NATICK, Mass. (Mar. 29, 2016) -- The U.S. Army Research Institute of Environmental Medicine's Military Nutrition Division is studying ways to improve gut health and prevent gastrointestinal illness among Soldiers operating in austere environments.

While the Army has spent decades making field rations nutritious and safe, researchers are only beginning to understand how food interacts with bacteria normally found in the human gut. Better understanding of this interaction could lead to better rations, healthy Soldiers, and improved performance on the battlefield.

As part of its study, USARIEM researchers have recruited volunteers in the Natick, Massachusetts area who are willing to eat nothing but Meals, Ready to Eat for 21 days. To help Soldiers customize their menus during the course of the study, USARIEM's team developed an MRE cookbook with more than 20 recipes.

The importance of gut health, which contributes to general health and disease and is influenced by interactions between our diets and bacteria living in the human gastrointestinal tract, has been known for centuries. As Greek physician Hippocrates said more than 2,000 years ago, "All disease begins in the gut." However, new technology and research findings are fueling the Military's current exploration of nutrition and gut health.

Research has shown poor gut health may compromise operational readiness. Gastrointestinal distress frequently causes lost duty time and reduces job performance during deployment. It may also be linked with sub-clinical inflammation during military training.

"What emerging science suggests is that the bacteria living in our gut can have a large impact on physical, mental and general health, not only in our warfighters but in everyone," Dr. J. Philip Karl of USARIEM said. "A recent explosion in technology now allows us to study the trillions of bacteria living in our gut in ways we never have been able to before. We think we can leverage those bacteria to have a favorable effect on warfighters out in the field and in garrison."

Karl, a nutrition scientist and the study's principal investigator, said improving gut health could help optimize military health and performance.

"A common problem some of our warfighters face when they travel overseas to regions where sanitation is not as high quality as it is in the U.S. is they are susceptible to pathogens that can cause diarrheal illnesses, such as Travelers' Diarrhea," Karl said.

Karl added, however, that creating an environment that allows healthy gut bacteria to flourish helps those bacteria "out-compete" bacteria that can cause gastrointestinal distress. According to Karl, gut bacteria basically eat what we eat. So, researchers are observing how they respond when study volunteers transition to a MRE-only diet.

"The bacteria in our guts can digest the foods we cannot," Karl said. "The byproducts of that digestion are often beneficial for health. They improve the integrity of our intestinal wall, which helps prevent unwanted compounds from getting into the bloodstream. They also create an environment in the gut that's conducive to the growth of healthy bacteria."

Volunteers began enrolling in June 2015, and Karl said 60 people will complete the study. Half of the current volunteers have committed to consuming only MREs for 21 days, while the other half provides a comparison by sticking to their normal diet. Both groups visit Natick Soldier Systems Center three times weekly to meet with study staff.

"We meet with volunteers multiple times throughout the study to collect fecal, blood and urine samples," Karl said. "We use these samples to assess if the MRE is impacting bacteria and whether that interaction influences health.

"What we're trying to do with all of our research is improve what we provide to the people who serve and protect our country. Everything USARIEM does is aimed toward benefiting our warfighters. That requires people donating their time, but it is one way to help contribute to our nation's warfighters."