Vitamin D is a hot topic, yet many folks still don’t understand it very well. According to the best and most current research, in fact, vitamin D is not really a vitamin.

As the website VitaminDCouncil.org explains, its true classification is as a prohormone—a substance that can be converted to a hormone—and it works by maturing, or turning on, genes. It is the key that unlocks binding sites on the human genome, triggering stem cells to stop dividing, complete their natural function and then die naturally. Every tissue in the body has stem cells that depend on vitamin D to function properly, and every living cell on this planet uses vitamin D in this fashion, even plankton.

Vital for Whole Body, Not Just Bones

Evidence is mounting that vitamin D is more vital to many bodily functions than was previously known. According to studies done by the Intermountain Medical Center Heart Institute and a research review published in Metabolism in 2011, higher levels of D in the blood can lower blood pressure and may double the chance of survival of a heart attack. One study of bone health found lower cancer rates among those supplementing with D. A study published in Neurology found that higher vitamin D levels and sun exposure were directly linked with a lower risk of early multiple sclerosis. Other studies have found positive impacts and reduced risks for diseases such as asthma, Alzheimer’s disease, diabetes and premature births.

Humans make vitamin D when they get enough UVB radiation. For example, 20-year-old Caucasians make about 20,000 international units (IU) of D in 20 minutes of sunshine on June 20 (the peak of summer), which comes out to 1,000 IU per minute. Once produced, D is stored in fat tissue and has a half-life of about one month.

The threshold level of vitamin D necessary to prevent dysfunction in the body had been based originally upon what was necessary to prevent rickets, the epidemic that prompted the addition of vitamin D to milk in the early 1900s. That number stuck for many years. However, based upon a 2008 report in Science, we now know that a higher level of D is necessary for the body to produce the natural germ killer, cathelicidin, which cleans up bacteria and viruses. This happens because vitamin D enables immature white cells to become mature and function optimally, just as it does all other cells.

With sufficient sun exposure, the body maxes out at an optimum level of 60 nanograms (ng) of D per milliliter of blood. For those of us that wear clothes, stay indoors, have pigmented skin and are older, supplementation may be necessary to get even adequate blood levels of 40 ng.

Wisconsin’s Vitamin D Deficiency Epidemic

Leading vitamin D researchers are reporting that folks with more skin pigment and the elderly produce less D and many have inadequate levels. By age 70, you will make a quarter of what you did at age 20. Very dark Africans take six times the sun exposure to make the same amount of D as Caucasians. In Milwaukee, vitamin D rates decline in winter, because the angle of the sun gets too low to get any effective UVB radiation from about October 1 to April 1, not to mention that we wear more clothing and avoid being outside in cold months. In a 2007 report, scientists at University of Wisconsin called Wisconsin’s low vitamin D status “epidemic.”

The Institute of Medicine last year, with bone specialists on its committee, stated that most adults should have at least 600 to 800 IU a day for bone health. The American Society of Endocrinology suggested that individuals should take higher doses if necessary to reach a blood level of at least 40 ng.

Based upon the research I’ve seen, I believe most people are deficient and need a loading dose in the range of 300,000 IU over the course of a month. If most Milwaukeans were to start at 5,000 IU a day, it would take them a year to get to a steady, sufficient blood level. A doctor might well prescribe 10,000 IU per day for a month, or 50,000 IU per week for 12 weeks. To be healthy, it is important to discover the D level in your blood and to work with a knowledgeable doctor to establish what you need and to stick with it for life.

Dr. John Whitcomb is a medical doctor board certified in anti-aging and regenerative medicine. He owns the Brookfield Longevity and Healthy Aging Clinic, located at 17585 W. North Ave., Ste. #160, in Brookfield. For more information, call 262-784-5300 or visit LiveLongMD.com.