The impact of leucine supplementation on body composition and glucose tolerance following energy restriction: an 8-week RCT in adults at risk of the metabolic syndrome.

BACKGROUND: L-Leucine (Leu) supplementation may benefit fat-free mass (FFM) per se and glucose metabolism. OBJECTIVES: To determine whether Leu supplementation during energy restriction blunted the loss of FFM, enhanced the loss of fat mass (FM) and improved glucose tolerance. DESIGN: Thirty-seven adults, aged 20-65 years, with increased waist circumference and at least one other metabolic syndrome (MetS) component, were selected. We employed a two-arm parallel, double blind, randomized control trial (RCT) design. Participants were randomly assigned to an intervention group (leucine - 3 g/d) or placebo (lactose - 2.67 g/d), while following an individualised energy restricted diet for an 8-week period. Detailed body composition (DEXA), oral glucose tolerance test (OGTT), insulin and components of MetS were measured before and after the trial. Analysis of covariance (ANCOVA) assessed the effect of Leu on an intention-to-treat (ITT) principle. Bootstrapping method with 1000 bootstrap samples was used to derive parameter estimates, standard errors, p-values, and 95% confidence intervals for all outcomes. RESULTS: Adjusted for baseline values and other covariates, FFM (p = 0.045) and lean tissue mass (LTM) (p = 0.050) were significantly higher following Leu. These outcomes were modified by a significant treatment x sex interaction that indicated Leu had the greater effect in men. However, on adjustment for body composition changes, there was no difference in insulin sensitivity, oral glucose tolerance, or change in MetS components following Leu. CONCLUSION: Short-term leucine supplementation during energy restriction resulted in a greater preservation of FFM and LTM particularly in men, but did not impact glucose metabolism.

Omega-3 Index, fish consumption, use of fish oil supplements and first clinical diagnosis of central nervous system demyelination.

Higher intakes of omega-3 polyunsaturated fatty acids (n3PUFAs) have been associated with lower MS risk. We aimed to test associations between the Omega-3 Index, blood levels of n3PUFAs, fish oil supplement use, and fish consumption with a first clinical diagnosis of CNS demyelination (FCD). Cases (n = 250) had a higher Omega-3 Index compared with a matched group of controls (n = 471) (average treatment effect (ATE)=0.31, p = 0.047, based on augmented inverse probability weighting). A higher percentage of cases than controls used fish oil supplements (cases=17% vs. controls=10%). We found that Omega-3 Index increased as time between FCD and study interview increased (e.g., at or below median (112 days), based on ATE, mean=5.30, 95% CI 5.08, 5.53; above median, mean=5.90, 95% CI 5.51, 6.30). Fish oil supplement use increased in a similar manner (at or below median (112 days), based on ATE, proportion=0.12, 95% CI 0.06, 0.18; above the median, proportion=0.21, 95% CI 0.14, 0.28). Our results suggest a behaviour change post FCD with increased use of fish oil supplements.

High-dose thiamine supplementation may reduce resting energy expenditure in individuals with hyperglycemia: a randomized, double - blind cross-over trial.

BACKGROUND: Despite the crucial role of thiamine in glucose and energy metabolism pathways, there has been no published study examining the impact of thiamine on energy metabolism in humans. OBJECTIVE: To assess the effects of thiamine supplementation on resting energy expenditure (REE) in individuals with hyperglycemia. METHODS: Twelve hyperglycemic patients completed this double-blind, randomized trial, where all participants received both thiamine (300 mg/day) and matched placebo for 6 weeks in a cross-over manner. REE was assessed by indirect calorimetry. Anthropometric measurements, fasting and 2-h plasma glucose, and glucose-induced thermogenesis were also assessed at the beginning and on the completion of each six-week phase. RESULTS: Participants consuming thiamine supplements experienced a significant decrease in the REE assessed at week six compared to the baseline [mean (SE): 1478.93 (73.62) vs.1526.40 (73.46) kcal/d, p = 0.02], and the placebo arm (p = 0.002). These results did not change significantly after adjusting for the participants' body weight and physical activity as potential confounders. Six-week intervention had no significant effect on the participants' body weight or waist circumference, in either supplement or placebo arms (all p values>0.05). However, correlation analysis highlighted significant positive relationships between the changes in REE, and those in fasting (rs = 0.497, p = 0.019) and 2-h plasma glucose (rs = 0.498, p = 0.018) during the six-week intervention period. CONCLUSION: Supplementation with high-dose thiamine may attenuate REE in patients with impaired glucose regulation. Our findings suggest that the impact of thiamine on REE may in part be explained by improved glycemic control. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12611000051943. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12611000051943.

