined.

Should you boil water given to young babies?

Boiling is the most certain way of killing all of these organisms. Even though the risk of any infection is probably far below 1 percent, I agree with the American Academy of Pediatrics in recommending that sterile water be used for young babies, even when used to prepare infant formula. In practice, this usually means boiling the water for one minute, at least for the first couple of months.

When does water become a positive good?

After the immune system has matured a bit, and solid foods have started, breast milk or formula should still be the primary beverages. But if a baby still seems thirsty between feedings and doesn’t want to nurse more, or is already getting 32 ounces of formula a day, water is the very best additional beverage. If this is the case, offer 2 to 4 ounces of water between feedings, especially in hot weather.

As children continue to grow, water remains an excellent beverage.

Too much fruit juice is not good for babies or toddlers, but that’s another story.