Vitamin D is crucial for control of about 5% of the human genome.  Studies have shown that low Vitamin D levels confer increased aging and increased all cause mortality.  Twin studies concur that a twin with lower Vitamin D levels have higher mortality.  It is important for DNA repair and anti-inflammatory substances, both of which are responsible for telomere length, ie. longevity.

It also was shown in cut infection risk by 50% in a large multi-country study.

It also affects muscle mass and athletic performance. In post menopausal women, Vit D increased 25% muscle strength.  Increases health and brain health.

100o IU daily increases Vit D3  increases by 5 ng per liter.

40-60 ng/liter had longer telomeres and is her recommended serum level.