Vitamin D is synthesized in the body from sunlight. But, due to winter season, weather conditions, and sunscreens, the body’s ability to produce optimal vitamin D levels may be inhibited.79 In fact, it has been proposed that annual fluctuations in vitamin D levels explain the seasonality of influenza.80 All of these factors point to the value of taking a daily vitamin D supplement to ensure optimal vitamin D intake.

Vitamin D has long provided significant support for healthy bone density.81-86 However, scientists have also validated the critical role that vitamin D plays in regulating healthy cell division and differentiation, and its profound effects on human immunity.87-90 These findings link a deficiency of vitamin D to a host of common age-related problems.

The objective of taking a vitamin D supplement is to achieve 25-hydroxyvitamin D blood levels of 50 ng/mL (and higher). Life Extension’s® analysis of over 13,000 vitamin D blood tests reveals that the minimum intake for most aging people should be around 7,000 IU a day. Some individuals (such as those weighing more than 180 pounds) may require higher potencies of vitamin D. When combined with 1,000-3,000 IU obtained from multinutrient formulas, this 7,000 IU vitamin D3 capsule should enable these individuals to attain 25-hydroxyvitamin D blood levels above the desired range of 50 ng/mL.