When preparing infant formula or offering a baby extra hydration, the question of whether to use distilled water is common for parents. While distilled water is exceptionally pure, its unique composition means it is generally unnecessary for regular infant feeding and can pose risks if used exclusively. The safety of using any water for a baby depends largely on their age, the specific application, and the water’s mineral content. For most healthy infants, choosing the water source requires understanding the difference between purity and mineral balance.
Understanding Distilled Water
Distilled water is a type of purified water created through a thermal process. This involves boiling water and collecting the steam as it condenses back into a liquid state. This method effectively separates the water vapor from nearly all dissolved solids, including minerals, salts, and contaminants. The resulting product is nearly 100% pure water, typically containing only one to five parts per million of total dissolved solids (TDS). This extreme purity means the water lacks flavor and the natural minerals found in other water sources.
Potential Health Risks for Infants
The primary concern with regularly feeding a baby distilled water is the absence of minerals, which makes the water hypotonic. A baby’s developing kidneys are less efficient than an adult’s at regulating fluid and electrolyte balance. Using water with no electrolytes can disrupt the delicate sodium balance in the infant’s bloodstream, especially if given in large amounts. This disruption can lead to hyponatremia, where the sodium concentration in the blood becomes too low. The excessive water influx causes cells, including brain cells, to swell, similar to water intoxication. Symptoms of this electrolyte imbalance can include nausea, vomiting, irritability, apathy, or lethargy. Replacing all formula water with distilled water is strongly discouraged unless specifically advised by a healthcare provider.
Recommended Water Sources for Babies
For mixing infant formula, safe tap water is generally the preferred choice, provided the local supply is tested and known to be safe. If there are concerns about tap water quality, such as an unknown well source or the presence of lead or nitrates, parents should use bottled water instead. Bottled water labeled as “purified” or “nursery water” is treated to remove contaminants but retains or has added minerals, making it a safer option than distilled water for consistent use.
Water Preparation Guidelines
For infants under three months of age, those born prematurely, or those with a weakened immune system, it is often recommended to boil the water used for preparing powdered formula. Boiling cold tap water for one minute and then cooling it to room temperature before mixing will kill potential bacteria or viruses. Note that boiling water does not remove chemicals like nitrates or lead; if these contaminants are present, bottled water must be used. If using fluoridated tap water, the American Dental Association suggests occasionally using low-fluoride bottled water to reduce the risk of mild dental fluorosis.