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May 26, 2004

Link between calcium and weight loss focus of Purdue summer camp

WEST LAFAYETTE, Ind. - While many teens go off to summer camp to swim, hike or learn to play tennis, participants in Purdue University's Camp Calcium will be the nation's first subjects in a controlled-diet study investigating the role of calcium and dairy products in moderating body weight.

conducting a bone scan
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"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, distinguished professor and head of Purdue'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 are supervised around the clock, and we weigh out everything they eat for every meal. This gives us information about their entire diet and gives us complete control over their calcium and dairy intake."

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 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.

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.

"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."

Experts estimate that approximately 60 percent of Americans are overweight or obese, including 25 percent of children under age 18. Weaver said that while obesity is a problem affecting people of all ages, it is especially important to address it in adolescents.

"Trends in obesity track from childhood to adulthood," she said. "If you start multiplying fat cells as a child, then you are going to be fighting this your whole life. If we can nip this in the bud early on, we'll have a longer-term impact. You can set lifelong healthy habits if you learn them while you're young."

The researchers emphasize that while they want to learn about weight moderation through calcium or dairy foods, the goal of the camp is not to help the participants lose weight.

"Given the length of our program, we can't count on seeing major body weight changes," Weaver said. "We're concerned with all the regulators that could lead to body fat and body weight changes, and how those factors are regulated by calcium or dairy products."

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, while 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.

Camp Calcium will accept applications from boys for this summer until June 1; registration for girls is already full. Registration for the camp is $100, and campers receive free room and board and are paid for their participation in the research. To enroll in the camp, please contact Martin at (765) 494-6559, martinb@purdue.edu.

Writer: Jennifer Cutraro, (765) 496-2050, jcutraro@purdue.edu

Sources: Berdine Martin, (765) 494-6559, martinb@purdue.edu

Connie Weaver, (765) 494-8237, weavercm@cfs.purdue.edu

Ag Communications: (765) 494-2722; Beth Forbes, forbes@purdue.edu
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PHOTO CAPTION:
Connie Weaver, center, and Berdine Martin, at right, conduct a bone scan on Purdue University junior Breanna Rayl. The scan, a procedure to measure bone density and body composition, is one type of assessment the researchers will perform on students attending Camp Calcium, Purdue's annual summer program that investigates various aspects of calcium metabolism in adolescents. (Purdue News Service photo/David Umberger)

A publication-quality photo is available at http://ftp.purdue.edu/pub/uns/+2004/weaver-calcium.jpg


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