Optimal vitamin D status is important for growth and development during childhood(1). Children with a circulating concentration of 25-hydroxyvitamin D [25(OH)D] below 25 nmol/L are at increased risk of rickets. In order to maintain 25(OH)D > 25nmol/L, a dietary intake of 10µg/d vitamin D is recommended for children aged 4 years and above(2,3). The aim of this study was to determine vitamin D status in healthy children and to investigate associations between 25(OH)D concentrations and muscle health, cognitive function, and parental knowledge of vitamin D, vitamin D habits, perceptions, and practices.

A cross-sectional study of healthy children aged 4 – 11 years conducted between 2019 – 2023 examined vitamin D status by measuring plasma 25(OH)D via the gold standard liquid chromatography tandem mass spectrometry and parathyroid hormone concentrations. Muscle strength (hand grip and balance) was determined by dynamometer, single and tandem stance balancing whilst cognitive function was assessed using the Cambridge Neuropsychological Test Automated Battery. Parents completed questionnaires to assess vitamin D knowledge, and perceptions, habits, and attitude towards vitamin D.

A total of 192 children (91 boys; 101 girls) with an average age of 8.2 years were recruited. Plasma 25(OH)D concentrations were 61.10±18.75 nmol/L (n = 190), with 68.4% of children defined as vitamin D sufficient (25(OH)D>50nmol/L). When stratified by winter months, only 58% of children were vitamin D sufficient. In single linear regression, plasma 25(OH)D concentrations were positively associated with dominant hand grip strength, single leg balance and the cognitive test ‘5choice movement time’ (p<0.05). Overall, there was a reported mean score of 41.9% for parental vitamin D knowledge and 68% of parents thought there was no harm in giving their child vitamin D fortified foods.

Approximately 70% of this sample of children were vitamin D sufficient, however insufficiency was prevalent in almost half of the cohort during the winter months. Benefits of optimal vitamin D for muscle and cognitive function were evident. These results support the promotion of the existing vitamin D dietary recommendations during the winter months for optimal child growth and development.

Sufficient vitamin D status is required in childhood for normal skeletal health and the development of muscle and motor function(1). Vitamin D primarily acts through the promotion of calcium absorption from the gut and mobilisation from bone tissue(2). Childrens’ vitamin D dietary intakes are currently below the recommended guidelines within the UK and Ireland suggesting a need for vitamin D3 supplementation to prevent the risk of developing vitamin D deficiency(3). The aim of this study was to examine the effect of 12 weeks’ supplementation with 10µg/d vitamin D3 vs placebo control on vitamin D status and to determine if improved vitamin D status impacted muscle function and cognition in children aged 4-11 years.

In the D-VinCHI randomised, double-blind, placebo-controlled trial, healthy children (n = 118; mean age 8.1±1.8 y; 51% girls) were randomly assigned to either placebo or 10µg/day of vitamin D3 for 12 weeks (year-round). Baseline and endpoint measures included anthropometric measures, hand grip strength, balance, and cognitive assessment. Blood samples were analysed for plasma 25hydroxyvitamin D [25(OH)D], and parathyroid hormone. Vitamin D consumption from food sources was assessed via a 13-item food frequency questionnaire.

Following the 12-week intervention vitamin D status [25(OH)D concentration] increased in the treatment group from 66.31 ± 17.25 nmol/L to 69.04 ± 16.92 nmol/L. Change in status was significantly different compared to the placebo group within which a decrease in 25(OH)D was observed from 63.67 ± 19.48 to 56.29 ± 18.58 nmol/L, p<0.001. Supplementation with vitamin D3 prevented deficiency of plasma 25(OH)D during the winter months. Vitamin D3supplementation had a positive effect on cognitive function, improving simple movement time from 707±380 to 599±207 milliseconds, compared to the placebo group within which time increased from 680±284 to 728±372 milliseconds, p = 0.017. Vitamin D mean dietary intake from food sources alone was 2.68µg/day. There was no effect of supplementation on muscle function.

Vitamin D3 supplementation maintained year-round sufficiency in children and importantly, prevented deficiency during the extended winter months. Vitamin D supplementation may enhance cognitive function via improvements in attention and psychomotor speed. The reported intakes of vitamin D food sources were low and were well below the current dietary reference value for this age group. Further health promotion policies and (bio)fortification strategies should be considered within this age group to maximise vitamin D status for optimal growth and development.

