Why Does Formula Cause Necrotizing Enterocolitis (NEC)?

Scientists aren’t sure why formula may increase the risk of NEC, but they have some ideas.

Because premature infants are born before 37 weeks and fully developed, their intestines can’t protect themselves as well as more developed infants. Human milk is protective, reducing inflammation and bacterial invasion, but cow’s milk may encourage the proliferation of damaging bacteria.

In a 2004 study, scientists found that breastmilk was protective against inflammation, inhibiting pathways that would normally proceed to damage intestinal cells.

Scientists also took a look at cow’s milk-based formula in the laboratory. In a 2010 study, they compared intestinal cells exposed to breastmilk to intestinal cells exposed to infant formula. They found that the formula significantly increased oxidation, cell damage, and cell death.

In a 2012 animal study, they found that infant formula, but not fresh breast milk, contains levels of free fatty acids (FFAs) that can be toxic to intestinal cells. When subjects digested preterm infant formula, it caused significant death of certain types of cells in the gut.

And in a 2020 Cochrane study, scientists noted that artificial formulas “do not contain the antibodies and other substances present in breast milk that protect the immature gut of preterm or low birth weight infants and reduce the risk of infection and severe bowel problems.”

Can NeoSure Cause NEC?

Similac Neosure Infant Formula is marketed specifically to premature babies. On Similac’s website, it is entitled: Similac NeoSure Infant Formula, for Babies Born Prematurely.

Then in the product description, the manufacturer describes the formula as “complete nutrition for babies born prematurely…This special blend has protein, calories, vitamins, and minerals, including calcium, to help your baby grow. Similac NeoSure is from the #1 infant formula brand for premature babies.”

The manufacturer goes on to boast that the product is the “#1 brand fed in the NICU” (Neonate Intensive Care Unit). NeoSure will help support brain and eye development, the copy reads, and support bone growth, yet has no artificial growth hormones.

Scientific journals have published numerous studies linking infant formula like NeoSure to NEC when fed to premature infants. One of the most recent, a 2019 Cochrane review, reported that feeding premature infants with formula increases rates of growth during the hospital stay, “but is associated with a higher risk of developing the severe gut disorder called ‘necrotizing enterocolitis.’”

Considering studies like these, it is natural to assume that Similac NeoSure, if fed to premature infants, could increase the risk of NEC. Yet the manufacturer fails to warn doctors or parents of the dangers. Instead, the company promotes the formula as specifically made for premature babies.

Does Similac Cause NEC?

In addition to Similac NeoSure, the Similac brand also produces other infant formulas marketed specifically for premature babies. These include:

• Similac Special Care 20
• Similac Special Care 24
• Similac Special Care 24 High Protein
• Similac Special Care 30

On manufacturer Abbot’s website, Similac Special Care 20 is advertised as “premature infant formula with iron,” and is said to help “low-birth-weight infants and premature infants.” The company also touts its “OptiGRO,” an exclusive blend of DHA, lutein, and vitamin E—ingredients, it says, that “are found in breast milk.”

Yet when it comes to NEC, infant formula and human breast milk are completely different. In a 2018 review, researchers found that while feeding formula to low-birth-weight infants helped improve weight gain and growth, it also created a higher risk of the infant developing NEC.

Does Enfamil Cause Necrotizing Enterocolitis (NEC)?

Like Similac, Enfamil also has infant formulas marketed specifically for premature babies. These include:

• Enfamil NeoPro EnfaCare Infant Formula
• Enfamil Premature Infant Formula 20 Cal with Iron
• Enfamil 24 Cal Infant Formula
• Enfamil Premature Infant Formula 24 Cal High Protein
• Enfamil Premature Infant Formula 24 Cal with Iron
• Enfamil Premature Infant Formula 30 Cal with Iron

The manufacturer makes claims similar to those made with Similac’s products. These formulas promote “catch-up growth,” reads the copy on the Target page, support the baby’s immune system, and contain brain-building nutrition. The manufacturer also boasts that the product is “inspired by breast milk” and promotes catch-up growth “similar to full-term breastfed infants.”

These claims lead parents and doctors to believe that this product is a safe alternative to human breastmilk, when in fact it is not. Studies have shown that human breastmilk is protective against NEC, whereas cow’s-milk-based infant formula seems to increase the risk of the disease.

Is Parent’s Choice Formula Recalled in 2021?

In August 2018, consumer advocate publication Consumer Reports revealed that it had analyzed 50 nationally distributed packaged foods made for babies and toddlers, and found that every product had measurable levels of at least one of these heavy metals: lead, cadmium, mercury, and inorganic arsenic.

Congress tasked a subcommittee to investigate. In February 2021, the committee confirmed the prior reports, finding toxic heavy metals in baby foods and recommending several steps to remedy the situation.

Most of the products came from Beech-Nut and Gerber, but there were some from other brands like Earth’s best, Ella’s Kitchen, Happy Baby, Walmart (Parent’s Choice), Plum Organics, Sprout, and others.

Despite these findings, none of the manufacturers implemented recalls of their products for this issue or any potential links to NEC.

Did Enfamil Get Recalled?

At the time of this writing, neither Enfamil nor any other infant formula product has been recalled because of potential links to NEC. 

Back in 2018, pharmacy retailer CVS pulled Enfamil powdered baby formula from its shelves nationwide after a Florida mother found evidence of product tampering. CVS conducted its own investigation, but after finding no related problems in markets outside of Tampa, Florida resumed sales a short time later.

