Maaltijden rijk aan eiwitten remmen de eetlust.*
Onderzoekers hebben weer een bewijs geleverd dat een maaltijd rijk aan proteïnes het hongergevoel reduceert en daardoor de eetlust afremt. Nu is ok vastgesteld waarom dat zo is. Door deze maaltijden wordt de productie van glucose in de dunne darm opgang gebracht waardoor de lever een signaal geeft aan de hersenen de eetlust af te remmen.
How
protein-enriched meals decrease hunger and reduce eating
Researchers
have uncovered new evidence to explain the observation that diets rich in
protein stunt the appetite, according to a report in the November Cell
Metabolism.
The
findings suggest a novel link connecting macronutrients in the diet to hunger,
the researchers said. The results also point to a potential new target for the
treatment of eating disorders, they added.
"It
is well known that protein feeding decreases hunger sensation and subsequent
food intake in animals and humans," said study author Gilles Mithieux of
INSERM and Universite Lyon in France. However, the mechanism by which proteins
exert their control over appetite remained unclear, the researchers said. In
fact, earlier studies have found that a rise in dietary protein shows little
effect on the major hormones that regulate hunger, they added.
In
a study of rats, Mithieux and colleagues made the surprising discovery that
diets heavy in protein spark the production of glucose in the small intestine.
That rise in glucose, sensed in the liver and relayed to the brain, led the
animals to eat less, they reported.
"The
current findings provide an answer to the question of how protein-enriched meals
decrease hunger and reduce eating, unsolved up to now," according to the
researchers. "Our data also bring to light a novel concept of control of
food intake, involving the small intestine glucose metabolism as a key relay
from the macronutrient composition of the diet to the amount of food ingested."
The
group found that protein feeding of rats markedly increased the activity of
genes involved in glucose production in the animals' small intestine. Those
activities led to glucose synthesis and release into the portal vein--the vessel
that conducts blood from digestive and other organs to the liver--a phenomenon
lasting after the assimilation of glucose from the diet.
Furthermore,
they found that the flux in glucose detected by the liver glucose sensor
activated parts of the brain involved in the control of appetite, causing a
decline in subsequent food consumption.
"In
addition to protein's ability to diminish appetite, it had also been suggested
that glucose appearance in the portal vein, as occurs during meal assimilation,
may induce comparable consequences," Mithieux said. "Here, we connect
these previous observations by reporting that intestinal synthesis of glucose is
induced following food digestion in rats specifically fed a protein-enriched
diet."
As
in rats, diets high in protein suppress appetite in people, the researchers
added. The human intestine also synthesizes glucose. "Therefore, glucose
metabolism in the small intestine may be a new target in the treatment of food
intake disorders," they said.
(November 2005) (Opm. Over eiwitten/proteïnes kijk bij Voedingsstoffen.)
