Changes in gastro-intestinal function in humans at an altitude of 3,500 m

Summary The gastric juice secretion, acid concentration and peptic activity were studied before and after pentagastrin stimulation in 10 sea level residents, first at sea level and then during 22 days sojourn at 3,500 m and in two other groups of 10 men, one of which consisted of natives of high altitude and the other of lowlanders acclimatized to high altitude. In addition, measurements of xylose excretion, energy, fat and protein utilization, along with fluid balance were made on sea level residents, referred to as sojourners, both at sea level and high altitude.The basal and maximal gastric juice volumes of the three groups at high altitude did not differ significantly. The maximal rate of acid production was lower in high altitude natives as compared to the other two groups. Peptic activity was higher in sojourners at high altitude, whereas it did not show any difference in acclimatised low landers as compared to sea level values of sojourners. There was no significant difference in D-xylose excretion in sojourners at high altitude. The food intake of sojourners was reduced at high altitude without any change in the efficiency of food utilization. There was no change in fluid balance.