Phuntila Tharabenjasin. Intestinal absorption of fluid containing different composition of carbohydrates in sedentary and athletes. Master's Degree(Exercise Physiology). Mahidol University. : Mahidol University, 2007.
Intestinal absorption of fluid containing different composition of carbohydrates in sedentary and athletes
Abstract:
Intestinal fluid absorption depends on several factors. The contribution of which
is still unclear. The objectives of this study are: 1) to determine whether the presence
of multiple types of carbohydrate (CHO) could offset the effect of hyperosmolality;
and 2) to test whether high CHO consumption in endurance athletes would enhance
CHO absorption.
Eight healthy sedentary males and 8 male marathoners aged 20-30 years
volunteered in this study. A triple-lumen tube was placed in the duodenojejunum and
electrolyte (E) solutions containing 4 different compositions of CHO (A: 2% glucose,
4% sucrose, 290 mOsm/kg; B: 5.6% glucose, 1.1% fructose, 4.5% sucrose, 680
mOsm/kg; C: 5.7% glucose, 1.1% fructose, 2.5% sucrose, 0.1% maltose, 669
mOsm/kg; D: double distilled water) were infused 10 cm distal to the pyloric sphincter
at 15 ml/min for 90 min. Fluid emerged from the proximal and distal sampling ports
(10 and 50 cm distal to infusion port, respectively) were collected at every 15 min and
analyzed for polyethylene glycol, CHO, Na+, and K+. Blood samples were also
collected from the antecubital vein every 30 min.
Results showed that all solutions produced water secretion in the duodenum of
both sedentary subjects and marathoners. However, water secretion in the latter was
less. In the jejunum, A and D caused water absorption, the latter is higher whilst B and
C produced water secretion in all subjects. In both groups of subjects, there were no
differences in the rate of CHO absorption in the duodenum and jejunum after infusion
of different CHO-E solutions. CHO absorption rates in each intestinal segment of the
sedentary subjects were comparable to those of athletes. Regression analyses indicated
that water flux depends primarily on fluid osmolality or total electrolyte fluxes, not
CHO fluxes, in both groups.
It is concluded that fluid absorption in the proximal jejunum depends partly on
solute (Na+ and Glucose) transport and osmotic flow of water. Multiple types of CHO
cannot offset the osmotic effect. Endurance athletes do not have a higher rate of CHO
absorption compared to sedentary persons.