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Switching Baby Formula

Switching baby formula is a significant change for infants, and it must be done with forethought and care. Side effects are typically mild, but in the worst cases they can be serious. Consult your child’s pediatrician regarding the best tactics for how to change your baby’s formula.

Last Modified: September 5, 2023
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What to Know About Switching Baby Formula

The need to change baby formula can happen for various reasons, including product improvements, medical issues, allergies, recalls and shortages. While all infant formulas sold in the United States meet the standards of the U.S. Food and Drug Administration, each brand’s ingredients can differ. As a result, small variations exist among formulas, such as different combinations of casein and whey proteins.

The three main types of proteins in infant formulas are:
  • Soy protein: It's an ideal option for babies allergic to whey or casein or with specific health issues.
  • Cow’s milk protein: Casein and whey are the most common proteins in formulas.
  • Hypoallergenic protein: These formulas are used for infants who cannot digest intact cow’s milk protein. Hypoallergenic formulas break down proteins to make them easier to digest. They can be expensive and typically don’t have much taste.

When you switch your baby’s formula, try to stick with the same protein content. That way, even if you’re switching to a different brand, it will help your little one tolerate the change. If you want to change to a different type of protein, discuss this with your child’s pediatrician first for more health information.

Side Effects

Gas, diarrhea and upset stomachs are the most prevalent side effects of baby formula. Sometimes a pediatrician will recommend changing formulas because of food allergies or formula intolerance. When you make the switch, you won’t know exactly how your baby will react. Discuss your baby’s diet with your pediatrician before making a switch.

Some infants, particularly premature infants with low birth weight, can experience necrotizing enterocolitis (NEC) from premature baby formula. NEC is a rare but severe condition that causes inflammation in newborns’ small and large intestines.

While the exact cause of NEC remains unknown, key risk factors are premature birth and formula feeding.

Common symptoms of NEC include:
  • Abdominal pain
  • Swollen abdomen
  • Lethargy
  • Bloody stool
  • Inability to feed
  • Change in heart rate, breathing and blood pressure

Pediatricians warn parents not to use imported formulas or homemade baby formula because of contamination or insufficient nutrition. Homemade formulas have been involved in cases of infants being hospitalized for malnutrition around the U.S.

Contamination can also occur with not only imported or homemade formula, but any formula if other ingredients are mixed in with the formula or the water used with the powdered mix is not properly filtered or boiled.

Allergic Reactions

Babies can have an allergic reaction to many things in their new world. Eggs, milk and peanuts are the top three allergens for kids, and most baby formulas contain cow’s milk protein. Some infants may also react to soy-based formulas.

Lactose intolerance is sometimes confused with protein intolerance. Protein intolerance is a result of an inability to process casein or whey. Lactose intolerance is a result of an inability to process the sugar in milk.

Two signs of an allergy to formula are weight loss and dehydration. Other possible allergic reactions include:
  • Hives
  • Chronic nasal stuffiness
  • Wheezing
  • Rash
  • Facial swelling

Lactose intolerance in babies means the body cannot produce enough lactase to digest lactose. The undigested lactose stays in the intestine, leading to gastrointestinal issues like vomiting and diarrhea.

If your baby is allergic to formula or is experiencing intolerance issues, talk to your pediatrician. They may recommend a hypoallergenic formula or lactose-free formula depending on the root cause of your baby’s symptoms.

Why Switch Baby Formula?

NEC lawsuits and other claims against baby formula, recalls and supply chain issues have left parents having to switch their baby’s formula.

Abbot’s voluntary baby formula recall has seen the country grappling with formula shortages. Walmart recently withdrew a batch of Mead Johnson powdered infant formula after a baby died of a bacterial infection possibly connected to the formula.

In addition, caregivers and parents may switch baby formula because of side effects and allergic reactions. It’s important to consult your pediatrician before switching formulas for your infant to ensure you find the right formula for their specific nutritional needs.

Lawsuit Information
Lawsuits are being filed by parents whose children were diagnosed with necrotizing enterocolitis (NEC) after consuming cow's milk-based formula. Learn more.
View Lawsuits

How to Switch Baby Formula

Switching baby formula should be done with a pediatrician’s expert guidance. Typically they will advise a gradual transition to account for sensitivity to new formulations.

Your pediatrician may also advise trying a combination of two-thirds of the current formula and one-third of the new products. When the baby accepts the combination, parents may then be advised to mix in a ratio of 1:1.

Professionals recommend switching to a store or generic brand formula equivalent to what the child was taking initially if possible. If you cannot find the generic brand, discuss alternative options with your pediatrician.

FDA regulated commercial brands in the U.S. are generally considered safe options. Homemade baby formula, however, can pose serious health risks to infants, as it may lack the necessary mix of nutrients.

Switching to Breastfeeding

Breastmilk is a superfood for babies because it contains the right balance of the nutrients they need. Babies who are fed breast milk experience statistically better health outcomes. Compared with formula, breastfeeding delivers nutrients that help with digestive health, nervous system development and brain growth.

Breast-fed infants are less likely to develop NEC and have fewer ear, digestive and lung infections. Mothers who switched from breast milk to formula can switch back to breastfeeding. Experts can help guide parents through relactation. Supplementation may be required during the process.

Most medications are safe to take while breastfeeding, but chemotherapy drugs, lithium and oral iodine are notable exceptions. For mothers unable to breastfeed or relactate, many are turning to breast milk banks. A growing number of NICU units at U.S. hospitals are also relying on donors and milk banks to supply vulnerable premature babies with breast milk.

How Long Does It Take for Babies to Adjust to New Formula?

It usually takes about seven to 14 days for babies to adjust to a new formula. They might like one immediately, but they also might not like any of them right away. Hypoallergenic formulas, for example, cause fewer or no allergic reactions, but they’re also known for less appealing tastes for babies.

Premature baby formula is designed for easy ingestion, but may not be sustainable for older infants. Remember, what works for another baby might not work for your infant. Consult your infant’s pediatrician for expert advice.

What to Do If Your Baby Rejects the Formula

You may notice that the new formula is upsetting your baby immediately. Some may take a few days before showing reactions. Monitor your baby keenly for about a week to observe any behavioral changes.

Note any changes in sleeping patterns, bowel movements or fussiness. If you notice any negative changes, it may mean the formula is upsetting your baby.
If the baby rejects the formula, you can choose relactation or try another formula. Talk to a pediatrician before making any changes for accurate information on choosing a formula closest to the nutritional benefits of breastmilk.

If your infant develops any severe reactions, contact urgent care or visit the nearest emergency room immediately.

Please seek the advice of a medical professional before making health care decisions.