Is Breastfeeding Really Best and Is Formula Harmful?

breastfeeding breast is best

As a diverse group of moms with myriad views, varied professions and education, and roots all over the country and abroad, we SciMoms feed our kids a wide range of foods, if they’ll eat them. But one feeding choice is clear. In our science-based and value-driven opinion, parents should feed infants safely and sufficiently by whichever methods work for their families. This includes breastfeeding, formula feeding, or a combination of breastmilk and formula. We say this as moms who all breastfed our babies for various amounts of time.

The science says that breast is best … or does it?

Breastfed infants fare better on the whole than their formula-fed counterparts, both in the U.S. and globally. The U.S. Department of Health and Human Services (HHS) explains that breastfed babies have a lower incidence of asthma, leukemia, obesity, ear infections, eczema, lower respiratory infections, necrotizing enterocolitis (a disease that affects the gastrointestinal tract in premature babies), sudden infant death syndrome (SIDS), and type 2 diabetes. According to the World Health Organization (WHO), higher IQ, greater school attainment, and higher salary in later years are also associated with breastfeeding. (Note:  IQ as a measure of intelligence is problematic in several ways.)

But with the exception of necrotizing enterocolitis—there is strong evidence that an exclusively human milk diet significantly reduces the risk of this devastating intestinal disease that mostly occurs in premature infants—the data don’t actually show that breastmilk itself leads to widely-touted improved outcomes in childhood and adulthood.

So why do breastfed babies do so much better if it isn’t breastmilk itself conferring these improved outcomes? The environment of exclusively breastfed infants tends to differ from the environment of infants who receive supplementary feeding or who are exclusively fed with formula or other substitutes.

In the developed world, breastfed infants tend to have more educated moms with higher incomes and better access to health care. Their moms are also less likely to smoke, among other characteristics that distinguish them from formula-feeding counterparts.

anastasia breastfeeding baby
Anastasia feeding her daughter. Her daughter received supplemental formula in the NICU and for a few months after birth, then went on to breastfeed for over three years.

In less economically developed nations, many caregivers who use breast milk substitutes have no choice but to prepare them without sanitation or safe water. This constitutes a public health crisis affecting billions of people globally. As I wrote in The Daily Beast about how “breast is best” campaigns are misguided, “[t]he reality is that billions of people today don’t have access to clean water, and that means breastfeeding can be a matter of life or death for babies where sanitation is a problem.”

Research on early childhood development and other health outcomes suggests that breast milk doesn’t live up to its  “liquid gold” status when accounting for these confounding factors.

The shifting paradigm

Until recently, the World Health Organization’s Baby-Friendly Hospital Initiative (BFHI) has been the gold standard for breastfeeding implementation worldwide since it launched in 1991, based on the seemingly iron-clad “breast is best” mantra.

Framed around the Ten Steps to Successful Breastfeeding guidelines, which are designed to “increase breastfeeding initiation and duration,” the initiative urges caregivers to give infants “no food or drink other than breast-milk, unless medically indicated” until the introduction of supplementary food at six months of age. BFHI accredited hospitals are also urged to promote “rooming in” and skin-to-skin contact throughout the hospital stay following birth.

Controversy has mounted in recent years over whether BFHI is actually helpful and could cause unintended harm. For example, sudden unexpected postnatal collapse (SUPC) and sudden unexpected infant death (SUID) among otherwise healthy newborns are strongly associated with rooming-in and skin-to-skin care. Newborn falls have been increasingly linked to BFHI recommendations. There’s also evidence that dehydration requiring hospital readmission has risen with the increased recommendation of exclusive breastfeeding. Despite all of this, more than 15,000 facilities in 152 countries and growing have earned the BFHI accreditation.

BFHI released its updated evidence document (EG) and implementation guidelines (IG) a few months ago. The Journal of the American Medical Association (JAMA) released a Clinical Guidelines Synopsis of the revised BFHI evidence document calling the BFHI into question, and also highlighted BFHI dialing back its controversial recommendations. Highlights (with my commentary in italics, based on my coverage of infant feeding policy over the past few years) include:

  • JAMA’s synopsis points out that BFHI has serious “stakeholder bias” and that BFHI should no longer be viewed as the leading public policy option for breastfeeding support—this is a major shift.
  • The JAMA synopsis says that “[w]hile supportive of breastfeeding exclusivity, the IG recognizes that supplementation may be necessary for some infants because of inadequate milk supply and maternal choice” —maternal choice has never been validated until now as a reason to use formula.  
  • The synopsis points out that “[t]he EG also notes that while there are many benefits to rooming-in, many mothers prefer not to and rooming-in ‘probably makes little to no difference to any breastfeeding at 6 months'” — BFHI has insisted for years that rooming in is crucial, so much so that some hospitals have eliminated infant nurseries.
  • JAMA notes that, “[c]onsistent with evidence that pacifiers reduce the risk of sudden infant death syndrome (SIDS) and high-QOE that pacifiers do not interfere with breastfeeding outcomes, the draft IG had proposed eliminating pacifier restrictions. Despite evidence that mothers value using pacifiers, this change was not included in the final IG. Instead, advice to counsel mothers about hygiene risks was added without mentioning the reduced risk of SIDS associated with pacifier use.” —So the BFHI knowingly chose to follow its bias against pacifiers despite evidence that it reduces SIDS risk and doesn’t interfere with breastfeeding outcomes. That’s disturbing.

