Even the positioning that occurs during feeding at the breast is important. Breastfeeding protects against ear infections not just because of breast milk’s anti-infective elements, but because of the posture of the baby’s head and the dynamics of the cycle of sucking, swallowing, and breathing while nursing. Bottle-fed infants may miss out on these protective elements. The quality and content of the breast milk can also differ when it is exclusively pumped. A mother’s breast milk changes according to a baby’s needs, as it ages, as well as throughout the course of a day and even the course of each feeding session. Research has confirmed that the fat concentration of expressed milk increases with the baby’s age in the same way that breastfed milk does. But if mothers don’t pump for long enough at each session, their infants may receive predominantly foremilk (which is high in carbohydrates) and not get enough hindmilk (which is high in fat). The fat is the good stuff. Even how you store pumped milk may limit its beneficial properties, according to some research. Freezing can break down its immunological cells and lipids (but doesn’t affect its antimicrobial proteins), refrigeration reduces ascorbic acid concentrations, and both storage methods reduce antioxidant activity, some studies show. You get the idea. Breast milk is a delicate substance, and lumping all breastfed children in one category and then claiming that the results represent breastfeeding in its totality is dangerous and misleading. We would never give any credit to a study that claimed to show that lowering fat in your diet did not improve long-term heart health if the study mostly included people who only decreased their fat intake for one day or even one week. But this is exactly what happens with some breastfeeding studies. In 2014 a highly publicized sibling study by Cynthia Colen, assistant professor of sociology at Ohio State University, made big headlines. “Is Breastfeeding Really Better?” asked the March 2014 New York Times article. A follow-up appeared on Slate, with a headline that had over 81,000 Facebook shares within two days: “New Study Confirms It: Breastfeeding Benefits Have Been Drastically Overstated.” It was a classic example of simplistic reporting going for the “breakthrough” headline that distorts reality.
Colen’s study, comparing siblings within the same family who were fed differently during infancy, suggests that breastfeeding might be no more beneficial than bottle feeding for ten of eleven long-term health and well-being outcomes in children ages four to fourteen. Those outcomes included body mass index, obesity, and hyperactivity. When restricting the sample to siblings who were fed differently within the same families, Colen and her coauthor found that the scores reflecting breastfeeding’s positive effects on ten of the eleven indicators of child health and well-being were closer to zero and not statistically significant—meaning that any differences could have occurred by chance alone. The study shows that the long-term beneficial effects of breastfeeding may be overstated, Colen said, and that other family conditions may contribute more to health outcomes in the absence of breastfeeding.
To get her findings, Colen used data from the 1979 cohort of the National Longitudinal Survey of Youth (NLSY), a nationally representative sample of young men and women who were between ages fourteen and twenty-two in 1979, as well as results from NLSY surveys between 1986 and 2010 of children born to women in the 1979 cohort. The group analyzed 1,773 “discordant” sibling pairs, or children from 665 surveyed families in which at least one child was breastfed and at least one other child was bottle-fed. The study authors examined behavioral assessments of children born between 1978 and 2006 and looked at outcomes from ages four to fourteen. They include three measures of physical health (body mass index, obesity, and asthma diagnosis), three behavioral indicators (hyperactivity, parental attachment, and behavioral compliance), and five outcomes specifically designed to predict academic achievement.
The data being used for the research comes from a twenty-eight-year study that included more than eight thousand children, yet Colen ends up with 1,773 individuals, or 22 percent of the original sample size. Kramer’s PROBIT study followed over seventeen thousand healthy mothers, more than double the sample size of the NLSY study.
