Meat Protein and Calcium: Do They Interact Synergistically or Antagonistically?

Meat Protein and Calcium: Do They Interact Synergistically or Antagonistically?

The primary objective is to determine whether meat interacts positively with calcium to improve calcium retention. The secondary objective is to determine whether any interaction between dietary protein and calcium affects biomarkers of bone metabolism.

This study tests the effects of dietary protein and calcium on calcium retention and indices of bone metabolism. It is a controlled feeding trial with a randomized crossover design (2x2 Factorial), studying 34 healthy post-menopausal women. The women are blocked on Body Mass Index (weight in kilograms divided by height in meters squared)and randomly assigned to a high calcium (HC,1500 milligrams per day) or low calcium (LC, 600 milligrams per day) group, and consume both low protein (LP,10% protein) and high protein (HP, 20% protein) diets for 7 weeks each. There is a 3-week "washout" between dietary periods, during which the subjects consume self-selected diets. After 3 week equilibration to each diet, the 2-day rotating menu is extrinsically labeled with a Calcium-47 radiotracer and retention is monitored for 28 days by whole body scintillation counting. In addition to Calcium retention, other endpoints include urinary indices of acid excretion and urine serum indices of bone resorption.

Inclusion Criteria:

• at least 3 years since last menses
• bone mineral density equal to or greater than 2.5 standard deviations from average bone mineral density for young adults,
• body mass index equal to or less than 35 kilograms/meter squared

Exclusion Criteria:

• taking prescription medication other than hormone replacement therapy