For more than half a century, researchers have known that the bacteria that colonize the gastrointestinal tract of mammals influence their host's cholesterol metabolism. Now, Jens Walter and colleagues of the University of Nebraska show that changes in cholesterol metabolism induced by diet can alter the gut flora. The research was published online ahead of print in the journal Applied and Environmental Microbiology.
In the study, the researchers added plant sterol esters to the diets of hamsters. The overall effect of this was to inhibit several bacterial taxa, from the families Coriobacteriacea and Erysipelotrichaceae, says Walter. But the immediate effect of the plant sterols was to physically block cholesterol absorption by the intestine. That decreased cholesterol levels in the liver and the plasma, prompting the hamster's body to respond by synthesizing more cholesterol. That, in turn, boosted cholesterol excretion into the gut, and that extra cholesterol was the direct inhibitor of those bacterial families.
"The abundance of these bacterial taxa and the levels of cholesterol in the fecal samples followed a mathematical model of bacterial inhibition," says Walter.
Practically speaking, the microbial inhabitants of the gut are part of the metabolic system. Researchers have shown that certain health problems are related to changes in the gut flora, such as can be induced by overuse of antibiotics. Since changes in diet can influence composition of the gut flora, health problems such as obesity might be targeted by dietary interventions designed to suppress bacteria that contribute to weight gain. "However, for these to be successful, we need to know which bacterial patterns not only are associated with disease, but actually contribute to it," says Walter, noting that his research showed that some alterations associated with metabolic disease might be the consequence, rather than the cause of the disorder.
Walter says that the work was a real student project. Among the coauthors, three were graduate students, and two were undergraduates. "As a supervisor, it is extremely nice to see young scientists work as a team, and staying dedicated through the five years that this project took to complete," he says.
American Society for Microbiology: http://www.asm.org
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
When you’re the size of a human, you worry about lions and tigers and bears. But if you’re …
An amateur fossil hunter has unearthed a 7ft skeleton of a carnivorous marine reptile on a beach in south Wales.
European regulators have recommended approval of the first medicine containing stem cells to treat a rare condition caused by burns to the eye.
Ecologists say birds could hear the oncoming storm from over 100 miles away
Marine scientists plumbing the deepest part of the ocean sent microphones and collection probes baited with chicken to the bottom of a trench near Guam. Now they watch, wait ... and listen.
Lead author of two retracted papers resigns her position after failing to reproduce new approach to generating stem cells
The winners of the 2014 Olympus BioScapes Digital Imaging Competition capture a rat brain, the mouthparts of a vampire moth and other small wonders
By analysing brain activity linked to hand and arm movements, a team has created a robotic arm that a paralysed woman can control with her thoughts
Adding laser tips to ordinary shoes can improve the stride and pace of people with Parkinson's disease
Technique could someday help repair injuries