Extra Water Can Be Harmful For Babies

by Mary Elizabeth Dallas
March 16, 2012

Water is the perfect thirst quencher on a hot day—unless you’re a baby under 12 months of age. Breast milk (or formula) provides all the water babies need, even those living in hot climates. Water also lacks the nutrients found in breast milk, and puts babies at greater risk for a serious condition called hyponatremia.

What is the problem with water?
Hyponatremia or “water intoxication” is one of the leading causes of seizures in infants, second only to fever. When babies are given too much water, it dilutes the level of sodium (salt) in the blood. Sodium controls blood pressure and helps nerves and muscles work properly. Sodium is found in the body fluids outside the cells. If the sodium level is low, nearby cells take in water (swell) in an attempt to restore the sodium balance. Most cells can hold the added water. Brain cells, however, are confined within the skull. When brain cells swell, symptoms including hyponatremic seizures can occur resulting in brain damage or even death.

Hyponatremic seizures occur most often in infants under 1 year of age. Their diet contains very few foods, making it hard to replace lost sodium. Also, their kidneys are still developing, so they can’t filter large amounts of water.

Symptoms of water intoxication in infants include:

• irritability or drowsiness
• low body temperature
• swelling of the face
• seizures

Any child who consumes too much water can experience water intoxication, however, the risk is greatest among children who are already dehydrated from a bout of vomiting or diarrhea.

Formula stretching and hyponatremia
A common risk factor for hyponatremia is formula stretching—diluting formula with more water than is recommended. Researchers investigating food insecurity found that some formula-feeding mothers, in an effort to stretch their food budget, water down formula (or skip feedings altogether). Families from two pediatric clinics in Cincinnati, where 45,000 patients from under-served neighborhoods are seen each year, participated in the study. Despite receiving public assistance, about 30 percent of these families (twice the national average) were unable to afford enough food to meet their basic nutritional needs. Among those who couldn’t purchase adequate amounts of food, 27 percent admitted to formula stretching.

Restricting nutrients during a period of rapid brain development, increases the risk for hyponatremia as well as the risk for learning, behavioral, and psychological problems, the researchers caution.

Because formula that is improperly mixed can lead to water intoxication, the American Academy of Family Physicians cautions caregivers to follow the directions on formula containers exactly—always measure carefully and never add extra water.

“Recent evidence suggests that mixing powdered or liquid infant formula concentrate with fluoridated water on a regular basis may increase the chance of a child developing the faint, white markings of very mild or mild enamel fluorosis,” says the Centers for Disease Control and Prevention (CDC).  If your drinking water has high levels of fluoride, the CDC and the American Dental Association (ADA) recommend that parents use either low-fluoride or fluoride-free water when mixing powdered or concentrated formula, or use ready-to-feed formula. Ready-to-feed formula contains little fluoride, reducing the risk for fluorosis. But it also eliminates the need for added water reducing the risk for water intoxication from either improper mixing or intentional stretching.

A 1991 study published in the American Journal of Diseases in Children analyzed 34 cases of water intoxication in infants over a period of 15 years. The researchers found that 24 of these incidents occurred between 1987 and 1990, a sizeable increase for a “previously rare condition.”

Nearly all of the infants (31 of 34) were living in poverty and were given excessive amounts of water by a caregiver. Most often, the water was used to satisfy thirst when the family’s supply of formula had run out.

While cost can be a factor, babies are given water for other reasons. The CDC reports that, in 1993, two infants in Wisconsin were hospitalized for water intoxication associated with bottled water.

Although one of the infants was given several ounces of water for several days because it was less expensive than infant formula, the second baby was given water to help relieve symptoms of an upper respiratory infection. Both mothers reported the labeling on the water they gave their babies led them to believe the products were safe and specifically designed for infants.

Experts from Johns Hopkins Children’s warned in 2008 about recurring cases of hyponatremia in the summer months. They cite that 3–4 otherwise healthy infants are rushed to the hospital each summer after suffering a seizure caused by too much water intake.

Although the seizures may have no lasting effect on the children’s health, the experts from Johns Hopkins noted seizures are “quite dramatic and completely preventable.”

Preventing hyponatremia
During your baby’s first year of life, breast milk or properly prepared infant formula is the best fluid source.

“There is no safe amount of free water for infants,” according to board certified pediatrician and neonatologist, Dr. Angela McGovern, M.D. from The Washington Hospital Center, Washington D.C. “Too much water can not only dilute the salts in the body putting infants at risk for seizures, it can make babies feel full without providing them any nutrition. For best health and nutrition in the first year of life, the only fluid an infant needs is breast milk or properly prepared formula.”

Once your baby is eating a variety of solid foods, McGovern adds, small amounts of water can be mixed with purees to get the right consistency. She noted, however, thinning foods with breast milk or formula is ideal.

By following these simple guidelines, parents and caregivers can reduce the risk of hyponatremic seizures. Water intoxication is a scary condition, but fortunately it is completely preventable.

A final caution—juice is not a substitute for water. Juice should not be given to babies under 6 months of age and should be limited to no more than 4 ounces a day in older babies and young children. Juice is also a poor substitute for breast milk or formula and a major contributor to obesity and tooth decay.

For more information on the safe use of water in babies and young children see “When Is It Safe To Give My Baby Water?”

Mary Elizabeth Dallas is a NY–based journalist with more than 15 years of experience, including CNN and ABC News. She is also relishing her newest challenge… motherhood. Today, she is using her experience to help inform parents on the key challenges and issues they face every day.