People often ask me what I personally do in terms of maintaining adequate vitamin D status. In short, my regimen is a combination of UV light exposure and oral supplementation, depending on the season of the year. Natural philosophy and modern practicality underlie the reasons for my personal regimen.
First, I strive to keep my 25(OH)D in the midpoint of the reference range at around 60 ng/ml. I know of no evidence that 80 ng/ml is better than 60 ng/ml. In fact, I know of no evidence that 60 ng/ml is better than 40 ng/ml. However, the occasional inaccuracies of blood testing, my innate conservative nature, and the simple common sense of being in the midpoint of the reference range are my rationales for maintaining my level around 60 ng/ml.
The second aspect of my personal regimen is that I am loath to avoid the sun. I believe, and numerous studies show, that sunlight does more for humans than simply raise their vitamin D levels. For example, bright light favorably affects mood and melatonin, while UV light increases endorphin production and triggers the body to produce numerous vitamin D-like compounds.
I seriously doubt science has exhausted this list of benefits. For that reason, in the warmer months, I try to get in a short sunbath once a week, being careful to cover my face and hands, and being careful never to burn. On the weeks I cannot sunbathe, I take 5,000 IU/day of vitamin D.
In the colder months, I usually simply take 5,000 IU/day, but I also try to get UV light on my skin by using the D Lite system (a sponsor of the Council) that I have on a wall in my office, or by going to a sun tanning parlor and using the older low-pressure sunbeds, at least once a month. My reasoning for occasionally using an artificial UV light source in the colder months is simple: nature designed the skin to meet UV light. Just like in the summer, I cover my face and hands, the areas where skin cancers are the most common, and I am very careful never to burn my skin. I take no vitamin D the week after I use a UV light source.
I think it is dangerous to completely avoid intense UV light and simply take vitamin D; which is a way of saying that vitamin D is the only good thing the sun does for you. In fact, a recent animal study confirmed that UV light, not vitamin D, worked the best in an animal model of multiple sclerosis. Furthermore, keep in mind that all the studies of latitude and UV intensity and most studies of 25(OH)D levels (most of which show the benefits of vitamin D) are mostly studies of UV light exposure.
Finally, I go to my dermatologist once every year for an examination of my skin. He is always amazed when I am happy if he finds a solar keratosis, or even a small non-melanoma skin cancer. I know that studies from the 1930s show those who have such skin lesions are less likely to develop internal cancers.