CR/intermittent feeding physiology

[Guest guest]

Hi All,

A new paper has reviewed the effects of CR and intermittent fasting physiology.

The

effects of intermittent feeding was of note with regard to the intestines of

snakes

increasing twice in size when they ate an occasional large meal.

Regarding:

Expected online publication date for the Annual Review of Physiology Volume 68

is

February 4, 2006. Please see http://www.annualreviews.org/catalog/pub_dates.asp

for

revised estimates.

They seem to misinform.

See the pdf-available below paper excerpts.

Wang T, Hung CC, Randall DJ.

The Comparative Physiology of Food Deprivation: From Feast to Famine.

Annu Rev Physiol. 2005 Oct 19; [Epub ahead of print]

PMID: 16236022

The ability of animals to survive food deprivation is clearly of considerable

survival value. Unsurprisingly, therefore, all animals exhibit adaptive

biochemical

and physiological responses to the lack of food. Many animals inhabit

environments

in which food availability fluctuates or encounters with appropriate food items

are

rare and unpredictable; these species offer interesting opportunities to study

physiological adaptations to fasting and starvation. When deprived of food,

animals

employ various behavioral, physiological, and structural responses to reduce

metabolism, which prolongs the period in which energy reserves can cover

metabolism.

Such behavioral responses can include a reduction in spontaneous activity and a

lowering in body temperature, although in later stages of food deprivation in

which

starvation commences, activity may increase as food-searching is activated. In

all

animals, the gastrointestinal tract undergoes marked atrophy when digestive

processes are curtailed; this structural response and others seem particularly

pronounced in species that normally feed at intermittent intervals. Such

animals,

however, must be able to restore digestive functions soon after feeding, and

these

transitions appear to occur at low metabolic costs.

.... SUMMARY AND FUTURE DIRECTIONS

Digestive status affects virtually all physiological and behavioral responses,

and

selective pressure to enhance feeding strategies and digestive processes must be

significant. The ectothermic vertebrates, with their lower metabolic rates, can

en-dure

prolonged periods of fasting, and many of these species exhibit much more

pronounced changes in gastrointestinal organs than are normal in healthy mammals

(see also Reference 147). The extreme structural and functional changes in their

dynamic guts make ectothermic vertebrates useful models to explore largely

unre-solved

issues regarding the interaction and prioritization of physiological functions

among organ systems. These issues are of basic physiological importance. Such

studies may contribute to our understanding of the mechanisms that enable organs

to adapt to physiological demands. They also may help us to understand the

factors

that in humans can promote intestinal repair following either intestinal

resections

or diseases such as colitis and Crohn’s disease in which there is inflammatory

destruction.

Al Pater, PhD; email: old542000@...

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