The effect of heat stress and high-fluoride intake through water containing
up to 2.67 ppm F on gastrointestinal function was studied in two different
groups of healthy male subjects (soldiers). In one group the study was con
ducted for 60 days and in the other group for 24 months on a longitudinal b
asis when they moved to a desert area. A significant increase in body weigh
t was seen only in the longer term study. No significant change in blood he
moglobin or total plasma protein was noted in either the shortterm or the l
ong-term study. There was a significant increase in blood albumin level on
the 15th day. The A:G ratio was significantly lower on the 60th day as comp
ared to the ratio on the 15th day. The subjects had more than 30% excretion
of D-xylose in 5 hr during all the test periods, thereby signifying unalte
red intestinal absorption.
The results indicate that healthy natives of tropical areas who are well ac
climatized to heat stress do not suffer from intestinal malabsorption on in
duction to a desert area. Even higher levels of fluoride intake through wat
er do not appear to affect protein metabolism and intestinal absorption whe
n adequate nutrition is maintained.