For the same reason that the conventional energy industry has not harnessed the full potential of solar energy (its free!), sunlight and its indispensable byproduct in our skin: vitamin D, represents a serious threat to the medical establishment, whose questionable and aggressive promotion of vaccination and drug-based strategies in place of inexpensive, safe and effective vitamin D supplementation (or better, carefully meted out recreation and sunlight exposure) for immunity, has many questioning their motives.
Vitamin D, after all, has a vital preventive role to play in hundreds of conditions, due to the fact that 1 in every 10 genes in the human body depends on adequate quantities of this gene-regulatory hormone to function optimally. In other words, the very genetic/epigenetic infrastructure of our health would fall apart without adequate levels.
Even the risk for developing cancer, one of the most feared health conditions of our time -- and the one the medical establishment has had the least success preventing and treating -- is intimately connected to your vitamin D status.
Indeed, a groundbreaking new meta-analysis on the sunlight - vitamin D connection, published in the journal Anticancer Research and based on data from over 100 countries, found that "a strong inverse correlations with solar UVB for 15 types of cancer," with weaker, though still significant evidence for the protective role of sunlight in 9 other cancers.
The relevant cancers were
"Bladder, breast, cervical, colon, endometrial, esophageal, gastric, lung, ovarian, pancreatic, rectal, renal, and vulvar cancer; and Hodgkin's and non-Hodgkin's lymphoma. Weaker evidence exists for nine other types of cancer: brain, gallbladder, laryngeal, oral/pharyngeal, prostate, and thyroid cancer; leukemia; melanoma; and multiple myeloma."
Sunlight exposure, after all, is essential for health from the moment we are born. Without it, for instance, infants are prone to developing neonatal jaundice. The very variation in human skin color from African, melanin-saturated dark skin, to the relatively melanin de-pigmented, Caucasian lighter-skin, is a byproduct of the offspring of our last common ancestor from Africa (as determined by mitochondrial DNA) migrating towards sunlight-impoverished higher latitudes, which began approximately 60,000 years ago.
In order to compensate for the lower availability of sunlight, the body rapidly adjusted, essentially requiring the removal of the natural "sunscreen" melanin from the skin, which interferes with vitamin D production. While a life-saving adaptation, the loss of melanin likely has adverse health effects, which include losing the ability to convert sunlight into metabolic energy, increased prevalence of Parkinson's disease (which involves de-melanization of the substantia nigra), and others effects which we will discuss in detail in a future article.
For now, it is important to point out that within the span of only 60,000 years (a nanosecond in biological time), many of the skin "color" differences among the world's human inhabitants reflect how heavily genetically-conserved was the ability of the human body to produce vitamin D.
It should also be pointed out that vitamin D is to sunlight, what ascorbic acid is to the vitamin C activity in food. In other words, sunlight likely provides a greater spectrum of therapeutic activity (when carefully meted out, preferably during solar noon) than supplemental vitamin D3, which is almost exclusively derived from UVB irradiated sheep's lanolin.
For further research, the following link reveals 50 therapeutic effects of sunlight exposure, as culled from research housed on the National Library of Medicine.