The first year of life is vital for a child’s growth, and proper nutrition is crucial to ensuring that infants have the necessary building blocks to support this period of rapid development. For about the first six months of life, an infant must consume exclusively either human milk or infant formula, with solid foods added to supplement human milk or formula from six months to one year. There are many considerations when deciding which path (or a combination of both) is right for a new parent feeding their baby—read on for the lowdown on different kinds of infant feeding, including important safety considerations surrounding the use of infant formula.

Human Milk and Infant Formula: The Basics

Human milk is considered the optimal source of nutrition for infants; it provides all of the nutrients needed for a baby’s development for approximately the first six months of life and has been found to have an array of health benefits. Human milk contains bioactive compounds that promote healthful gastrointestinal, immune, and brain development. In addition, research shows a link between human feeding and subsequent decreased risk for chronic diseases like type II diabetes. Additionally, human milk feeding can help foster bonding between a mother and her baby (although fathers, partners, and other caregivers can bond in different ways with alternative feeding methods). The current World Health Organization recommendation is to exclusively feed infants human milk, if the mother is able to do so, for the first six months of life.

After the first six months, an infant’s needs for certain nutrients, particularly iron and vitamin D, are difficult to meet through human milk alone, and complementary solid foods are recommended to be introduced between four and six months. The current Dietary Guidelines recommend continuing human-milk feeding until an infant is 12 months or older with the addition of complementary foods. Complementary foods help support a baby’s increased nutrient needs and introduce infants to new flavors, textures, and preparations of foods.

While exclusive human-milk feeding is recommended as the gold standard of nutritional care for the first six months of life, how a parent feeds their infant is also a personal decision that can be influenced by many factors. Not everyone is able to adequately support their newborn through human milk—some are unable to produce enough human milk, and others may have different reasons for choosing not to feed with human milk. For those who cannot or who choose not to feed their babies human milk, infant formula has been used as a safe tool to help ensure that newborns receive proper nutrition during this critical growth stage. Infant formula is designed to mirror the nutritional profile of human milk, although it lacks some specific bioactive compounds found in human milk and therefore cannot be considered completely identical in benefits to human milk.

Although no single infant formula is seen as superior, the Centers for Disease Control and Prevention (CDC) recommends choosing an iron-fortified formula to help meet a formula-fed infant’s iron needs. Commercially available infant formula is regulated by the U.S. Food and Drug Administration (FDA) to ensure the products meet federal nutrient requirements. Infant formulas can be cow-milk-based, soy-based, or contain a specialized formula, and infant formula products are available in three forms: powder, liquid, and ready-to-feed.

Infant Formula Safety Considerations

While powdered infant formula is the most cost-effective option, there are safety considerations that are specific to this kind of formula. Powdered formula requires mixing with water before feeding, so it’s important to ensure the water is from a safe source. If you choose powdered formula, be sure to follow the CDC’ preparation guidelines, since too much water may dilute the mixture and lower its nutritional content, whereas too little water may overwork the infant’s developing kidneys and digestive system, leading to dehydration.

Moreover, powdered infant formula is not sterile and may contain pathogens, such as Salmonella enterica or Cronobacter bacteria, which can cause serious and potentially fatal illness in infants. Some infants are more susceptible to Cronobacter bacteria, especially newborns (in particular, those less than 2 months old), infants born prematurely, and infants with weakened immune systems. However, there are some extra precautions that can help lower the risk of contamination by Cronobacter and other pathogens, like cleaning, sanitizing, and storing feeding items safely; preparing and storing powdered infant formula safely; making sure the formula is never expired and remains in good condition; and keeping the formula scoop dry. (More tips can found via the CDC.) Once powdered formula is prepared, it should be used within two hours to avoid spoilage—although you can store any leftovers for up to 24 hours in the refrigerator. To help further reduce risk of exposure to Cronobacter and other pathogens like Salmonella, you may want to consider using liquid infant formula, which is sterile.

More Considerations: Homemade Infant Formula, Formula from Other Countries, and More

The FDA and the American Academy of Pediatrics do not support the production or use of homemade infant formula due to clear safety concerns and the possible nutritional inadequacies of homemade formulas. If you are experiencing limited access to infant formula, the FDA recommends that you contact your child’s healthcare provider for recommendations and support. Further, is not recommended that you dilute formula to increase its longevity, since dilution may lead to nutritional inadequacies. In addition, parents and caregivers should exercise caution when purchasing infant formula products online from other countries, since they may not be subject to the same regulations or nutritional guidelines as infant formula products in the United States.

And remember, since infant formula is a food, it’s important to be aware of and to mitigate any potential risk of contamination and to track any infant formula recalls. If your formula product has been recalled, stop using it immediately. The Partnership for Food Safety Education’s “Recall Basics” further advises to dispose of the product right away, keep any containers closed if they have not been opened, and wash your hands after handling the product. You may also want to consider taking a picture of the recalled product and saving your grocery shopping receipts in case you are able to take the products back to the store for a refund. To be informed about any future recalls, consult the FDA’s recall website, where every recall is publicly available.

Infant Formula: The Bottom Line

Both human milk and infant formula are safe and effective feeding options for a growing infant—and many parents use a combination of both in their child’s first year of life. If you choose to feed your baby with formula, be sure to review these key safety considerations—particularly for powdered infant formula—and ask your healthcare provider if you are unsure of what type of nourishment is best for your baby.

This article was written by Debbie Fetter, PhD, and reviewed by Alyssa Pike, RD.