When it is nice and sunny out, I tell my kids we are heading outside for some vitamin D. My three year old thought she would get a gummi vitamin or something when we were outside. She was not humored when I said it came from the sun. She looked at me like I had five heads. I am don’t even apply sunscreen right away so the rays of health have a chance to be absorbed. As you can see I think vitamin D is very important. So. Let’s see what a doctor has to say.
Dr John Cuomo, Executive Director of Research and Development at USANA Health Sciences answers important questions on why this vitamin D is vital:
What are the main functions of vitamin D in the body?
Vitamin D appears to have many functions in the body. Every cell, regardless of where it is located has a vitamin D receptor. This would indicate that vitamin D has multiple functions and the scientific evidence backs this up. The best documentation of the importance of vitamin D is in bone health. Absorption and utilization of calcium appears to be a vitamin D controlled process. Other minerals including magnesium, boron and silicon may also depend on vitamin D to be absorbed and deposited into the bone matrix. The RDA data for vitamin D is based solely on the function for uptake and utilization of minerals for bone health. So while bone health, and prevention of osteoporosis is an extremely important function of vitamin D, it is part of what makes vitamin D important to your health. There are numerous studies showing that Vitamin D is also essential for overall immune system function and for muscle strength. Epidemiological studies also show links to glucose metabolism, cell proliferation, osteoporosis, osteomalacia, impaired muscle function, infection, autoimmune disorders, diabetes, some cancers and CVD.
What are the best natural sources?
One of the best ways to get vitamin D is to expose your skin to sunlight. 15 to 30 minutes of sun exposure between the peak hours of 10am-2pm will make thousands of IU of vitamin D. Just be careful not to burn. Dietary sources are lower. Some product such as milk and orange juice are fortified with vitamin D, but the dose is usually low and the form is different than from sun exposure. Some fish also have vitamin D but the amounts vary significantly.
Is the vitamin D in milk etc a chemically made version and, if so, does it differ (like vitamin e) from the natural source?
The story here is a little different than for vitamin E. The form of vitamin D produced in skin naturally from sunlight is cholecalciferol or vitamin D3. This is also the form used in most nutritional supplements like USANA Vitamin D tablets. Milk is fortified with vitamin D2 or ergocalciferol. While it is naturally derived, it is not the same as the D3 that we produce naturally from sun exposure. In addition there are several clinical studies on supplementation with D2 vs. D3, and it looks like D3 is more bioavailable, and a better choice.