UVR-Induced Vitamin D:
The Elephant Sitting In The Living Room—Part II

by Patricia E. Reykdal and Donald L. Smith

This is the second in a series of articles that discuss the what, where, when, how and why reasons that vitamin D is so important to the health and welfare of Americans. The first installment showed that cancer, diabetes, multiple sclerosis, coronary heart disease, rickets and osteoporosis are all diseases “mediated”by vitamin D.

It also addressed the fact that the dermatology community advises the public to practice sun avoidance and slather on sunscreen every day of the year, regardless of the time of day or season, and that this advice is a major factor contributing to the pandemic of diseases associated with suboptimal blood levels of vitamin D. The article stated that anyone advocating anything (sun avoidance, inappropriate sunscreen use, banning teenagers from tanning, regulations, etc.) that causes the North American public to avoid sensible, moderate and responsible UVR exposure is, de facto, advocating increasing the incidence and mortality of diseases like cancer, diabetes, multiple sclerosis, coronary heart disease and osteoporosis. Turn to page 46 of the June issue to see the article or log on to www.lookingfit.com. 

This second installment addresses how much vitamin D is necessary for optimal health, where to get vitamin D, the recommended dosage, maintaining optimal vitamin D blood levels for specific periods of life and much more. 

Before we can answer this, we first must answer a more important question of what blood level of vitamin D (25-hydroxy) is necessary for humans to attain and maintain year-round for optimal health? It previously was thought that 50 nmol/L was adequate for maintaining bone health. However, a group of vitamin D experts recently recommended adopting a target level of 70-80 nmol/L.

We now know that the maintenance of bone health is not the only function of vitamin D. In fact, a substantial body of scientific evidence shows that the cellular regulation and signaling functions of vitamin D are important for our total health and well-being. Therefore, we believe that a vitamin D blood level of 150 nmol/L (140-160) is required in order to maintain optimal health.

We recommend that a blood level of 150 nmol/L (140-160) of vitamin D be adopted as the “target level” because 1) studies of lifeguards and outdoor workers who all attained and maintained this level after a few weeks of summer sunlight exposure and 2) studies showing that while bone health only may require 75-80 nmol/L, vitamin D-mediated diseases require a higher level because the incidence of the disease decreases as the blood level of vitamin D increases.

Therefore, attaining and maintaining the same level of vitamin D we “naturally” will attain and maintain when we have daily exposure to summer levels of ultraviolet radiation is necessary for optimal health and well-being.

The American Academy of Dermatology Web site states: “Get vitamin D safely through a healthy diet that includes vitamin supplements. Don’t seek the sun.” However, compelling evidence shows this advice is deadly wrong.

Several recent studies show that we cannot get enough vitamin D from our diets—even by ingesting vitamin D-supplemented products like milk to attain and maintain an optimal blood level of vitamin D. Moreover, although it is possible to attain and maintain a blood level of 150 nmol/L by using vitamin D supplements, doing so is not easy or safe.

Consider that it takes a daily ingestion of 6,000-10,000 IU (International Units) of vitamin D to attain and maintain the 150 nmol/L level. However, only 2,000 IU capsules are approved for use in the United States without a prescription (only 1,000 IU capsules are approved for use in Canada). Although several studies have shown that high doses (6,000-10,000 IU) can be tolerated safely, the “consensus opinion” is that no more than 2,000 IUs should be taken daily (1,000 IU in Canada). The U.S.

Department of Agriculture’s (USDA) recommended daily allowance is only 400 IU for most age groups. Thus, neither diet nor supplements can be relied upon to attain/maintain an optimal (150 nmol/L) blood level of vitamin D for the average North American citizen.

Sensible, moderate and responsible exposure to UVR, on the other hand, especially in the controlled environment of an indoor tanning salon, can be relied upon to safely and effectively stimulate an optimal blood level of vitamin D (150 nmol/L). [Note: there has never been a toxic reaction reported for UVR-induced vitamin D.]

After several weeks of researching our library of scientific articles, we found three mistakes that led to the erroneous belief that only 5 to 10 minutes of sunlight exposure to the face and hands two or three times a week was sufficient to attain and maintain an adequate blood level of vitamin D.

