Beauty Goodies

Vitamin D: A Healthy Dose of Sunshine

March 29, 2010 Health & Fitness

When hearing about Vitamin D, it is probably reminiscent of your mother telling to drink your daily glass of milk for strong bones and teeth. But strong bones is not all Vitamin D is good for,  and lacking this essential vitamin may cause other health problems.  Vitamin D deficiency is  the common cause of bone diseases such as osteoporosis and osteomalacia. However, there is increasing medical evidence that Vitamin D deficiency may be culprit to a variety of other diseases such as influenza, autoimmune diseases, common cancers, and heart disease.  In fact, many people may be Vitamin D deficient  and are unaware of it,  making Vitamin D deficiency one of the most common and silent  medical conditions.

Here Comes the Sun

While supplements and fortified foods may provide Vitamin D,  they may not necessarily contain the proper recommended dose . One of the main ways that humans obtain Vitamin D is through sun exposure. Research shows that when the skin is exposed to UVB rays from the sun,  a vitamin D precursor  is converted into Vitamin D3.  Vitamin D3 is metabolized in the liver into the active form of Vitamin D that is stored in the body until it is needed.

But won’t too much sun exposure cause skin aging and skin cancer? Bingo!  That’s where the controversy lies. A good way to obtain Vitamin D is  through sun exposure,  yet being a sun goddess will predispose you to unwanted age spots, wrinkles, sun damage, and of course, skin cancer.  Staying out in the sun for 10-15 minutes can generate up to 10 times more Vitamin D than a glass of milk, which  typically contains only 100 International Units (IU) of Vitamin D.   Clinical studies show that adequate Vitamin D3 may be produced in as little as 10-15 minutes of sun exposure at least twice per week to the face, arms, hands, or back,  preferably without sunscreen.  However, it was also found that there is a limit to the amount of Vitamin D produced through UVB exposure, and after reaching the production limit, further exposure actually destroys the vitamin D, thus decreasing its levels.  Therefore, spending the whole summer day out on the beach without any sunscreen is not healthy practice for you or your skin!

It is important to also note that sunscreens block most UVB light,  which is the source that promotes the conversion of factors into the active form of Vitamin D. That capacity is not  reduced to zero, but to get the most “sunshine vitamin,” bare skin should be exposed. The main goal is to maintain an optimal level of Vitamin D levels and have healthy skin.  The best way to do so is limiting “bare skin” sun exposure to just 15 minutes a few times a week AND keeping sunscreen handy to apply to sun-exposed areas after you’ve had your dose of sunshine. Oral supplementation and diet are also important sources in obtaining Vitamin D.

D is For Deficient

How can one find out if he or she is Vitamin D deficient?  The only way to determine Vitamin D deficiency is through a 25-hydroxyvitamin D test (known as a 25(OH)D Calcidiol test).  Sufficient levels should be 40-65ng/ml in both adults and children.  This test can be done by your physician.

In order to maintain Vitamin D levels in the body,  recent literature suggests a minimum intake (through skin production, supplementation, or diet) of 1,000 units per day,  and preferably 2,000-3,000 units per day.  A glass of milk produces a ball park of 100 units. The basic multi-vitamin typically contains only 400 units.  Over the counter supplements of Vitamin D typically are 400 IU-1,000 IU and come in two forms: Vitamin D2 and D3.  Vitamin D3 is preferred.

So how much Vitamin D do we really need? According to the Food and Nutrition Board of the National Academies,  the current recommended Adequate Intake (AI) levels of daily Vitamin D is 200 IU for people under the age of 50,  400 IU ages 51-70, and 600 IU ages 71 and older.  Although these are recommended, these dosages are not enough,  according to Michale Holick, MD,  who is a Vitamin D expert at Boston University.  A dose of 1,000-2,000 IU per day is recommended,  with safe sun exposure.  1,000 IU was found to be tolerable by adults and infants,  without risk of Vitamin D toxicity.

Where else can Vitamin D be found?  Good dietary sources of Vitamin D are oily fish (such as salmon, tuna, catfish, sardines), fortified foods (dairy, cereals, yogurt), egg yolks, and cooked beef liver.

So maximize your health by getting enough vitamin D the safe way- your body and skin will thank you!

Sources:
Regulation of Vitamin D Production Is Independent of Skin Color. Ivan Camacho, Julia Tzu1 and Robert S. Kirsner. Journal of Investigative Dermatology (2010)
Cosmetic Dermatology: Principles and Practice. Leslie Baumann.
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Tags: SPF, sun exposure, sunscreen, Vitamin D