By Greg Breining
Could a microbiome shaped by parasites lead to better health? Elise Morton, a postdoctoral ecologist at the University of Minnesota, is examining the microbiome—the trillions of bacteria and other microscopic organisms that live in the human gut—from rural villagers in western Africa. Her work may help shed light on a popular debate: If we had the microbiome of our hunter-gather ancestors, would we be free of modern diseases such as allergies, asthma, obesity, and inflammatory bowel disease?
Morton and colleagues, including Laure Ségurel, a researcher from the French National Center for Scientific Research in Paris, and Morton’s adviser, assistant professor of genetics, cell biology, and development Ran Blekhman, have sequenced the gut bacteria of 64 people from three subsistence groups in the Cameroon rainforest. Some were farmers, others fishermen, and others hunter-gatherers.
Their microbiomes differed markedly from those of industrialized people and from one traditional group to another. Diet played an important role, but the biggest shaper of the gut community was parasitic infection. Presence of the amoeba Entamoeba produced a microbiome that was more diverse in the number and composition of microbes.
Just why wasn’t clear. Perhaps the ameoba changed the community directly by preying on various classes of microbes. Or perhaps the amoeba triggered the humans’ immune response in a way that changed the makeup of the gut community. It’s possible that the parasitic infection was beneficial, important for immune system development while doing no harm to the human host. While Morton’s work doesn’t yet answer the question whether there’s a Paleo-gut shaped by parasitic infection that will restore modern humans to health, it does support the idea that the microbiome is highly adaptable. “The microbiome is a core component of our physiology that affects many aspects of our health and even behavior. It’s clearly something that we can control in a way that can have significant effects on our health,” Morton says.