An ailment that afflicts U.S. soldiers fighting in Iraq has prompted the U.S. government to call upon a Washington State University researcher for her assistance.
Linda Massey, professor of human nutrition at WSU Spokane, is a world expert on diet’s influence on kidney stones. Kidney stones are uncommon in people under the age of 30; however, soldiers in Iraq, most of whom are in their 20s, have an increased risk of developing kidney stones due to their unique lifestyle.
Since 1991, Massey has studied the effects of variables such as milk, meat, soy protein, caffeine, salt and vitamin C on the formation of kidney stones. She was asked by a committee of the National Academy of Sciences’ Institute of Medicine to testify in August on what soldiers should eat to prevent kidney stones while in combat in Iraq. Other experts testified about other ways to improve the soldiers’ diets.
“For soldiers who develop kidney stones, it’s like they got shot in the leg,” Massey said. “It takes them out of combat.”
Water and bullets
Soldiers often become dehydrated — the main reason kidney stones develop — because of the hot climate in Iraq and the protective clothing that keeps their sweat from evaporating, Massey said. Soldiers also tend to take in fewer calories than they spend and to drink less water in order to eliminate/urinate less often.
“It’s hard to eat or go to the bathroom with bullets flying at you,” Massey said. “Staying alive for these soldiers is more important than preventing kidney stones.”
Dehydration, coupled with not eating enough during their rigorous days, makes soldiers’ urine more concentrated and more acidic. This results in higher levels of calcium oxalate and uric acid, which cause the formation of kidney stones.
Soldiers also are reliant on caffeine to keep them awake during long days in combat, and caffeine (a diuretic) increases urinary calcium, which contributes to kidney stone formation.
WSU is one of fewer than 10 universities nationwide with metabolic laboratories where researchers can study people in live-in facilities while the subjects’ diets are strictly regulated. In her studies, Massey recruited people who tend to form kidney stones. Eight subjects per week lived in the facility while Massey provided all their food and checked their urine composition.
“For the consultation for the Institute of Medicine, I put all my research together and put it in the context of Iraq,” Massey said.
Her findings suggest that a diet that prevents kidney stones is similar to the recommended diet for people who are trying to prevent or treat chronic diseases, such as heart disease and cancer.
She suggests a diet of moderation, variety and balance. This means not eating too much of a certain type of food, eating a variety of foods that provide similar nutritional benefits, and having a balanced intake of all the food groups.
Furthermore, because staying hydrated is imperative to preventing kidney stones, Massey suggests drinking eight glasses of water a day.
For soldiers in combat, however, these dieting tips are hard to follow.
“These soldiers will not have fresh fruit or green veggies out in the field,” Massey said, “so they may benefit from special nutrition supplements.”
Massey recommended magnesium-potassium-citrate supplements. All three elements are beneficial for preventing kidney stones. Magnesium can be found naturally in foods such as whole grains and green vegetables; fruits, vegetables and legumes are rich in potassium; and citrate is found in most citrus fruits and juices.
The Institute of Medicine is in the process of adapting military field rations so, among other things, soldiers no longer are as prone to kidney stone formation. Massey said it will take about a year to create new recipes, contract a company to make those foods and ship them to soldiers overseas.
She said the committee’s findings can be used in the future to further develop combat soldiers’ diets, wherever the soldiers’ are fighting.
“A good diet is a good diet,” she said, “regardless if you’re fighting in Iraq or maintaining homeland security.”