Sleep deprivation lowers Leptin

Why would food-choice shift to high-calorie items when there's
sleep deprivation, it's simple - cortisol [PMID 14974927].

http://www.sciencedaily.com/releases...1206210355.htm

Source: University Of Chicago Medical Center
Date: 2004-12-07

Sleep Loss Boosts Appetite, May Encourage Weight Gain


Researchers at the University of Chicago have found that partial
sleep deprivation alters the circulating levels of the hormones
that regulate hunger, causing an increase in appetite and a
preference for calorie-dense, high-carbohydrate foods. The study,
published in the 7 Dec. 2004 issue of the Annals of Internal
Medicine, provides a mechanism linking sleep loss to the epidemic
of obesity.

Research subjects who slept only four hours a night for two nights
had an 18 percent decrease in leptin, a hormone that tells the
brain there is no need for more food, and a 28 percent increase in
ghrelin, a hormone that triggers hunger.

The study volunteers, all healthy young men, reported a 24 percent
increase in appetite, with a surge in desire for sweets, such as
candy and cookies, salty foods such as chips and nuts, and starchy
foods such as bread and pasta.

"This is the first study to show that sleep is a major regulator
of these two hormones and to correlate the extent of the hormonal
changes with the magnitude of the hunger change," said Eve Van
Cauter, Ph.D., professor of medicine at the University of
Chicago. "It provides biochemical evidence connecting the trend
toward chronic sleep curtailment to obesity and its consequences,
including metabolic syndrome and diabetes."

In the last 40 years, American adults have cut their average sleep
time by nearly two hours. In 1960, U.S. adults slept an average of
8.5 hours a night. By 2002, that had fallen to less than seven
hours a night. Over the same period, the proportion of young
adults sleeping less than seven hours increased from 15.6 percent
to 37.1 percent. Now, only 23.5 percent, or less than one out of
four young adults, sleeps at least eight hours a night.

As sleep time fell, average weights rose. In 1960 only one out of
four adults was overweight and about one out of nine was
considered obese, with a body mass index of 30 or more. Now two
out of three adults is overweight and nearly one out of three is
obese.

Whether and how these two trends are connected, however, is
unclear. Sleep-deprived rats eat more than those allowed normal
sleep. Several epidemiologic studies showed that people who sleep
less are more likely to be overweight. One recent study found that
those who reported less than four hours of sleep a night were 73
percent more likely to be obese.

By providing the first data on the relationship between sleep and
the hormones that regulate hunger, this study helps to confirm and
begins to explain the connection.

Van Cauter and colleagues studied 12 healthy male volunteers in
their early 20s to see how sleep loss affected the hormones that
control appetite. Theses hormones -- ghrelin and leptin, both
discovered in the last ten years -- represent the 'yin-yang' of
appetite regulation. Ghrelin, made by the stomach, connotes
hunger. Leptin, produced by fat cells, connotes satiety, telling
the brain when we have eaten enough.

Van Cauter's team measured circulating levels of leptin and
ghrelin before the study, after two nights of only four hours in
bed (average sleep time 3 hours and 53 minutes) and after two
nights of ten hours in bed (sleep time 9 hours and 8 minutes).
They used questionnaires to assess hunger and the desire for
different food types.

"We were particularly interested in the ratio of the two
hormones," said Van Cauter, "the balance between ghrelin and
leptin."

After a night with four hours of sleep, the ration of ghrelin to
leptin increased by 71 percent compared to a night with ten hours
in bed.

As hunger increased, food choices changed. After two nights of
curtailed sleep the volunteers found foods such as candy, cookies
and cake far more appealing. Desire for fruit, vegetables or dairy
products increased much less.

"We don't yet know why food choice would shift," Van Cauter
said. "Since the brain is fueled by glucose, we suspect it seeks
simple carbohydrates when distressed by lack of sleep." At the
same time, the added difficulty of making decisions while sleepy
may weaken the motivation to select more nutritious foods, making
it harder to push away the doughnuts in favor of a low-fat yoghurt.

