Kathryn L. Beck

Vitamin D and Autism Spectrum Disorder: A Literature Review

Low vitamin D status in early development has been hypothesised as an environmental risk factor for Autism Spectrum Disorder (ASD), given the concurrent increase in the prevalence of these two conditions, and the association of vitamin D with many ASD-associated medical conditions. Identification of vitamin D-ASD factors may provide indications for primary and secondary prevention interventions. We systematically reviewed the literature for studies on vitamin D-ASD relationship, including potential mechanistic pathways. We identified seven specific areas, including: latitude, season of conception/birth, maternal migration/ethnicity, vitamin D status of mothers and ASD patients, and vitamin D intervention to prevent and treat ASD. Due to differences in the methodological procedures and inconsistent results, drawing conclusions from the first three areas is difficult. Using a more direct measure of vitamin D status—that is, serum 25(OH)D level during pregnancy or childhood—we found growing evidence for a relationship between vitamin D and ASD. These findings are supported by convincing evidence from experimental studies investigating the mechanistic pathways. However, with few primary and secondary prevention intervention trials, this relationship cannot be determined, unless randomised placebo-controlled trials of vitamin D as a preventive or disease-modifying measure in ASD patients are available.

Dietary Determinants of and Possible Solutions to Iron Deficiency for Young Women Living in Industrialized Countries: A Review

Iron deficiency is a concern in both developing and developed (industrialized) countries; and young women are particularly vulnerable. This review investigates dietary determinants of and possible solutions to iron deficiency in young women living in industrialized countries. Dietary factors including ascorbic acid and an elusive factor in animal protein foods (meat; fish and poultry) enhance iron absorption; while phytic acid; soy protein; calcium and polyphenols inhibit iron absorption. However; the effects of these dietary factors on iron absorption do not necessarily translate into an association with iron status and iron stores (serum ferritin concentration). In cross-sectional studies; only meat intake has consistently (positively) been associated with higher serum ferritin concentrations. The enhancing effects of ascorbic acid and meat on iron absorption may be negated by the simultaneous consumption of foods and nutrients which are inhibitory. Recent cross-sectional studies have considered the combination and timing of foods consumed; with mixed results. Dietary interventions using a range of focused dietary measures to improve iron status appear to be more effective than dietary approaches that focus on single nutrients or foods. Further research is needed to determine optimal dietary recommendations for both the prevention and treatment of iron deficiency.

Vitamin D and skeletal muscle function in athletes.

Purpose of reviewTo highlight recently published data about the vitamin D status of athletes, and effect of vitamin D supplementation on muscle strength and performance in the athletic population.The vitamin D receptor exists in skeletal muscle, and muscle weakness has been reported in individuals who are severely deficient [25(OH)D <25 nmol/l]. Experimental findings reveal the cellular and genomic mechanisms implicating vitamin D in muscle mass, strength and function, and raise questions about the role of vitamin D in the achievement of optimum athletic performance. Recent findingsAthletes appear to have the same risk of vitamin D deficiency and seasonal variance in status as nonathletic members of the same population, with the exception of athletes who train and compete indoors whose risk of deficiency is somewhat greater. Interventions with vitamin D supplements have had mixed results, with a positive effect on muscle function observed only in participants with insufficient status [25(OH)D <50 nmol/l]. SummaryThere have been relatively few robust interventions with vitamin D supplementation in athletic populations who are vitamin D deficient, and none which have been able to establish the ideal 25(OH)D concentration for optimum performance.

