Side effects of formula milk | Benefits and Risks of Infant Formula

Common Side Effects of Infant Formula

Common side effects of infant formula are usually caused by food allergies, contaminated formula, or using formula without adequate nutrition.

For example, many infant formulas are made with cow’s milk, and cow’s milk allergy is one of the most common childhood allergies. About seven percent of babies under 12 months old are allergic to cow’s milk protein, according to the UK’s National Health Service.


Symptoms of cow’s milk allergy include: Skin reactions, stomach problems and stuffy nose. Severe allergies can cause swelling and breathing difficulties.

Feeding baby formula made with incorrect nutrition can also harm your baby. The CDC warns parents not to use homemade infant formula or buy imported formula online from third-party sellers due to issues such as insufficient nutrition or contamination.

All infant formula sold legally in the United States follows FDA guidelines for safety and nutrition. For example, in August 2021, the FDA announced a baby formula recall for formulas manufactured by Able Group because the formulas did not contain enough iron. Iron deficiency anemia in infants could cause irreversible problems with cognitive and functional development.

Serious side effects of formula milk

Infant formula rarely causes serious side effects. But food allergies, nutrient deficiencies, or infant formula contamination can lead to serious health issues if left unchecked.

Premature babies can also develop a serious condition called necrotizing enterocolitis (NEC) when they drink cow’s milk infant formula like Enfamil or Similac. NEC affects about one in 1,000 children born prematurely, according to the Cleveland Clinic. The risk is highest in babies who weigh less than two pounds at birth.

Life-threatening food allergy symptoms such as swelling of the mouth or throat, hives and vomiting are a medical emergency. These can occur a few days to a few weeks after starting cow’s milk formula. Babies can also be allergic to soy protein formulas. Seek emergency medical attention immediately.


Infant formula contains all the nutrition a baby needs, but studies show that formula-fed babies may be at increased risk of respiratory infections, allergies, Sudden Infant Death Syndrome (SIDS), obesity, cognitive development problems and other health risks compared to breastfed babies. .

Source: Italian Journal of Pediatrics

Rarely, infant formula can be contaminated with a type of bacteria called Cronobacter. This can happen during manufacturing, home preparation, or during feeding if bottles are not properly cleaned.

Babies under three months of age or with weakened immune systems are particularly susceptible to bacterial infections, and Cronobacter can cause serious and life-threatening infections. Be sure to prepare formula in a clean, sanitized area and keep your hands clean.

What is necrotizing enterocolitis (NEC)?

Necrotizing enterocolitis is a gastrointestinal disease that usually affects infants. It’s fatal in up to 50% of all cases, according to a 2021 paper by Drs. Jacob G. Ginglen and Nikolai Butki. NEC causes inflammation that can lead to tissue death in the intestine and colon. This can lead to holes in the intestine, sepsis and death.

Symptoms of NEC include lack of appetite, tenderness or swelling in the abdomen, bloody stools, vomiting, and sluggishness. It usually affects babies between three and 12 days after birth, but can occur several weeks later.

Studies show that premature babies fed cow’s formula alone or in addition to breastfeeding are more likely to develop NEC. One of the first studies to link cow’s formula to NEC was a 1990 study in The Lancet which showed that NEC was up to 10 times more common in formula-fed premature babies. .

Parents of premature babies who developed NEC are filing infant formula lawsuits against the makers of Enfamil and Similac for failing to warn them of the risk.

Trial Information

Lawsuits are being brought by parents whose children have been diagnosed with necrotizing enterocolitis (NEC) after consuming cow’s milk formulas. Learn more.

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Side effects of changing formula

Sometimes your baby’s pediatrician may recommend changing baby formulas. This may be due to food allergies, formula intolerance, or other medical issues. Some babies may have side effects from changing formula, but these are usually mild digestive issues, such as changes in stool.

Signs that a baby does not tolerate a type of formula well include: diarrhea, constipation, gas, or frequent vomiting. More serious intolerance problems include: bloody stools, congestion or wheezing after eating.

It can be a shock to a baby’s sensitive digestive system if you switch formulas too quickly. Parents should transition a baby to the new formula by adding it slowly at feeding times. Be sure to consult your pediatrician on how to properly transition your baby and how long to test a new formula to avoid side effects.

Please seek the advice of a healthcare professional before making healthcare decisions.

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