Milk and Yogurt Compared to Calcium and Vitamin D Supplements for Bone Health in Women

 

 

USDA, ARS Western Human Nutrition Research Center (WHNRC) invites healthy postmenopausal women, ages 50-65 years of age, to participate in a year long study of the effects of dairy vs. calcium and vitamin D supplements on bone metabolism.

 

Who is conducting this study?

The study is conducted by Marta Van Loan, PhD and Marjorie Garrod, PhD. The study has been reviewed and approved by the UC Davis Committee for the Protection of Human Studies. There is only minimal health risk associated with participation in this study.

 

What is the purpose of the study?

The study will compare dairy products (both milk and yogurt) to calcium and vitamin D supplements on maintaining bone metabolism in postmenopausal women.

 

Who can participate?

Healthy postmenopausal women, 50 to 65 years of age, without osteoporosis, who eat no more than 2.5 servings of dairy per day, may be eligible to participate.  Volunteers must be willing and able to come to the research center (WHNRC) on the UC Davis campus for screening visits.  There are a total of 25 visits over the course of one year.  Screening visits will be done at the WHNRC, but study visits can be scheduled at the WHNRC, Mather VA Hospital or UCDMedicalCenter, if that is more convenient. 

 

Who is NOT eligible to participate?

* Women who are not yet 2-years postmenopausal.

 

* Women with osteoporosis.

 

* Women with intolerance or allergy to dairy products. 

 

* Women who eat more than 2 servings of dairy per day.

 

* Women who are not willing to discontinue calcium and vitamin D supplements during the study.

 

* Women with known medical conditions, including anemia, kidney disease, lupus, or

  gastrointestinal disease or surgery.

 

* Women who are taking hormonal therapy are pregnant, or nursing.

 

What do I need to do to participate?

You would first complete a health screening at the WHNRC on the UC Davis campus. The appointment would last about 60 minutes, and would occur in the morning after an overnight fast. A health history questionnaire will be completed, a blood sample taken to assess your general health, and a screening bone density test (DXA) will be done to ensure that your bone density is within the limits set for the study.

 

If you are eligible, your participation in the research could last up to 12 months. You would be asked to collect a baseline 24-hour urine sample. You will be provided with instructions and supplies to do this at home. Then, you will be asked to consume a small amount (100 nCi) of a radioactive calcium isotope that is used to measure the changes in bone over time. The radiation exposure from the amount of isotope used in this study is less than the radiation dose from one hour flying in an airplane.

 

During the next 6 months, while the calcium isotope equilibrates, subjects will be asked to collect 24-hour urine collections at days 90, 120, 150 and 180 to establish each individual's calcium excretion. At about day 138, you will be asked to stop taking all dietary supplements, in preparation for the intervention phase of the study.

 

Next, you would start one of two treatments, either 4 servings of dairy foods per day added to your typical diet for 42 days (6 weeks),orcalcium and vitamin D supplements daily for 42 days (6 weeks). You will also be asked to record your compliance with the treatments and collect 3-day dietary records, using a small booklet. After the first treatment there is a washout period of 42 days (6 weeks) where you would take no calcium or vitamin D supplements and continue your usual diet.  After the washout period you would start on the opposite treatment. This means if you were assigned the dairy foods during the first treatment, now you will get the calcium and vitamin D supplements, and vice versa. Again, you will also be asked to record your compliance with the treatment and collect 3-day dietary records, using a small booklet. During both treatment and washout periods, you will be asked to collect one 24-hour urine collection each week. Blood samples would be taken at 4 different time points (days 180, 222, 264, and 306). Your participation in the study would end when you finish the second treatment.

 

What are your compensations from this study?

You would receive a free bone density test and all dairy products and supplements would be provided by the WHNRC.  Volunteers would also be compensated at the rate of $10 per 24-hour urine collection for a total of up to $240 for completion of the study.

 

What should I do if I have questions?

Call (530) 752-5177 and Press #6