The consumption of larger portion sizes (PS) of food has been implicated in the increased prevalence of childhood obesity. The home is usually the first place children learn about food, however, little is known about how parents determine child PS in the home environment. This narrative review aimed to explore parental beliefs, decisions, strategies and barriers to the provision of appropriate food PS for children in the home environment. Results indicate that parental decisions on child food PS are based on the amounts they serve themselves, personal intuition and knowledge of child appetite. Owing to the habitual nature of food provision, parental decisions on child PS may be taken without conscious thought and/or could be part of a complex decision-making process influenced by several interlinked factors, including parental childhood mealtime experiences, other family members and child weight status. Strategies to determine child-appropriate PS include modelling the desired PS behaviour, use of unit-based food packaging and PS estimation aids, and providing the child with a degree of autonomy to rely on their own appetite cues. A lack of knowledge/awareness of PS guidance is a key barrier identified by parents to the provision of age-appropriate PS, warranting the inclusion of salient child-appropriate PS guidance within national dietary recommendations. Further home-based interventions to improve the provision of appropriate child PS are required, leveraged on parental strategies already in use, as outlined in this review.

Adequate I intake is important before conception and during pregnancy for optimal infant neurodevelopment. Recent studies have highlighted the prevalence of I deficiency in the UK and Ireland. It is possible that optimal I intake may be impeded by a poor knowledge of I nutrition. This study aimed to investigate I knowledge among women of childbearing age in the UK and Ireland and to determine whether a relationship exists between I knowledge and dietary I intake. Females (aged 18–45 years) were invited to complete an online questionnaire, which assessed knowledge of I and estimated dietary I intake using a FFQ. A total of 520 females of childbearing age completed the study. I knowledge was poor; only one-third (32 %) of the participants correctly identified pregnancy as the most important stage of the lifecycle for I, and 41 % of participants could not correctly identify any health problem related to I deficiency. The median daily I intake was estimated as 152 µg/d. Almost half (46 %) of the participants failed to meet dietary recommendations (140 µg/d) for I. A higher dietary I intake was positively associated with greater I knowledge (r 0·107; P=0·016). This study suggests that knowledge of I nutrition is low among women of childbearing age, and those with a greater knowledge of I nutrition had a higher dietary I intake. Initiatives to educate women of childbearing age on the importance of I nutrition should be considered as part of a larger public health strategy to address I deficiency.

Vitamin D is typically supplied in capsule form, both in trials and in clinical practice. However, little is known regarding the efficacy of vitamin D administered via oral sprays – a method that primarily bypasses the gastrointestinal absorption route. This study aimed to compare the efficacy of vitamin D3 liquid capsules and oral spray solution in increasing wintertime total 25-hydroxyvitamin D (25(OH)D) concentrations. In this randomised, open-label, cross-over trial, healthy adults (n 22) received 3000 IU (75 µg) vitamin D3 daily for 4 weeks in either capsule or oral spray form. Following a 10-week washout phase, participants received the opposite treatment for a final 4 weeks. Anthropometrics and fasted blood samples were obtained before and after supplementation, with samples analysed for total 25(OH)D, creatinine, intact parathyroid hormone and adjusted Ca concentrations. At baseline, vitamin D sufficiency (total 25(OH)D>50 nmol/l), insufficiency (31–49 nmol/l) and clinical deficiency (<30 nmol/l) were evident in 59, 23 and 18 % of the participants, respectively. Overall, baseline total mean 25(OH)D concentration averaged 59·76 (sd 29·88) nmol/l, representing clinical sufficiency. ANCOVA revealed no significant difference in the mean and standard deviation change from baseline in total 25(OH)D concentrations between oral spray and capsule supplementation methods (26·15 (sd 17·85) v. 30·38 (sd 17·91) nmol/l, respectively; F=1·044, adjusted r2 0·493, P=0·313). Oral spray vitamin D3 is an equally effective alternative to capsule supplementation in healthy adults.

Traditionally only a small proportion of the workforce was engaged in shift work. Changing economic pressures have resulted in increased engagement in shift work, with approximately 17 % of the workforce in Europe engaged in this work pattern. The present narrative review aimed to summarise the data on the effects of shift work on the diet, lifestyle and health of employees, while addressing the barriers to, and opportunities for, improving health among shift workers. Shift work can result in low-quality diet and irregular eating patterns. Adverse health behaviours are also reported; particularly increased smoking and poor sleep patterns. These altered lifestyle habits, in conjunction with disruption to circadian rhythms, can create an unfavourable metabolic phenotype which facilitates the development and progression of chronic disease. Although the data are inconclusive due to issues such as poor study design and inadequate control for confounding factors; shift workers appear to be at increased mental and physical health risk, particularly with regard to non-communicable diseases. Information is lacking on the obstacles to leading a healthier lifestyle while working shifts, and where opportunities lie for intervention and health promotion among this group. In order to provide an informed evidence base to assist shift workers in overcoming associated occupational hazards, this gap must be addressed. This review highlights the unique nutritional issues faced by shift workers, and the subsequent effect on health. In societies already burdened with increased incidence of non-communicable chronic diseases, there is a clear need for education and behaviour change interventions among this group.

