Dietary calcium intake in rural black South African children. The relationship between calcium intake and calcium nutritional status.

Dietary calcium intake in relation to calcium status in rural black South African children was investigated. Fifteen subjects in each age group, 3-5 years, 8-10 years, 13-16 years with lowered serum calcium (less than 2.25 mmol/l) and raised serum alkaline phosphatase (greater than 300 i.u./l) were matched with controls having normal serum biochemistry. A dietary interview and 24-h recall was conducted with each subject; nutrient value of the diet was calculated from standard food tables. At 3-5 years, although the study group had significantly lower calcium intakes, there was no significant relationship between dietary calcium intake and calcium status. Study children in the age groups 8-10 years and 13-16 years had significantly lower dietary calcium intakes than controls and dietary calcium intake showed significant correlation with serum calcium levels, serum alkaline phosphatase levels, bone mineral density, metacarpal cortical thickness and calcium excretion. Thus it appears that low dietary calcium intakes may be reflected by hypocalcaemia, elevated alkaline phosphatase and decreased bone mineral content in pre-adolescent children.