Role of nutrition in performance enhancement and postexercise recovery

A number of factors contribute to success in sport, and diet is a key component. An athlete’s dietary requirements depend on several aspects, including the sport, the athlete’s goals, the environment, and practical issues. The importance of individualized dietary advice has been increasingly recognized, including day-to-day dietary advice and specific advice before, during, and after training and/or competition. Athletes use a range of dietary strategies to improve performance, with maximizing glycogen stores a key strategy for many. Carbohydrate intake during exercise maintains high levels of carbohydrate oxidation, prevents hypoglycemia, and has a positive effect on the central nervous system. Recent research has focused on athletes training with low carbohydrate availability to enhance metabolic adaptations, but whether this leads to an improvement in performance is unclear. The benefits of protein intake throughout the day following exercise are now well recognized. Athletes should aim to maintain adequate levels of hydration, and they should minimize fluid losses during exercise to no more than 2% of their body weight. Supplement use is widespread in athletes, with recent interest in the beneficial effects of nitrate, beta-alanine, and vitamin D on performance. However, an unregulated supplement industry and inadvertent contamination of supplements with banned substances increases the risk of a positive doping result. Although the availability of nutrition information for athletes varies, athletes will benefit from the advice of a registered dietician or nutritionist.

Dietary Intake, Anthropometric Characteristics, and Iron and Vitamin D Status of Female Adolescent Ballet Dancers Living in New Zealand

Ballet dancing is a multifaceted activity requiring muscular power, strength, endurance, flexibility, and agility; necessitating demanding training schedules. Furthermore dancers may be under aesthetic pressure to maintain a lean physique, and adolescent dancers require extra nutrients for growth and development. This cross-sectional study investigated the nutritional status of 47 female adolescent ballet dancers (13-18 years) living in Auckland, New Zealand. Participants who danced at least 1 hr per day 5 days per week completed a 4-day estimated food record, anthropometric measurements (Dual-energy X-ray Absorptiometry) and hematological analysis (iron and vitamin D). Mean BMI was 19.7 ± 2.4 kg/m2 and percentage body fat, 23.5 ± 4.1%. The majority (89.4%) of dancers had a healthy weight (5th-85th percentile) using BMI-for-age growth charts. Food records showed a mean energy intake of 8097.3 ± 2155.6 kJ/day (48.9% carbohydrate, 16.9% protein, 33.8% fat, 14.0% saturated fat). Mean carbohydrate and protein intakes were 4.8 ± 1.4 and 1.6 ± 0.5 g/kg/day respectively. Over half (54.8%) of dancers consumed less than 5 g carbohydrate/kg/day, and 10 (23.8%) less than 1.2 g protein/kg/day. Over 60% consumed less than the estimated average requirement for calcium, folate, magnesium and selenium. Thirteen (28.3%) dancers had suboptimal iron status (serum ferritin (SF) < 20 μg/L). Of these, four had iron deficiency (SF < 12 μg/L, hemoglobin (Hb) ≥ 120 g/L) and one iron deficiency anemia (SF < 12 μg/L, Hb < 120 g/L). Mean serum 25-hydroxy vitamin D was 75.1 ± 18.6 nmol/L, 41 (91.1%) had concentrations above 50 nmol/L. Female adolescent ballet dancers are at risk for iron deficiency, and possibly inadequate nutrient intakes.

The effect of gold kiwifruit consumed with an iron fortified breakfast cereal meal on iron status in women with low iron stores: A 16 week randomised controlled intervention study

BackgroundDietary treatment is often recommended as the first line of treatment for women with mild iron deficiency. Although it is well established that ascorbic acid enhances iron absorption, it is less clear whether the consumption of ascorbic acid rich foods (such as kiwifruit) with meals fortified with iron improves iron status. The aim of this study is to investigate whether the consumption of ZESPRI® GOLD kiwifruit (a fruit high in ascorbic acid and carotenoids) with an iron fortified breakfast cereal meal increases iron status in women with low iron stores.Methods/DesignEighty nine healthy women aged 18-44 years with low iron stores (serum ferritin (SF) ≤ 25 μg/L, haemoglobin (Hb) ≥ 115 g/L) living in Auckland, New Zealand were randomised to receive an iron fortified breakfast cereal (16 mg iron per serve) and either two ZESPRI® GOLD kiwifruit or a banana (low ascorbic acid and carotenoid content) to eat at breakfast time every day for 16 weeks. Iron status (SF, Hb, C-reactive protein (CRP) and soluble transferrin receptor (sTfR)), ascorbic acid and carotenoid status were measured at baseline and after 16 weeks. Anthropometric measures, dietary intake, physical activity and blood loss were measured before and after the 16 week intervention.DiscussionThis randomised controlled intervention study will be the first study to investigate the effect of a dietary based intervention of an iron fortified breakfast cereal meal combined with an ascorbic acid and carotenoid rich fruit on improving iron status in women with low iron stores.Trial registrationACTRN12608000360314

