Why
Obese Diabetics Overeat and Can’t Loose Weight!
Due
to the hormone ghrelin which reduces appetite after eating not going
down.
Recently,
researchers discovered a so-called "hunger hormone" that
rises just before eating and falls after a meal. Now, UK researchers
have discovered that while this fluctuating pattern may occur in lean
people, the hormone behaves quite differently in those who are obese.
Co-author
Dr. Steve R. Bloom of the Imperial College at Hammersmith Campus in
London, UK, and his colleagues found that obese people have
lower-than-average levels of the hunger hormone ghrelin in their
bodies when hungry, and these levels don't change after obese people
eat.
As
such, obese people with unchangeable levels of ghrelin may not realize
they are no longer hungry after eating.
"If,
although low, (ghrelin) failed to go down properly after eating, you
might still feel somewhat hungry inappropriately and eat more than you
should," Dr. Bloom explained.
Ghrelin,
a hormone produced by the stomach, is named for the Hindi word for
growth. Past studies have shown it can make people so ravenous they
eat nearly one-third more food than usual.
During
the study, Bloom and his team measured the levels of ghrelin and the
hormone leptin in 13 lean and 10 obese people, both when they were
hungry and immediately after they ate.
Leptin
is often called the "obesity hormone," because previous
research has shown it may notify the brain to reduce appetite after
eating, when fat cells are "full." The relationship between
the two hormones is currently being investigated, but Bloom said that
leptin may inhibit the body's production of ghrelin.
The
investigators found that, when hungry, lean people had more than twice
the concentration of ghrelin in their blood of those who were obese.
After eating, ghrelin concentrations did not change in the obese, but
dropped 40% in lean people before inching back up to normal levels.
The
concentration of blood leptin also decreased after eating in lean
people, but showed no decline in those who were obese, according to
the report in the June issue of the Journal of Clinical Endocrinology
& Metabolism.
Bloom
explained that researchers have not investigated whether low ghrelin
levels induce obesity, or if obesity decreases the overall amount of
ghrelin in the body. "This hasn't been directly tested but it is
assumed that the low ghrelin is a consequence of obesity," he
said.
However
ghrelin is involved in the development of obesity, Bloom suggested
that manipulating the level of the hormone in the body may one day
help to correct the problem.
"If
a drug to block ghrelin could be identified--not difficult with modern
mass chemical library screening--it would lessen hunger and tend to
reduce food intake," he said.
"A
1% reduction in food intake for a year would have a major impact on
obesity," Bloom added. SOURCE: The Journal of Clinical
Endocrinology & Metabolism 2002;87:2984-2987.
