Ready-to-feed formula is a premixed liquid formula that offers bottle-feeding parents convenience but at a high cost. Most parents who feed their babies artificial formula opt for powdered formula rather than ready-to-feed because it is significantly cheaper and can be stored longer. (Ready-to-feed infant formula can be refrigerated for up to 72 hours after opening then needs to be discarded.) Although you may notice a difference in texture between the two types of formula, if your baby is healthy and you have access to clean water, there's no reason to use ready-to-feed formula. (See below for more about water-related concerns.)
A growing awareness of the potential health risks of bisphenol A (BPA) has prompted manufacturers to turn their attention to formula packaging. BPA is a chemical found in plastics which has been implicated in neurological problems, reproductive health concerns, cardiovascular diagnoses, diabetes, and more. The risks are thought to be higher for infants and children. BPA has been widely used in baby bottles and the lining of infant formula cans, causing special concern for parents who use these items. The U.S. Department of Health and Human Services (DHHS) cautions parents that “small amounts of BPA [can be found] in liquid infant formulas sold in cans.” By comparison, the “FDA has found that powdered infant formula typically has no detectable level of BPA.” However, just as the leading baby bottle manufacturers have removed BPA from their products, many infant formula manufacturers have removed BPA from their packaging. Fortunately, manufacturers know that BPA-free packaging is desirable, so look for the “BPA-free” seal when shopping for formula.
With powdered formula, correct and safe preparation is essential. Some tips:
- Choose safe water. Although experts often recommend fluoridated water to reduce the risk of cavities, infants who are fed formula mixed with fluoridated water can get too much fluoride. The American Dental Association (ADA) cautions that too much fluoride on emerging teeth can cause enamel fluorosis, permanent staining on both your child’s baby and permanent teeth. Your local water company can tell you if your water is fluoridated (and the amount of fluoride) or has substantial natural fluoride (0.7 mg/L or more). If your water contains high levels of fluoride, consider using low-fluoride water, such as bottled water or water filtered through a fluoride-removing home water treatment system. Also, avoid using well water, which can have high levels of nitrates or other contaminants.
- If you’re using tap water, use cold—not hot or warm. Also, run the water for 15–30 seconds before filling your baby’s bottle. Many homes have lead in their plumbing pipes. High lead levels have been associated with a host of neurological and developmental delays. Cold water picks up less of the lead than hot water, and allowing the water to run for several seconds ensures that you are not giving your baby the water that has been standing in your pipes, absorbing potential contaminants. Alternatively, you may prefer to use water that has been filtered through any of a variety of systems that remove lead.
- Consider boiling water used to mix formula. The instructions on most powdered formula containers direct parents to boil water used for mixing infant formula; new packaging now recommends that parents talk with their baby’s health care provider or health department. The idea behind boiling was to sterilize the water, and minimize exposure to bacteria in young babies with immature immune systems. Studies have not shown significant benefits to this added step. If you do choose to boil the water, follow the Food and Drug Administration (FDA)’s directions: bring it to a rolling boil for about 60 seconds, and allow it to cool before using. Don’t boil it for longer periods or boil it a second time, as this can increase the level of impurities. Keep in mind that powdered formula itself is not sterile. Contaminated formula has been linked to serious illness in preterm infants. So mothers of preterm infants who are unable to breastfeed or provide donor human milk are urged to use liquid formula which is sterile.
- Measure scrupulously. Babies can be sickened by formula that has either too much water or too much powdered mix. Make sure you follow the instructions on the formula container and measure carefully.
- Shake the bottle. Make sure the formula is thoroughly blended before offering it to your baby. This will ensure that your baby gets all the nutrients in the formula.
Here are some more tips from the Mayo Clinic on safe preparation and storage of formula.