Sheila Fallon Friedlander, MD
Dr Friedlander reviews the many questions that face clinicians regarding vitamin
D in their pediatric patients. Patients still come in and ask and about what do regarding Vitamin D and sun protection; as dermatologists it is important to provide them with accurate and useful information.
Why do we or should we care about Vitamin D? In the 1700s, it was noted that some children had “bowed” legs. Some of them also developed tetany and laryngeospasm. This was more frequent during the industrial revolution likely due to less exposure to direct sunlight. In 1921, sunlight was found to be a treatment for Vitamin D deficiency , in1922 cod liver oil was found to be helpful and in 1925 scientists identified Vitamin D1 and Vitamin D2. The concept that has evolved over the last few years is that of Vitamin D as the “super hormone.” It is well established that Vitamin D is important for bone mineral density and bone strength and appropriate levels decrease risk for fracture. Over the last decade, several studies have demonstrated that Vitamin D may also protect us from certain types of cancer, multiple sclerosis and cardiovascular mortality; however, there is still much controversy around these studies.
How can Vitamin D do so much?
Vitamin D binds to cell surface receptors and nuclear receptors (VDR). The presence of polymorphisms in the receptor may be a reason why not all studies show the same results with the same Vitamin D levels. Vitamin D has an impact on gene expression and regulates growth and differentiation.
Vitamin D Synthesis
Vitamin D synthesis is a complicated process. The overall concept is that precursors are present on the skin surface, and when the precursors are exposed to sunlight, we get one form of Vitamin D3, cholecalciferol That is then metabolized in the liver to another form that can be measured. Finally, in the kidney, the final , active form is synthesized. This active form, 1,25-Vitamin D3, does not have a long half-life, and therefore levels of this form are not used in clinical practice.
Vitamin D Deficiency—How much?
A recent study found that 70% of children in the United States have low levels of Vitamin D. What is really a low level? This can be confusing and puzzling. as “normal” values vary depending on the expert discussing the isse and healthcare providers have no perfectly clear standards . There were also some studies that rickets may also be increasing. In a study conducted in Glasgow, the researchers looked at all children with suspected Vitamin D deficiency from 2002-2008. There were a total of 160 cases, the median age was 24 months, the majority of the patients were dark skinned and 40% of the patients presented with bowed legs. (There was one seizure). There were twice as many cases of Rickets in 2008 as in the previous six years. The question is, are people looking harder now because they are more aware?
Why are dermatologists concerned about this?
As dermatologists, we tell our patients to protect themselves from the sun; therefore, we are interfering with “the natural order” of getting sunlight. Are we putting our patients at risk with this advice? Is there really a problem?
The problem is that the ultraviolet action spectrum for Vitamin D photosynthesis is identical to that for DNA damage and skin cancer, so we cannot separate out this action spectrum.
Ultraviolet radiation from the sun is a carcinogen. It is responsible for the majority of 1.3 million cases of skin cancer in the United States every year. In animal models, ultraviolet radiation is directly related to squamous cell carcinoma, basal cell carcinoma and metastatic melanoma. The use of sunscreen decreases one’s risk of malignant melanoma. Ultraviolet radiation compromises the skin’s function and can negatively affect one’s appearance.
Sunscreen, Vitamin D & Skin Cancer
In a 2011 review by Burnett and Wang, they found that sunscreen use has little or no impact on clinically relevant Vitamin D levels. Eide et al, in 2011, showed us that an increased baseline serum 24-OH Vitamin D level was significantly associated with an increased non-melanoma skin cancer risk. Basically, the more Vitamin D people had, the more skin cancer they had.
Natural Sources of Vitamin D Other Than the Sun
It can be hard to get enough Vitamin D from food.
- Milk (but 4 glasses needed to get 400 IUs)
Not such a good idea for the lactose-intolerant
- Salmon, mackerel – but you need wild for the highest amount (600-1000 IU & $$$$)
- Shittake mushrooms
- Cod liver oil (grandma was right!)
- Could make it if you eat mushrooms & salmon a lot
Some feel that a little sun may be helpful to get the extra Vitamin D, but how much?