"Our modern industrial society seems to have forgotten the
importance of sleep," Van Cauter said. "We are all under pressure
to perform, in school, at work, in social and professional
settings, and tempted by multiple diversions. There is a sense
that you can pack in more of life by skimping on sleep. But we are
finding that people tend to replace reduced sleep with added
calories, and that's not a healthy trade."

Modern scientific study of sleep began at the University of
Chicago in 1953 with the discovery of REM sleep and subsequent
studies that described the multiple stages of sleep. For many
years, research on the consequences of sleep deprivation focused
on the brain. Since 1999, however, the Van Cauter laboratory has
published a series of studies describing the metabolic and
hormonal consequences of chronic partial sleep loss which is now
common. Such studies include:

* A 1999 study showing that a significant sleep debt could trigger
metabolic and endocrine changes that mimic many of the hallmarks
of aging. * A 2000 paper that mapped out the stages of age-related
sleep deterioration and showed how changes in sleep were mirrored
by changes in hormone secretion, which in turn reduced sleep
quality.

* A 2001 study demonstrating that inadequate sleep could foster
insulin-resistance, a risk factor for Type 2 diabetes.

* A 2002 study showed that sleep deprivation could slow the
response to vaccination, suggesting that sleep loss could reduce
the ability to fight off an infection.


###The National Institutes of Health, the European Sleep Research
Society, the Belgian Fonds de la Recherche Scientifique Medicale,
the University of Chicago Diabetes Research and Training Grant and
the University of Chicago Clinical Research Center funded this
study. Authors include Esra Tasali and Plamen Penev of the
University of Chicago and Karine Spiegel of the Universite Libre
de Bruxelles, Belgium.

------------------------------------------------------------------------

This story has been adapted from a news release issued by
University Of Chicago Medical Center.

Can't find it? Try searching ScienceDaily or the entire web with:
Search Web sciencedaily.com

4 hours sleep is pretty extreme. I wonder what effect 7 hours instead of
the 8.5 cited in the article would have. It is interesting, but I don't
think they have found the key to American obesity.

"John G." wrote in message
ups.com...
Why would food-choice shift to high-calorie items when there's
sleep deprivation, it's simple - cortisol [PMID 14974927].

http://www.sciencedaily.com/releases...1206210355.htm

Source: University Of Chicago Medical Center
Date: 2004-12-07

Sleep Loss Boosts Appetite, May Encourage Weight Gain


Researchers at the University of Chicago have found that partial
sleep deprivation alters the circulating levels of the hormones
that regulate hunger, causing an increase in appetite and a
preference for calorie-dense, high-carbohydrate foods. The study,
published in the 7 Dec. 2004 issue of the Annals of Internal
Medicine, provides a mechanism linking sleep loss to the epidemic
of obesity.

Research subjects who slept only four hours a night for two nights
had an 18 percent decrease in leptin, a hormone that tells the
brain there is no need for more food, and a 28 percent increase in
ghrelin, a hormone that triggers hunger.

The study volunteers, all healthy young men, reported a 24 percent
increase in appetite, with a surge in desire for sweets, such as
candy and cookies, salty foods such as chips and nuts, and starchy
foods such as bread and pasta.

"This is the first study to show that sleep is a major regulator
of these two hormones and to correlate the extent of the hormonal
changes with the magnitude of the hunger change," said Eve Van
Cauter, Ph.D., professor of medicine at the University of
Chicago. "It provides biochemical evidence connecting the trend
toward chronic sleep curtailment to obesity and its consequences,
including metabolic syndrome and diabetes."

In the last 40 years, American adults have cut their average sleep
time by nearly two hours. In 1960, U.S. adults slept an average of
8.5 hours a night. By 2002, that had fallen to less than seven
hours a night. Over the same period, the proportion of young
adults sleeping less than seven hours increased from 15.6 percent
to 37.1 percent. Now, only 23.5 percent, or less than one out of
four young adults, sleeps at least eight hours a night.

As sleep time fell, average weights rose. In 1960 only one out of
four adults was overweight and about one out of nine was
considered obese, with a body mass index of 30 or more. Now two
out of three adults is overweight and nearly one out of three is
obese.

