Lectures from Microbiology

                This week’s reading by Benezra et al., “Anthropology of Microbes” really caught my eye.  Last semester, I took Microbiology with Dr. Petra Levin and for one of the guest lectures, Dr. Frederico Rey came from WashU Med – Department of Microbiology in and talked about gut microbial communities.   He discussed his research and I was quite surprised when I read today’s article that the topics were almost identical.  In case any others were interested, I thought it would be neat to develop some of the article’s points in more detail. 

                The main purpose of microbiome studies is to determine why and how the human gut differs from person to person.  When we are born, everyone is germfree, but immediately acquire a vast host of microbes that constantly change throughout our lifetimes.  Variation in its composition may be partially attributed to genetics as mentioned in the article, but there are also numerous other environmental factors that come into play. 

Dr. Rey’s research studied three different populations –Venezuela, Malawi, and USA.  He found that at birth, all babies had microbes that were involved in the folate production pathway since infants do not normally consume folate.  However, as they grew older, microbial populations begin change.  US microbiomes exhibit higher number of genes and microbes that degrade and metabolize sucrose, sugar substitutes (ie. Sorbitol), and proteins, whereas Malawian and Venezuelan populations have an overrepresentation of genes encoding enzymes that degrade plant polysaccharies (ie. Arabinans, xylans).  These differences reflect differences in diet: US population primarily consume processed sugars and meats, while Malawian/Venezuelan mostly vegetarian and complex sugars. 

Anthropology can implemented with the results of Dr. Rey’s research to provide useful insight on how nutrition and disease can affect different populations.  An important consequence of different microbial communities is that the efficiency of nutrient absorption also differs.  This can help explain some culture specific diseases and how we can solve these problems.  For example, obesity is relevant in the US and much research is investigating the various factors that affect it, such as genetics, cultural practices, and consumerism.  An aspect that is not studied the composition of our guts.  A separate study showed that two genetically identical mice, raised in completely bacteria free environment (ie. sterile glass box), will have an extremely inefficient digestive system and consume much more than an average mouse to stay alive.  The interesting part arises when you feed them different microbial communities.  Microbes from previously obese mice will induce obesity in the new mice and vice versa.   Given that obesity is so culturally engrained in our culture, this new outlook may provide a pedestal for a new field of anthropology.