Dr Saskia Wilson-Barnes

Vitamin D deficiency has been commonly reported in elite athletes, but the vitamin D status of UK university athletes in different training environments remains unknown. The present study aimed to determine any seasonal changes in vitamin D status among indoor and outdoor athletes, and whether there was any relationship between vitamin D status and indices of physical performance and bone health. A group of forty-seven university athletes (indoor n 22, outdoor n 25) were tested during autumn and spring for serum vitamin D status, bone health and physical performance parameters. Blood samples were analysed for serum 25-hydroxyvitamin D (s-25(OH)D) status. Peak isometric knee extensor torque using an isokinetic dynamometer and jump height was assessed using an Optojump. Aerobic capacity was estimated using the Yo-Yo intermittent recovery test. Peripheral quantitative computed tomography scans measured radial bone mineral density. Statistical analyses were performed using appropriate parametric/non-parametric testing depending on the normality of the data. s-25(OH)D significantly fell between autumn (52·8 (SD 22·0) nmol/l) and spring (31·0 (SD 16·5) nmol/l; P < 0·001). In spring, 34 % of participants were considered to be vitamin D deficient (<25 nmol/l) according to the revised 2016 UK guidelines. These data suggest that UK university athletes are at risk of vitamin D deficiency. Thus, further research is warranted to investigate the concomitant effects of low vitamin D status on health and performance outcomes in university athletes residing at northern latitudes.

The primary source of vitamin D is through synthesis in the skin, following exposure to sunlight containing ultraviolet B (UVB) radiation. Supply through skin exposure can be supplemented by the diet, but there are relatively few dietary sources, especially those which provide a large amount of vitamin D per serving. Research into the effects of vitamin D status in different population groups has become an increasingly popular topic. The current interest surrounding vitamin D research in sport remains focused on the potential ergogenic effects of vitamin D on physical performance. However, the relationship between vitamin D (dietary intake and status) and musculoskeletal health in university athlete cohorts residing at higher latitudes (>40°N) remains underinvestigated. Within this review, the possible physiological roles that vitamin D may play within sport performance for recreational and professional athletes, as well as military recruits, will be discussed. The focus will be on muscular strength, cardiovascular health and the incidence of illness, including upper respiratory tract infections. Specifically, the effect that vitamin D deficiency {defined as a plasma/serum 25-hydroxyvitamin D [25(OH)D] concentration of <25 nmol/l} may have on musculoskeletal health, including the incidence of stress fractures, is discussed. The review also seeks to highlight avenues for future research within vitamin D and sport, in particular for populations residing at higher latitudes (>40°N) where wintertime vitamin D deficiency is prevalent. It is hoped that this review will help to raise the awareness of the importance of existing advice in the UK for the avoidance of vitamin D deficiency and international vitamin D guidelines (such as in the US) on the achievement of vitamin D sufficiency [serum 25(OH)D >50 nmol/l] for optimum health and performance in athletes, both professional and recreational.

Personalised nutrition is a novel public health strategy aiming to promote positive diet and lifestyle changes. Tailored dietary and physical activity advice may be more appropriate than a generalised ‘one-size-fits-all’ approach as it is more biologically relevant to the individual. Information and computing technology, smartphones and mobile applications have become an integral part of modern life and thereby present the opportunity for novel methods to encourage individuals to lead a healthier lifestyle. This article introduces the European Union-funded PROTEIN project (PeRsOnalised nutriTion for hEalthy livINg) consortium and introduces the associated work packages. The primary objective of the PROTEIN project is to produce a novel adaptable mobile application suite based on sound nutrition and physical activity advice from experts in their field, accessible to all population groups, with differing health outcomes, whose behaviour can be tracked with a variety of sensors and health hazard perception. The mobile application ‘ecosystem’ that will be developed by the consortium includes a platform, mobile suite, cloud services, artificial intelligence advisor, game suite, modelling of expert’s knowledge, users’ behaviour data collection, data analysis and a dashboard for healthcare professionals. It is proposed that users will find the provision of personalised nutrition advice and real-time data capture through a smartphone application useful, and importantly, will be encouraged by this to make positive health behaviour changes.

The potential ergogenic effects of vitamin D (vitD) in high performing athletes has received considerable attention in the literature and media. However, little is known about non-supplemented university athletes and students residing at a higher latitude. This study aimed to investigate the effects of vitD (biochemical status and dietary intake) on exercise performance in UK university athletes and sedentary students. A total of 34 athletes and 16 sedentary controls were studied during the spring and summer months. Serum vitD status and sunlight exposure were assessed using LC-MS/MS and dosimetry, respectively. Muscular strength of the upper and lower body was assessed using handgrip and knee extensor dynamometry (KE). Countermovement jump (CMJ) and aerobic fitness were measured using an Optojump and VO2max test, respectively. Statistical analysis was performed using paired/ independent t-tests, ANCOVA and Pearson/ Spearman correlations, depending on normality. VitD status increased significantly over the seasons, with athletes measuring higher status both in spring (51.7±20.5 vs. 37.2±18.9 nmol/L, p = 0.03) and summer (66.7±15.8 vs 55.6±18.8 nmol/L, p = 0.04) when compared to controls, respectively. Notably, 22% of the subjects recruited were vitD deficient during the spring term only (<25nmol/L, n 9). Subjects with ‘insufficient’ vitD status (<50nmol/L) elicited significantly lower CMJ when contrasted to the vitD ‘sufficient’ (>50nmol/l) group (p = 0.055) and a lower VO2 max (p = 0.05) in the spring and summer term (p = 0.05 and p = 0.01, respectively). However, an ANCOVA test showed no significant difference detected for either CMJ or VO2max following adjustments for co-variates. In conclusion, we provide novel information on the vitD status, dietary intake, physical fitness and sunlight exposure of UK young adults across two separate seasons, for which there is limited data at present.