Whether and how these two trends are connected, however, is
unclear. Sleep-deprived rats eat more than those allowed normal
sleep. Several epidemiologic studies showed that people who sleep
less are more likely to be overweight. One recent study found that
those who reported less than four hours of sleep a night were 73
percent more likely to be obese.

By providing the first data on the relationship between sleep and
the hormones that regulate hunger, this study helps to confirm and
begins to explain the connection.

Van Cauter and colleagues studied 12 healthy male volunteers in
their early 20s to see how sleep loss affected the hormones that
control appetite. Theses hormones -- ghrelin and leptin, both
discovered in the last ten years -- represent the 'yin-yang' of
appetite regulation. Ghrelin, made by the stomach, connotes
hunger. Leptin, produced by fat cells, connotes satiety, telling
the brain when we have eaten enough.

Van Cauter's team measured circulating levels of leptin and
ghrelin before the study, after two nights of only four hours in
bed (average sleep time 3 hours and 53 minutes) and after two
nights of ten hours in bed (sleep time 9 hours and 8 minutes).
They used questionnaires to assess hunger and the desire for
different food types.

"We were particularly interested in the ratio of the two
hormones," said Van Cauter, "the balance between ghrelin and
leptin."

After a night with four hours of sleep, the ration of ghrelin to
leptin increased by 71 percent compared to a night with ten hours
in bed.

As hunger increased, food choices changed. After two nights of
curtailed sleep the volunteers found foods such as candy, cookies
and cake far more appealing. Desire for fruit, vegetables or dairy
products increased much less.

"We don't yet know why food choice would shift," Van Cauter
said. "Since the brain is fueled by glucose, we suspect it seeks
simple carbohydrates when distressed by lack of sleep." At the
same time, the added difficulty of making decisions while sleepy
may weaken the motivation to select more nutritious foods, making
it harder to push away the doughnuts in favor of a low-fat yoghurt.

"Our modern industrial society seems to have forgotten the
importance of sleep," Van Cauter said. "We are all under pressure
to perform, in school, at work, in social and professional
settings, and tempted by multiple diversions. There is a sense
that you can pack in more of life by skimping on sleep. But we are
finding that people tend to replace reduced sleep with added
calories, and that's not a healthy trade."

Modern scientific study of sleep began at the University of
Chicago in 1953 with the discovery of REM sleep and subsequent
studies that described the multiple stages of sleep. For many
years, research on the consequences of sleep deprivation focused
on the brain. Since 1999, however, the Van Cauter laboratory has
published a series of studies describing the metabolic and
hormonal consequences of chronic partial sleep loss which is now
common. Such studies include:

* A 1999 study showing that a significant sleep debt could trigger
metabolic and endocrine changes that mimic many of the hallmarks
of aging. * A 2000 paper that mapped out the stages of age-related
sleep deterioration and showed how changes in sleep were mirrored
by changes in hormone secretion, which in turn reduced sleep
quality.

* A 2001 study demonstrating that inadequate sleep could foster
insulin-resistance, a risk factor for Type 2 diabetes.

* A 2002 study showed that sleep deprivation could slow the
response to vaccination, suggesting that sleep loss could reduce
the ability to fight off an infection.


###The National Institutes of Health, the European Sleep Research
Society, the Belgian Fonds de la Recherche Scientifique Medicale,
the University of Chicago Diabetes Research and Training Grant and
the University of Chicago Clinical Research Center funded this
study. Authors include Esra Tasali and Plamen Penev of the
University of Chicago and Karine Spiegel of the Universite Libre
de Bruxelles, Belgium.

------------------------------------------------------------------------

This story has been adapted from a news release issued by
University Of Chicago Medical Center.

Can't find it? Try searching ScienceDaily or the entire web with:
Search Web sciencedaily.com

http://www.sciencedaily.com/releases...0428062149.htm
------------------------------------------------------------------------

Source: Saint Louis University
Date: 2004-04-29

Winning The Battle Of The Bulge: We're A Scrimmage Closer To Victory

ST. LOUIS -- Saint Louis University researchers believe they've won a
major skirmish in the battle of the bulge, and their findings are
published in the May issue of Diabetes.

