Friday, June 16, 2006
On Tuesday, the New York Times had a focus on the wonders of breast feeding. I was surprised how much the government appears to be encouraging breast feeding. The article states,
There is no black-box label like that affixed to cans of infant formula or tucked into the corner of magazine advertisements, at least not yet. But that is the unambiguous message of a controversial government public health campaign encouraging new mothers to breast-feed for six months to protect their babies from colds, flu, ear infections, diarrhea and even obesity. In April, the World Health Organization, setting new international bench marks for children's growth, for the first time referred to breast-feeding as the biological norm.
"Just like it's risky to smoke during pregnancy, it's risky not to breast-feed after," said Suzanne Haynes, senior scientific adviser to the Office on Women's Health in the Department of Health and Human Services. "The whole notion of talking about risk is new in this field, but it's the only field of public health, except perhaps physical activity, where there is never talk about the risk."
A two-year national breast-feeding awareness campaign that culminated this spring ran television announcements showing a pregnant woman clutching her belly as she was thrown off a mechanical bull during ladies' night at a bar — and compared the behavior to failing to breast-feed.
"You wouldn't take risks before your baby's born," the advertisement says. "Why start after?"
Slate.com's Sydney Speisel has slightly different point of view and believes that breast feeding and its benefits may be overstated. He states,
Nursing is credited with preventing infants from getting cancer, allergic diseases, Crohn's disease, cavities, SIDS, and with improving IQ. For mothers, it's also asserted to prevent diabetes, certain cancers, and postpartum depression. In most cultures, however, vast differences—economic, educational, ethnic, psychological, biological—separate women who choose to breast-feed from women who choose formula-feeding. These differences are exaggerated when researchers compare, as they commonly do, the babies of women who breast-feed exclusively for six months and those who exclusively formula-feed for that length of time. The difficulty of doing research on humans thus poses a particular problem for studies of breast-feeding. Breast-fed babies may on average have higher IQ scores, say, but is the difference because of the breast-feeding or some other factor, like coming from a family with a higher income level or more education or fewer siblings? In the studies that have been done to date, untangling the observed effects is a nearly impossible exercise in subjective judgment. That's especially the case for evaluating subtle effects like IQ level, or the much later development of childhood cancer, allergies, or tooth decay.
Other benefits of breast-feeding seem pretty clear and incontrovertible. Large-scale studies in the developing world have reported a striking drop in infant mortality as formula-feeding is replaced by nursing. But while the role of breast-feeding in preventing infection is real, it is also widely misunderstood.
When you ask a bunch of doctors about how breast-feeding prevents infection, they get it wrong—I know they do, because I've asked the question. Doctors tell you that colostrum (produced in the first three days or so after a baby is born) and breast milk are full of maternal antibodies. Next, doctors say that these maternal antibodies are absorbed into the infant's blood circulation and thus serve to protect infants from disease.
That's the correct description of the immunology of breast-feeding for most mammals. It's also true that human colostrum and milk are rich in maternal antibodies—colostrum is pretty much antibody soup. And babies take in these antibodies as they nurse. But human babies are never able to absorb maternal antibodies from milk or colostrum into the bloodstream, except perhaps in the minutest amounts. Maternal antibodies in milk and colostrum protect against infection—but only locally, working inside the baby's gastrointestinal tract. . . .
None of this is my discovery. It was well-known, even commonplace, in the immunological literature of 40 years ago. But as the field turned to other matters, these findings just sort of fell out of fashion (though I've certainly come upon plenty of modern papers whose authors understand the idea). Because of the modern aversion to looking at older research, a surprisingly large number of doctors, especially nonimmunologists, have either forgotten this aspect of human immunity or never knew about it. And perhaps nobody wanted to bring the older findings to light for fear that doing so might discourage breast-feeding. (I can assure you that I feel some trepidation as I write this.)
What should we make of the facts about the immunobiology of lactation? First, it bears repeating that even if the immunological benefits are often overstated, there is clear and obvious benefit to breast-feeding in most of the developing world. Second, though it is harder to demonstrate in a scientifically satisfying way, there are probably other biological benefits. And there are surely economic reasons to give babies human milk instead of formula, which costs between $1,500 and $3,000 a year. In the developing world, the economic case against formula-feeding might be as potentially lifesaving as the immunological one: Money stolen from a poor family's budget for formula will not be available for food, housing, education—or even soap.
In the end, though, I find myself falling back on the same logic (or lack of logic) that appealed to me when my babies were born. Biologically speaking, it seems as if breast-feeding ought to be better for babies. At the same time, I am strongly convinced that there are two kinds of nutrition, physical and psychological, and that both are equally important. This conviction persuades me that it's better for a mother to formula-feed her baby pleasurably than to breast-feed and hate it. Fortunately, the majority of mothers enjoy nursing. But not all. Some women don't like to nurse, and others, even with the best help, find it physically difficult or daunting or intolerably uncomfortable. Sometimes, also, babies just aren't good nursers. In the end, I always encourage a mother to choose the feeding method that is most satisfying to her.