Long gone are the days when baby oil was applied to the skin to get the perfect California tan. Educated and marketed to for the last 20 years, we recognize that long exposure to the sun will cause premature aging and skin cancer.

Today we have many varieties of SPF lotions, and fabrics that block out the UV & UVB rays, along with self-tanners to give one that sexy bronze appeal without any long-term skin damage. Americans have become so diligent in applying the white stuff from head-to-toe that one may not even consider the loss of our main natural source of Vitamin D.

Even though there has been a lot of media around Vitamin D deficiency lately, one must consider many factors. For example, pregnant or lactating women, post-menopausal women and people with dark skin color will probably need higher Vitamin D levels than others. In other words, there are no direct answers. However, one thing is certain: the type of Vitamin D that often shows up deficient in people is the same kind we normally get from the sun.

According to Kirschmann in Nutrition Almanac, sun block that is higher than SPF- 8 prevents the body from receiving the sun’s natural source of Vitamin D. This is known as the circulating level, and fair skinned people would benefit from 10-15 minutes of exposure to sunlight three times a week in the summer months. Yet, in the northern hemisphere, especially in the middle of winter, the sun does not put out enough rays to adequately supply the body with sufficient amounts of Vitamin D3.

Another important thing to consider is your skin color. Those with very fair skin may need less time in the sun, while those with darker pigments would need significantly more time in the sun, and this is without sunblock.

The human skin was designed to absorb Vitamin D from the sun, and unfortunately there are very few foods or supplements that provide the same benefits. According to Kirschmann in Nutrition Almanac, the best sources of Vitamin D in whole foods are cold-water fish, egg yolks and butter. The fortified Vitamin D that is added to foods, such as orange juice, cereals, and supplements is known as Vitamin D2 or ergocalciferol. This form does not provide the body with the same nutrients needed to help absorb calcium for bone growth as does the Vitamin D3 we get from the sun.

The body’s digestive system needs to be in a healthy functioning state in order to best absorb nutrients. To illustrate this idea, consider automobile maintenance. Most of us are aware that in order to keep our cars running smoothly we must change the oil frequently, and perhaps even use quality grade oil.

Well, the stomach or gastrointestinal tract (GI) is the engine of our bodies. The GI tract needs a healthy environment to process and break down foods in order to absorb and convert food into energy. Since Vitamin D is fat-soluble, it must be mixed with other fats so it can dissolve and be absorbed by the small intestine. It is also stored for long periods in the liver and fatty tissue (Anderson & Young, 2008, p.1).

The body receives many benefits from Vitamin D: it promotes healthy digestion and when combined with Vitamin A, another fat-soluble vitamin, it has been shown to enhance the immune system. According to Hendler, in The Doctors’ Vitamin & Mineral Encyclopedia, Vitamin D is also effective in treating some forms of cancer.

The recommended dosage as stated by the US RDA is 400IU daily, however as previously stated, each person may have different requirements. Too much Vitamin D can result in toxicity.

If you are concerned about deficiency, there are tests that show Vitamin D levels. Please consult your physician or nutrition professional for more information regarding dosage and testing.

References:

Anderson, J., & Young, L., (2008, August 8). “Fat-Soluble Vitamins”. Colorado State University Extension. Retrieved March 10, 2009 from http://www.ext.colostate.edu/pubs/foodnut/09315.html

Hendler, S.S. (1990). The Doctors’ Vitamin & Mineral Encyclopedia. New York: Simon Schuster

Hollis, B., W. (2005, February). “Circulating 25-Hydroxyvitamin D Levels Indicative of Vitamin D Sufficiency: Implications for Establishing a New Effective Dietary Intake Recommendation for Vitamin D1”. The Journal of Nutrition. Retrieved March 4, 2009 from http://jn.nutrition.org/

Kirschmann, J.D., & Nutrition Search Inc. (2007). Nutrition Almanac (6th ed.). San Francisco: McGraw Hill. 

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