San Diego State: Common Foods Can Improve Gut Microbiome

Common Dietary Compounds Can Help to Improve Gut Microbiome

Researchers at San Diego State University (SDSU) are saying that many common foods can be useful for boosting the diversity of the gut microbiome and thus promoting good health.

A Bacteriophage

The research team studied some select foods from a long list of foods with antimicrobial properties. It found that these contain compounds that set off bacteriophages, or phages, which are viruses that infect and replicate within bacteria.

The action of phages makes them useful for getting rid of harmful bacteria in the gut.

“The microbiome is composed of hundreds of different bacteria and the phages they host,” said research associate Lance Boling, a molecular biologist at SDSU. “We could actually tackle certain conditions by adjusting the foods we consume, that will affect microbial diversity which in turn will influence health and diseases.”

Bacteria stop growing over time and die off as phages are triggered.

The researchers published their findings in the journal Gut Microbes.

Sculpting the gut microbiome

The state of the gut microbiome is critical to the health and wellness of a person. This community of microorganisms plays a role in metabolism, body weight, moods, and cognition, among others.

The gut microbiota may also promote inflammation capable of leading to disorders, including irritable bowel syndrome, diabetes, and cancer.

In this study, researchers identified foods that have an antimicrobial effect. They then carried out an analysis on them to come up with a shortlist.

Foods, herbs, and spices that were studied included honey, licorice, oregano, and stevia, a natural sugar substitute from the stevia plant. Among the others were aspartame, clove, bearberry (uva ursi), and neem plant extract.

The research team also tested toothpaste. This is because it is believed to have antimicrobial properties.

It was found that honey, stevia, aspartame, uva ursi, and neem were the most potent triggers of bacteriophages.

At the initial stage, bacteria increased in numbers. Their numbers dropped, however, when phages are triggered until they peter out.

The findings suggest that foods may be used as medicine to fix imbalances of the gut microbiome.

“This shows we could sculpt the human gut microbiome with common dietary compounds,” microbial ecologist Forest Rohwer, a viromics research pioneer, said. “The ability to kill specific bacteria, without affecting others, makes these compounds very interesting.”

The researchers also observed that certain foods inhibit phages. They said that this could be helpful for controlling pathogenic viruses.

Activating phages

Bacteriophages kill their host cells after infecting and replicating in them. They then emerge into the environment and can start infecting other bacterial cells. This process continues as long as there are bacteria around to infect.

Hundreds of new phages are released in the microbiome when a bacterial cell bursts or dies.

“There aren’t many known chemical triggers, and we wanted to find these ‘prophage’ inducers – or what causes the phage DNA to detach and replicate,” said Boling, who works in Rohwer’s lab.

The SDSU scientists reduced a list of 117 food compounds with known or seeming antimicrobial effects to 28. These they tested on Bacteroidetes and Firmicutes, two of the main gut phyla, including both helpful and harmful strains.

Unlike other research on increasing the number of curative phages, this study looks into the reductive effect of common foods on the growth of common gut bacteria and the production of phages.

The researchers compared this reductive effect to “landscaping” the gut. They said it was like “pulling weeds from a garden so that more desirable plants have room to grow.”

Eating for health

The researchers said that food compounds could help deal with or prevent disorders linked to imbalances of the gut microbiome. As such, they can be useful for enhancing overall health.

However, the scientists cautioned that undue consumption of foods with antimicrobial effects may result in low gut diversity. This is also a known side effect of excessive antibiotic use.

“We are excited about finding more prophage inducers and determining the molecular mechanisms by which they work,” said Rohwer, who also stated that there were probably thousands of beneficial compounds for getting rid of harmful microbes.

The SDSU team expressed the need for further research into foods that trigger phages. This should help to better understand the molecular mechanisms associated with the production of the viruses and their release into the environment.

References

Boling, L., Cuevas, D. A., Grasis, J. A., Kang, H. S., Knowles, B., Levi, K., … Rohwer, F. (2020). Dietary prophage inducers and antimicrobials: toward landscaping the human gut microbiome. Gut Microbes, 11(4), 721–734. https://doi.org/10.1080/19490976.2019.1701353

Nagappan, P. (2020, January 15). Landscape the jungle of our gut microbiome. San Diego State University. https://www.sdsu.edu/news/2020/01/common-foods-can-help-landscape-jungle-our-gut-microbiome?utm_source=go&utm_medium=redirect&utm_campaign=newscenter.sdsu.edu