A bacterium that produces an insulin-like peptide can give mice type 1 diabetes, and infection with the microbe seems to predict the onset of the disease in humans, a study finds.

Milk fortifiers of human origin show no evident advantage in the development of the gut microbiota of premature infants over fortifiers derived from cows, while the intake of the mother’s own milk does, two studies suggest.

When consumed for as little as two weeks, common alternatives to sugar affect intestinal bacterial communities, with some reducing the body’s ability to regulate blood glucose levels, a study finds.

Mixtures of viruses that attack inflammatory bowel disease–causing bacteria in mice also survive the digestive tract and are well-tolerated in humans, a study finds.

IgA antibodies appear to bind to specific species of commensal gut bacteria in mice, according to a study.

Researchers are going beyond fecal samples to understand how the patterns of commensal microbes in the gastrointestinal tract influence development and health.

The Scientist spoke with Brigham and Women’s Hospital and Harvard Medical School researchers Scott Weiss and Yang-Yu Liu, who propose that people bank stool samples when they’re young and healthy so that they can be transplanted to rejuvenate the gut microbiome later on.

Experiments in animals and observations in humans suggest that the amount of proline circulating in one’s plasma has a strong association with depression severity.

Microbes in the gut influence the death of support cells in the brain by producing isoamylamine, a study suggests.

Studies are finding that a single course of antibiotics alters the gut microbiomes of healthy volunteers—and that it can take months or even years to recover the original species composition.

Acting through the microbiome, the fiber arabinoxylan reduces cholesterol in many people, while another fiber, called long-chain inulin, increases inflammation, a study finds.

New techniques have shown that people reached the New World far earlier than the long-standing estimate of 13,000 years ago, but scientists still debate exactly when humans arrived on the continent—and how.

Diverse lines of evidence point to humans’ presence in the New World long before the dawn of Clovis culture. But rewriting this chapter of human history raises many questions about how these early people came to inhabit these continents.

Use of the drugs in children under the age of two was associated with lower antibody levels after the jabs—perhaps, researchers suggest, due to microbiome alterations.

A study shows that a molecule produced by intestinal microbes can enter the brain and that its presence is also associated with altered brain connectivity.

Research in mice and flies suggests that bacteriophages, including those found in dairy foods, may have an influence on an animals’ ability to learn and remember information.