Project Number: 1950-51000-057-00
Project Type: Appropriated

Start Date: May 01, 2004
End Date: Apr 30, 2009

Objective:
LAB:Bone Health Refine the approach to determining the vitamin D requirement for optimal musculoskeletal and dental health in men and women. Define the impact of dietary protein and the acid/base balance of the diet on musculoskeletal health in men and women. Define the impact of calcium and vitamin D intake on insulin resistance and risk of developing Type 2 diabetes in ment and women. LAB:Vitamin K Identify and measure the amounts of individual dietary forms of vitamin K in key foods and estimate their relative contribution to total dietary vitamin K intake. Define endogenous and exogenous factors affecting bioavailability of phylloquinone, develop stable isotope measurement techniques and determine if age, lipid profile and current vitamin K nutritional status influence the absorption and transport of phylloquinone in younger and older women. Determine the impact of vitamin K supplementation, in an amount that is expected to be nutritionally optimal and safe, on bone, joint and vascular health in elderly men and women.

Approach:
LAB:Bone Health The Bone Metabolism Laboratory will perform a randomized, controlled trial (RCT) to evaluate the impact of calcium intake on the vitamin D requirement. In the same study, the impact of endogenous hormone levels, gender, and other clinical characteristics on vitamin D metabolism will be examined by linear regression and other analyses. A series of three protein and amino acid intervention studies will be conducted in humans to define the impact of protein and the acid-base balance of the diet on short-term indicators of bone strength. These studies should provide the data needed to devise a dietary supplement to promote bone health. The effect of this supplement on rates of bone loss will be evaluated in a large RCT in older men and women. LAB:Vitamin K This project will identify the distribution of vitamin K in the food supply, and evaluate dietary and non-dietary determinants of the bioavailability of vitamin K from these foods. Specifically, stable isotopes will be used in metabolic studies to compare the absorption and transport of vitamin K from a green vegetable in a vitamin K-deplete state vs. a vitamin K-replete state. The impact of vitamin K supplementation on changes in bone density and vascular calcification will be examined in clinical trials with elderly men and women. Vitamin K food composition data generated from food analysis will be incorporated into the national nutrient databases for the purpose of menu design, dietary assessment and national intake surveys. Information will be collected on the physiological significance of the measures currently used to assess vitamin K nutritional status and the impact of vitamin K supplementation on bone and vascular health.