Cooked food alters gut bacteria population: Study

Eating cooked food alters the microbiomes of both mice and humans, according to a study with implications for understanding how cooking may have prehistorically altered the evolution of the microbes in our gut.

The study, published in the journal Nature Microbiology, noted that many aspects of human health, including chronic inflammation and weight gain, are strongly influenced by the ecological health of the microbes present in and on us -- collectively called our microbiome.

"Our lab and others have studied how different kinds of diet -- such as vegetarian versus meat-based diets -- impact the microbiome," said senior author of the study Peter Turnbaugh of the University of California, San Francisco (UCSF) in the US.

The researchers, including those from UCSF, examined how cooking impacted the microbiomes of mice by feeding diets of raw meat, cooked meat, raw sweet potatoes, or cooked sweet potatoes to groups of animals.

Earlier research had demonstrated that cooking altered the nutrients and other bioactive compounds in both meat and tubers, the study noted.

The research team found that raw meat had no discernible effect on the animals' gut microbes compared to the cooked ones.

However, the study noted that raw and cooked sweet potatoes significantly differed in their impact on the animals' microbiomes.

The researchers added that the microbes' patterns of gene activity, and the biologically crucial metabolic products they produced differed between mice that ate cooked and those that fed on raw food.

They then used a more diverse array of vegetables, performing what they called a "mad scientist experiment" -- feeding the mice an assortment of raw and cooked sweet potato, white potato, corn, peas, carrots, and beets.

The researchers said that as the host soaked up calories in the small intestine, it left less for hungry microbes further down the gut.

They added that many raw foods contained potent antimicrobial compounds that appeared to directly damage certain microbes.

"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," Turnbaugh said.

The study, the researchers said, highlighted the importance of considering the other components of our diet, and how they impacted gut bacteria.