Osteoporosis
Conditions
Keywords
protein, calcium, parathyroid hormone, bone markers, calcium kinetics, absorption
Brief summary
Osteoporosis is a major health problem in men and women in this country and the incidence of this disease is rising. We think that environmental factors such as nutrition may play a role in the increasing prevalence of osteoporosis. In particular, we think that a diet that is too low in protein may be contributing to bone loss. The primary purpose of this study is to compare the long-term impact of a low protein diet on measures of bone and calcium metabolism.
Detailed description
The protocol is composed of a 9.5-week study, consisting of a 3-week adjustment period followed by a 6.5-week experimental period. During the adjustment period, subjects consume a well-balanced lead-in diet designed to stabilize baseline Ca homeostasis. In the subsequent experimental period, subjects will consume the experimental diet containing 0.7 g protein/kg, 800-1200 mg phosphorus, 800 mg calcium and 2300 mg sodium. During days -6 to -1 of the adjustment diet, 5-10 and days 40-45 of the experimental period, we will measure Ca absorption and kinetics. Weekly assessments of Ca homeostasis will be done using our standard measures of calcitropic hormones, markers of bone turnover, and urine and serum minerals.
Interventions
OTHERLow protein diet
Low protein diet for 6.5 weeks
Sponsors
United States Department of Agriculture (USDA)
Yale University
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
FEMALE
Age
20 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy Asian or Caucasian women between the ages of 20-40 years.
Exclusion criteria
* Diseases or medical conditions: gastrointestinal diseases, osteoporosis, diabetes, hypertension, liver disease, thyroid disorders, kidney disease, kidney stones, cancer, heart disease, eating disorders, obesity, hypogonadism , amenorrhea, oligomenorrhea, abnormal serum FSH or estradiol levels, birth control medication, or other hormone-altering medications, pregnancy. * Lifestyle: smoking, excessive exercise (although moderate exercise is allowed), prescription medications known to influence vitamin D or calcium metabolism or gastric acid, excessive body weight change during the past 6 months, food allergies, unusual eating habits, or medically prescribed diets. * Also excluded are prisoners and individuals who are cognitively impaired.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Calcium absorption and kinetics | Baseline, day 5 and week 6 |
Secondary
| Measure | Time frame |
|---|---|
| Serum Parathyroid hormone | baseline and weekly |
| Markers of bone turnover | baseline and weekly |
Countries
United States
Outcome results
None listed