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Nutrition


BY SUSIE PARKER-SIMMONS USOC SPORTS DIETITIAN


The Importance of Vitamin D For Shooters


Vitamin D has many func-


tions, ranging from optimal bone health to immune and muscle function, but little is known about vitamin D status and performance in shooters. It is accepted, however, that they are at similar risk for low vitamin D status than the nonathletic population. The risk factors for vitamin D defi ciency in shooters include: •


Indoor practices (pis- tol and rifl e)


• •


• •





Dark or extremely fair skin


Living and training at northern latitudes Sunscreen use


Limited sun expo- sure


Low dietary vitamin Food Sources Rich in Vitamin D Food Wild Salmon


Sun-dried Mushrooms


Serving Size


3.5 oz 1 oz


Canned Sardines 3.5 oz Farmed Salmon 3.5 oz Ahi Tuna


Fortifi ed Milk


Orange Juice, Fortifi ed


Cod


3.5 oz 8 oz


Soy Milk, Fortifi ed 8 oz 8 oz


3.5 oz Cereals, Fortifi ed Varies


Vitamin D (IU)


981 400-500


270 249 164 100 100 100


80 40-100 May 2014 | USA Shooting News 61 • D intake


Spinal cord injury (SCI) shooters.


The best assessment for


vitamin D status includes 25 hydroxy vitamin D3 or 25(OH) D. Vitamin D status can be determined at any time of the day and does not have to be measured in the fasted state. It is best to as- sess vitamin D status at the end of the summer (or early fall) and winter months, al- though baseline testing is justifi ed at any time of the year, especially if low status may be suspected. For food sources rich in vitamin D, look at the table below.


Safe sun exposure, espe- cially in the summer months may help shooters to build up their vitamin D stores as the skin can synthesize about 10,000-20,000 IU of vitamin D in less than 30 minutes. However, if sun- screen (>SPF 15) or sun- block is used, nearly 98% of UVB rays from the sun are effectively blocked and so is vitamin D synthesis. Most individuals can benefi t from fi ve-30 minutes of sun expo- sure several times per week. Sunlight should reach arms, legs and trunk for greatest benefi ts.


A combination of safe


sun exposure, diet and sup- plementation should be con- sidered in shooters with low


Proposed Reference Range for Vitamin D Vitamin D Toxicity


Optimal Status (bone and muscle)


Normal Vitamin D Status


ng•mL-1 nmol•mL-1 >150 ≥40a


>375 100


30 – 80 75 – 200


Vitamin D Insuffi ciency 30 – 80 52.5 – 72.5 Vitamin D Defi ciency ≤20


≤50


*Conversion factor between units is 2.5. a Bischoff-Ferrari, 2012; Ginde et all., 2013, Barker et al., 2013.


vitamin D status. The dos- age and duration of vitamin D supplementation depends on the season at which the defi ciency was identifi ed and the degree of defi ciency. See your local doctor or dietitian for guidance on supplemen- tation.


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