A New Diet Quickly Alters Gut Bacteria – By Rachael Rettner | December 2013
This shows that diet can impact our health more quickly than many pharmaceutical drugs and gives us some power over our bodies.
The types of bacteria in your gut today may be different tomorrow, depending on what kinds of food you eat, a new study suggests.
In the study, participants who switched from their normal diet to eating only animal products, including meat, cheese and eggs, saw their gut bacteria change rapidly — within one
While the participants were on the animal-based diet, there was an increase within their guts in the types of bacteria that can tolerate bile (a fluid produced by the liver that helps break down fat), and a decrease in bacteria called Firmicutes, which break down plant carbohydrates
Gut bacteria also tended to express (or “turn on”) different genes during the animal-based diet, ones that would allow them to break down protein.
In contrast, the gut bacteria of another group of participants who ate a plant-based diet expressed genes that would allow them to ferment carbohydrates.
The differences between the gut bacteria of the people on the plant-only and animal-only diets “mirrored the differences between herbivorous and carnivorous mammals,”
The findings suggest “the choices that people make on relatively short time scales … could be affecting the massive bacterial communities that live inside of us,” David said.
The study also adds evidence to the idea that human diets — acting through the gut bacteria — influence the risk of certain diseases
People on the animal-based diet had higher levels of a bacterium called Bilophila wadsworthia, which grows in response to bile acids and has been linked with inflammatory bowel disease in mice
People who ate the plant-based diet saw fewer changes in the abundance of bacterial species in their gut than people who ate the animal-based diet.
This may have, in part, been due to the fact that humans produce bile acids in response to eating animal products, and bile acids, in turn, influence bacterial growth, according to the researchers.
The study included 10 people
This is an extremely small sample size!
Because the study was small, the researchers are cautious about generalizing their results to the population as a whole.
But “the changes we saw appeared to be uniform across these subjects, suggesting that if we were to recruit more people, we would see similar results,” David said