Human gut microbiome evolution: From hunter-gatherers to a western lifestyle
|BaAka adult women and children prepare to process a blue duiker (Philantomba monticola) |
after a net hunt [Credit: Carolyn A. Jost-Robinson]
The hunter-gatherers analyzed in the study, called the BaAka pygmies, rely heavily on wild game, fish, and fruits and vegetables for sustenance. However, the Bantu population relies fully on a market economy. These agriculturalists grow tubers, fruits, and other plants, make use of flour-like products, and raise goats for meat. They also use antibiotics and other therapeutic drugs when available.
|A Bantu marketplace [Credit: Andres Gomez]|
Sequencing data revealed that while the BaAka and Bantu gut microbes were from similar bacterial species, the abundance of traditional bacterial groups was diminished in the Bantu. Further comparisons with western microbiome data showed that the Bantu microbiome composition falls on a spectrum between the BaAka and western populations. "The BaAka microbiome is more similar to that of wild primates than it is to western humans," says Gomez.
When the researchers delved into the functions of the different bacterial communities, they found a potential gradient between the BaAka and western microbes in pathways involved in processing carbohydrates and foreign substances. "We suspect that the enrichment in carbohydrate- and xenobiotic-processing pathways that we see in Bantus and US Americans is related to access to more digestible sugars and therapeutic drugs, while the hunter-gatherers consume more fibrous plants and do not have access to drugs or antibiotics," says Gomez, though he cautions that the team needs better functional approaches to support these predictions.
"The study supports the idea that diet is the most important driver of microbiome composition in humans," says Gomez. "We are what we eat, and our microbiome is a very important reflection of lifestyle."
Source: Cell Press [February 25, 2016]