To Wean or Not to Wean: Who Says When Is Enough

by Kelly Griffith
Issue 97, November/December 1999

Breastmilk is by far the best nutrition for human babies. The reams of scientific data supporting that fact would impress even the most unenlightened skeptic. If a pharmaceutical company had made the stuff, everyone in America would know that it helps babies fight infection,1 hastens a mother’s postpartum recovery,2 and provides countless other benefits to both mom and baby.3

But when does all that good stuff end?

Scientific research and the slowly changing attitudes of an often-traditional medical establishment continue to push the boundaries of status quo thinking that says these benefits somehow halt at six months, nine months, or one year. More and more mothers have discovered the benefits of nursing through the potty-training stage and beyond, while their children continue to reap many known and unknown benefits of a lengthy nursing period.

While extended breastfeeding is not the societal norm in the US, many doctors, health experts, and even mothers believe that it should be. And the research agrees with them.

What the Research Shows
A better approach might be to ask, "What does the research not show?" What it does not show is at what point the long list of benefits of nursing stops.

Dr. Katherine A. Dettwyler, PhD, associate professor of anthropology and nutrition at Texas A&M University, has spent a career studying breastfeeding. As coeditor of Breastfeeding: Biocultural Perspectives, and researcher on milk composition and weaning, Dettwyler has concluded one thing for sure: Most children in America are weaned from the breast too early. Way too early.

In Breastfeeding: Biocultural Perspectives, Dettwyler wrote about the natural age of weaning for humans, meaning the length of time humans would likely nurse if cultural expectations did not interfere.

In comparing humans to other primates, research showed that humans’ natural age of weaning is a minimum of two and a half years and a maximum of between six and seven years. Researchers compared things such as the age of sexual maturity; the age of the eruption of permanent molars; the time when children quadrupled their birthweight; and the length of gestation.4 In every other primate, nursing continues for years, not just months.

According to Dettwyler, "The very word infant in zoological terms refers to the time between birth and the eruption of the first permanent molars." Dettwyler further emphasizes, "The research looking at weaning time in primates and dental eruption shows that breastfeeding ends when infancy ends, when the first permanent molars are erupting. In humans, that happens between 5.5 and 6.5 years."

Moreover, Dettwyler has compiled references for all the studies that address the benefits of breastmilk beyond six months, data that will be included in the upcoming new edition of her book. She cites 23 studies, not including numerous studies on allergies, that link positive outcomes with breastfeeding beyond six months.

"Another important consideration for the older child is that they are able to maintain their emotional attachment to a person rather than being forced to switch to an inanimate object such as a teddy bear or blanket," Dettwyler wrote in the book. "I think this sets the stage for a life of people-orientation, rather than materialism, and I think that is a good thing."

Elsie E. Gulick, PhD, RN, a professor at Rutgers University, found that the benefits of human milk lasted long after actual breastfeeding had stopped. In Pediatric Nursing, Gulick wrote of her research with children ages 16 through 30. "The findings support the theoretic premise that duration of breastfeeding is directly related to infant health and indirectly related to toddler health,"5 Gulick wrote.

Most research doesn’t currently look at children breastfed more than 24 months, because most American women don’t nurse for more than just a few weeks, and most surveys indicate that only around 20 percent are still breastfeeding at six months.

"I am collecting brief data from moms who have nursed beyond three years," Dettwyler says of a survey that so far includes 600 responses representing 2,000 children. "Most of these are US moms . . . I am gathering data first of all simply to show that lots of women in the US are nursing children beyond three years. I also hope that this data bank will become the foundation of a long-term study on the health benefits and cognitive development of children breastfed for three years or longer."