Objective: To assess whether there are any differences in the postprandial physiological responses to apple drink (control), calcium phosphate (tricalcium phosphate, TCP) and high-calcium skim milk (HCSM) with or without additional magnesium in postmenopausal women. Design: Randomized, controlled, cross-over. Measurements after overnight fast before each drink, and subsequently every hour for 8 h postprandially. Results: There was no difference in baseline serum calcium, PTH or C-telopeptide levels between drinks. There were no overall differences in serum calcium after apple or after either milk, but after TCP serum calcium increased from a baseline value of 2.12 AE 0.08 to a mean peak of 2.21 AE 0.12 mmol=l (s.d.) (P ¼ 0.0001) after 2 h. There were no significant differences in serum PTH after either apple or HCSM þ Mg. In contrast, after TCP, serum PTH decreased from 2.76 AE 0.69 to a mean nadir of 2.23 AE 0.65 pmol=l (P ¼ 0.0001) after 1 h, and after HCSM, it decreased from 2.71 AE 0.78 to a mean nadir of 2.51 AE 0.87 pmol=l (P ¼ 0.007) after 2 h. Serum C-telopeptides decreased after each drink, reaching nadirs after 5 h. At this time the serum values for each of the high calcium drinks were not different from each other, but were significantly less than for apple (P ¼ 0.001 for each), being 0.22 AE 0.09 ng=ml for apple, 0.15 AE 0.08 for TCP, 0.14 AE 0.07 for HCSM and 0.16 AE 0.07 for HCSM þ Mg. Conclusion: Despite differences in serum calcium and PTH responses to the three high-calcium drinks that we tested, there was no distinguishable difference in serum C-telopeptides between high calcium drinks.

High-calcium milk enriched with potassium has a small hypotensive effect in healthy people aged over 40 years.

The aim of this study was to investigate the impact of magnesium-enriched, high-calcium milk on serum parathyroid hormone (PTH) and biochemical markers of bone turnover in postmenopausal women. We recruited 50 healthy postmenopausal women to take part in this randomised controlled study. Half of the women consumed two serves of high-calcium skim milk enriched with magnesium (milk group) and half consumed two serves apple drink per day (apple group), each for 4 weeks. The milk provided 1200 mg calcium and an additional 106 mg magnesium. We investigated the responses of serum PTH, as well as the serum and urinary calcium, magnesium and biochemical markers of bone turnover. There was no effect of time or drink on the clinical biochemistry, serum PTH or urine markers of bone resorption (free deoxypyridinoline and N-telopeptides). Serum C-telopeptides (CTX), another marker of bone resorption, did not change with time in the apple group. However, in the milk group, serum CTX deceased significantly from 0.43 +/- 0.04 ng/mL to 0.32 +/- 0.02 at 2 weeks (p < 0.0001) and 0.28 +/- 0.02 at 4 weeks (p < 0.0001). In the milk group, urinary calcium and magnesium each increased during the night but not during the day. Overall, these data suggest that milk has an antiresorptive effect on bone, but that this is not accompanied by measurable changes in serum PTH.

The purpose of this study was to assess the agreement between the 24 h diet recall and a short 17-item 24 h food intake recall in assessing calcium intake. The calcium intakes of 21 women over the age of 50 were assessed by both methods on four occasions. The mean calcium intakes were similar using both methods, being 1034+/-398 mg/day by 24 h diet recall and 822+/-412 mg/day (SD) by 17-item 24 h food intake recall. The 17-item 24 h food intake recall tended to underestimate calcium intake compared with the 24 h diet recall, with the limits of agreement being between -1197 and -727 below and 370 and 682 mg/day above 24 h diet recall values over the four assessments. The 17-item 24 h food intake recall identified 8% more women with inadequate calcium intakes than the 24 h diet recall method did. Although there is poor agreement in calcium intake between the 24 h diet recall method and the 17-item 24 h food intake recall, the latter provides a quick and simple means for assessing extremes of calcium intake and whether day to day calcium intake is adequate.

No abstract