Vitamin D from Sunshine: How Much is Enough? and Interactions with Vitamins C, Thiamin, and Niacin
Throughout the ages fresh air and sunshine has been associated with good health. Millions of our forbears spent their lives under conditions that ordinary folk today would consider extreme exposure to sunshine. A tiny minority of people today (e.g. roofers) spend an extreme amount of time out in the sun. OSHA has not passed any rules requiring limits to sun exposure. Even extreme sun exposure does no obvious harm. Even the impact of extreme sun exposure on the skin is controversial. Defenders of the sun claim that accelerated skin aging and higher rates of skin cancer are caused by sunburns. Common sense suggests that extreme sun exposure accelerates skin aging - we've all seen the consequences with our own eyes. No more science is needed. No one has to run a study. Again - the facts are the facts. Extreme sun exposure does what it does to the skin. OSHA (and everyone else) has reviewed the facts and exposure to sun in the workplace is not subject to any rules.
Study after study has associated increased exposure to the sun with improved average health. Increasing exposure to the sun increases the daily dose of vitamin D. So - we know with certainty that there is a dose-response realtionship between sunshine-derived vitamin D and health. Higher doses result in better average health. The relationship between vitamin D dose and health is non-linear. Complete deprivation of vitamin D causes death within less than a year. Just the tinest amount of vitamin D from the sun or food prevents death, and a tiny amount enables a normal life expectancy.
I was asked to comment on this article.
My differences from this author are in the details. A general problem I have is with the unspoken paradigm that there is an optimum daily dose. There isn't. Needs for vitamins, A, B1, B3, C, and D fluctuate with age and state of health. Vitamin D is no exception. I use vitamin D to fight off respiratory infections. When I feel I'm coming down with a cold, I take extra vitamins A, B1, B3, and C by mouth, and get extra sunshine. I've found the extra sunshine to be so obviously beneficial that I bought a sunlamp so that I can get the UVB I need at any time. When fighting off a cold, I want more sun exposure. This is just my story.
As I get more and more vitamin D from the sun, I have found myself remarkably intolerant to vitamin D supplements. In fact, I've been reacting badly even to eating large servings of salmon. One reason is that, contrary to my expectations, I am not very tan. When I have a cold, I get in the sun for about 3 minutes once an hour every hour between 10 and 2 and then use the sunlamp before bed. My perception is that I'm making more vitamin D every time I'm in the sun. The reality is that all this extra sun is not making me significantly more tan.
I simply don't understand the view that the winter sun in CT doesn't make vitamin D. A UVB meter placed in direct sunshine at noon in CT will register UVB. The more obvious trouble is the cold weather. No one wants to get into underwear equivalent clothing and get into the sun when it is so cold. This problem is straightforward to overcome. The Romans built solariums. We just don't think it is important enough. Sunlamps can also solve this problem, but I won't recommend them until more research is done about the safety of sun lamps.
I don't like vitamin D blood testing. It is a very difficult measurement and I don't trust the numbers. There is very little data and it is, in my opinion, being over interpreted. I don't understand how studies of tiny numbers of people can distract commentators from the big picture. Sunshine is essential for health and there is an obvious dose response relationship. Higher doses of sunshine result in better average health. Extreme doses of sunshine do no obvious harm. To me, the obvious conclusion is to recommend getting as much sunshine as can be practically managed. I'm also pointing out that alot of sunshine is practical, although socially unacceptable. Setting aside just one sunny day a month for sun therapy may pump up vitamin D levels alot higher than you might think - especially if you are light skinned. Even on these sun therapy days, I think just 5 minutes in underwear equivalent clothing per hour for every hour between 10 am and 2 pm will achieve a maximum daily dose of sunshine-derived vitamin D.
My final word on this is that despite an association with health, sunshine remains controversial. The body is highly sensitive to sun exposure. You can literally feel the sun - even a faint morning sun. If you stand in the sun, how you feel about it changes. Sometimes you get more comfortable - sometimes less. People "decide" how much sun they want and/or need and then it's very difficult to change their views. People "decide" they want to stay out of the sun. It's very hard to change how people feel about the sun with logic. It was proven beyond doubt and published in the early 1800s that sunshine prevent rickets. Despite this, in the 1870's there was a major rickets epidemic in northern Europe and the U.S. There was a medical industry even back in the 1870's. Their children suffered from rickets along with everyone else. It is what it is. Time and again communities of people have found it difficult to use sunshine to improve health.