Relationship between Long Chain n-3 Polyunsaturated Fatty Acids and Autism Spectrum Disorder: Systematic Review and Meta-Analysis of Case-Control and Randomised Controlled Trials.

Omega-3 long chain polyunsaturated fatty acid supplementation (n-3 LCPUFA) for treatment of Autism Spectrum Disorder (ASD) is popular. The results of previous systematic reviews and meta-analyses of n-3 LCPUFA supplementation on ASD outcomes were inconclusive. Two meta-analyses were conducted; meta-analysis 1 compared blood levels of LCPUFA and their ratios arachidonic acid (ARA) to docosahexaenoic acid (DHA), ARA to eicosapentaenoic acid (EPA), or total n-6 to total n-3 LCPUFA in ASD to those of typically developing individuals (with no neurodevelopmental disorders), and meta-analysis 2 compared the effects of n-3 LCPUFA supplementation to placebo on symptoms of ASD. Case-control studies and randomised controlled trials (RCTs) were identified searching electronic databases up to May, 2016. Mean differences were pooled and analysed using inverse variance models. Heterogeneity was assessed using I2 statistic. Fifteen case-control studies (n = 1193) were reviewed. Compared with typically developed, ASD populations had lower DHA (−2.14 [95% CI −3.22 to −1.07]; p < 0.0001; I2 = 97%), EPA (−0.72 [95% CI −1.25 to −0.18]; p = 0.008; I2 = 88%), and ARA (−0.83 [95% CI, −1.48 to −0.17]; p = 0.01; I2 = 96%) and higher total n-6 LCPUFA to n-3 LCPUFA ratio (0.42 [95% CI 0.06 to 0.78]; p = 0.02; I2 = 74%). Four RCTs were included in meta-analysis 2 (n = 107). Compared with placebo, n-3 LCPUFA improved social interaction (−1.96 [95% CI −3.5 to −0.34]; p = 0.02; I2 = 0) and repetitive and restricted interests and behaviours (−1.08 [95% CI −2.17 to −0.01]; p = 0.05; I2 = 0). Populations with ASD have lower n-3 LCPUFA status and n-3 LCPUFA supplementation can potentially improve some ASD symptoms. Further research with large sample size and adequate study duration is warranted to confirm the efficacy of n-3 LCPUFA.

Exploring the Relationship between Body Composition and Eating Behavior Using the Three Factor Eating Questionnaire (TFEQ) in Young New Zealand Women

Obesity is a leading cause of morbidity and mortality, yet is preventable. This study aimed to investigate associations between body mass index, body fat percentage and obesity-related eating behaviors. Women (n = 116; 18–44 years) were measured for height, weight and body fat using air displacement plethysmography (BodPod). Women completed the validated Three Factor Eating Questionnaire to assess their eating behaviors using Restraint, Disinhibition and Hunger eating factor categories and sub-categories. The eating behavior data were analyzed for associations with body mass index and body fat percentage, and comparisons across body mass index and body fat percentage categories (< vs. ≥25 kg/m2; < vs. ≥30%, respectively). Women had a mean (standard deviation) body mass index of 23.4 (3.5) kg/m2, and body fat percentage of 30.5 (7.6)%. Disinhibition was positively associated with both body mass index (p < 0.001) and body fat percentage (p < 0.001). Emotional Disinhibition was positively associated with body fat percentage (p < 0.028). Women with low Restraint and high Disinhibition had significantly higher body mass index and body fat percentage than women with high Restraint and low Disinhibition. Disinhibition seems likely to be an important contributor to obesity. Tailored intervention strategies focused on counteracting Disinhibition should be a key target area for managing weight/fat gain.