The present analysis aimed to investigate the changes in the reported portion sizes (PS) of foods and beverages commonly consumed by Irish adults (18–64 years) from the North South Ireland Food Consumption Survey (NSIFCS) (1997–2001) and the National Adult Nutrition Survey (NANS) (2008–10). Food PS, which are defined as the weight of food (g) consumed per eating occasion, were calculated for comparable foods and beverages in two nationally representative cross-sectional Irish food consumption surveys and were published in NSIFCS and NANS. Repeated measure mixed model analysis compared reported food PS at the total population level as well as subdivided by sex, age, BMI and social class. A total of thirteen commonly consumed foods were examined. The analysis demonstrated that PS significantly increased for five foods (‘white sliced bread’, ‘brown/wholemeal breads’, ‘all meat, cooked’, ‘poultry, roasted’ and ‘milk’), significantly decreased for three (‘potatoes’, ‘chips/wedges’ and ‘ham, sliced’) and did not significantly change for five foods (‘processed potato products’, ‘bacon/ham’, ‘cheese’, ‘yogurt’ and ‘butter/spreads’) between the NSIFCS and the NANS. The present study demonstrates that there was considerable variation in the trends in reported food PS over this period.

In recent years, new functional roles of vitamin D beyond its traditional role in calcium homoeostasis and bone metabolism have emerged linking the fat-soluble vitamin to various non-communicable diseases. Vitamin D deficiency (25-hydroxyvitamin D (25(OH)D) < 25–30 nmol/l) and sub-optimal status (25(OH)D < 50–100 nmol/l) are increasingly associated with unfavourable metabolic phenotypes, including insulin resistance, type 2 diabetes and CVD; conditions also commonly linked with overweight and obesity. Early studies reported poor vitamin D status in the morbidly obese. More recently, it has been observed that a graded relationship between vitamin D status and BMI, or specifically adiposity, exists in the general population. A number of hypotheses have been proposed to explain the potential mechanisms whereby alterations in the vitamin D endocrine system occur in the obese state. Plausible explanations include sequestration in adipose tissue, volumetric dilution or negative feedback mechanisms from increased circulating 1,25-dihydroxyvitamin D3. Others hypothesise that heavier individuals may partake in less outdoor activity, may also cover-up and wear more clothing than leaner individuals, thus decreasing sun exposure and limiting endogenous production of cholecalciferol in the skin. Moreover, in some but not all studies, BMI and adiposity have been negatively associated with the change in vitamin D status following vitamin D supplementation. It therefore remains unclear if body size and/or adiposity should be taken into account when determining the dietary requirements for vitamin D. This review will evaluate the current evidence linking vitamin D status and supplementation to overweight and obesity, and discuss the implications for setting dietary requirements.

Childhood obesity is of concern worldwide. The portion size (PS) and energy density (ED) of food are two major determinants of children's energy intake (EI). Trends towards increasing PS are most apparent and best documented in the USA, where PS of numerous food products have increased in the marketplace over the past three decades, particularly high-energy dense foods. Analyses of population-level dietary surveys have confirmed this trend in children for both in- and out-of-home eating, and a plethora of observational evidence positively associates PS, ED and adiposity in children. A limited number of intervention studies provide clear evidence that children, even as young as 2 years, respond acutely to increasing PS, with some studies also demonstrating the additive effects of increased ED in promoting excessive EI. However, most of the evidence is based on children aged 3–6 years and there is a paucity of data in older children and adolescents. It is unclear whether decreasing PS can have the opposite effect on children's EI but recent acute studies have demonstrated that the incorporation of lower energy dense foods, such as fruit and vegetables, into children's meals down-regulates EI. Although a direct causal link between PS and obesity remains to be established, the regular consumption of larger PS of energy dense foods do favour obesity-promoting eating behaviours in children. Further research is required to establish the most feasible and effective interventions and policies to counteract the deleterious impact of PS and ED on children's EI.