FOR IMMEDIATE RELEASE
Contact:
Donna Krupa
703.527.7357 (direct
dial)
703.967.2751 (cell) or
djkrupa1@aol.com
NEW RESEARCH IDENTIFIES WHY
MEN AND WOMEN MAY DIFFER IN FOOD CHOICES
The physiological response of the vagus nerve can
dictate taste and digestive reactions to food. A study suggests that gender
is a major factor in how the nerve functions
PITTSBURGH, Pa. -- The National Institute of
Nutrition, Canada, recently reported that men and women see nutrition
differently. For example, nearly three quarters of women now consider
nutrition to be extremely or very important, compared with little over half
of men. Forty-four percent of women, versus 33 percent of men, describe
their eating habits as excellent or very good. Women express more concern
than men about specific nutrition issues, such as calcium (80 percent vs. 54
percent) and iron (65 percent vs. 41 percent), as well as fat (87 percent
vs. 69 percent). Forty percent of women and 25 percent of men consider
themselves to be extremely or very knowledgeable about nutrition.
Background and Study
The vagus is a nerve that passes from the brain to the
pharynx, larynx, trachea, lungs, heart, pancreas, liver, and
gastrointestinal tract as far as the left colic (splenic) flexure. This
nerve is essential to digestive and is activated at the onset of, and during
food ingestion.
One study examined how
stimulation of the vagus nerve contributed to emptying of the stomach in
lean men and women. The activity of the vagus nerve was greater in
men compared to women. In another study, secretion of hormones under the
influence of vagal innervation were studied. The release of the hormones
were greater in men compared to women after a high fat meal.
The author of the study, “Gender Differences in Vagally
Mediated Hormonal and Gastric Responses,” is Karen L. Teff, Ph.D., from the
Monell Chemical Senses Center and University of Pennsylvania Health System,
Philadelphia, Pa. Her findings will be presented at the upcoming
conference, Genomes and Hormones: An Integrative Approach to Gender
Differences in Physiology. The program is being sponsored by the
American Physiological Society (APS), beginning October 17, 2001, at the
Westin Convention Center, Pittsburgh, Pa.
Methodology and Results
The vagal contribution to gastric emptying was
evaluated by determining the difference in gastric emptying rate under
normal ingestive conditions and during inhibition of vagal activity with
atropine.
Gastric emptying was measured using a dual-radio
labeled method (technetium and indium) in lean men and women. In that
group, blockade of vagal activity significantly delayed the gastric emptying
in men (78 percent maximum counts at 90 minutes post-ingestion, atropine as
compared against 35 percent maximum counts with saline) but had no effect in
women.
The vagally mediated responses to taste in food were
determined by monitoring release of two hormones under vagal control,
insulin and pancreatic polypeptide. Normal weight men and women were fed a
high fat and low fat foods.
v
Men exhibited significant increases in release of insulin
(key to protein synthesis and glucose utilization) and pancreatic
polypeptide release;
v
Women did not display any increase in insulin and their
release of pancreatic polypeptide was reduced.
These data suggest that vagal responses to the taste of
food differ between men and women.
Conclusion
The data in Dr. Teff’s study reveal that women
exhibited diminished vagally-mediated hormonal and gastric responses to food
than men. This finding could be a key indicator of why men and women differ
in their rate of digestion and their taste in foods.
-end-
The
American Physiological Society (APS) was founded in 1887 to foster basic and
applied science, much of it relating to human health. The Bethesda,
MD-based Society has more than 10,000 members and publishes 3,800 articles
in its 14 peer-reviewed journals every year.
***
Editor’s Note: To receive a copy of the abstracts, to interview speakers or
for more information, contact Donna Krupa at 703.527.7357(direct dial),
703.967.2751 (cell) or djkrupa1@aol.com.
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