Vitamin D is obtained from sun exposure, sun lamps, or supplements. Studies worldwide reveal that blood levels of Vitamin D are woefully low in most people. Adults and children with the lowest levels of Vitamin D in their blood have 50% more respiratory infections and more days of absence from work or school.
An international team of researchers published results in the July 12, 2010 issue of the American Medical Association journal Archives of Internal Medicine that showed a greater risk of cognitive decline in older individuals with vitamin D insufficiency compared to those with sufficient levels.
Since the sun can cause skin damage and even skin cancers, it is prudent to avoid sun exposure and instead take a Vitamin D supplement. However, do not take Vitamin A at the same time as it decreases the beneficial action of Vitamin D. Only recently has Vitamin D been recognized as one of the most important vitamins associated with disease resistance and anti-aging problems. The serious health minded persons with concerns of aging diseases should have periodic blood tests to monitor their Vitamin D blood level and be monitored by a knowledgable healthcare professional.