Vitamin D is a fat soluble vitamin that has important effects on calcium (including
absorption of calcium from the diet) and bone metabolism. Vitamin D is known to be stored
in fat tissue, and it is also present in the circulation. The purpose of this study is to
investigate the relationship between levels of vitamin D in fat tissue and in blood.
Although vitamin D is known to be stored in fat tissue, researchers are not sure about the
role that fat tissue plays in vitamin D metabolism. This study will help develop the
methodology necessary to further investigate the role of fat tissue in vitamin D metabolism
and will assess the relationship between levels of vitamin D in fat tissue and in blood. 50
subjects who are referred for gastric bypass surgery will be enrolled in this study.
Subjects will complete questionnaires about their medical history, travel history and food
intake. Prior to or during surgery, subjects will be asked to provide a blood sample for
selected chemistries related to vitamin D metabolism. During gastric bypass surgery, the
surgeon will collect small pieces of fat tissue from the fat under the skin and within the
abdomen by surgical biopsy. These samples will be used to refine the methodology for
determining the levels of vitamin D in blood and fat tissue and for comparing levels of
vitamin D in various tissues.
- Obese patients referred for gastric bypass surgery
- Patients must not be taking bile acid-sequestering medications or anti-seizure