How Much Vitamin D is Required to be Protective Against Deficiency During the Winter Months?

Overview

Vitamin D is essential to bone health. In Canada, it is obtained by sunlight exposure of the skin (between April and October) or by a few foods such as fatty fish, eggs or fortified milk and margarine. This study has 3 main goals which are to determine if Veteran's have enough vitamin D stored in their body, if adding a supplement of 2000 IU/d is enough to correct low vitamin D stores and, if specially formulated foods using an approved vitamin D supplement, are appropriate to maintain vitamin D stores in relation with functional and cognitive status. Initially, a 2000 IU supplement of vitamin D will be provided for 8 weeks. After this period, the participants will be randomly separated into 3 groups (Group A, B or C) for a period of 24 weeks. Group A will receive their usual menu. Group B will receive their usual menu with 1 portion of food containing 500 IU of added vitamin D. Group C will receive their usual menu with 1 portion of food containing 1000 IU of added vitamin D. Food intake will be assessed every 8 weeks and blood samples will be taken every 4 weeks to monitor change in blood concentration of vitamin D and other indicators of bone health. The investigators will document weight and height, hand grip strength, the mid-arm and mid-calf circumferences, the capacity to perform activities of daily living, the number of prescriptions and changes in health condition. The investigators will also take an X-ray the tibia and upper arm to document the amount and quality of bones in those regions. A total of 60 veterans of Ste-Anne's Hospital will participate in this study. Knowing more about vitamin D status and intake will help in confirming the required vitamin D recommendations for the elderly men living in long-term care institutions.

The main objectives of the proposed 2 phase-protocol in aged Canadian veterans (n=60) are to evaluate the impact of 2000 IU/day of vitamin D3 supplementation (tablets or liquid form) on correcting low vitamin D status and the associated impact on biochemistry, bone health markers and markers of inflammation in a Fall period (Before and After, 8 weeks) and, 2) evaluate which food-based supplementation will maintain vitamin D3 status thereafter from winter through spring by measuring serum 25(OH)D concentration following intake of vitamin D delivered (with liquid form vitamin D3) using foods as the vehicle providing an additional 1000 IU/day or 500 IU/day compared to regular meals offered at Ste-Anne's Hospital (SAH) (Randomized Controlled Trial, 3 groups, 24 weeks). Anthropometry (weight, height, BMI, mid-arm and mid-calf circumferences), grip strength, biochemical markers of bone health (25(OH)D, PTH, calcium, ionized calcium and phosphate), assessments of cognitive and functional status (Mini-Mental State Evaluation, Frail Elderly Functional Assessment, Physiotherapy Functional Mobility Profile and Pain Assessment Checklist) as well as volumetric bone mineral density using peripheral quantitative computed tomography (pQCT) will be gathered. The long-term goal of the research program is to use novel food-delivery systems and approaches to enhancing vitamin D intake that meets the needs of this population. For years, medications have been delivered through foods but few studies have applied this to natural health products such as vitamin D. In chronic care, the number of prescription pills is high often 13 or more not accounting for multiple administrations over a day. Further documentation of health related indicators such as capacity to perform daily activities and chronic pain intensity would relate to quality of life and improve our understanding of vitamin D in more than bone health related issues. The reality of long-term care facilities (financial, human and material resources) needs to be addressed for the newly developed delivery modes to meet the needs of these residents and the projected increase in care required for our aging Canadian population. Large scale interventions will need to take place to give more insight on efficacy and efficiency of this new food delivery approach.