We know that white skin is more efficient than dark skin at “procuring” Vitamin D conversion from the sun. White skin is also more vulnerable to the bad, cancer-associated effects of the sun. How much one needs really depends from patient to patient.
So where do experts stand on this issue? In New Zealand, they feel that sun exposure depends on the time of year and UV index along with one’s skin type. In the summer months, they believe that people receive sufficient Vitamin D through incidental sun exposure outside peak UV times (11am-4pm). For skin types 1 or 2, the recommendation is 5 minutes per day to the face, hands and forearms. For skin types 5-6, the recommendation is up to 20 minutes per day. (www.dermnetnz.org) However, according to the AAD and the AAP, this is a no-go. They feel it is inappropriate to recommend intentional exposure to natural or artificial UV light in order to obtain Vitamin D. These two organizations believe the risks clearly outweigh the benefits and Vitamin D should come from diets and supplements.
So, to the rescue came supplemental Vitamin D3; however, it is still not clear how much to give, but researchers began to demonstrate the positive effects of Vitamin D3 and its potential to reduce many health risks; therefore, people began to supplement and supplement and supplement….In 2001, $40 million was spent on Vitamin D supplements, in 2009, $425 million was spent and the federal government took notice.
The government got involved and asked the Institute of Medicine (IOM) to provide some answers regarding Vitamin D:
- What health outcomes are impacted by Vitamin D levels?
- How much Vitamin D is needed for a beneficial effect?
- How much is too much?
The IOM determined that, with no sun exposure, 600 units of supplement is a good idea for just about everyone. Babies need a little less and older patients (70+) will do well with 800 units. There many experts who felt that these levels were inappropriately low. Why would the IOM be so rigid about how much Vitamin D people need?…because the risk-benefit data are not clear. The colorectal data is the most supportive; that is Vitamin D is protective. Prostate, pancreatic, and cardiovascular data is conflicting, i.e., there is data that shows an increased risk with higher doses. There is an increased risk of renal stones with modest (400mg) supplements. Some of these problems, as Dr Friedlander mentioned before, could be due to Vitamin D receptor polymorphisms. There may be a U-shaped curve of response where a little is bad, a moderate amount is good, and too much is also bad.
The IOM and Their Conservative Recommendations
We should not base recommendations on imprecise, suboptimal data. Risks are also possible with increased dose.
It is important to remember that there is data that shows an increased risk of prostate and other cancers, increased cardiovascular mortality and stones with increased doses of Vitamin D. A little Vitamin D is bad, moderate amounts is good, and too much can be bad. For now, patients should stick with 600 IU/day, unless they are considered to be in a high-risk population. This includes breast fed infants, older adults, individuals who have limited sun exposure, people with dark skin, and those with fat malabsorption. Healthcare providers should consider blood levels and higher supplemental intake for elderly adults and those with dorders putting them at risk for Vitamin D malabsorption..
- Does everyone need to be supplemented?Not a bad idea
Age IU <1 400 1-70 600 70+ 800
- Should everyone get Vitamin D levels?No, it can be expensive.
Yes, for high risk populations.
- What kind of supplement is best?
- Vitamin D3
- Is more Vitamin D better?Perhaps not
- Does Vitamin D support bone Health?Absolutely
- Does Vitamin D protect us from MS, cardiovascular disease and cancer?Evidence is imprecise, inconclusive, inconsistent and insufficient at this time
- Should I get Vitamin D from the sun?Not needed
Vitamin D “Pseudo-controversy”
Sunlight (UVR) is a known carcinogen. You can’t make Vitamin D in your skin without inducing DNA damage. Vitamin D is certainly good for you and you can get a sufficient amount with incidental sun exposure and a reasonable diet +/- supplements.
What’s a clinician to do?
- Adhere to IOM guidelines – for now
- <1yr = 400 IU
- 1-70 = 600 IU
- 70+ = 800 IU,
- Identify high risk groups, test prn,
- Breast fed, dark skin, elderly, malabsorbers
- Counsel your patients that supplements are more dependable & safer than sun exposure