Mortality maps for diseases related to Vitamin D show a strong correlation with the amount of environmental ultraviolet B (UVB) available from natural sunlight. Those living at higher latitudes receive less natural UVB and therefore have greater risk. During the winter months, regions such as Canada and Northern Europe receive practically zero UVB. This is because the sun’s rays strike the earth at a more shallow angle, geometrically causing the rays to travel a longer path through the earth’s atmosphere and ozone, filtering out nearly all of the UVB. Consequently, most people living far away from the equator have the lowest amount of Vitamin D at the end of the winter, after months of depletion. The risk of Vitamin D deficiency is compounded for those with dark skin because their skin pigment acts like a filter, reducing the amount of UVB delivered to the biologically active skin beneath. Black skin can require five to ten times longer UVB exposure to create the same amount of cutaneous (in the skin) Vitamin D as a white person. Other groups with greater risk of Vitamin D deficiency include: all people over the age of 50 because Vitamin D absorption decreases with age, people in religious groups that keep fully clothed for all outdoor activities, and obese people because their excess fat retains their Vitamin D.

A human can use 1000 (Holick) to 3600 (Heaney 2003) International Units (IU) of Vitamin D per day, so there is a need for constant intake to maintain the target concentration. If UVB is not available, the only other options are to get Vitamin D orally, or for the most severe cases, by needle. Food provides only a limited amount of the daily requirement, for example in Canada, milk has only 100 IUs per 250 ml glass. Oral Vitamin D dosing suggestions are seasonal and range from; 400 IU/day for those over 50 years of age per Canada’s Food Guide, 1000 IU/day year-round per the Canadian Cancer Society, and up to 2000 and 4000 IU/day depending on risk factors per other organizations.

The only method to determine Vitamin D status is by a blood test for precursor Vitamin D known as any of: “25-hydroxy-Vitamin-D” “25(OH)D” “25D” or “Calcidiol”. (IMPORTANT: This is not to be confused with a similarly named test for activated Vitamin D known as any of: “1,25-dihydroxyVitamin-D” “1,25(OH)2D3” “1,25D3” or “Calcitriol”). 25-hydroxy-Vitamin D tests are available in Canada at LifeLabs, but a physician’s requisition is required, and full or partial payment by the patient. The ideal concentration of calcidiol has not been established. Various sources suggest 35–70 nanograms per millilitre of blood (ng/mL), and ideally more than 50. Periodic Vitamin D blood tests are needed to determine current status, the effectiveness of previous actions taken, and your action plan for the future. Other methods to quantify efficacy might be to perform an ultrasonic bone density test. This can be done on the heel of the foot, using a device such as the McCue C.U.B.A. This test may be particularly informative for those in risk of osteoporosis and osteomalacia, such as post-menopausal women.

If most of a person’s skin area is exposed to UVB light, and the skin receives enough UVB such that it gets just under the state of mild sunburn, known as “suberythema” or one Minimal Erythema Dose (1 MED), it can produce the equivalent of up to 25,000 IU of oral Vitamin D (Holick). However, it is not advisable to regularly take 1 MED because that dose is too close to burning (erythema), and such a large dose is not necessary if instead regular lower doses are taken; but this does show that getting Vitamin D using UVB light is much more effective than getting Vitamin D through diet or supplements. Erythema is undesirable because it causes patient discomfort, is a risk factor for skin cancer, and dosing beyond erythema does not produce any additional Vitamin D. By irradiating a larger area of skin, a lower dose per unit area can be taken to create the same amount of Vitamin D, thus maximizing Vitamin D production while minimizing the risk of adverse effects. Or, in other words, the risk is minimized by spreading it over a larger area. Alternatively, if a small phototherapy device is used, treatments can be taken on different parts of the body on alternate days. If the device used includes significant quantities of UVA light (such as a commercial tanning machine and some UV products marketed for Vitamin D), skin tanning usually occurs, which acts as a UVB filter and results in longer treatment times to achieve the same Vitamin D production, while needlessly exposing the patient to UVA light. If some areas of the body have received significant amounts of cumulative UV during a patient’s lifetime; such as the face/head, forearms, chest and shoulders/upper back, etc.; it is sensible to exclude these skin areas from further UV exposure. Conversely, using skin areas that have received very little cumulative UVB during a patient’s lifetime are the best sites to use, such as the buttocks. 

