Vitamin D status in elite Irish athletes

Abstract

Recent evidence suggests that vitamin D insufficiency is associated with an increased risk of stress fracture, total body inflammation, infectious illness and impaired muscle function (1,2) and is thus likely to impair the training ability of athletes in addition to affecting their overall health. Though not widely studied, vitamin D deficiency and insufficiency have been reported among athletes, irrespective of geographic location (3) . The aim of the current study was to assess vitamin D status in two groups of elite Irish athletes sampled in different months of the year.Non-fasting blood samples were taken from consenting volunteers (n 66) and total serum 25-hydroxyvitamin D (25(OH)D) was quantified by enzymeimmunoassay (IDS Limited, Boldon, UK). Serum calcium and plasma parathyroid hormone (PTH) concentration were also assessed (using the I-lab 650 Clinical Chemistry analyser and ARCHITECT i1000SR integrated system, respectively). *Significant difference between athletic groups (P < 0.05, independent t-test). Significance remained after controlling for age and gender (P < 0.001, ANCOVA); †mean daily intakes estimated from a validated food frequency questionnaire . Among the paralympians, the serum 25(OH)D and calcium concentrations of wheelchair-bound athletes were significantly lower compared to that of their able-bodied counterparts (P = 0.013 and P = 0.001, respectively), without significantly affecting PTH concentrations (P = 0.676). There were no significant differences in mean daily vitamin D (P = 0.903) or calcium (P = 0.210) intakes between the two groups of paralympians. Mean daily vitamin D and calcium intake were significantly correlated after controlling for age and gender (r = 0.464, P = 0.030), however were not associated with circulating 25(OH)D, PTH or calcium concentrations.This study highlights a high prevalence of vitamin D deficiency among elite Irish athletes, particularly at the end of winter. Inadequate sun exposure, rather than diet, is the likely cause of lower 25(OH)D concentrations observed in the wheelchair athletes. A serum 25(OH)D concentration ‡ 80 nmol/L has recently been postulated as desirable for athletes (2) however, the majority of athletes sampled in this study failed to reach this level. Vitamin D supplementation should therefore be considered for these athletic groups.

Evaluation of Dietary Intakes and Supplement Use in Paralympic Athletes

“…Calcium and vitamin D have roles in bone-building and muscle strength and function [ 19 , 20 , 21 , 22 ]. Females did not meet the recommendation for calcium on average, and neither gender met the recommendations for vitamin D from diet alone.…”

“…Females did not meet the recommendation for calcium on average, and neither gender met the recommendations for vitamin D from diet alone. Others have reported insufficient serum vitamin D levels in up to 51% of Canadian and US Paralympic athletes [ 23 ] and 27% of Irish Paralympic athletes [ 22 ], depending on the season. A study looking at Swiss elite wheelchair athletes reported a high frequency of vitamin D deficiencies all year round; however, deficiencies were greater in the winter and for indoor sports [ 24 ].…”

Cardiorespiratory Fitness and Diet Quality Profile of the Lithuanian Team of Deaf Women’s Basketball Players

“…According to our study results, vitamin D deficiency and iron deficiency was found in the diet and body of the deaf women athletes. Similarly, low serum vitamin D levels have been found in healthy and disabled athletes in other countries such as Canada, Swiss, and Ireland [21][22][23]. It should be noted that the serum concentration of 25(OH)D is the best indicator of vitamin D status.…”

“…However, the insufficient consumption of vitamin D with food remains one of the most pressing nutritional problems in athletes, especially in the athletes with disabilities. Moreover, clinical trials show a lack of an active form of vitamin D in athletes’ serum [ 21 , 22 , 23 ]. The deficiency of iron storage in the body leads to anaemia and the deterioration of aerobic capacity of athletes [ 24 , 25 ].…”

Dietary intakes of calcium, iron and vitamin D in club and county female Gaelic footballers

“…Inadequate intakes of calcium and iron are common in females ( 3 ) , with inadequate iron intakes previously documented in female team sports ( 4 ) . Vitamin D insufficiency is also evident in male Gaelic footballers but has yet to be examined in females ( 5 ) . Therefore, the aim of this study was to evaluate calcium, iron and vitamin D intakes of club and county female Gaelic footballers, and compare them to recommended dietary allowances (RDAs) ( 2 ) .…”