[Vitamin D Deficiency in Sports]. / Vitamin-D-Mangel im Sport.

Vitamin D Deficiency in Sports Abstract. A deficiency in vitamin D is very common in the general population as well as in athletes. The aim of this overview is to assess the level of knowledge about the importance of vitamin D for athletes. A deficiency in vitamin D is present in up to 90 % of athletes. Risk groups are young athletes, female athletes, athletes with a limitation such as paraplegia, vegetarians, athletes with a resorption disorder such as celiac disease, athletes training and competing indoors (e.g. ice hockey, basketball, boxing, rhythmic gymnastics), and older athletes. Dark skin pigmentation, the use of sunscreen, the time of day of the training (early morning, late evening) and the geographical location influence the risk for a deficiency in vitamin D. Exposure to the sun and a balanced diet are often not enough to prevent a vitamin D deficiency.

Associations of CYP24A1 copy number variation with vitamin D deficiency and insulin secretion.

Vitamin D plays an important role in insulin secretion. As the enzyme that initiates degradation of the active metabolite of vitamin D (1,25-(OH)2 vitamin D), 24-hydroxylase encoded by CYP24A1 may be associated with insulin secretion. In this study, we aimed at investigating the association between copy number of CYP24A1 and the concentration of insulin. Included in the study were 1528 rural people from Henan Province of China. The copy number of CYP24A1 and the concentrations of serum 25(OH) vitamin D3 and insulin were determined. Association between copy number of CYP24A1 and vitamin D deficiency was investigated with logistic regression model. Correlation between copy number of CYP24A1 and serum insulin was observed by Spearman correlation. The results suggested that copy number variation of CYP24A1 was associated with vitamin D deficiency. Higher copy number of CYP24A1 was a risk factor for vitamin D deficiency (adjusted odds ratio: 1.199; 95% confidence interval: 1.028-1.397; P = 0.021). Furthermore, copy number of CYP24A1 was positive correlated with the concentration of serum insulin (r = 0.115; P < 0.001), regardless of vitamin D status, age, and body mass index (BMI). Increased copy number of CYP24A1 is associated with not only vitamin D deficiency but also increased serum insulin. Vitamin D supplement may be beneficial to individuals with high copy number of CYP24A1. Novelty Increased copy number of CYP24A1 was a risk factor of vitamin D deficiency. Increased copy number of CYP24A1 was associated with increased serum concentration of insulin independent of age, BMI, and vitamin D status.

Effect of multiple micronutrient fortified milk consumption on vitamin D status among school-aged children in rural region of Morocco.

Vitamin D deficiency is a health problem in both developed and developing countries. The aim of this study was to determine the effect of multi-vitamin fortified milk consumption on vitamin D status among children living in the mountainous region of Morocco. Children aged 7 to 9 years (n = 239; 49% of girls vs 51% of boys) participated in a double-blind longitudinal study, where they were divided in 2 groups: a fortified group that received daily 200 mL of fortified ultra-high-temperature (UHT) milk enriched with 3 µg of vitamin D3 and a nonfortified group that received 200 mL of nonfortified UHT milk with a natural abundance of vitamin D3 (about 1.5 µg). Blood samples were collected 3 times (at baseline, then at the fourth and ninth months). The average weight, height, and z score of body mass index for age of participants were 22.8 ± 2.6 kg, 121.5 ± 5.2 cm, and -0.2 ± 0.6 kg/m2, respectively. At baseline, 47.5% of children had a concentration of 25-hydroxyvitamin D below 50 nmol/L. At the end of the study the prevalence of vitamin D <50 nmol/L decreased significantly by 37.6% in the fortified group. These results reveal prevalent vitamin D insufficiency (<50 nmol/L) during winter among rural Moroccan school-aged children, which seems to be better improved by consuming the fortified milk instead of the nonfortified one.