Distilled water is water that has been purified through a process of boiling and subsequent condensation. This method effectively removes environmental contaminants, bacteria, and viruses, but also almost all dissolved minerals and salts. For parents preparing infant formula, the question of whether this highly purified water is appropriate or necessary for their baby is a common and important concern. The answer depends heavily on how the water is used and the infant’s age, with safety being the primary consideration.
The Chemical Profile of Distilled Water
The unique characteristic of distilled water is its extreme purity, resulting from the distillation process which leaves behind nearly 99.9% of dissolved solids and minerals. This demineralization removes elements like calcium, magnesium, and sodium, as well as contaminants such as lead and nitrates. Because it lacks these dissolved electrolytes, distilled water is often labeled as deionized, demineralized, or purified.
The absence of minerals is the primary theoretical concern when discussing consumption for babies. Consuming large amounts of demineralized water on its own could disrupt the body’s delicate electrolyte balance. However, the formula itself is engineered to provide the necessary balance of electrolytes and nutrients, making the mineral content of the water less of a factor when used correctly to reconstitute formula.
When Infants Need Additional Water
Infants under six months old typically do not require any water beyond what they receive from breast milk or formula. These primary sources of nutrition provide all the necessary hydration. Offering plain water to a baby younger than six months can be counterproductive and even harmful.
Giving water too early may reduce the infant’s intake of nutrient-dense breast milk or formula, potentially affecting growth and development. Another risk is water intoxication, a condition where the dilution of sodium in the bloodstream leads to an imbalance of electrolytes. For this reason, parents should never dilute formula with extra water. Water can be introduced in small amounts, generally 4 to 8 ounces per day, once the baby begins eating solid foods around six months of age.
Preparing Formula: Safety and Water Choice
The safety of the water used is paramount when preparing powdered or liquid-concentrate infant formula. Tap water is generally acceptable, but parents must confirm the local water source is safe and free of contaminants. For high-risk infants, including those under two months of age, premature babies, or those with compromised immune systems, medical guidance recommends boiling the water regardless of the source.
To sterilize tap water, bring it to a rolling boil for a full minute, then allow it to cool to room temperature before mixing with the formula. This process kills potential microbes, which is a necessary precaution for a young digestive system. Using hot tap water is not recommended, as it may contain higher concentrations of metal contaminants leached from household plumbing.
A significant concern with tap water is the presence of fluoride, which is added to many public water supplies. Regularly mixing powdered or liquid-concentrate formula exclusively with fluoridated tap water can increase the risk of dental fluorosis, a cosmetic condition appearing as faint white lines or streaks on the teeth.
Distilled water is an acceptable option for formula preparation because the distillation process effectively removes fluoride and other contaminants. Other alternatives include bottled water labeled as purified, deionized, or demineralized, as these also indicate a low-fluoride content. Parents concerned about fluoride exposure can use low-fluoride water for formula preparation some of the time, or opt for ready-to-feed formula, which contains minimal fluoride.