Des Moines Register
05-23-06
ISU researchers examine hormone's role in hunger
By LISA ROSSI
REGISTER AMES BUREAU
Ames, Ia. — Some days, Heather Bogden, 57, of Ames can't get her hands on
enough sweets and carbohydrates. She wonders why.
Iowa State University researchers are trying to answer that question by figuring
out the secrets behind appetite. They believe some of the answers can be found
in a hormone called ghrelin, which some call the "hungry hormone," said ISU
graduate student Michelle Bohan.
Bogden doesn't struggle with her weight, but she recently was diagnosed with
Type 2 diabetes, which requires her to avoid sweets and count carbs to control
her blood sugar levels.
"It seems like no matter what I do, there are certain indicators that don't go
down," Bogden said of her diet and how well her diabetes is controlled.
It is believed that ghrelin, a hormone, triggers a response to eat and is the
counterpart to the hormone leptin, which causes fullness, researchers said.
Some wonder whether certain types of food affect ghrelin levels.
Bohan worked on a study released this month that charted how the high-protein
Atkins diet and the more carb-heavy American Heart Association, or AHA, diet
influenced the appetites of a small group of young men and women.
The study, which analyzed ghrelin levels at various times over four weeks, found
that the amount of ghrelin in the blood was no different before meals in women
following the Atkins diet compared with when they followed the AHA diet.
However, when participants on the Atkins diet fasted for 15 hours, they showed
lower ghrelin levels than those on the AHA diet.
"If you fast, you may not be as hungry eating Atkins," said Bohan, who is a
graduate student in biochemistry. "But when eating normally, you don't see a
statistical difference."
Bohan studied two groups of men and two groups of women, all between the
ages of 19 and 30, for the study.
In January 2005, eight female students ate three meals a day for four weeks in
the dining area of the Human Metabolic Unit in ISU's LeBaron Hall. Eight men did
the same thing this spring, according to a news release on the study. Participants
were fed the Atkins diet for 14 days and the heart association diet for 14 days.
The women's test results are complete; Bohan is awaiting test results for the
men.
Don Beitz, a distinguished professor of biochemistry and animal science
who worked on the study with Bohan, said they started the research to figure out
whether those who consumed the Atkins diet, which reportedly causes
participants to be less hungry, had lower levels of ghrelin.
The goal of studying the hormone is to someday find a way to control it in the
bloodstream, if it does indeed cause obesity, he said.
"People say, 'It's my hormones making me overweight,' " Beitz said.
"Is ghrelin that hormone? ... What if there is an implant that you can use to
decrease all the hormones that stimulate appetite - decrease them 10 percent.
Think what that would do."
Colette Heimowitz of Atkins Nutritionals in Long Island, N.Y., said people who eat
Atkins diets have reported they are less hungry.
She said that the study does not explain how protein influences hunger levels.
More study details
ISU graduate student Michelle Bohan worked on the study with Don Beitz, a
distinguished professor of biochemistry and animal science.
Funding for the research came from a U.S. Department of Agriculture Special
Research Grant to Iowa State's Center for Designing Foods to Improve Nutrition,
which operates on a mission to create strategies to improve nutrition.
Diane Birt, interim director for the center, said ghrelin is a "very hot topic for
research."
"We're like everyone else," she said. "We'd like to have an easy fix to help people
control what they eat. It probably won't be that easy."