Caffeine intake of 150–300 mg after a 10-h fast increased
urinary calcium excretion 2–3 h after exposure
in adolescent men and women (Massey and
Hollingbery 1988), women 22–30 years of age
(Massey and Wise 1984, Massey and Opryszek
1990), men 21–42 years of age (Massey and Berg
1985), and women 31–78 years of age consuming
5200 mg caffeine day1 (Bergman et al. 1990).
Tolerance to the renal effects of caffeine does not
develop, as habitual coffee intake had no effect on the
increase in calcium excretion associated with an acute
caffeine dose (Massey and Opryszek 1990). Caffeineinduced
hypercalciuria was not affected by oestrogen status (Bergman et al. 1990), gender or age (Massey and Wise 1992). Barger-Lux et al. (1990) reported that caffeine intakes of 400 mg person1 day1 for 19 days led to evidence of altered bone remodelling in healthy premenopausal women between the ages of 35 and 44, but had no effect on fractional calcium absorption, endogenous faecal calcium or urinary calcium excretion.
An earlier study in the same population suggested that caffeine consumption of 175 mg person1 day1 was positively associated with
increased 24-h urinary calcium excretion (Heaney and Recker 1982).