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Oklahoma Sports and Fitness July/August 2015 : Page 32

Vitamin D and the Athlete: What's the Big Deal? NUTRITION | SLOAN TAYLOR, MS, RD, CSSD, LD Nutritional advice can be tricky. Nutritional research can be downright confusing. In one corner you may hear that we need to worry about "X" but then months later, you may hear that "X" is good for you and please consume at will (coffee often seems to fall into this category). It’s not surprising that consumers tend to disregard the mixture of “do’s and don’ts” and simply dismiss the latest proclamation. But Vitamin D is a nutrient that has gained progressive and consistent attention. Even though nutritional agencies (government and consumer advocacy groups altogether) don’t agree on how much Vitamin D is appropriate they do agree on one thing: we need more than we thought. The pit fall is that many individuals (and also nutritional agencies) stood firm on the fact that our bodies do make Vitamin D. Step outside and your skin exposed to ultraviolet B (UVB) radiation immediately begins production and continues for up to eight hours after exposure. 1 Acquired simply with sunlight, Vitamin D is often referred to as the “sunshine vitamin.” But the issue with the original Recommended Dietary Allowance (RDA) was that it was not necessarily enough and that one blanket recommendation does not cover all needs and all individuals. Latitude, season, time of day, ozone amount, and skin pigmentation are all influential factors. The darker your skin is, the longer the exposure required to make Vitamin D. Yes, sunshine does indeed begin the production of this vitamin (categorized also as a hormone) but where you live and how much skin exposure (frequency and duration) you have will dictate how much you will make. This begs the question: does a person risk the potential of skin cancer for more Vitamin D production? The sensible answer is no and the solution is to increase your Vitamin D by means other than sunlight. Vitamin D is acquired from the skin, from the diet, and from supplements. As discussed, your limited time in the sunlight may not provide enough. The diet is a bit tricky too. You see, Vitamin D is a nutrient that is not found in many foods. You can find it in fortified dairy products (milk, cheese, and yogurt), fortified breakfast cereals, margarine, shrimp, sardines, salmon, swordfish, tuna, mackerel, catfish, egg yolk, and shitake mushrooms. But how much of this do you eat? It’s not easy to find an individual that consumes the RDA by diet alone and one that likes the limited list above as a daily intake. Dairy products are an excellent source but not all people can or want to consume dairy items. This brings us to supplementation. muscle 2 (not just bone as we once thought). The effect on muscle is what intrigues the athletic world. There is also ongoing research for Vitamin D and cancer along with current research in progress that Vitamin D may affect brain function. Vitamin D supplementation is then worth investigation. Consumer Lab (consumerlab. com) publishes test results on nutritional products and has an extensive Vitamin D review for purchase. Their mission is “to identify the best quality health and nutrition products through independent testing.” They have identified that both Vitamin D2 (ergocalciferol) and Vitamin D3 (cholecalciferol) are absorbed with equal efficiency, however, D3 (cholecalciferol) may be more efficient at raising the clinical measure of Vitamin D status. 3 The National Institutes of Health (NIH) Office of Dietary Supplements is an agency of the United States Department of Health and Human Services. It is the government’s primary agency responsible for biomedical and health-related research. This agency states that the best indicator of Vitamin D status is the serum concentration of 25(OH)D (calcidiol). This is a biomarker of exposure but it does not indicate the amount of Vitamin D stored in body tissues. 4 The short answer is that you want your number to be above 50 if looking at nanomoles per liter (nmol/L) or you want your number to be above 20 if looking at nanograms per milliliter (ng/ mL). You would benefit to be tested by your physician and know how to read your own results below: Supplements seem to be an answer and a convenient way to acquire Vitamin D. An athlete who exercises predominantly indoors would be wise to investigate their Vitamin D status and then increase their level with diet, Vitamin D supplements, or both. The cause for concern is no longer limited to just bone health such as bone strength and fracture potential. Multiple research studies have revealed the identification of the Vitamin D receptor in many tissues. Vitamin D, therefore, does more than Serum 25-Hydroxyvitamin D [25(OH)D] concentrations first realized and it has nmol/L ng/mL Health Status potential regulation of (nanomoles/liter) (nanograms/liter) acquired immunity, innate < 30 < 12 Vitamin D deficiency immunity, cardiovascular 30-50 12-20 Inadequate health, and the biological ≥ 50 ≥ 20 Adequate processes within skeletal > 125 > 50 Adverse effects 32 JULY / AUGUST 2015 | OKSPORTSANDFITNESS.COM

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