I'm reading an interesting book on nutrition and gene expression.  I
just came across a nugget list members *might* appreciate.  The
quotation are from:

White BD, et.al. Nutritional aspects of neuropeptide gene epression. In:
Nutrients and gene expression: Clinical aspects. Ed: Berdanier CD. Boca
Raton:  CRC Press, 1996, pp. 51-82.

"We have presented data showing that several neuropeptides play a role
in the regulation of food intake.  Though most are produced in the
brain, some are also released by the gastrointestinal tract or related
areas.  These are called gut-brain peptides.  Some of the neuropeptides
act on a short-term basis, regulating meal-to-meal food intake, while
others appear to have long-term effects influencing body weight.  Food
intake status appears to play a role in the regulation of many of these
neuropeptides.  This would be an integral part of the affector branch of
a feeding control system.  Thus neuropeotides, appear to regulate
feeding, while food status in turn feeds back to control the regulation
of neuropeptides." (P. 72)

I find it interesting that the authors find that food does not simply
relate to neuropeptide release.  Food intake and status results in nerve
cells expressing the genes that ultimately produce certain
neuropeptides.  In the text, the authors discuss one of the more widely
studied neuropeptides called neuropeptide Y (NPY) which is linked to
feeding behavior.  They conclude that NPY has an "orexogenic" effect
thus stimulating feeding.  NPY formation and release appears to be
linked to diets which are low in protein and high in carbohydrates.  You
can imagine the implications for the paleodiet hypothesis given this
information.

"More recently, the effects of these neuropeptides on macronutrient
selection have been examined.  Many neuropeptides have been shown to
cause an alteration in the selection of specific macronutrients.  This
suggests that specific macronutrients may, in turn, play a role in the
regulation of neuropeptides.  Though such studies are only just
beginning, the available evidence supports this idea.  More work is
needed to further elucidate the effects of macronutrients on the
regulation of neuropeptides."  (p. 73)

This may offer some explanations for alterations in feeding behaviors
vis-a-vis alterations in food cravings while on a paleodiet.  In
addition, it may give some significant insights into brain-mediated
behaviors across the board and how diet and food choices influence
"psychologies".

"The latest National Health and Nutritional Examination Survey (NHANES)
has determined that the prevalence of obesity is increasing in the US.
One in three people are now overweight.  This contributes to
cardiovascular disease, diabetes, stroke, and some forms of cancer.
Attempts at caloric reduction in order to lose body weight are largely
unsuccessful in the long term.  This is due in part to a lack of
understanding of the basic mechanisms that regulate food intake.  A
better understanding of how dietary macronutrients regulate
neuropeptides that, in turn, regulate feeding would contribute to our
overall understanding of these basic mechanisms."  (p. 73)

This drives home the point that weight loss and weight gain is MORE than
just a calorie BALANCE issue.  Calorie counting is simply a convenience
thought up by scientists studying food and nutrition as a way to
tabulate statistical data.  Calories are a model of food and nutrition
and like any model it does not capture adequately the reality it
attempts to represent.

Enjoy!  Andrew  =8-)
--
Andrew S. Bonci, BA, DC, DAAPM
Assistant Professor, Department of Diagnosis
Cleveland Chiropractic College
6401 Rockhill Road
Kansas City, Missouri   64131
(816) 333-7436 ex39