Dr. Holick: A study was done in Mass General Hospital. They found over 50% of inpatients - these are young adults, and middle aged, and older adults - were vitamin D deficient. Typically, on average, probably 50-80% of nursing home residents, 50-60% of inpatient hospital patients, and on average I would estimate, 40% of the population in the United States at large, if they're not getting some sensible sun exposure, are probably deficient in vitamin D.
Adams: And let me bring you back to the mental effects of this. What's the correlation - beyond depression, are there other areas?
Dr. Holick: Well, there's a fellow in Australia that's done a very interesting study. And what he's concluded is the possibility that if you're born during the wintertime, you're at higher risk of developing schizophrenia later in life. And during the wintertime you're more prone to vitamin D deficiency. And he's done studies in mice to show that vitamin D seems to be critically important for the development of the brain. So there is some suggestive evidence that maybe indeed vitamin D deficiency, especially in utero as well as in infancy could potentially increase that individual's risk of developing schizophrenia later in life.
Adams: Fascinating. So here's another question then. If sunlight could be bottled up and put in capsules and patented by pharmaceutical companies, how much would they charge for it?
Dr. Holick: Well, vitamin D is available pharmaceutically. And it's shocking but true that they're charging about $10 per pill for my patients.
Adams: $10 per pill?
Dr. Holick: Yes.
Adams: And that's for 1000 units?
Dr. Holick: No, that's for 50,000 units. I typically treat my patients with 50,000 units of vitamin D once a week for 8 weeks, followed by 50,000 units of vitamin D every other week. And that's a great way to fill up the vitamin D tank if it's empty, and to maintain it in its full state for the patient for the rest of his or her life.
Adams: Do you think part of the reason the health benefits of natural sunlight aren't getting a lot of attention is because there's no money in it? I mean, sunshine's free.
Dr. Holick: It certainly is a part of it. And like I said, the problem is that vitamin D deficiency has such subtle but incredibly important health implications. It's the subtlety that's the problem. I mean, when you mention the word cancer, everybody's aware of that, and everybody's aware of how serious cancer is. And so people will immediately help fund that kind of research, and promote that kind of research.
But to suggest that sensible sun exposure, making vitamin D, vitamin D probably evolved early in evolution to modulate cell growth, decrease risk of cancer, modulate your kidney to produce the blood pressure hormone renin, which regulates your blood pressure ... I mean all of those things are very subtle, you can't feel your blood pressure, and you can't feel your cells growing, but you certainly know if you have cancer. By then it's too late, what you really want to do is take preventative measures, and one of those is to make sure you're getting an adequate source of vitamin D, both from vitamin supplements and from sensible sun exposure.