Iron status and self-perceived health, well-being, and fatigue in female university students living in New Zealand.

Objective: To determine the relationship between iron depletion and self-perceived health, well-being, and fatigue in a female university student population living in New Zealand. Methods: A total of 233 women aged 18–44 years studying at Massey University, Auckland, were included in this cross-sectional analysis. Serum ferritin (SF), hemoglobin (Hb), and C-reactive protein (CRP) were analyzed from a venipuncture blood sample. Participants completed the SF-36v2 General Health Survey (SF-36) and the Multidimensional Fatigue Symptom Inventory–Short Form (MFSI-SF) questionnaire, and anthropometric measurements (height and weight) and data on demographics, lifestyle, and medical history were obtained. Characteristics of iron-sufficient (SF ≥ 20 μg/L, Hb ≥ 120 g/L) and iron-depleted (SF < 20 μg/L, Hb ≥ 120 g/L) participants were compared, and multiple regression analyses were carried out to determine predictors of health, well-being, and fatigue using a p value of <0.01 to indicate statistical significance because multiple comparisons were being made. Results: There were no significant differences in self-perceived health and well-being determined using the SF-36 questionnaire between women who were iron sufficient and women who were iron depleted. Although MFSI-SF physical fatigue was significantly lower in those with iron depletion (p = 0.008), it was not predicted by current iron status in a multivariate model controlling for factors expected to be associated with iron status and fatigue (p = 0.037). However, smoking, a history of suboptimal iron status, and having a current medical condition were significant (negative) predictors of MFSI-SF physical fatigue, explaining 22.5% of the variance (p < 0.001). There were no significant differences in the other measures of fatigue determined using the MFSI-SF between women who were iron sufficient and those who were iron depleted. Conclusions: Women with iron depletion did not differ significantly from women who were iron sufficient with regard to self-perceived health, well-being, or fatigue. Future studies investigating fatigue should control for previous diagnosis of suboptimal iron status, smoking, and presence of a medical condition.

Associations between dietary patterns, socio-demographic factors and anthropometric measurements in adult New Zealanders: an analysis of data from the 2008/09 New Zealand Adult Nutrition Survey

PurposeTo investigate associations between dietary patterns, socio-demographic factors and anthropometric measurements in adult New Zealanders.MethodsDietary patterns were identified using factor analysis in adults 15 years plus (n = 4657) using 24-h diet recall data from the 2008/09 New Zealand Adult Nutrition Survey. Multivariate regression was used to investigate associations between dietary patterns and age, gender and ethnicity. After controlling for demographic factors, associations between dietary patterns and food insecurity, deprivation, education, and smoking were investigated. Associations between dietary patterns and body mass index and waist circumference were examined adjusting for demographic factors, smoking and energy intake.ResultsTwo dietary patterns were identified. ‘Healthy’ was characterised by breakfast cereal, low fat milk, soy and rice milk, soup and stock, yoghurt, bananas, apples, other fruit and tea, and low intakes of pies and pastries, potato chips, white bread, takeaway foods, soft drinks, beer and wine. ‘Traditional’ was characterised by beef, starchy vegetables, green vegetables, carrots, tomatoes, savoury sauces, regular milk, cream, sugar, tea and coffee, and was low in takeaway foods. The ‘healthy’ pattern was positively associated with age, female gender, New Zealand European or other ethnicity, and a secondary school qualification, and inversely associated with smoking, food insecurity, area deprivation, BMI and waist circumference. The ‘traditional’ pattern was positively associated with age, male gender, smoking, food insecurity and inversely associated with a secondary school qualification.ConclusionsA ‘Healthy’ dietary pattern was associated with higher socio-economic status and reduced adiposity, while the ‘traditional’ pattern was associated with lower socio-economic status.