Gut bacteria are rapidly evolving to digest ultra-processed foods, finds study

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By Claudia Tanner

The bacteria living in our guts are evolving at extraordinary speed to keep pace with modern diets – and they're doing it differently depending on where in the world we live.

In a study published in Nature, UCLA evolutionary biologists have discovered that gut bacteria in industrialised populations have rapidly developed the ability to digest synthetic starches found in ultra-processed foods—substances that have only existed for a few decades. Scientists believe natural selection must have been acting strongly to make these genes dominant so quickly.

"The discovery that the ability to digest novel starches is a target of natural selection in gut bacteria is interesting, but we found an even more robust, stronger signal that there are different targets of selection across many genes and many species in industrialised and non-industrialised populations," said Richard Wolff, a UCLA doctoral student and the study's first author.

“What are the gut microbiomes in industrialized populations responding to? We’ve picked out one example with these starches, but there’s likely many possibilities we haven’t grappled with yet.”