The decline in brain function with aging is costly. The maintenance of optimal brain health is a priority among the elderly. Complex modifiable factors impact brain function such as education level, ongoing use of cognitive skills such as mentoring and social interaction. In most instances, substantial time and effort will be required to improve brain function in the elderly. There is an urgent need for an option that will yield rapid results. Investigator(s) believe intensive Vitamin D replacement presents such a solution.

Emerging scientific information supports an important role for Vitamin D in brain health. Much of this data is based on the association that higher Vitamin D values are linked to better brain function. However, an association does not prove a cause and effect. To prove that Vitamin D values play a causal role in cognition carefully controlled studies are needed. Currently, there are very few controlled interventional studies in the elderly demonstrating that Vitamin D levels can improve brain function. The 25(OH) Vitamin D is the best indicator of Vitamin D status. The normal range for 25(OH) Vitamin D is usually between 30 and 100 ng/ml. Preliminary data indicates that 25(OH) Vitamin D values of greater than 40 ng/ml are needed to improve brain function. Prior Vitamin D studies have used varying replacement protocols and types of Vitamin D such that stable 25(OH) Vitamin D values in the high normal range have rarely been achieved.

Brain Impairment usually occurs gradually in dementia, giving the patient and the provider an option to slow or halt progression of cognitive deterioration. Disruption in the white matter (reflecting the nerve fibers that conduct electric impulses) of the brain as well as reduction in brain volumes are linked to dementia and increasing chances of disability. These white matter abnormalities and reduction in brain volumes are commonly present in the elderly and are closely linked to Vitamin D deficiency. Animal studies using Vitamin D support a benefit to cognition. There is a paucity of carefully controlled clinical trials involving humans using appropriate Vitamin D replacement protocols. However, a few preliminary studies do support a benefit to cognition in humans over a study period ranging from 1-15 months. The present proposal addresses this relative deficiency by conducting a double blind controlled study in the Vitamin D insufficient community dwelling elderly.

The hypothesis is that daily 5000 IU Vitamin D3 will regress or at least prevent progression of white matter abnormalities or shrinking of brain volumes. There are specific anatomical defects in the brain linked to Vitamin D deficiency. These deficits include impaired visual memory and executive (higher brain functions). Investigator(s) will assess brain function by tracking changes in a battery of computerized tests that have been proven reliable in assessing brain function. These changes in computerized testing of brain skills will be matched to changes in brain imaging over the course of the 1 year study. Brain imaging will be done using a 3-Tesla Magnetic Resonance Imaging scan (MRI).

Once the institutional review board approves this study, free living participants (\> 65 yrs.) without prior brain disease or dysfunction will be recruited. The participants with Vitamin D insufficiency (25(OH) Vitamin D \< 30 ng/ml) will be randomized into two groups. Both participant groups will be treated for 1 year with daily Vitamin D3 supplements. The standard of care group will get 800 IU daily whereas the active group will get 5000 IU daily. Cognitive tests, chemistry profile will be done at baseline and every 4 months for 1 year. The basic chemistry profile (blood work) includes kidney function and calcium levels which also provide safety monitoring. Based on published information, Vitamin D3 doses planned in this study are far below the doses required for toxicity. The brain MRI will be done at baseline, 4 and 12 months.

Additional strengths of this study include a multidisciplinary team with published expertise and experience in Vitamin D replacement, brain and memory function.