Science News has a fascinating short story, Gut bacteria reflect dietary differences, by Gwyneth Dickey, that highlights one of the ecological dimensions of ‘enculturation’ that I think some symbolic models of culture have a hard time grasping. It turns out that a Western diet produces a less-varied gut ecology in Italian children than was found in African children. Moreover, the old adage ‘you are what you eat’ could apply in a particularly interesting way to those who eat termites.
The original article, Impact of diet in shaping gut microbiota revealed by a comparative study in children from Europe (urban Florence) and rural Africa (Boulkiemde province, Burkina Faso), by Carlotta De Filippo and colleagues, is open access on the Proceedings of the National Academy of Sciences website, so you should definitely surf over there if you find this interesting.
De Filippo and colleagues discuss the microbiome, the ‘complex consortium of trillions of microbes, whose collective genomes contain at least 100 times as many genes as our own eukaryote genome’ (see also Gill et al. 2006). This enormous, varied ecosystem in the gut, a symbiotic community, supplements human metabolic capabilities, provides a first line of defense against pathogens, modulates gastrointestinal development and even informs the configuration of the immune system (paraphrased from De Filippo et al. 2010).
Different gut ecologies brought about both by environmental factors and by food production techniques, dietary preferences, and even food handling practices are one way that human groups might inadvertently induce biological variation in our species, a subtle culture-biology link through the populations in our gastrointestinal tracts. Now De Filippo and colleagues has gone out and actually demonstrated this variation empirically, using high-throughput 16S rDNA sequencing and biochemical analyses of fecal microbiota.