It has long been accepted by the scientific community that Vitamin D, also known as the "sun vitamin" or "sunshine vitamin", plays an important role in muscle strength, bone formation, regulation of cell growth and reducing the risk of autoimmune diseases.
Yet, it is estimated that 30-50% of the U.S. population is either Vitamin D insufficient or deficient. Low levels of Vitamin D in the blood have been associated with cardiovascular disease, respiratory disease, diabetes, multiple sclerosis, rheumatoid arthritis, periodontal disease, rickets, obesity and other diseases, medical disorders and conditions. Deficiencies in Vitamin D have also been linked to certain types of cancer.
Numerous ecological, observational and laboratory studies, as well as controlled trials, indicate that adequate levels of Vitamin D reduces the risk of many types of cancers, most notably breast, colon and rectal cancer. Scientific evidence also suggests that Vitamin D protects against many other types of cancers, including cancer of the bladder, prostate, kidneys, stomach and esophagus.
Vitamin D is converted in the liver to a prehormone called calcidiol. Calcidiol may then be converted in the immune system or in the kidneys into calcitriol. When it is converted in the immune system, it acts like a cytokine. Cytokines aid in regulating the body's responses to infections and/or diseases by interacting with the cells of the immune system. When calcidiol is converted into calcitriol by the kidneys, it becomes the biologically active form of Vitamin D and acts like a hormone in regulating various functions, including the concentration of calcium and phosphate in the bloodstream.
Calcitriol is widely recognized by the medical community to be a potent anti-proliferative agent. In other words, calcitriol is believed to slow the proliferation (the spread or growth) of various malignant cells by limiting the blood supply to the tumor cells and inhibiting their motility. Additionally, calcitriol is associated with inducing the apoptosis (death or suicide) of cancer cells.
Unfortunately, many of us have insufficient (or even deficient) levels of Vitamin D in our blood to benefit from the vitamin's cancer protection, inhibition and fighting properties. This is partly so because it is present only in a limited number of foods - primarily in oily, fatty fish such as salmon, tuna and mackerel. And, although we can obtain Vitamin D from exposure to the sun, many of us spend much of our time indoors, use topical sun-blocks and/or live in locations where we have limited or only seasonal access to the UVB (ultraviolet B) portion of the sun's rays. It is the UVB band of the sun's ultraviolet spectrum that allows our bodies to produce Vitamin D.
Therefore, in order to ensure that we have adequate levels of Vitamin D, many of us may benefit from taking supplements. The Recommended Daily Allowance (RDA) established by the Food and Nutrition Board (FNB) of the National Academy of Sciences (NAS) for Vitamin D is currently 400 IUS (10 mcg) for infants aged 0 to12 months, 600 IU (or 15 mcg) for children, men and women (including pregnant and lactating women) aged 1 to 50 years and 800 IU (20 mcg) for men and women aged 51 years and above.
It should be noted that Vitamin D is fat and not water soluble, and excessive amounts derived from supplements are stored in body fat. Therefore, taking large doses in the form of supplements can cause toxicity. You should always consult with your health care professional on the optimal dosage for you.
Disclaimer: Nothing in this Article is intended or should be construed as medical advice, diagnosis or treatment. All content herein is for informational purposes only. You should consult with and seek the advise of a physician or qualified health professional before taking any supplements, herbs or over-the-counter medicine; modifying, restricting or altering your food, beverage or supplement intake; starting an exercise or diet program; or making any dietary, nutritional, exercise or lifestyle changes in order to determine it is right and advisable for your individual needs.