High bioavailability of calcium in fortified Horlicks (R)

Objective: To compare the bioavailability of calcium carbonate-fortified Ho rlicks (R) with calcium naturally present in milk. Design: Randomised crossover within-subject comparison using a double label stable isotope technique. Setting: Institute of Food Research, Human Nutrition Unit. Participants: Sixteen pre-menopausal women aged 23-40 y, habituated to a hi gh-calcium diet (mean 1240 mg/day). Results: Mean true fractional calcium absorption was 38.8% (s.d. +/- 14.5) from Horlicks (R) and 21.2% (s.d. +/- 4.6) from milk. Significantly more ca lcium was absorbed from a serving of Horlicks (R), than from the same quant ity of calcium present in 420 g semi-skimmed milk (P < 0.001). Conclusions: Fortified Horlicks (R) is a highly bioavailable source of calc ium. A single serving, containing at least 500 mg calcium, provides half th e reference nutrient intake for the population sub-group with the highest r equirement (adolescent boys) and more than half for all others. Sponsorship: SmithKline Beecham funded this research project. Descriptors: calcium; absorption; bioavailability; milk; fortification; sta ble isotopes.