Depending on geographic latitude, most people should be able to maintain proper Vitamin D levels by judicious use of natural sunlight (short mid-day exposures without sunscreen), as well as food and supplements; adjusted for the seasonality of naturally occurring UVB in sunlight. The greatest single warning when using natural sunlight is sunburns. Moderation – DON’T GET BURNED, because sunburns are painful and a risk factor for skin cancer. It is much better to take 10 minutes per day for a week than 70 minutes in one session. There is some excellent guidance for using natural sunlight for Vitamin D in chapter 7 of Dr. Holick’s book: “The UV Advantage“. Some people, however, are not capable of absorbing the necessary amount of Vitamin D orally. Malabsorption problems are likely to occur in people with crohn’s disease, kidney/liver disease, gastric bypass surgery, bowel resection, cystic fibrosis and cholestatic liver disease. These patients might consider use of a UVB phototherapy device, which has the advantage that the UVB dose can be closely controlled, always available and repeatable. Natural UVB from sunlight, on the other hand, is subject to many variables including: distance from the equator, time-of-year, time-of-day, and cloud cover; thus making it more difficult to optimize Vitamin D production, and exposing the patient to increased risk of sunburn, should they ever underestimate the sun’s skin burning potential. Natural light contains UVB and UVA, but only the UVB wavelengths (up to ~315 nm) contribute to Vitamin D production. UVA serves primarily to induce tanning, with a minor contribution to erythema (burning). Sunscreen lotions are formulated to block both UVA and UVB. Here is a recent talk Dr. Holick gave at the Boston University Medical Center.  

The objective with UVB phototherapy for Vitamin D production is generally the same as that for skin disorders: to take only enough UVB to first correct the underlying problem, then to minimize dose and frequency to maintain that healthy state in balance. For example, at the start of UVB phototherapy for psoriasis, treatments are taken 3 to 5 times per week while the dose increased progressively to avoid sunburn. Then, once significant clearing is achieved, dose and frequency can usually be reduced and maintained in balance indefinitely, usually using UVB doses much less than the maximum (Haykal & DesGroseilliers 2006, Walters 1999). It is reasonable to expect the same result for restoration of Vitamin D levels, with regular Vitamin D blood tests used to confirm progress. Solarc’s UVB devices are provided with a User’s Manual that contains detailed exposure guidelines based on skin type (dark skin or light skin), device power, and waveband type. Please also request the SolRx “Vitamin D User’s Manual Supplement”.

There are three main candidate fluorescent ultraviolet lamp waveband types for Vitamin D, but it is important to remember that only UVB produces Vitamin D in the skin:

• UVA Cosmetic Tanning Lamps. As found in tanning salons worldwide. These lamps produce no more than about 5% UVB, with the remainder being potentially harmful UVA.
• UVB Broadband Lamps. In use for at least 60 years for the medical treatment of psoriasis, but now being used far less often in favor of UVB-Narrowband lamps.
• UVB Narrowband Lamps. The gold standard for medical treatment of skin disorders such as Psoriasis, Vitiligo and Eczema. Nearly all SolRx devices use UVB-Narrowband lamps (Philips /01 311 nm).

All of these lamps will produce Vitamin D, but as with the treatment of skin disorders, UVB-Narrowband is almost certainly the best choice. For a detailed study of this subject, please keep reading below.

In Canada, all of Solarc’s UVB devices (UVB-Narrowband and UVB-Broadband) have received Health Canada approval to add “Vitamin D Deficiency” to the “Indications of Use” on July 21, 2008 per Health Canada Device Licence #12783. This includes the SolRx E-Series, 1000-Series, 500-Series, and 100-Series. In the USA, using the FDA’s 510(k) process, Solarc failed in its attempt to get “Vitamin D Deficiency” added to the “Indications for Use”, because no comparable “predicate” (pre-existing) device existed, and to obtain approval would have required a severely cost prohibitive Premarket Approval “PMA” application. Solarc is therefore not permitted to promote SolRx devices for “Vitamin D Deficiency” in the USA; and instead only for the approved “Indications for Use” of psoriasis, vitiligo and eczema. In this context, “Vitamin D Deficiency” is considered to be an “off-label” use, but a physician can still request information regarding that off-label use, and the physician is legally permitted to write a prescription for the patient to obtain the product. This concept is known as the “practice of medicine”, which means that a physician can prescribe or administer any legally marketed product for any off-label use that they deem to be in the best interest of the patient. The same holds true for the many other skin disorders that UVB is also used to treat.

