Just found the attached PDF file on Sunlight and D3. There is a lot of great info in it and I decided to paste these few paragraphs to give you a feel for it.
Adams: In your research on this, how common is vitamin D deficiency in, say, the American population?
Dr. Holick: What’s really remarkable is that vitamin D deficiency is epidemic throughout the entire United States, through all age groups. And I’ll give you some examples. It’s well known that elders throughout the United States are at high risk. And upwards of 40-60% are at risk for vitamin D deficiency. But we also now realize that even younger adults that are otherwise active and who may be always wearing sunscreen before they go outdoors, or they never see the light of day because they’re working all the time. When we did a study in Boston, we found that students and doctors 18-29 years of age, at the end of the winter, 32%
were vitamin D deficient.
Adams: Wow.
Dr. Holick: More shocking, though, was that we also looked at young girls (working with Dr Sullivan and Dr Rosen in Maine) -- and these are Caucasian girls ages 9-11 - and we found that 48% were vitamin D deficient at the end of the winter. And 17% remained vitamin D deficient at the end of the summer because of wearing all the sun protection.
Adams: Now that’s even more shocking, it’s obviously a chronic deficiency.
Dr. Holick: But here’s even a bigger shock. I had been concerned, and others had been concerned as well, that if you’re not exposed to any sunlight or if you have very deep skin pigmentation, that you need 1000 international units of vitamin D to satisfy your body’s requirements. And so we reasoned that probably women during pregnancy, even though they’re taking their prenatal vitamins that contain 400 units of vitamin D, they’re only getting 40% of what they need. So we did a study at our hospital, and we looked at women coming in and giving birth, and we measured their vitamin D levels -- their 25-hydroxy vitamin D levels,
and the infants’ 25-hydroxy vitamin D levels at birth. 49 infant-mother pairs were looked at, mostly African-American and Hispanic but some Caucasian as well. 76% of mothers were severely vitamin D deficient. 81% of infants were severely vitamin D deficient.
Adams: That’s astonishing.
Dr. Holick: And so, what we’re now becoming more concerned about, me and many of the experts, is that infants that are vitamin D deficient at birth can remain vitamin D deficient for the first several months after birth, it may put them at risk of developing many chronic diseases later in life, including type 1 diabetes, rheumatoid arthritis, multiple sclerosis, as well as many of the common cancers of the breast, colon and prostate.