The question is, what happens next? My educated guess is that there will be a significant lag in these changes actually reaching new moms. This is clear because hospitals keep announcing their newly-earned “prestigious” BFHI accreditation. Meanwhile, it remains difficult to parse through the prevailing “breast is best” adage.

Nature’s perfect food?

layla bottle feeding pumped breastmilk bottle
Layla feeding her son a pumped bottle.

Often referred to as “liquid gold,” adherents of the prevailing “breast is best” mantra cite the unique properties of breastmilk that science and industry can’t duplicate. There is credence to the argument that breastmilk is fundamentally different from formula. For example, evidence shows that human milk has a unique microbiome, and that the microbial composition varies from mother to mother, but that there are a few core bacteria consistently present in most milk samples.

This human-milk microbiome has an effect on the infant intestinal microbiome, along with other factors before, during, and after birth. Other factors include the maternal diet during pregnancy, mode of delivery, and caretaker handwashing. There appears to be an association between breastfeeding or partial breastfeeding and abundance of specific bacterial species with probiotic effects.

There is no evidence, however, that microbial and other differences between breastmilk and formula lead to disparities in health outcomes for infants.

But I’ve heard that breastmilk saves hundreds of thousands of lives

A 2016 paper in The Lancet which concluded that “[t]he scaling up of breastfeeding to a near universal level could prevent 823,000 annual deaths in children younger than 5 years” led to a slew of headlines and a prevailing notion that lack of optimal breastfeeding literally kills children. This meta-analysis looked at associations between breastfeeding and outcomes in children and in mothers from 22 systematic reviews and meta-analyses.

Since there are ethical barriers to randomized controlled infant feeding trials, the paper in The Lancet relied on mathematical modeling to arrive at its findings. The researchers extrapolated from data in small studies with their own confounding factors and limitations, including small size and geographical differences.

There aren’t real-world data to corroborate that scaling up breastfeeding to universal levels could prevent hundreds of thousands of deaths per year.  There are, however, plenty of real-world data to show that improving access to clean water and sanitation around the world could save millions of lives, including those of children who don’t have access to breast milk.

Writing in Slateobstetrician-gynecologist Dr. Amy Tuteur explains reasons that the medical establishment has pushed so hard in favor of exclusive breastfeeding even though it doesn’t actually improve outcomes, including formula companies convincing women in the 1970’s in developing nations to stop breastfeeding and use formula instead:

“The formula companies’ action was both unethical and inexcusable, but the result was not merely appropriate disgust with manufacturers but inappropriate demonization of formula itself. Today, white-hat bias leads breastfeeding researchers to avoid any conclusion that recommends formula and might thereby enrich its manufacturers.”

Making the right choice

If you have access to safe and regulated formula, clean water, and conditions with which to prepare infant formula, and your infant was not born prematurely, there are several feeding options, including exclusive breastfeeding, combo feeding, and exclusive formula feeding. That’s right— we’re saying that it’s absolutely okay to choose to use formula.

breastfeeding vs bottlefeeding infographic
Breastfeeding and bottlefeeding infographic from UnityPoint Health, used with permission. Read the accompanying article Breastfeeding vs. Bottle-feeding: A Heated Debate.

I reached out to pediatrician and medicine and health columnist Dr. Daniel Summers, who had the following to say:

“Very little frustrates me more than seeing breastfeeding treated as some kind of zero-sum benefit, as though the introduction of formula will inflict irreparable harm on a newborn’s system. I think it’s important to support mothers who opt to breastfeed, and there are certainly established benefits that go along with doing so. But those benefits are often overstated, with little evidence to support some of the claims made, and new mothers can feel inordinate pressure to provide them, even at unsustainable cost to themselves. Supplementing with formula, or opting to formula feed from the start, doesn’t mean your child won’t thrive, and having a mom who is less stressed and exhausted provides plenty of benefits for both baby and mother.”  

In 2009, Hanna Rosin wrote in The Atlantic of “breast is best” feeding advice from prominent “parenting guru” Dr. William Sears, who presents popular yet exaggerated or misinterpreted studies to promote breastfeeding:

“[T]he medical literature looks nothing like the popular literature. It shows that breast-feeding is probably, maybe, a little better; but it is far from the stampede of evidence that Sears describes. More like tiny, unsure baby steps: two forward, two back, with much meandering and bumping into walls. A couple of studies will show fewer allergies, and then the next one will turn up no difference. Same with mother-infant bonding, IQ, leukemia, cholesterol, diabetes. Even where consensus is mounting, the meta studies—reviews of existing studies—consistently complain about biases, missing evidence, and other major flaws in study design.”