The problems with the Colen sibling study are varied. I’ll start by following the money. After putting in a public records request to Ohio State University for their corporate funding sources, the query revealed that in 2014, the same year Colen’s study was released, Abbott Labs, the maker of Similac, contributed between $250,000 and $499,000 to the school. A spokesperson confirmed that the school had not received funds from Mead Johnson or Nestlé in the last three to five years; however, drug companies such as Bristol-Myers Squibb and Novartis pharmaceuticals are hefty contributors. Beyond missing these important linkages, the sensational headlines missed the fact that Colen and her coauthor, David Ramey, deliberately skipped over the infant and toddler years, where breastfeeding has the greatest impact, reducing incidences of respiratory and ear infections, diarrhea, and sudden infant death syndrome. To establish breastfeeding duration, mothers who responded yes to the “Did you breastfeed?” question were simply asked the age of the baby when they stopped breastfeeding completely. The survey made no distinction between exclusive breastfeeding and mixed feeding, nor did it ascertain whether the breastfeeding occurred by bottle or only at the breast. For the body mass index definitions and conclusion, the study authors were using data based on CDC growth charts that, as discussed in an earlier chapter, misrepresent the normal growth pattern of babies. These distinctions have major ramifications for outcomes, particularly obesity measures. For example, Colen’s sibling study found breastfeeding’s beneficial influence on body mass index decreased by 66 percent between siblings across families and siblings within families—an outcome that could be affected by how the child was breastfed and for how long. But these important details about methodology are not discussed when flashy study headlines hit the media.
Probe a little deeper and you’ll find that 32 percent of the mothers in Colen’s sample smoked during pregnancy, 43 percent said they drank during pregnancy, and the mean family income of her group was $60,000, slightly above the $53,657 median household income for the U.S. Yet there’s no discussion of how the potential effects of smoking, alcohol use, and socioeconomics may impact results. For the behavioral assessments, the authors relied mostly on data from interviews, where mothers were asked questions about whether their child has difficulty concentrating, is easily confused, or obeys when told to eat. There was no mention of how the researchers accounted for bias in the responses. Knowing the immense pressure women feel to breastfeed and the immense guilt they have when they don’t, is a mother more likely to represent her formula-fed child as equally competent as her breastfed child? It’s an important question. In addition, the footnotes to the NLSY data sets show that the siblings can be biological, step, or adopted, which raises a number of questions about how the siblings may be genetically different beyond whether they were breastfed or not. Yet the authors of the sibling study analyzed all pairs in the same way.
The most problematic aspect of the study is the authors’ questionable assumption that all sibling pairs were born into and developed in the same environment, where nothing was different except whether they were breastfed or not. Anyone who has multiple children can tell you that from the arrival of one child to the next, life circumstances can be very different: parental employment, health, and marital status all change, and thus so do priorities, stress levels, and other factors. Let’s look at the experiences of my two children, who are four years apart. Even though both were breastfed exclusively for twelve months, what happened after the breastfeeding period was very different for each child. For example, I freelanced and worked at home until my first child, my daughter, was three years old. That means that after being weaned, my daughter ate mostly homemade food that I dutifully prepared with fresh and organic ingredients; I had time to devote to cooking nutritious family meals. She also had my undivided attention for reading, music lessons, playdates, and other developmental activities. By the time my son arrived, o
ur family financial situation dictated that I return to work after taking off one year (the maximum time my company would hold your job). After my son’s breastfeeding period and after I returned to work, my son was in the care of a nanny. I did not prepare homemade baby foods the way I used to. I simply did not have the time. He ate more store-bought baby foods. In fact, the whole family ate more store-bought, processed foods. And while I did my best to find a caregiver who agreed to follow the strict schedule I left for reading, music, playtime, and limiting television, I was not in control of his daily activities. I am completely aware that my second child’s lived experience was very different than that of my first. And it didn’t have anything to do with breastfeeding. This is the nature of life. Anytime we are comparing siblings over an extended period of time beyond the breastfeeding years, it is unfair and slightly irresponsible to conclude that the reason for any difference in their health or developmental outcomes should be attributed to breastfeeding alone or examined only within the context of breastfeeding.