A Vitamin D phototherapy treatment typically begins with a shower or bath (which sheds dead skin that would otherwise block some of the UVB light, and removes any foreign material on the skin that might result in an adverse reaction), followed immediately by the UVB light treatment, and then, if necessary, the application of any moisturizers. During treatment, the patient must always wear the UV protective goggles supplied and unless affected, males should cover both their penis and scrotum using a sock. Treatments are typically 3 to 5 times per week, with every second day being ideal for many patients. A significant increase in Vitamin D can be expected in 4 to 12 weeks, after which treatment times and frequency can be reduced and Vitamin D blood levels maintained indefinitely, even for decades. For further information regarding the use of a Solarc UVB device to treat Vitamin D deficiency, please read our Vitamin D User’s Manual Supplement (pdf).

Vitamin D toxicity (hypervitaminosis D) is possible when [25(OH)D] levels reach approximately up to about ~200 ng/ml. Vitamin D toxicity has not been observed to result from exposure to natural sunlight because the skin stops making Vitamin D once erythema (sunburn) is reached. Further exposure does not create more Vitamin D, thereby automatically preventing Vitamin D toxicity. However, Vitamin D toxicity is possible by taking chronic daily excessive amounts of Vitamin D orally, in the order of 40,000 IU/day or more; or theoretically in lesser amounts if combined with significant UVB skin exposure. Vitamin D toxicity has also been observed in a few patients using UVB-Broadband and UVB-Narrowband devices. This emphasizes the need for regular Vitamin D tests, and especially for those taking high UVB doses and/or supplements over a long period of time.

There are several ways that Vitamin D is linked to psoriasis:

• The action spectrum for psoriasis corresponds to the best wavelengths for Vitamin D production.
• Patients beginning UVB phototherapy for psoriasis are also typically Vitamin D deficient.
• The popular psoriasis topical drug, Calcipotriol (trade name: Dovonex^®), is a Vitamin D derivative. This suggests that psoriasis patients especially should be following suggestions for Vitamin D supplementation. One wonders how many psoriasis patients were simply Vitamin D deficient before getting the disease?

To learn more, there are many medical abstracts on this subject at: PubMed

Considering that primates have been evolving for some 85 million years, and humans for a couple million years, all while living in an environment awash with natural ultraviolet light from the sun, it is reasonable that we have developed ways to use UV beneficially (Vitamin D production), and a means to prevent overexposure (tanning). As some humans migrated away from the equatorial regions of Africa, the skin lightened to compensate for less UVB exposure. With reduced pigment filtering, more Vitamin D could be produced for a given amount of UVB, which could be very limited for regions such as Scandinavia. Then in recent history, at about the time of the industrial revolution, people began to spend more time indoors, and were more fully clothed when going outdoors. Nowadays, we are even more protected from the sun, with many working in buildings all day, dire warnings from some to avoid any UV exposure whatsoever, and now even many cosmetics for daily use including a sun block; with the overriding concern being increased risk of skin cancer. It has been suggested that the virtual elimination of UVB exposure for a large number of people, especially in regions far away from the equator, has created a health crisis in the form of Vitamin D deficiency and its many associated diseases. This has occurred in a relatively infinitesimal amount of time, leaving no time for an evolutionary correction.

If humans need Vitamin D, then it is logical to think that animals with fur also need Vitamin D. They do, but how can they do this if their fur blocks light? The answer is that they make Vitamin D in their fur (or feathers in the case of birds) and in the action of grooming themselves, they lick the nutrient from their fur and ingest it orally. It is interesting to note that Vitamin D tablets are made from defatted lamb’s wool that is exposed to UVB and then purified.