Purdue University has invited teens to a unique summer camp called Camp Calcium. Instead of swimming, hiking and eating s’mores around the campfire, participants at this camp will be paid subjects in a controlled diet study investigating the role of calcium and dairy products in moderating body weight.
The researchers specifically want to address whether calcium alone, or calcium in the form of dairy foods, plays a role in managing body weight. The study was designed to measure both possibilities.
"We're on the cutting edge this year," said Berdine Martin, camp director and research associate in Purdue's Department of Foods and Nutrition. "This is the first time anyone has looked at this question in a clinical setting, under tightly controlled conditions, in any population, let alone teen-agers."
Recent studies have suggested that calcium or dairy product consumption may help people lose weight. None of these studies, however, have provided the level of dietary supervision Camp Calcium participants will receive, said Connie Weaver, head of Purdue University’s foods and nutrition department.
"What sets Camp Calcium apart is that we are watching every single thing our campers eat every day," Weaver said. Participants will be supervised 24/7, and everything they eat will be weighed and recorded.
Camp Calcium, a summer program that has taken place at Purdue since 1990, is designed to investigate various aspects of calcium metabolism in girls from ages 12-14 and boys from 13-15. This is the eighth time Purdue has offered the camp.
Participants will spend two separate three-week sessions on the Purdue campus where they will live in a student resident hall and eat all their meals together in one of the dining halls. Campers will have the chance to participate in numerous recreational activities while on campus, from learning how to climb trees or arrange flowers to improving their soccer or basketball skills at the Recreational Sports Complex.
The first session this year will take place from June 6-26, and the second will run from July 18 through Aug. 2.
The study includes three separate meal plans designed to help researchers sort out the effects on body fat metabolism of either calcium supplements or calcium provided through dairy foods. One meal plan is a control, which provides 650 milligrams of calcium a day - lower than the recommended Dietary Reference Intake for calcium, but close to the amount the average teen consumes daily, Martin said.
The other two plans double the amount of calcium relative to the control meal plan. One plan boosts calcium intake with supplements, while the other relies on dairy foods as a source of calcium.
"There are a number of theories about how calcium or dairy products can influence body fat metabolism, leading to changes in body weight or body fat distribution," Martin said. "It's a relationship we don't really understand yet, and this year's Camp Calcium is designed to help us better understand that relationship."
One theory is that calcium binds with fats in the digestive system, making a large, bulky complex that the body can't absorb. Because that fat can't be absorbed, the body can't obtain any calories from it. This is one mechanism of calcium-mediated weight loss other researchers have proposed, Weaver said.
She also said that not all of the calcium a person consumes would be bound up with fats in this scenario, which ensures the body is still able to absorb adequate calcium.
Another theory holds that calcium moderates the switching of an enzyme or enzymes involved in fat metabolism. Some researchers have suggested that dietary calcium can affect the production of certain hormones believed to control an enzyme that causes the body to either store or burn fat. And still another theory holds that some of the proteins in milk and other dairy products help the body burn fat, Weaver said.
The current evidence is inconclusive, but Weaver hopes to better understand the interplay of these factors by monitoring both the foods Camp Calcium participants consume as well as the wastes they excrete.
Data from previous camps has been used to establish the Institute of Medicine's Dietary Reference Intake, or DRI, calcium requirements for adolescents, and also is being used in a forthcoming Surgeon General's report on osteoporosis and bone health.