Maximizing calcium retention by the skeleton within the genetic potential is a key strategy
to prevent osteoporosis. It has been shown that calcium retention varies between blacks and
whites and between gender within race. This study is designed to study the relationship
between calcium intakes and calcium retention in Asian adolescent girls and boys. It is
hypothesized that calcium intakes which maximize calcium retention will be lower in Asians
than for whites studies under the same conditions. In addition it is thought that the
differences between races in the physiological mechanisms involved in calcium metabolism
will result in a lower calcium intake required to observe a plateau in calcium retention.
This is turn could be translated into lower calcium requirements in Asians relative to
Caucasians for achieving optimal peak bone mass.
Adolescent Asian boys and girls will consume a controlled diet for two three-week periods.
The basal diet will contain 600 mg/d calcium and will be supplemented with beverages
fortified with calcium citrate malate to achieve a range of intakes from 600-2100 mg Ca/d.
Each participant will be studied on one of four combinations of a lower and a higher calcium
intake within that range in a cross-over design.
- healthy teens of Asian descent
- malabsorptive disorders
- smoking, illegal drugs
- oral contraceptives
- drugs that influence calcium metabolism
- body weight for height greater than 85 percentile