Scientists out of the University of California San Francisco set out to explore how exposure to heat impacts the physical and chemical properties of food and, in turn, how this affects the delicate microbial environment in our intestines.
The team split mice into four groups and fed them different diets: raw meat, cooked meat, raw sweet potatoes or cooked sweet potatoes. While they found no difference in the microbiomes of the mice who ate raw vs cooked meat, there was a significant change between the two groups eating raw vs cooked sweet potato. Not only was the bacteria in their bodies completely different, but the diet had also determined whether certain genes were ‘on’ or ‘off’ and the metabolic products (aka, waste) they produced.
Intrigued by the findings, the team then replicated the same experiment with a variety of vegetables (e.g. white potatoes, corn, peas, carrots and beetroot) and got the same results.
“We were surprised to see that the differences were not only due to changing carbohydrate metabolism but also may be driven by the chemicals found in plants,” Dr Peter Turnbaugh, an associate professor of microbiology and immunology at UCSF and the study’s lead author explained. “To me, this really highlights the importance of considering the other components of our diet and how they impact gut bacteria.”
In an effort to see if the same microbial changes would occur in humans, researchers partnered up with a professional chef to prepare a raw and cooked menu. The participants stuck to each diet for three days before providing stool samples. Again, it was clear that the gut bacteria between the two groups were distinctively different.
“It was exciting to see that the impact of cooking we see in rodents is also relevant to humans, although interestingly, the specifics of how the microbiome was affected differed between the two species,” Dr Turnbaugh added.
“We’re very interested in doing larger and longer intervention and observational studies in humans to understand the impact of longer-term dietary changes.”
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