Is it possible that the hundred trillion microbes that make up the microbiome in the human gut "know" what nutrients they need, and in seeking them influence our dietary choices? This interesting theory holds that, in some cases, our intestinal flora nudges us toward fat or sugar and possibly obesity. A new review of recent scientific literature concludes that our microbes actually can trigger cravings, as their attempts to receive more of the foods they need for growth affect our eating behavior. The authors of the review write that it is “unclear” how the microbes might do this, but suggest that they may influence food choices by releasing signaling molecules into the gut, which has links to the immune system, endocrine system and nervous system. Another possibility: according to researchers from the University of California, San Francisco, Arizona State University and the University of New Mexico, gut bacteria may sway our eating decisions in part by acting through the vagus nerve, which connects 100 million nerve cells from the digestive tract to the base of the brain. On the upside, the reviewers note that our food choices can alter the microbiome within 24 hours. Better yet, the authors write that microbiota “are easily (manipulated) by prebiotics, probiotics, antibiotics, fecal transplants, and dietary changes…(offering) a tractable approach to otherwise intractable problems of obesity and unhealthy eating.”
My take? We know that our individual microbiomes are very different from one another, and it appears our own unique balance of organisms influences our health. Recent research suggests, however, that our microbiomes in general are becoming increasingly unbalanced for a number of reasons, including diets heavy in processed foods and increased exposure to antibiotics via both medical treatments and residues in foods from animals treated with the drugs. This review suggests that it's likely we ultimately have the power to control our own microbiomes, instead of the other way around.
“Athena Aktipis, Carlo Maley, Joe Alcock, “Is eating behavior by manipulated the gastrointestinal microbiota? Evolutionary pressures and potential mechanisms.” BioEssays doi: 10.1002/bies.201400071