NUTRITION – VITAMIN D – ATHLETES


6 RESEARCH ARTICLES + 7 GRAPHICS – CLICK ON GRAPHIC TO ENLARGE



THE IMPACT OF 1 YEAR OF VITAMIN D SUPPLEMENTATION ON VITAMIN D STATUS IN ATHLETES – 2016


Backx EM1, Tieland M1, Maase K2, Kies AK3, Mensink M1, van Loon LJ4, de Groot LC1.
BACKGROUND/OBJECTIVES
– To assess the prevalence of vitamin D deficiency in Dutch athletes
– Define the required dosage of vitamin D3 to prevent vitamin D deficiency over the course of a year
SUBJECTS/METHODS
– 128 athletes, 54 male and 48 female athletes (18-32 years)
– Athletes with either:
(A) deficient (<50 nmol/l)
(B) or an insufficient (50-75 nmol/l) 25(OH)D concentration
– They were randomly assigned to take 400, 1100 or 2200 IU vitamin D3 per day orally for 1 year

– Athletes who had a total 25(OH)D concentration above 75 nmol/l at baseline continued with the study protocol without receiving vitamin D supplements
– Serum total 25(OH)D concentration was assessed every 3 months, as well as dietary vitamin D intake and sunlight exposure
RESULTS:
– Nearly 70% of all athletes showed an insufficient (50-75 nmol/l) or a deficient (<50 nmol/l) 25(OH)D concentration at baseline
– After 12 months, serum 25(OH)D concentration had increased more in the 2200 IU/day group than the sufficient group receiving no supplements and the 1100 IU/day group
– Supplementation with 2200 IU/day vitamin D resulted in a sufficient 25(OH)D concentration in 80% of the athletes after 12 months
CONCLUSIONS:
– Vitamin D deficiency is highly prevalent in athletes.
– Athletes with a deficient or an insufficient 25(OH)D concentration can achieve a sufficient 25(OH)D concentration within 3 months by taking 2200 IU/day


SSE #148 THE IMPORTANCE OF VITAMIN D FOR ATHLETES – 2014


Enette Larson-Meyer
KEY POINTS
(1) The blood 25(OH)D concentration is the best indicator
(2) A blood vitamin D concentration of >75 nmol/L but preferably >100 nmol/L should be maintained
(3) “Suboptimal” vitamin D status is linked to increased risk for acute illness, inflammatory injury, stress fracture, muscle pain/weakness and suboptimal muscle performance
(4) Regular consumption of vitamin D-containing foods alone is not likely to maintain sufficient vitamin D status
PRACTICAL APPLICATIONS
(1) Vitamin D status may be achieved by sensible sun exposure (5 to 30 min of exposure depending on skin pigmentation (5 min for fair skinned and 30 min for dark skinned) to arms, legs and back at close to solar noon several times a week) and/or supplementation and dietary intake to provide at least 1,500 – 2,000 IU/day
(2) Supplementation in winter is recommended for all athletes living/training at >35° north or south


SSE #147 VITAMIN D MEASUREMENT & SUPPLEMENTATION – 2014


Graeme L. Close
KEY POINTS
(1) Vitamin D is associated with bone health, immune function, cell cycle and skeletal muscle homeostasis
(3) Athletic populations show markedly poor vitamin D concentrations, particularly during the winter months
SUMMARY
(1) Data suggests vitamin D deficiency is endemic and its frequency is on the rise, a consistent observation in athletic sub-groups
(2) This may primarily be owing to a sun-shy lifestyle and poor dietary sources of vitamin D


VITAMIN D AND THE ATHLETE – 2014


Owens DJ, Fraser WD, Close GL
(1) Vitamin D receptors are in many tissues suggesting a more global role for Vitamin D than previously considered
(2) Unlike other vitamins that are obtained food, Vitamin D is unique since synthesis following ultraviolet B (UVB) exposure is the predominant route of entry into circulation
(3) Vitamin D could be better classed as a seco-steroid; its structure is similar to that of a steroid; its production is derived from a cholesterol precursor in the skin
(4) Impaired muscle function and reduced regenerative capacity, impaired immune function, poor bone health and impaired cardiovascular function have all been associated with low Vitamin D in athletes


VITAMIN D AND SKELETAL MUSCLE FUNCTION IN ATHLETES – 2014


von Hurst PR, et al
PURPOSE OF REVIEW:
– H
ighlight recently published data about Vit D status of athletes, and effect of Vit D supplementation on muscle strength and performance
– Vit D receptor exists in skeletal muscle, and muscle weakness has been reported in individuals who are severely deficient [25(OH)D <25 nmol/l]


VITAMIN D SUPPLEMENTATION IN ATHLETES – 2013


Larson-Meyer E. Nestle Nutr Inst Workshop
(1) Vitamin D deficiency can have a profound effect on immunity, inflammation and muscle function
(2) Athletes Vit D status varies among different populations and is dependent on skin color, early- or late-day training, indoor training and geographic location
(3) Studies in athletic populations suggest that maintaining adequate vitamin D status may reduce stress fractures, total body inflammation, common infectious illnesses, and impaired muscle function, and may also aid in recovery from injury


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