Things get even more dangerous when scientific reporting focuses solely on the findings with little regard for the researchers and funders involved. At times, we need to analyze the scientists delivering the decision-guiding information the way we analyze politicians and CEOs—with a critical eye. In January 2013, The New England Journal of Medicine published a headline-grabbing report, “Myths, Presumptions and Facts about Obesity,” which disputed, among other factors, links between breastfeeding and a lower risk of childhood obesity. The media enthusiastically spread the word, saying the study debunked any association between breastfeeding and a lower risk of obesity later in life. The media did not cover the many holes in the NEJM study, such as the lack of systematic review—a type of literature review that critically analyzes multiple research studies or papers. Nor did the media dig into where or why those holes existed. But the most glaring problem was the funding source of the research and the numerous conflicts of interests of the study authors. The authors disclosed receiving compensation, travel reimbursement, lecture fees, and consulting fees from several groups, including Mead Johnson (makers of Enfamil infant formula), the Global Dairy Platform and other dairy associations (most infant formula is made from dairy products), and various drug makers. The authors also received funding from Kraft Foods, McDonald’s, Coca-Cola, PepsiCo, and Jenny Craig—all huge processed-food makers—which studies have found markedly decrease scientific objectivity. In fact, the disclosures took up a half page of fine print of the journal. And these were not one-off, here-and-there payments. For example, a lead author, Arne Astrup, disclosed receiving payment for board membership from the Global Dairy Platform, Kraft Foods, Knowledge Institute for Beer, McDonald’s Global Advisory Council, Arena Pharmaceuticals, Basic Research, Novo Nordisk, Pathway Genomics, Jenny Craig, and Vivus; receiving lecture fees from the Global Dairy Platform, Novo Nordisk, Danish Brewers Association, GlaxoSmithKline, Danish Dairy Association, International Dairy Foundation, European Dairy Foundation, and AstraZeneca; owning stock in Mobile Fitness; holding patents regarding the use of flaxseed mucilage or its active component for suppression of hunger and reduction of prospective consumption and other patents, including one for a method to regulate energy balance for weight management.
The disclosure section continued: “Dr. Pate reported receiving consulting fees from Kraft Foods. Dr. Rolls reports having a licensing agreement for the Volumetrics trademark with Jenny Craig. Dr. Thomas reports receiving consulting fees from Jenny Craig. Dr. Allison reports serving as an unpaid board member for the International Life Sciences Institute of North America; receiving payment for board membership from Kraft Foods; receiving consulting fees from Vivus, Ulmer and Berne, Paul, Weiss, Rifkind, Wharton, Garrison, Chandler Chicco, Arena Pharmaceuticals, Pfizer, National Cattlemen’s Association, Mead Johnson Nutrition, Frontiers Foundation, Orexigen Therapeutics, and Jason Pharmaceuticals; receiving lecture fees from Porter Novelli and the Almond Board of California; receiving payment for manuscript preparation from Vivus; receiving travel reimbursement from International Life Sciences Institute of North America; receiving other support from the United Soybean Board and the Northarvest Bean Growers Association; receiving grant support through his institution from Wrigley, Kraft Foods, Coca-Cola, Vivus, Jason Pharmaceuticals, Aetna Foundation, and McNeil Nutritionals; and receiving other funding through his institution from the Coca-Cola Foundation.” The list went on.
Marion Nestle, a New York University professor of nutrition and food studies, was quoted as saying in a news interview: “I can’t understand the point of the paper unless it’s to say that the only things that work to prevent obesity are drugs, bariatric surgery, and meal replacements, all of which are made by companies with financial ties to the authors.”
