Urban Diets Lead to Decline in Gut Bacteria That Digest Plants ( arstechnica.com )

This article discusses a new study on the link between gut bacteria and diet, particularly the ability to digest cellulose, a major component of plants.

Key Points:

• Humans have gut bacteria that can break down cellulose, but the amount varies depending on diet.
• Rural populations and hunter-gatherers have more of these bacteria compared to urban dwellers.
• The decline is likely due to modern, processed diets low in fiber.
• Some cellulose-digesting bacteria may have come from our primate ancestors, while others were acquired from domesticated herbivores like cows.
• These bacteria, though digesting cellulose for themselves, may provide benefits to human health through byproducts and immune system interaction.

The study identified:

• Four distinct groups of cellulose-digesting bacteria in humans.
• A historical decline in these bacteria with dietary changes.
• Potential benefits to gut health from these bacteria, even if they contribute minimally to direct food processing.