Formula-fed vs. breast-fed babies: Can we create a better formula?

Can Formula-Fed Babies Ever Have the Same Outcomes as Their Breast-Fed Peers?

Can Formula-Fed Babies Ever Have the Same Outcomes as Their Breast-Fed Peers?

What women really think.
June 21 2015 7:52 PM

Creating a Better Formula

“Breast is best,” but could the alternatives ever be almost as good?

Better baby formula.
Researchers all over the world are working to make formula even closer to breast milk than it already is.

Photo by Thinkstock

Though many charges in the so-called “mommy wars” are trumped up, there’s one issue within them that is demonstrably fraught: breast-feeding. Formula-feeding women are told that “breast-feeding is optimal” and that they do their babies a disservice by not nursing. Some American hospitals are so pro-nursing that their entreaties to breast-feed make new moms feel uncomfortable. The latest flashpoint in the breast-feeding wars is about whether or not women with surplus supply should be selling their breast milk or whether they should only be giving it away altruistically. What undergirds this particular strain of controversy—and pretty much all of breast-feeding-related controversies—is the notion that breast milk is so far superior to formula that it’s an unparalleled, precious, nearly magical commodity.

Jessica Grose Jessica Grose

Jessica Grose is a frequent Slate contributor and the author of the novel Sad Desk Salad. Follow her on Twitter.

The question that follows is always pretty much the same: How do we get more women to breast-feed, and for longer? For some reason, an equally valid question is rarely asked: How do we improve formula so formula-fed babies have the same outcomes as their breast-fed peers?

For the purpose of this piece, let’s leave aside legitimate arguments about the ethical shortcomings of some formula companies and the question of whether breast milk is really so superior for full-term, otherwise healthy infants who live in developed countries with clean water. Instead, we’ll start by simply looking at the facts on how many infants may be formula-fed. In the United States—where we have no paid maternity leave, stringent welfare-to-work requirements, and pockets of culture not especially friendly to breast-feeding—as of 2011, only about 40 percent of infants are exclusively breast-fed through three months of age. Fewer than 20 percent of infants are exclusively breast-fed through six months, as the American Academy of Pediatrics recommends.


Yet even if America found enlightenment on breast-feeding overnight, it’s doubtful that the vast majority of babies would be exclusively breast-fed for the recommended half a year. Take, for example, Norway, where formula advertising is banned, women can take about a year of paid maternity leave, and women are allowed to take two hours a day to pump when they’re back at work. Despite these benefits, in Norway only about 63 to 70 percent of infants are exclusively breast-fed through three months, and, depending on the study, between a little over 2 and 9 percent are exclusively breast-fed through 6 months.

We should continue to encourage breast-feeding, and we should make our workplaces and public spaces more welcoming for women to breast-feed. Breast-feeding is still the gold standard of infant nutrition, and even the formula companies will tell you so. The point is that millions upon millions of babies will get some formula at some point. Are we making sure it’s the best possible formula?

The good news is that there are researchers all over the world working to make formula even closer to breast milk than it already is. Right now they are focusing on three major areas of improvement: changing the kinds and amounts of proteins in formula; making it more dynamic (as breast milk’s composition changes with the age of the child, so should formula’s); and trying to mimic the gut microbes of breast-fed babies.

Babies have always been fed with alternatives to breast milk. Before commercial formula became available, cow, sheep, and goat milk were most commonly fed to infants in the absence of mother’s milk or a wet nurse. According to the Institute of Medicine’s 2004 Infant Formula: Evaluating the Safety of New Ingredients, “few [of these] infants survived until infant formulas based on cow milk with added water and carbohydrate were introduced.” An early such formula, released in 1867, was made from a combination of cow’s milk, wheat flour, malt flour, and potassium bicarbonate. By the 1920s, researchers were removing the cow milk fat and substituting it with vegetable oils, decreasing protein levels, and adding specific vitamins and minerals.


Researchers continued to tinker. In 1959, they added iron; in the early ’60s, they rejiggered the whey-to-casein ratio. (Whey and casein are two different kinds of dairy protein; when milk coagulates, casein is in the curds, and whey in the liquid.) In the 1980s, they added the amino acid taurine, which helps with fat absorption and liver function, followed in the 1990s by nucleotides, which help with weight gain and head growth, and in the early aughts by long-chain polyunsaturated fatty acids (in the form of DHA and ARA), which are meant to help with brain development.

Though each formula company has its own ratios, the basic set of ingredients is very similar brand to brand. That’s because the FDA has an Infant Formula Act, originally passed in 1980 and updated since then, setting specific nutritional requirements and a standard composition for formula.

The approach to formula science in the 21st-century represents a philosophical sea change, says Bruce German, a food chemist and the director of the Foods for Health Institute at UC Davis. “We got pretty complacent about food and health in the 20th century, largely because we got the essential nutrients—people didn’t die of nutrient-deficiency diseases anymore,” German explains. “So we had a chemical approach to food.”