"We figured out how obesity occurs," says William A. Banks, M.D.,
professor of geriatrics in the department of internal medicine and
professor of pharmacological and physiological science at Saint Louis
University School of Medicine. "The next step is coming up with the
solution."

The scientists used mice to look at how leptin, a hormone secreted by
fat cells that tells us to stop eating, gets into the brain. They found

that in obese mice, high triglycerides, a type of fat in the
bloodstream, prevents leptin from getting into the brain, where it can
do its work in turning off feeding and burning calories.

"High triglycerides are blocking the leptin from getting into the
brain.
If leptin can't get into the brain, it can't tell you to stop eating,"
says Banks, who is principal investigator and a staff physician at
Veterans Affairs Medical Center in St. Louis.

"This is a big deal. We now know what is keeping leptin from getting to

where it needs to do its work."

Paradoxically high triglycerides occur in both fat and starving animals

and make the brain think the body's starving so the animal keeps
eating,
which makes it gain more weight.

"We figured out why the troops aren't getting to the front. There is
all
of this leptin in the blood but it isn't getting to the brain because
triglyerides are impairing the transportation system.

"We feel that we now understand what part of the system is broken - why

leptin isn't working. We have a better understanding of why people are
becoming obese," Banks says.

The research points scientists to a new direction in solving the
obesity
epidemic.

"Lowering triglyceride levels may very well be a big part of the
answer," Banks says. "This is a reasonable deduction that should be
tested."

John Morley, M.D. director of the division of geriatric medicine at
Saint Louis University and a co-investigator, agreed.

"If you lower triglycerides, you should theoretically help the body's
own leptin to work better so people can get skinnier," Dr. Morley says.


Effective medications to lower triglyceride levels now are available,
as
is leptin, which can be injected into the body. Banks cautioned that
the
theory needs more testing before it is put into practice.

"All the bits and pieces are there but we have to be extra cautious,"
Banks says.

Solving the obesity problem has huge health implications for Americans.

The nation's weight problem is fast overtaking tobacco use as the
leading cause of preventable death. Obesity is linked to many chronic
diseases including heart problems, several kinds of cancer and
diabetes.

During the last decade, the obesity rate in America has doubled. Nearly

two-thirds of U.S. adults are overweight or obese and 15 percent of
young people between 6 and 19 are overweight.


###Established in 1836, Saint Louis University School of Medicine has
the
distinction of awarding the first M.D. degree west of the Mississippi
River. Saint Louis University School of Medicine is a pioneer in
geriatric medicine, organ transplantation, chronic disease prevention,
cardiovascular disease, neurosciences and vaccine research, among
others. The School of Medicine trains physicians and biomedical
scientists, conducts medical research, and provides health services on
a
local, national and international level. The division of geriatric
medicine recently was listed among the top 10 programs in the country
by
U.S. News & World Report.
------------------------------------------------------------------------
This story has been adapted from a news release issued by Saint Louis
University.

hard to say ... I can imagine if you count calories and make sure everything
stays the same, sleep deprivation can actually help you lose weight because it
takes energy to stay awake. I've actually heard people stay up days on end to
try to lose weight in this fashion.

In article . com, John
G. writes
Why would food-choice shift to high-calorie items when there's
sleep deprivation, it's simple - cortisol [PMID 14974927].

http://www.sciencedaily.com/releases...1206210355.htm

Source: University Of Chicago Medical Center
Date: 2004-12-07

Sleep Loss Boosts Appetite, May Encourage Weight Gain

So this explains why some breastfeeding mums don't lose the babyweight
till they wean! My friend had twins and actually gained while nursing.
--
Jane Lumley

In article . com, John
G. writes
Why would food-choice shift to high-calorie items when there's
sleep deprivation, it's simple - cortisol [PMID 14974927].

http://www.sciencedaily.com/releases...1206210355.htm

Source: University Of Chicago Medical Center
Date: 2004-12-07

Sleep Loss Boosts Appetite, May Encourage Weight Gain

So this explains why some breastfeeding mums don't lose the babyweight
till they wean! My friend had twins and actually gained while nursing.
--
Jane Lumley