• Mistake 1. Although it should have been obvious, it was overlooked that sunlight cannot irradiate both sides of the body at the same time. For example, a 360-degree HID/high-pressure sunbed irradiates the entire surface of the body while a 180- degree mattress HID/high-pressure unit requires the client “turn over” halfway through the session in order to irradiate both sides of the body. While it may only take 8 to10 minutes of whole-body exposure in a 360-degree HID/high-pressure unit to stimulate the minimal required dose of vitamin D-effective photons, it would take 16 to 20 minutes for a 180-degree mattress HID/high-pressure unit to deliver the same dose. The same thing is true for sunlight. Therefore, somewhere along the line it was overlooked that sunlight only irradiates one side of the body at a time and takes twice as long for sunlight (or a mattress HID/high-pressure unit) to stimulate the same dose of vitamin D-effective photons that it would take a 360-degree HID/high-pressure unit to stimulate.
• Mistake 2. A paper by Matsuoka, et al, titled “In Vivo Threshold For Cutaneous Synthesis Of Vitamin D3” defined the minimal dose of whole-body UVR exposure that was required to stimulate the cutaneous production of vitamin D. However, the irradiance source used in this study was the FS Series sunlamp in a 360-degree vertical booth that had 60 percent UVB and takes only 1.8 minutes (0.9 minutes per side) to emit the minimal required dose (21 mJ/cm^2) of vitamin D-effective photons. Sunlight, at noon on a typical Midwestern summer day, has virtually no energy below 300 nanometers and only 5.1 percent UVB and takes 22.4 minutes (11.2 minutes per side) of whole-body exposure and 52 minutes (26 minutes per side) of face and hand exposure to emit the same minimal dose of vitamin D-effective photons. So, it takes 12.3 times longer for whole-body sunlight exposure and 29.7 times longer for face and hand exposure to stimulate the same minimal required dose of vitamin D-effective photon than it did for the FS Series sunlamps.
• Mistake 3. Although the dermatology community usually mentions that it takes longer for people with darker skin types to stimulate the same amount of vitamin D, the time required is rarely mentioned. The graph on the following page shows this important relationship it takes an “average” North American citizen 32.9 minutes (per side) of whole-body exposure and 76.9 minutes (per side) of face and hand exposure to sunlight on a typical Midwestern summer day to deliver the minimal required dose of vitamin D-effective photons.

The bottom line is that for a skin subtype 2A, it takes 22.4 minutes (11.2 minutes per side) of whole-body exposure or 52 minutes (26 minutes per side) of face and hand exposure—not 5 to 10 minutes of face and hand exposure to sunlight on a typical Midwestern summer day to stimulate the minimal required dose of vitamin D-effective photons. Therefore, 5 to10 minutes of face and hand exposure can be seen to be woefully inadequate for a skin subtype 2A, and it takes much longer for darker skin types/subtypes.

Maintaining Optimal Vitamin D Blood Levels At Different Ages Or Life Situations

We need to maintain optimal vitamin D blood levels (150 nmol/L) throughout our lifetime; however, there are several periods when maintenance of this level is especially critical.

First of all, sub-optimal vitamin D blood levels in the mother during the prenatal period can adversely imprint the baby and make it more susceptible to vitamin D-mediated diseases like cancer, diabetes, multiple sclerosis, coronary heart diseases, rickets and osteoporosis later in life. Therefore, common sense dictates that women of child-bearing age should make absolutely certain that they maintain optimal (150 nmol/L) vitamin D blood levels prior to and during their pregnancies. The next critical period occurs during adolescence when bone growth is most pronounced.

These two periods of life illustrate why the strident campaign by the dermatology community to encourage adolescents and women of child-bearing age to avoid any and all sensible, moderate and responsible exposure to UVR can be seen to be completely wrong and counterproductive. Moreover, the support given by the media and regulatory agencies for the dermatologists’ UVR-avoidance message make them as responsible for this deadly wrong advice as the dermatology community.

The only way that North American citizens safely can attain and maintain a blood level of 150 nmol/L of vitamin D is to utilize sensible, moderate and responsible exposure to UVR, eat a balanced diet and take a 1,000-2,000 IU supplement daily.

It takes 22.4 minutes (11.2 minutes per side) of whole-body sunlight exposure on a typical Midwestern summer day two or three times per week for a skin subtype 2A to attain/maintain this level. Since sunlight is an uncontrolled and unreliable source of vitamin D-effective photons year-round, the use of a controlled, consistent, convenient and cost-effective sunbed for 8 to 10 minutes per session, two or three times per week year-round, would allow North American citizens to attain and maintain the same level.

The dermatology community’s message to avoid UVR and slather on a sunscreen every day no matter the time of day or season has caused millions of North American citizens to become unnecessarily afraid of UVR exposure. The result is a pandemic of diseases like cancer, diabetes, multiple sclerosis, coronary heart disease, rickets and osteoporosis that are “mediated” by vitamin D. Tragically, this message has resulted in the unintended adverse consequences of 150 to 200 deaths due to the adverse affects of underexposure to UVR for every one death due to the adverse effects of overexposure to UVR every year.

The third installment of this series will go right to the heart of the argument used by the dermatology community—that UVR induces Cutaneous Malignant Melanoma (CMM). Once this message is shown to be false, deceptive and misleading the dermatology community message no longer will be accepted at face value by the North American public, media and regulatory agencies. It is our opinion that it is only a matter of time before the recent class-action lawsuit against the leading sunscreen companies for disseminating incomplete information will be expanded to include the American Academy of Dermatology.

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