Mushrooms are the only plant source which provide a natural occurring vitamin D 2 precursor, a plant sterol, ergosterol (although vitamin D3 is still the preferred form for best absorption). The Berkeley Wellness Letter learned that the Monterey Mushroom Company and Dole are producing enhanced vitamin D content in their mushrooms through exposure to ultraviolet light in the growing process, similar to how humans obtain vitamin D from exposure from the sun on the skin. Since vitamin D is a fat-soluble vitamin and usually accumulates in body fat, this makes it less available to other parts of the body. Several studies have confirmed the link between adiposity and vitamin D deficiency. Other research has identified an inverse association between vitamin D status with diabetes and metabolic syndrome. Having adequate vitamin D can improve insulin sensitivity and may assist with weight loss in those who have insulin resistance. Consequently when blood sugar is controlled adequately there is also less hunger and cravings. More and more health benefits are being revealed regarding vitamin D’s major significance related to immunity protection, including protection from various forms of cancer as well.
Most health experts are suggesting 1,000-2,000 mg. in supplemental form, (preferably vitamin D3) if you are not in the sun very much. I suggest being tested before ingesting larger mega doses amounts. The FDA needs a dire update in the RDA's which were established in the 1950's, in vitamin D and other nutrients as well. Most doctors, knowledgeable in nutrition, believe in at least 1,000 mg. daily for optimal health even if your levels are adequate.
