This study will evaluate the effect of vitamin D supplementation on the neurocognitive function of older people with lower than normal levels of vitamin D at baseline
Inclusion Criteria: * Adults aged 65 years and older. * Level of vitamin D (25-OH vitamin D) is less than 30 ng / ml. * Stable health status as assessed by the treating primary care physician. * Do not take supplements containing vitamin D. * Normal cognitive function as determined by MoCA Test screening and clinical assessment * Adequate literacy to enable the performance of cognitive assessment instruments * Provide informed consent as required by the Ethics Committee. Exclusion Criteria: * Age younger than 65 years * Health status not stable as determined by the treating primary care physician * A diagnosis of dementia * Taking supplements containing Vitamin D * Significant visual or hearing impairment not corrected by spectacles or hearing aids * Impaired competency limiting the subject's ability to provide informed consent