Journal of Dental Research, Vol 73, 1173-1179, Copyright © 1994 by International & American Associations for Dental Research Online Journals
Lack of significant effect of coffee and caffeine on fluoride metabolism in rats
X. Chen and G. M. Whitford
Department of Oral Biology, School of Dentistry, Medical College of Georgia, Augusta 30912-1129.
It has been reported that rat plasma fluoride (F) concentrations are higher
by up to 100% when F is administered ig in coffee or a caffeine solution
compared with when it is administered in water. It was hypothesized that
the consumption of caffeinated beverages has contributed to the prevalence
of dental fluorosis. The present studies were done to determine the
physiological mechanisms for these effects. For approximately 2 h after F
was administered in coffee, plasma F concentrations were higher than when
administered in water, decaffeinated coffee, or a caffeine solution (3
mg/kg), but the intergroup differences were small and generally not
statistically significant. The 4-hour plasma AUC values did not differ with
statistical significance. There were no differences among the groups in the
renal or extrarenal (skeletal) clearances of F, which suggested that the
higher plasma F concentrations in the coffee groups may have been due to a
slight and transient increase in absorption rate. The possibility that
caffeine per se might elevate endogenous plasma F and calcium
concentrations was excluded after caffeine (25 mg/kg) ig without F was
given. In addition, the renal excretion, clearance, and fractional renal
clearance of calcium did not differ among the groups. The results indicated
that decaffeinated coffee and caffeine had no effect on F metabolism,
whereas caffeinated coffee appeared to increase the initial absorption rate
but not the 4-hour bio-availability.(ABSTRACT TRUNCATED AT 250 WORDS)
