Katherine Hunt’s Study of Microbes in Mothers’ Milk Expands the Human Biome
Katherine Hunt graduated from Moscow High School in 2003. She studied nutrition in the college's School of Family and Consumer Sciences as an undergrad, earned a master’s in animal science, then continued on as a doctoral student.
The research on women was funded by grants from United Dairymen of Idaho and National Institutes of Health,in addition to the Idaho Agricultural Experimental Station, and Initiative for Bioinformatics and Evolutionary Studies at the University of Idaho.
It’s time to get beyond us and them, says Katherine Hunt, who completed her doctoral studies Friday, June 15, in the University of Idaho’s College of Agricultural and Life Sciences and found her work discussed on the New York Times website Monday, June 18.
The us and them relates not to Democrats and Republicans but to bacteria. It may even include such disreputable candidates as Staphylococcus and Streptococcus, better known and feared as Staph and Strep.
Hunt acknowledges a tough campaign ahead to get people thinking positively about bacteria on or in their bodies. She said, “That’s sort of what we went up against. Anytime you say bacteria people get scared. Maybe we can shift that dogma.”
“We teach kids germs are bad, wash your hands,” she said. “But bacteria also are doing a lot to promote health and maintain well being.”
Her research adviser, Mark McGuire, who now heads the Department of Animal and Veterinary Science, agrees. After all, he notes, we are more them than us if you consider our bodies hold more bacterial cells than our own.
Antibiotics are mostly about taking sides, which is necessary in some cases, but maybe not all.
“It’s keeping that balance that is potentially the most important aspect that we need to understand,” McGuire said.
A lot of antibiotics, McGuire noted, begin with bacteria and are compounds the microbes produce to war with each other. The research is really about understanding what this team of bacteria is doing, whether it’s in the nose or in the gut or anywhere on the body the bacteria are living.
Her research found that human mothers pass along hundreds of species of bacteria in breast milk to their infants. One woman’s milk carried 100 species; another’s carried 600 species.
Science writer Carl Zimmer invoked Hunt’s research in his Science Times story about the human biome, that community that relies on each of us as its environment.
The study was published a year ago, June 17, 2011, in the Public Library of Science One. It reported the results of monitoring the breast milk of 16 Moscow-area women.
The study reflects the discovery side of science, said McGuire, who’s own research has looked as much at non-living, components of milk such as conjugated linoleic acids, healthful fats found in both human and bovine milk.
One mystery that begs more study is the presence in milk of complex sugars, oligosaccharides, that the breast produces but babies cannot digest. An answer may be the sugars are there to support bacteria that do rely on them and that help the baby’s gut develop.
There may be a risk too that the sugars can promote the growth of Staph bacteria that eventually lead to mastitis. Understanding that relationship could lead to treatments for women or identifying those at risk of mastitis.
For Hunt’s study, the original question was simple. “The bottom line was: what’s in milk?” McGuire said.
“We knew there were compounds in there that are nutrients in there to provide building blocks for nursing infants. We know there are some cells, mom cells to protect nursing infants. We didn’t know if there were bacteria there.”
“We were sort of in the right place at the right time,” Hunt said, to answer those questions.
She called on a relatively new interdisciplinary research group, the Institute for Bioinformatics and Evolutionary Studies led by biologist Larry Forney. IBEST was busy advancing identification techniques for bacterial communities in the human biome through molecular biology and statistics.
“We can finally get a look at what these bacteria are that live on and in us,” she said.
“We are certainly questioning who is the host and who is the symbiont or the parasite,” McGuire said. “Certainly there are a lot more bacterial cells than our own cells in our bodies and how they contribute to our health and wellbeing is an area of tremendous interest right now.”