Summer 2016

Battle-Ready Bellies

The keeper of the digestive peace

By Julie Flaherty

Previous Next

J. Philip Karl, N14, is a research dietitian at the U.S. Army Research Institute of Environmental Medicine. Photo: John Soares

Traveler’s diarrhea is an intestinal illness usually caused by a bacterial infection. It’s a drag for vacationers, but far worse for deployed soldiers.

“They are not going to be out in the field fighting; they are going to be compromised,” says J. Philip Karl, N14, a research dietitian at the U.S. Army Research Institute of Environmental Medicine in Natick, Massachusetts. “It’s a huge problem.”

A means of keeping the digestive peace may lie in the portable Meals Ready to Eat (MREs) that soldiers rely on in the field. Karl is conducting a study of how these packaged rations affect the digestive system to figure out whether tweaking the ingredients could boost the gut health of military personnel.

“We know that bacteria that live in our intestinal tract have a big influence on human health,” he says. By changing the prebiotic content of the meals, likely by adding combinations of dietary fibers that beneficial gut bacteria consume, he hopes to encourage healthful microbes to thrive in the intestine. “We think we can create an environment that really deters the growth and invasion of pathogenic bacteria or viruses.”

Karl, who has worked at the Army lab since 2004, has always been interested in eating behaviors. But he became fascinated by microbiology and bacteriology while finishing his doctorate at Tufts, where he contributed to a whole-grains study at the Jean Mayer USDA Human Nutrition Research Center on Aging.

Adding beneficial bacteria directly into the meals is unlikely for now, as the MREs have to be shelf-stable for three years at 80 degrees. Karl says the military’s high-tech food science might get there one day. But a brownie with extra fiber? It could be a first line of peptic defense.

Julie Flaherty, the editor of this magazine, can be reached at

Top Stories

Ready, Set, Go!

Baby boomers will face many barriers to good nutrition as they age. It’s time to get prepared

Trouble Brewing

Climate change affects not only how much food we grow, but how it tastes. For crops like tea, small differences could have big economic consequences

Low-Acid Redux

Fewer grains and more fruits and vegetables may keep your bones strong

Unnatural Disaster

A quarter-million people died in the Somalia famine of 2011. It didn’t have to happen 

Tufts Nutrition Top 10

How to stay hydrated when it’s hot

Editor's Picks

Restaurant Pitfall

Today’s Special: A whopping number of calories

Sipping Toward Disaster

Soda and other sugary drinks are even worse for us than we thought. Can we kick the habit?

Shifting America’s Diet

Factions continue to duke it out over what the nation’s dietary guidelines should be, but the scientists have had their say: less meat, less sugar, and please, eat your veggies

Pass It On

What mothers (and fathers) eat can affect the lifetime health of their children

Feed Your Stem Cells

Is nutrition the future of brain health? Neuroscientist Dennis Steindler says yes