The microbes in the human gastrointestinal tract, known as the gut microbiome, have a significant impact on out health and well-being. Scientists have begun to learn more about the complex relationships between diet, gut microbes, and disease. New research has now revealed that an nutrient and additive commonly found in the diet, called ergothioneine (EGT), can promote the survival of a microbe that can promote cancer development. EGT appears to shield the microbes from a natural phenomenon called oxidative stress, which is caused by an excess of free radicals, or reactive oxygen species (ROS).
Antioxidants like EGT can protect cells from oxidative stress, and excessive oxidative stress is a common feature of disease. Immune cells can release ROS on purpose to kill bacteria, and bacteria have ways to prevent damage caused by ROS - they can use antioxidants too. In this case, the microbes are using EGT from the diet. The findings have been reported in Cell.
The study authors determined that bacteria can take up EGT, which is naturally found in grains, beans, and mushrooms, to survive longer.
The pathogenic microbe Helicobacter pylori, which is associated with gastric cancer development, outcompeted other microbes for survival in a host, using EGT to do so. The researchers used mass spectrometry and a new tool they called “reactivity-guided metabolomics” to identify specific molecules in complex environments, to show the microbes had ingested the EGT from the diet.
“We were excited to discover an unconventional mechanism that enables bacteria to withstand oxidative stress during infection,” said senior study author Stavroula Hatzios, an assistant professor at Yale University.
Bacteria take up EGT in a different way than human cells, so it could be possible to develop a specific drug that can inhibit the uptake of this nutrient by microbes in the gut, she added.
Human cells can take up dietary EGT, which has been shown to be an anti-inflammatory molecule that can prevent disease. Reduced EGT levels have been associated with a wide variety of diseases, including autoimmune and cardiovascular disorders. Bacterial uptake of EGT could have a significant influence on human health.