Vitamin D has major health benefits. The best source of vitamin D is from the sun, but you also see many foods fortified with Vitamin D. Unfortunately, milk and other foods fortified with vitamin D often contain a synthetic form called ergocalciferol, or vitamin D2.
This synthetic form isn’t as potent and doesn’t last long in the body. In fact, synthetic vitamin D becomes toxic in your body at far lower levels. Too much synthetic vitamin D2 may be linked to health problems. A number of studies link synthetic vitamin D2 to irritation of the lining of blood vessels.
In fortified milk, you may not know even how much you are getting. When Dr. Michael Holick and his colleagues at the Boston University School of Medicine tested samples of milk, they found 8 out of 10 samples contained either 20 percent less or 20 percent more vitamin D than the amount the label advertised — and some of the milk tested contained no vitamin D at all.
[Source]
Chapter: Vitamins :: 20 January 2010