That the authors received ongoing compensation from food and drug companies is a conflict of interest and puts the study results in serious question. Are we really to believe that these authors are objectively evaluating the science? Was this conflict of interest ever raised during what we would expect to be a rigorous peer review process? Peer review is at the heart of the processes of not just medical journals but of all of science. The peer review was conceived to improve the merit of papers actually being published and was supposed to be an objective process. Considered the sacred cow of science, it is the method by which grants are allocated, papers published, academics promoted, and Nobel Prizes won. Articles in peer-reviewed journals are considered to have more scientific integrity than those appearing in publications without peer review, which are seen as less rigorous and so not taken as seriously. The general public has come to rely on these markers to help them weed out valuable research findings from the questionable ones. But the peer review process has also come under intense scrutiny in recent years, particularly after several notable cases of reviewer bias and even fabricated peer review reports. “In August 2015, the publisher Springer retracted sixty-four articles from ten different subscription journals ‘after editorial checks spotted fake e-mail addresses, and subsequent internal investigations uncovered fabricated peer review reports,’ according to a statement on their Web site. The retractions came only months after BioMed Central, an open-access publisher also owned by Springer, retracted forty-three articles for the same reason,” wrote one author on a commentary on peer review fraud published in NEJM in December 2015. Turns out, some of the quality measures we’ve been taught to rely on aren’t as infallible as we would like to believe. And many are using these scientific findings to make significant health decisions. Even if you can possibly look beyond the financial entanglements of the study authors, it was clear that the authors ignored a growing body of research on the connection between breastfeeding and obesity. There are several studies that show that breast milk contains complex nutrient combinations that may influence insulin resistance and metabolic responses. One study comparing the milk of humans and other species suggested that the high lactose and cholesterol content of human milk supports growth of the central nervous system, whereas the high protein and mineral content of other species’ milk supports rapid gains in physical size.
Feeding at the breast also creates a unique habit of self-regulation. Studies show breastfed infants are more quickly able to recognize feelings of satiety. They nurse until they feel full and then they stop. Imagine eating a plate of food with your eyes closed—with only your stomach to tell you when you’ve had enough. Therefore, a breastfed baby is less likely to be obese because from birth he learns to eat from his internal feeding cues to determine if he is full or not. In contrast, formula feeding is a more parent-driven feeding activity, with the regulation of intake directed by the parents rather than the infant. Compared with nursing infants, bottle-fed infants are fed on a more regular schedule, and the average number of feeds consistently suggests that parents are driving intake patterns. Subsequent research has shown that common bottle feeding practices, such as “emptying the bottle” and serving larger volumes of formula at feeding
s, are associated with excess weight gain in the first six months of life. In one study published in the journal Pediatrics, infants whose mothers were randomized to consume carrot juice during the third trimester or during the first two months of lactation consumed greater amounts of, and showed fewer negative facial responses in response to, a carrot-flavored cereal compared with infants whose mothers did not drink carrot juice or eat carrots during pregnancy and lactation. The study suggests that flavors within both the amniotic fluid and breast milk may help guide infants toward flavors and shape early preferences. These are powerful nuances to the linkages between obesity and breastfeeding that may not fit into a simple “breakthrough” headline. The 2013 NEJM study authors did not acknowledge any of this growing body of research and none of the reporting covered the omission.
This type of simplistic reporting is dangerous and irresponsible. And there are four players in these fiascos: scientists, who face an increasingly competitive grant environment and are looking for media attention but don’t have the time to help the public or policy makers understand the science; the media, with editors who insist on story hooks and reporters who are looking for short headlines and sound bites but rarely educate readers on the scientific process; doctors who unknowingly tout faulty science; and the general public, particularly women, who are leaning on science to help justify the false “choices” they make about how to feed their babies. Science is no longer just a tool for decision making. Or a way to better inform mothering. Science has also become a WMD—a weapon for mom destruction. When Colen’s study and its provocative headline were released, the writer of the Slate piece concluded her professionally written and scientifically researched column with, “Hopefully this study will give women who can’t or don’t want to breast feed for whatever reason more ammunition to tell the breast-is-best purists to piss off.” The gloves were off. Science—and, in this case, a questionable study—was the “ammunition” of choice. Women took to the comment section of the post and hit social media to bash and attack each other in the name of new research. Desperate to defend their choices, women use any science that sounds good to build a case to support a position and destroy the counternarrative. Mothers who have likely spent hours vetting physicians, a child care provider, or a stroller are willing to take most science by the headline, without the tools and resources to probe deeper.
The Big Letdown Page 9