So, the last player in the Vital-Blu Series, Vitamin D3, is a bit of an enigma…its so very simple, relatively easy to make in our skin (go outside in the daytime), not expensive, but oh so critical to our very existence. Most everyone has heard that vitamin D is needed for strong bones, but far fewer know that vitamin D3 is not really a vitamin per se…its a pro-hormone, a tremendously powerful agent that actually plays a key role in regulating some 2000+ of genes in our DNA. Its effects throughout the body are many, but perhaps my favorite is its role in maintaining the tight junctions between our (epithelial) cells. If these flat inner wall cells of our vessels and organs are not butted up tightly to one another, then things can slip through the cracks. One of the most disastrous things that can wiggle through loose junctions are tumor cells. Cancer, if it remains isolated as a primary tumor, is far less deadly than cancer that metastacizes or spreads throughout the body. Metastasis virtually relies on loose junctions to move around the body. So, get adequate sunlight safely, get your vitamin D level checked (I recommend a level of 50-80 ng/dl) and take the appropriate D3 supplement to supplement the sun, especially in the non-summer months. The dose of 5,000 iu is fairly common for adults requirements. You may need more or less depending on your individual characteristics.