Which is to say that we took breast milk apart, looked at the combination of protein, carbohydrate, fat, and vitamins, and tried to make formula a chemical surrogate for breast milk. But it turns out that not everything in breast milk needs to be replicated in formula. Components that are not essential nutrients but provide other benefits are only now being recognized, for example, “Human milk is full of undigestible matter,” German says. The new approach looks at what breast milk does, not merely what it is.


What is breast milk doing that formula isn’t doing? For one, using protein much more efficiently. “Breast milk protein is unusually effective as a source of protein,” German says. “Traditionally, infant formula has not been able to get babies to grow as well on the same amount of protein.” So formula manufacturers added more protein, “which has had some consequences. German says; for one thing, formula-fed babies tend to put on more weight as adipose tissue than their breast-fed peers.

The goals for protein improvement in formula are twofold: to lower protein and change the composition of that protein. Right now, the proteins are whey and casein, but that could change. Adding bovine lactoferrin and milk fat globule membrane could potentially close whatever cognitive gaps there are between breast-fed and formula-fed infants, says Sharon Donovan, a professor of nutrition and health at the University of Illinois and who has done studies on piglets fed with bovine lactoferrin. Lactoferrin is an iron-binding protein, and that may help create good microbial growth and kill bad microbes (microbes need iron to proliferate). Other lactoferrin piglet studies have suggested that the protein may improve cognition and neurodevelopment.

Bo Lönnerdal, a distinguished professor of nutrition and internal medicine at UC Davis, has been working on studies using milk fat globule membrane, or MFGM, which is a three-layer membrane that surrounds fat globules and is made up of a diverse group of proteins. A study he worked on in the April 2014 edition of the American Journal of Clinical Nutrition showed that infants fed a lower-protein formula that was supplemented with MFGM from two to six months had cognitive scores that were closer to breast-fed infants than infants fed with standard formula. The babies were tested at 12 months of age using a standardized infant and toddler test called the Bayley Scale. On this scale, infants fed regular formula had a mean score of 101.8 and breast-fed infants 106.4, while the babies fed formula supplemented with MFGM had a score of 105.8. (The study did not look at babies fed a combination of breast milk and formula.)

Breast milk is “personal, dynamic, and active,” as German puts it. “The milk that mothers make at day five is different than the milk at day 50, because the baby is different.” As such, one of the big developments coming down the pike is staged formula. German cites the Nestle BabyNes formula system, which works like a Nespresso or Keurig machine, except that you insert capsules of formula instead of coffee. There are six stages of capsules that are specifically formulated for six different stages of a child’s life up to 36 months. Right now the BabyNes is only available in France, Switzerland, Hong Kong, and China, and its high cost—the machine alone goes for about $300, and the formula costs about $1.35 per 90mL bottle—means it’s not a realistic option for many families. (A Nestle representative says that there’s no date set for an American launch of the product.)


Abbott, maker of Similac formula, is researching the microbiome, because improving the gut bacteria of formula-fed infants may help bridge the immunity gap between them and breast-fed infants, according to Robert H. Miller, Abbott’s divisional vice president for R&D. Similac added “prebiotics” (compounds that stimulate the growth of beneficial bacteria) to their formula in 2008. Abbott is also studying human milk oligosaccharide, a kind of carbohydrate that stimulates flora in breast-fed infants, as a possible future addition.

When a potential new formula ingredient is identified, it takes anywhere from three to eight years to hit the market, according to estimates from Miller and Lönnerdal. Formula is “the most highly regulated food product in the world,” Miller says. New ingredients must be tested through animal trials, often with piglets, before going through clinical trials with infants. Those trials have to prove not only that the addition is nutritionally adequate but that it has actively improved the formula. That’s when the whole thing goes to the FDA for approval.

None of this is to say that formulas aren’t already adequate nutrition. “Infant formulas are vastly improved and continue to improve,” Sharon Donovan says. Their nutrient components have become closer to breast milk over the past two decades, and it’s worth noting here that some of the fiercest exclusive-breast-feeding purists rely on pre-1990 studies to support their case. Formula will never be identical to breast milk, because breast milk is idiosyncratic; its content is unique to the woman and infant pair, and is influenced by genes, diet, time of day, time of feeding, and even the baby’s gender.

But even in a world with very long and fully paid maternity leaves, there will always be women who can’t or don’t want to breast-feed for many reasons—from physical inability to past emotional trauma to wanting a more egalitarian child-care arrangement. And there will be lots of women who will supplement their breast-feeding with formula, for many valid reasons. As we’re still in a cultural moment where breast-feeding is negatively associated with a woman’s earning power, having formula that parents can feel even more confident about feeding their children is all to the good.