Researchers have pointed out that increasing levels of vitamin D3 among the general population could prevent chronic diseases that claim nearly one million lives throughout the world each year. Incidence of several types of cancer could also be slashed in half.
Vitamin D also fights infections, including colds and the flu, as it regulates the expression of genes that influence your immune system to attack and destroy bacteria and viruses.
Before the year 2000, very few doctors ever considered the possibility that you might be vitamin D deficient. But as the technology to measure vitamin D became inexpensive and widely available, more and more studies were done, and it became increasingly clear that vitamin D deficiency was absolutely rampant.
According to experts, you don’t want to be in the “average” or “normal” range, you want to be in the “optimal” range. The reason for this is that as the years have gone by, researchers have progressively moved that range upward.
At present, based on the evaluation of healthy populations that get plenty of natural sun exposure, the optimal range for general health appears to be somewhere between 50 and 70 ng/ml. For treatment of chronic disease such as cancer, recommendations go even a bit higher than that. According to experts in the field, adults need to supplement with about 5000 IU each day to achieve the optimal level.