Gut reaction: Scientists study factors influencing intestinal microbes

November 8, 2013

Study results from Texas A&M University and University of North Carolina School of Medicine scientists on the effect of diet complexity and estrogen hormone receptors on intestinal microbiota has been published in the September issue of Applied and Environmental Microbiology.

To date, research has shown that promoting the growth of certain beneficial intestinal microorganisms can help to improve overall health. The study was to determine the effect of certain factors on intestinal microbiota.

"In this study, we wanted to determine if steroid hormone nuclear receptors, specifically estrogen receptor beta, affect the composition of intestinal bacteria," said Dr. Joseph Sturino, lead researcher in the nutrition and food science department at Texas A&M's College of Agriculture and Life Sciences, College Station.

"Some steroid hormones, like estradiol, and dietary phytoestrogens are known to influence the development of chronic gastrointestinal inflammation and estrogen-responsive cancers of the breast, prostate and colon," Sturino said.

Some of these effects are the result of differential and tissue-specific gene regulation by estrogen receptor beta, Sturino said. That aspect of the study was the focus of the lab work performed by Dr. Clinton Allred, also in the college's nutrition and food science department and a collaborator on the published study.

They hypothesized that some estrogenic regulatory signals are mediated, in part, by the activity of microorganisms present in the gut and that diet modification can be used to change those.

In order to investigate the effects of both receptors and diet on intestinal microorganisms, the scientists initially raised female mice on a fiber-rich diet containing plant-derived estrogenic compounds called isoflavones, comprising a complex diet. The animals were then fed an isoflavone-free diet that was rich in highly refined sugars for two weeks, comprising a simple diet. The composition of the fecal bacteria was surveyed over the course of the study.

"As you might expect, significant differences were found between the fecal microorganisms of mice fed a biochemically complex diet containing isoflavones and those that were fed a simple diet that lacked isoflavones," he said. "Interestingly, however, we also found that the microorganisms differed between mice that expressed beta and those that did not."

Distinct patterns for Lactobacillales were exclusive to and highly abundant among mice fed a complex diet containing isoflavones, Sturino explained.

"Some Lactobacillales have probiotic function when taken in adequate numbers in food or dietary supplements, so indigenous species might also act to promote gut health," he said.

In contrast, he noted, the relative diversity of Proteobacteria increased significantly following the transition to the simple, isoflavone-free diet. Proteobacteria includes a number of species commonly associated with intestinal disease, including Escherichia, the "E" in E. coli O157:H7, and salmonella.

These and other study results demonstrated that steroid receptor status and complexity might play important roles in microbiota maintenance, Sturino said.

"While the balance and content of microorganisms in the gut changes as we age, we are only now learning how our genetics and dietary choices affect our health by modifying the composition and activity of these microorganisms," he said.

In the long term, Sturino believes that this study will aid in the development of novel probiotics, prebiotics, nutritional strategies and pharmaceuticals to improve overall health by promoting the growth and activity of beneficial intestinal .

Explore further: Researchers find link between intestinal bacteria and white blood cell cancer

Related Stories

Researchers find link between intestinal bacteria and white blood cell cancer

July 16, 2013
(Medical Xpress)—Researchers from UCLA's Jonsson Comprehensive Cancer Center have discovered that specific types of bacteria that live in the gut are major contributors to lymphoma, a cancer of the white blood cells.

Microbes in the gut help determine risk of tumors

November 5, 2013
Transferring the gut microbes from a mouse with colon tumors to germ-free mice makes those mice prone to getting tumors as well, according to the results of a study published in mBio, the online open-access journal of the ...

Newly developed medium may be useful for human health, biofuel production, more

June 26, 2013
Texas A&M University System scientists from the departments of nutrition and food science and poultry science have developed a new medium for the cultivation of beneficial microorganisms called lactobacilli.

Genetic makeup and diet interact with the microbiome to impact health

September 25, 2013
A Mayo Clinic researcher, along with his collaborators, has shown that an individual's genomic makeup and diet interact to determine which microbes exist and how they act in the host intestine. The study was modeled in germ-free ...

Study: Probiotics reduce stress-induced intestinal flare-ups

March 14, 2013
For those with irritable bowel syndrome who wonder if stress aggravates their intestinal disorder, a new University of Michigan Health System study shows it's not all in their head.

Gut microbe battles obesity

May 14, 2013
(Medical Xpress)—Akkermansia muciniphila is one of the many microbes that live in our intestines. This bacterium, which feeds on the intestine's mucus lining, comprises between 3 and 5 percent of the gut microbes of healthy ...

Recommended for you

Want to win at sports? Take a cue from these mighty mice

July 20, 2017
As student athletes hit training fields this summer to gain the competitive edge, a new study shows how the experiences of a tiny mouse can put them on the path to winning.

'Smart' robot technology could give stroke rehab a boost

July 19, 2017
Scientists say they have developed a "smart" robotic harness that might make it easier for people to learn to walk again after a stroke or spinal cord injury.

Engineered liver tissue expands after transplant

July 19, 2017
Many diseases, including cirrhosis and hepatitis, can lead to liver failure. More than 17,000 Americans suffering from these diseases are now waiting for liver transplants, but significantly fewer livers are available.

Lunatic Fringe gene plays key role in the renewable brain

July 19, 2017
The discovery that the brain can generate new cells - about 700 new neurons each day - has triggered investigations to uncover how this process is regulated. Researchers at Baylor College of Medicine and Jan and Dan Duncan ...

New animal models for hepatitis C could pave the way for a vaccine

July 19, 2017
They say that an ounce of prevention is worth a pound of cure. In the case of hepatitis C—a disease that affects nearly 71 million people worldwide, causing cirrhosis and liver cancer if left untreated—it might be worth ...

Omega-3 fatty acids fight inflammation via cannabinoids

July 18, 2017
Chemical compounds called cannabinoids are found in marijuana and also are produced naturally in the body from omega-3 fatty acids. A well-known cannabinoid in marijuana, tetrahydrocannabinol, is responsible for some of its ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.