This incident was not related to the recent concerns about NEC. Infant formulas often promoted specifically to premature babies remain on the market. At the time of this writing, they still have no warnings alerting doctors or patients to the potential dangers of NEC.

Why Was Gerber Recalled?

Gerber infant formulas have not been recalled because of issues with NEC. The company did recall one lot of Good Start Gentle Baby Formula in 2012, but that was because of an “off-odor” that seemed to indicate a manufacturing error.

Is Similac Pro-Sensitive Being Discontinued?

Back in September 2010, Abbot Laboratories recalled about 5 million cans of powdered infant formula, including Similac Advance Sensitive Powder. This was the precursor to the current Similac Pro-Sensitive formula.

The company took this action after an internal quality review found “the remote possibility of the presence of a small common beetle” in a Michigan factory. The ingestion of the beetle or its larvae could cause intestinal discomfort in small children.

No liquid formulas were affected by this recall, and it was not related to the recent concerns about toxic heavy metals or NEC. Similac Pro-Sensitive remains available on the market today.  

Is There a Recall on Similac Formula?

Despite the concerns related to toxic heavy metals and NEC, there is no recall on Similac infant formulas.

What’s Wrong with Similac Formula?

When fed to normal infants, Similac formulas are considered to be generally safe. Though breastfeeding is the gold standard, as stated by the American Academy of Pediatrics (AAP), mothers who cannot breastfeed for whatever reason may choose to use infant formula as an alternative.

Similac formula and other infant formulas, however, can increase the risk of NEC when given to premature or low-birth-weight infants. It may be best to breastfeed or use donor human milk when promoting growth in these infants.

Is Similac Pro-Sensitive Safe for Newborns?

Similac Pro-Sensitive infant formula is designed for babies with “sensitive tummies,” according to the manufacturer. It contains human milk oligosaccharide, a prebiotic “like that found in breast milk,” that is supposed to help support a baby’s developing immune system.

The product is also advertised as being suitable for infants with lactose sensitivity, and as helping to strengthen the immune system “to be more like the breastfed infant than ever before.”

Some lawsuits have already been filed against manufacturers for making these claims—that their infant formulas are like breast milk. In a class-action lawsuit filed in November 2021, an Illinois plaintiff claimed that Abbot Laboratories frequently makes claims that its formulas are close to breastmilk, but that they have no evidence to back up this claim. The plaintiff added that the claims were false, deceptive, and misleading.

Similac Pro-Sensitive seems safe for newborns as long as they aren’t premature or low-birth-weight. As with other infant formulas, it could increase the risk of NEC if fed to these infants.

What is Similac Sensitive Good For?

Babies who have difficulties digesting standard infant formulas may do better with an alternative formula, like Similac Sensitive. It’s best to always check with your pediatrician first. You may be able to find the source of your baby’s discomfort, and then you can be sure to find the best solution.

Is Similac Soy Bad for Babies?

Some mothers who don’t breastfeed may choose to use soy formula as an alternative to cow’s-milk formula. They may be concerned about allergies, lactose intolerance, or other feeding issues.

But scientific research has suggested that soy-based formulas may not be safe for babies.

In a 2018 study, for instance, researchers investigated soy formula compared to cow’s-milk formula and breast milk. They found that infants who consumed soy-based formula as newborns had some reproductive-system cells and tissues, compared to the other two groups. The differences, measured months after birth, were subtle but suggested a need for additional studies.

The concern is that soy-based formulas contain estrogen-like compounds that may affect the body’s endocrine system and potentially interfere with normal hormonal development. Scientists don’t yet know the long-term effects but believe it should be investigated.

The National Institute of Environmental Health Sciences (NIEHS) also suggests caution. The organization states on its website that soy contains naturally occurring compounds that can act like the hormone estrogen in the body:

“Although there have been no specific health problems documented in human infants receiving soy formula, it is recognized that infants go through developmental stages that are sensitive to estrogens…In some cases, the health effects resulting from a soy-based diet may not be apparent until years later.”

Is Similac Soy Isomil Being Discontinued?

Despite the potential health concerns associated with soy-based infant formulas, Similac Soy Isomil and other soy products remain available on the market.

Is There a Recall on Similac Alimentum?

Similac Alimentum is a corn-based formula that is made up of 8 percent soy oil. It’s also made up of about 15 percent sugar, 18 percent casein hydrolysate (derived from cow’s milk), and safflower oil. It has not been recalled and remains available on the market.

What Baby Formula is On Recall 2021?

The only recall affecting baby formulas in 2021 was announced in August. At that time, the FDA alerted the public to a recall affecting nearly 80,000 units of baby formula products distributed by Able Groupe. They were all sold on www.littlebundle.com and were not available at any retail store.

In total, 21 different products were part of the recall, eight of which were found to have insufficient iron levels. Brand names included:

• HiPP
• Holle
• Bioland
• Kendamil

The FDA requires baby formula products with less than one milligram of iron per 100 calories to state on the label that more iron may be needed. The FDA also noted that the products “did not bear mandatory labeling statements in English.”

Low iron levels could negatively impact babies born prematurely or underweight, putting them at risk for iron deficiency anemia.

All of these products were manufactured in Europe and distributed in the U.S. by Able Group.  Yet the manufacturers failed to submit to the FDA the required pre-market notifications for these new formulas—another reason the FDA encouraged a recall.