Vitamin C (ascorbate) is an essential micronutrient in humans, being required for a number of important biological functions via acting as an enzymatic cofactor and reducing agent. There is some evidence to suggest that people with type 2 diabetes mellitus (T2DM) have lower plasma vitamin C concentrations compared to those with normal glucose tolerance (NGT). The aim of this study was to investigate plasma vitamin C concentrations across the glycaemic spectrum and to explore correlations with indices of metabolic health. This is a cross-sectional observational pilot study in adults across the glycaemic spectrum from NGT to T2DM. Demographic and anthropometric data along with information on physical activity were collected and participants were asked to complete a four-day weighed food diary. Venous blood samples were collected and glycaemic indices, plasma vitamin C concentrations, hormone tests, lipid profiles, and high-sensitivity C-reactive protein (hs-CRP) were analysed. A total of 89 participants completed the study, including individuals with NGT (n = 35), prediabetes (n = 25), and T2DM managed by diet alone or on a regimen of Metformin only (n = 29). Plasma vitamin C concentrations were significantly lower in individuals with T2DM compared to those with NGT (41.2 µmol/L versus 57.4 µmol/L, p < 0.05) and a higher proportion of vitamin C deficiency (i.e. <11.0 µmol/L) was observed in both the prediabetes and T2DM groups. The results showed fasting glucose (p = 0.001), BMI (p = 0.001), smoking history (p = 0.003), and dietary vitamin C intake (p = 0.032) to be significant independent predictors of plasma vitamin C concentrations. In conclusion, these results suggest that adults with a history of smoking, prediabetes or T2DM, and/or obesity, have greater vitamin C requirements. Future research is required to investigate whether eating more vitamin C rich foods and/or taking vitamin C supplements may reduce the risk of progression to, and/or complications associated with, T2DM.

A cohort of 50-year-olds from Canterbury, New Zealand (N = 404), representative of midlife adults, undertook comprehensive health and dietary assessments. Fasting plasma vitamin C concentrations (N = 369) and dietary vitamin C intake (N = 250) were determined. The mean plasma vitamin C concentration was 44.2 µmol/L (95% CI 42.4, 46.0); 62% of the cohort had inadequate plasma vitamin C concentrations (i.e., <50 µmol/L), 13% of the cohort had hypovitaminosis C (i.e., <23 µmol/L), and 2.4% had plasma vitamin C concentrations indicating deficiency (i.e., <11 µmol/L). Men had a lower mean plasma vitamin C concentration than women, and a higher percentage of vitamin C inadequacy and deficiency. A higher prevalence of hypovitaminosis C and deficiency was observed in those of lower socio-economic status and in current smokers. Adults with higher vitamin C levels exhibited lower weight, BMI and waist circumference, and better measures of metabolic health, including HbA1c, insulin and triglycerides, all risk factors for type 2 diabetes. Lower levels of mild cognitive impairment were observed in those with the highest plasma vitamin C concentrations. Plasma vitamin C showed a stronger correlation with markers of metabolic health and cognitive impairment than dietary vitamin C.

Objective: Parents report that children's eating behaviours are a major barrier to providing them with a healthy diet. Links between problem eating behaviours and parental feeding practices are not well established and have not previously been examined in overweight children. The aim of the present study was to assess associations between problem food behaviours, dietary intake and parental feeding practices of overweight children aged 4-8 years. Design: Participants were recruited for a lifestyle intervention (n 203). At baseline, children's BMI was measured and parents completed comprehensive questionnaires about the feeding practices they used, the problem food behaviours their children exhibited and the foods their child consumed. A fussy eating scale was developed and associations were determined using correlations and regression analysis, including interactions. Setting: Dunedin, New Zealand. Subjects: Overweight children aged 4-8 years.Results: Healthy eating guidance and monitoring by parents were related to the consumption of fewer unhealthy foods (B = − 0·4, P = 0·001 and B = − 0·4, P < 0·001). Conversely, a lack of parental control (child control) was related to a higher intake of unhealthy foods (B = 0·5, P < 0·001). Parents of children who were fussy eaters monitored their child's food intake less (P < 0·001) and allowed the child more freedom over what he/she ate (P < 0·001). These children consumed fewer fruit and vegetables than those who were not fussy eaters (P < 0·001). However, fussy eaters with food-restrictive parents ate more fruit and vegetables (B = 2·9, P < 0·001). Conclusions: These results suggest that a more structured food environment might be beneficial for the diet and food behaviours of young overweight children.

Social jetlag may be an important and measurable public health target in children.

BackgroundReduced time dedicated to physical education and free play in recent decades emphasizes the need to promote opportunities for sport participation in adolescents in order to increase physical activity levels. The purpose of this study was to examine the association of sociodemographic and biological characteristics, behavioural patterns, and school-related and sport-specific variables with time spent participating in sport.MethodsA total of 1837 secondary school students (age: 14.6 ± 1.2 years; 50.9 % boys) from 19 of 23 schools in the Otago Region (New Zealand) completed an online sport survey and Youth Physical Activity Questionnaire in 2009. Using multilevel modeling, we examined the association of individual-, school- and sport-related variables on sport participation and the amount of time spent in sports.ResultsHigher rates of sport participation were associated with lower neighbourhood deprivation scores (OR (95%CI): 0.75 (0.49-1.14), 0.57 (0.38-0.86), 0.48 (0.28-0.81)), higher quintiles of physical activity (2.89 (2.10-3.96), 2.81 (1.68-4.70), 3.54 (2.24-5.57), 3.97 (1.99-7.95)), highest quintiles of screen time (1.58 (0.94-2.65), 1.99 (1.42-2.80), 2.17 (1.43-3.30), 1.88 (1.37-2.57)) and boys only school status (2.21 (1.57-3.10)). Greater amount of time spent in sports was associated with male gender (0.56 (0.43-0.74), lower neighbourhood deprivation scores (0.72 (0.59-0.93), 0.78 (0.58-1.04), 0.62 (0.39-1.00)), higher quintiles of physical activity (3.18 (2.29-4.41), 4.25 (2.91-6.20), 8.33 (5.58-12.44), 6.58 (4.07-10.64)), highest quintile of screen time (1.83 (1.31-2.56), greater availability of sports outside school (1.68 (1.22-2.32)), better sport management (2.57 (1.63-4.07)) and provision of sport courts at school (0.57 (0.40-0.81)). Conversely, obesity was associated with less time spent participating in sport (0.50 (0.31-0.80)).ConclusionResults support the use of sport participation as an effective strategy to increase physical activity levels and identify target groups and areas for interventions, program design and policy development. Interventions should focus on improving accessibility to sport programs for all adolescents, providing adequate sport grounds at school, and promoting good sport management practices. Programs and policies encouraging sport participation should address in particular the needs of adolescents living in deprived neighborhoods, those attending coeducational and girls-only schools, and those who are obese.