Effects of calcium supplementation using AAACa or milk on nocturnal bone resorption in young women

In order to study the effect of calcium supplementation on bone resorption, a randomized controlled crossover study was carried out on eight healthy 18-19 year old female volunteers using either AAACa heated oyster shell with vacuum-heated seaweed or milk. Regimen A consisted of an oral dose of 200 mg calcium in the form of AAACa. B 200 ml milk after breakfast and supper and at bedtime, and C control with no calcium supplement. Early morning fasting blood and urine sampling was carried out after 7 days of calcium supplementation. Serum calcium was higher in groups A and B than in C, and serum intact parathyroid hormone (PTH) was significantly lower in group A than in groups B and C, according to a paired t-test. Urinary excretion of crosslinked collagen degradation product, pyridinoline and deoxypyridinoline showed a similar decrease in groups A and B but not in C. The more effective suppression of PTH by AAACa than by milk may be due to its higher bioavailability and the absence of phosphate stimulating PTH secretion.