OK, I’m going to take off my kitchen apron (currently with the logo “Kathy’s Lefse Kitchen”. Designs also available in my house have very appealing blueberries, or “Coco – Celebrating 90 years”, a loving reminder of a great family celebration) and put on my nutritionist apron, or hat, or what have you. I was thinking about Vitamin D after my sister-in-law mentioned that on a recent mole check her dermatologist recommended Vitamin D supplementation. It’s an odd juxtaposition – Vitamin D is made in our bodies from exposure to sunlight, yet exposure to sun is recommended to be avoided from a viewpoint of skin cancer.
Vitamin D also has a special place in my history, as my alma mater, the University of Wisconsin- Madison, was home to one of the great researchers for Vitamin D. Harry Steenbock invented the process for using ultraviolet radiation to add Vitamin D to milk and other foods back in the 1920’s. The library at the College of Ag and Life Sciences that I attended was named after him, so I spent many hours studying with some awareness of his name. Yet, I also spent many hours at Babcock Hall, named after another great researcher at UW who developed the Butterfat Milk Test. But rather than studying there, I could be found there eating their wonderful ice cream. (OK, this is what I did in college, contrary to all the bad publicity the UW-Madison continues to receive as a “party school”.)
Vitamin D is a fat-soluble vitamin which can provide for the body’s needs in one of two ways…through the action of sunlight on the skin, or through food sources such as cold-water fish, butter, and egg yolks. Milk in the US is supplemented with Vitamin D by law so that is a major source. When the sun shines on the skin, the ultraviolet rays activate a form of cholesterol which is present in the skin, converting it to Vitamin D. Because the body can provide sufficient Vitamin D to meet its needs simply through exposure to sunlight, some feel it is not really a vitamin, but instead is a hormone. However, the amount of Vitamin D converted through sunlight exposure varies according to the time of year, latitude and longitude that you live at, and the color of your skin. So everyone does not get the same amount.
There are good scientific studies showing that modest exposure to sunlight can be good for preventing cancer, including skin cancer, by increasing levels of Vitamin D in the body. You can get you Vitamin D needs (at least partially) through exposure of the skin to sun. Excessive exposure to the sun also in known to cause skin cancer. Oh, such irony.
In general, non-white skin requires more sun. The further north you live, the fewer UV-B rays you get. Those are the only kind of ultraviolet light that stimulates Vitamin D production. Those in the northern parts of the United States, Northern Europe, etc. probably cannot get the amount of Vitamin D they need through sunlight alone, and will always need a supplement. Those in the southern United States can probably get enough UV-B in the months May through September. For the rest of the year they will need a supplement. Those that live close to equator are the most likely to get the amount of UV-B that they need. But this is also assuming that they are outside at least two hours per day in the sun. Full spectrum sun. Take your glasses off and let it get into your eyes, it will regulate your glands. You will feel so much better.
That same old word keeps coming up over and over. Balance. Too little – problems. Too much – also problems. So it is with sunshine.