This still holds true ten years later. We SciMoms strongly believe that infant feeding comes down to an informed choice that takes into account family lifestyle, mother’s schedule and employment status, employer pumping policy, personal comfort, and more.

Check out this detailed thread from Layla outlining the lengths to which she went, with the support of her employer, to ensure that her son had breastmilk even when she traveled for work.

Breastmilk is not free

Parents also have to weigh the costs associated with breastfeeding and formula feeding. While it is possible to breastfeed without any special equipment or accessories, each SciMom used a combination of costly items and services, including pumps, nursing bras, breast pads, creams, bottles, and lactation consultants. And that’s only the beginning.

Breastmilk is only “free” if a mother’s time is worth nothing— the costs vary from person to person. Consider that those who breastfeed long-term are more likely than those who breastfed for a shorter duration (or not at all) to switch to part-time work or to leave the workforce for a period significantly longer than the typical U.S. maternity leave of 3 months. In addition, there is an earnings penalty for lost work experience.

If you choose to breastfeed “exclusively”—BFHI defines “exclusive” as giving no other food or drink—you’ll have to nurse at least 8-12 times in a 24-hour period for the first month. After the first month, an exclusively breastfed baby will probably nurse 7-9 times per day. According to, breastfed infants usually take smaller, more frequent feedings than formula-fed infants.

It’s important to note that the prevailing notions that newborns who nurse frequently will get enough milk and that newborns don’t need much milk in the first few days of life aren’t necessarily correct. Up to 15 percent of moms don’t produce enough milk, due to several factors including genetics. Newborns who don’t get enough milk can develop dehydration, low blood pressure, and hypoglycemia (low blood sugar), which can cause irreversible brain injury and, in rare cases, death. Insufficient supply in the first days after birth, before milk “comes in,” is more common in first-time mothers. It helps to be aware of warning signs that your infant isn’t getting enough milk, including a baby that still seems hungry after feeds. Do not hesitate to contact your healthcare provider if you’re unsure.

I wish I knew that supplementing a healthy, full-term newborn with formula while waiting for my milk to come in wouldn’t ruin my chances at establishing exclusive breastfeeding. I also wish I knew that exclusive breastfeeding isn’t nearly as important as I believed it to be. I described my experience in SELF Magazine:

“After my daughter lost too much weight in the days following birth, my doctor gently suggested supplementing with formula until my milk fully came in. After two days of nursing, pumping to increase supply, and supplementing with a bottle, we ditched the formula and I nursed her exclusively until we began solid foods.”

I’ll never forget walking into the drugstore to buy formula that day— I felt like an utter disappointment, and that I’d failed to provide my daughter the best start at life. Turns out that there’s scant evidence to support that bottle feeding a newborn can lead to nipple confusion or that supplementing with formula before milk fully comes in reduces the chances of a long-term breastfeeding relationship between mother and baby.

Research actually suggests that early limited supplementation can be a temporary feeding strategy for parents dealing with weight loss in newborns, and it may even reduce long-term formula use. Throughout history, babies have been fed milk from wet nurses, animals, and other substitutes to their own mothers’ milk for myriad reasons, including insufficient milk in the days following birth.

None of this is to say that long-term formula use is a problem., a resource from the American Academy of Pediatrics, tells new parents that “[e]ven though formula feeding is not identical to breastfeeding, formulas do provide appropriate nutrition. Both approaches are safe and healthy for your baby, and each has its advantages.”

This isn’t just a science conversation, it’s a values judgement too

If science is the only factor on which we base infant feeding policy, and if the science showed that breastmilk leads to significantly better health and socioeconomic outcomes, then it makes sense to prescribe exclusive breastfeeding across the board. Even in that hypothetical situation, depending on the circumstances, I personally believe that a mother would still have the right not to breastfeed, because women have a right to bodily autonomy.

I can’t speak for the other SciMoms, but I support an overhaul in how we talk about infant feeding as a society—for one I would be happy to see us stop saying that “breast is best.” Fiona Woollard, Associate Professor of Philosophy at the University of Southampton, whose current research is in the Philosophy of Pregnancy, Birth and Early Motherhood delves into the language used to describe infant feeding in a 2018 paper in the Journal of Medical Ethics:

“When it comes to descriptions of maternal behaviour, we should reject the assumption that there has to be a single appropriate default for infant feeding. Breastfeeding is normal and should not be stigmatised or seen as a lifestyle choice that can only be accommodated under ideal circumstances. The phrase ‘breast is best’ should be avoided. But we should not treat breastfeeding as a baseline in a sense that implies that women who formula feed are harming their babies. Extreme care should be taken before using morally powerful terms such as ‘risk’, ‘harm’ and ‘danger’. Where possible, neutral terms such as ‘difference’ should be used, accompanied by clear information about the outcomes presented non-comparatively.”

The fact is, the science doesn’t show that breastmilk itself is inherently and significantly superior to responsibly manufactured and safely prepared infant formula. Given all of the above, parents with infants should use whichever feeding method works best, taking into account the resources, culture, and health of the family.