This high rate of natural production of vitamin D3 cholecalciferol (pronounced koh·luh·kal·sif·uh·rawl) in the skin is the single most important fact every person should know about vitamin D—a fact that has profound implications for the natural human condition.
Technically not a "vitamin," vitamin D is in a class by itself. Its metabolic product, calcitriol, is actually a secosteroid hormone that is the key that unlocks binding sites on the human genome. The human genome contains more than 2,700 binding sites for calcitriol; those binding sites are near genes involved in virtually every known major disease of humans.
Current research has implicated vitamin D deficiency as a major factor in the pathology of at least 17 varieties of cancer as well as heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects, periodontal disease, and more.
Vitamin D's influence on key biological functions vital to one's health and well-being mandates that vitamin D no longer be ignored by the health care industry nor by individuals striving to achieve and maintain a greater state of health.
If well adults and adolescents regularly avoid sunlight exposure, research indicates a necessity to supplement with at least 5,000 units (IU) of vitamin D daily. To obtain this amount from milk one would need to consume 50 glasses. With a multivitamin more than 10 tablets would be necessary. Neither is advisable.
How To Get Enough Vitamin D
There are 3 ways for adults to ensure adequate levels of vitamin D:
- regularly receive midday sun exposure in the late spring, summer, and early fall, exposing as much of the skin as possible for 20–30 minutes (being careful to never burn). (Those with dark skin will need longer exposure time — up to six times longer.)
- regularly use a sun bed (avoiding sunburn) during the colder months.
- take 5,000 IU per day for 2–3 months, then obtain a 25-hydroxyvitamin D test. Adjust your dosage so that blood levels are between 50–80 ng/mL (or 125–200 nM/L) year-round.
Vitamin D's Co-factors
Vitamin D has co-factors that the body needs in order to utilize vitamin D properly. They are:
- magnesium
- zinc
- vitamin K2
- boron
- a tiny amount of vitamin A
Magnesium is the most important of these co-factors. In fact, it is common for rising vitamin D levels to exacerbate an underlying magnesium deficiency. If one is having problems supplementing with vitamin D, a magnesium deficiency could be the reason why.
Read more about vitamin D's co-factors.

