Vitamin D – The Under-appreciated Vitamin
Vitamin D, underappreciated by the general public (not to mention the medical profession), it is one of the most common nutritional deficiencies; it really possesses hormone-like activity and is believed to regulate the expression of over 2,000 genes, making its function the most widespread of any essential nutrient.
Most people associate Vitamin D with the childhood disease rickets, or soft weak bones. Some people know that Vitamin D is needed for optimal calcium absorption and that it is the “Sunshine Vitamin”. Most people are unaware that Vitamin D deficiency, with a multitude of adverse consequences, is the most widespread vitamin deficiency in this country.
Vitamin D3 (cholecalciferol) is produced in the skin from exposure to Ultraviolet B. Vitamin D3 is made in the skin when 7-dehydrocholesterol (Yes- Vitamin D is produced from cholesterol), reacts with UVB, present in sunlight daily at tropical latitudes , but only during the spring and summer seasons in temperate regions, and almost never at higher arctic and sub-arctic latitudes; including the northern United States. This is because the UVB radiation is filtered out by the atmosphere due to the low elevation of the sun in the sky. Adequate amounts of vitamin D3 can be made in the skin after only ten to fifteen minutes of sun exposure at least two times per week to the face, arms, hands, or back without sunscreen. With longer exposure to UVB rays, equilibrium is reached in the skin, and the vitamin simply degrades as fast as it is generated. The skin produces approximately 10,000 IU vitamin D in response to 20–30 minutes summer sun exposure. This is an amazing 50 times more than the US government’s recommendation of 200 IU per day! If nothing else this should tell you that the RDA is ridiculously low.
Vitamin D is a prohormone, meaning that it has no hormone activity itself, but is converted to the active hormone 1, 25-D (calcitrol) in the liver and kidneys. Calcitrol is actually a secosteroid hormone that targets over 2000 genes (about 10% of the human genome). Current research indicates that Vitamin D deficiency is a major factor in at least 17 varieties of cancer as well as heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects, periodontal disease, and more.
What is the prevalence of Vitamin D deficiency? One recent inner city study showed that 25% of the participants were overtly deficient and that a significant portion had well below optimal blood levels. Are you Vitamin D Deficient? Good Question! There is no way to know for certain until you get a 25-hydroxyvitamin D test, also called 25(OH)D. Optimal levels are between 50-80 ng/ml year-round, in both children and adults. Deficiency is defined as levels below 25ng/ml. Researchers have found that the body does not reliably begin storing cholecalciferol in fat and muscle tissue until its blood levels get above 50 ng/ml. That is, at levels below 50 ng/ml, the body uses up vitamin D as fast as you can make it, or takes it, meaning that you have less than optimal levels.
What are the chances you are Vitamin D deficient? If you don’t get your skin exposed to 20-30 minutes of sunlight at least twice per week, if you work indoors, wear sunscreen, live in northern regions or if you are of a race other than Caucasian (dark skin does not allow for penetration of UVB radiation as well) you probably have sub-optimal levels.
What are some of the consequences of Vitamin D deficiency? Osteoporosis, heart disease, hypertension, autoimmune diseases, certain cancers, depression, chronic fatigue, and chronic are some of the conditions associated with deficiency.
How can you get tested for Vitamin D deficiency? You could try asking your primary care physician. Good luck with that, since most seem unaware of the prevalence or severity of deficiency. You will love this- Medicare will no longer pay for your doctor to check you for deficiency, but should you have one they will cover the cost of treatment (which is very inexpensive). Talk about a Catch-22! Typical of our health care system to not prevent a whole host of diseases with an inexpensive remedy, but to cost taxpayers thousands of dollars once the disease develops.
How can you make sure you get enough Vitamin D? There are 3 ways: regularly receive midday sun exposure in the late spring, summer, and early fall, exposing as much of the skin as possible, regularly use a sun bed (avoiding sunburn) during the colder months or take supplemental Vitamin D for three months, then obtain a 25(OH)D test. Adjust your dosage so that blood levels are between 50–80 ng/ml.