Higher fish consumption and lower risk of central nervous system demyelination.

BACKGROUND/OBJECTIVES: The evidence for diet as a risk factor for multiple sclerosis (MS) is inconclusive. We examined the associations between fish consumption and risk of a first clinical diagnosis of central nervous system demyelination (FCD), a common precursor to MS. METHODS: The 2003-2006 Ausimmune Study was a case-control study examining environmental risk factors for FCD, with participants recruited from four regions of Australia and matched on age, sex, and study region. Dietary intake data were collected using a food frequency questionnaire. We used conditional logistic regression models to test associations between fish consumption (total, tinned, grilled, and fried) and risk of FCD (249 cases and 438 controls), adjusting for history of infectious mononucleosis, smoking, serum 25-hydroxyvitamin D concentrations, socio-economic status, omega-3 supplement use, dietary under-reporting, and total energy intake. RESULTS: Higher total fish consumption (per 30 g/day, equivalent to two serves/week) was associated with an 18% reduced risk of FCD (AOR 0.82; 95% CI 0.70, 0.97). While we found no statistically significant associations between grilled and fried fish consumption and risk of FCD, higher tinned fish consumption (per 30 g/day) was associated with a 41% reduced risk of FCD (AOR 0.59; 95% CI 0.39, 0.89). CONCLUSIONS: Tinned fish is predominantly oily, whereas grilled and fried fish are likely to be a combination of oily and white types. Oily fish is high in vitamin D and very long chain polyunsaturated omega-3 fatty acids, both of which may be beneficial in relation to MS.

Prevalence and predictors of vitamin D deficiency in a nationally representative sample of adults participating in the 2011-2013 Australian Health Survey.

Vitamin D deficiency is recognised as a public health problem globally, and a high prevalence of deficiency has previously been reported in Australia. This study details the prevalence of vitamin D deficiency in a nationally representative sample of Australian adults aged ≥25 years, using an internationally standardised method to measure serum 25-hydroxyvitamin D (25(OH)D) concentrations and identifies demographic and lifestyle factors associated with vitamin D deficiency. We used data from the 2011-2013 Australian Health Survey (n 5034 with complete information on potential predictors and serum 25(OH)D concentrations). Serum 25(OH)D concentrations were measured by a liquid chromatography-tandem MS that is certified to the reference measurement procedures developed by the National Institute of Standards and Technology, Ghent University and the US Centers for Disease Control and Prevention. Vitamin D deficiency and insufficiency were defined as serum 25(OH)D concentrations <50 nmol/l and 50 to <75 nmol/l, respectively. Overall, 20 % of participants (19 % men; 21 % women) were classified as vitamin D deficient, with a further 43 % classified as insufficient (45 % men; 42 % women). Independent predictors of vitamin D deficiency included being born in a country other than Australia or the main English-speaking countries, residing in southern (higher latitude) states of Australia, being assessed during winter or spring, being obese, smoking (women only), having low physical activity levels and not taking vitamin D or Ca supplements. Given our increasingly indoor lifestyles, there is a need to develop and promote strategies to maintain adequate vitamin D status through safe sun exposure and dietary approaches.

Iodine-containing supplement use by pregnant women attending antenatal clinics in Western Australia.

BACKGROUND: Iodine requirements increase during pregnancy and although national recommendations for daily iodine supplementation (150 µg) exist, there is no research related to the uptake of these recommendations by pregnant women in Western Australia. AIMS: To investigate the use of iodine-containing supplements and associations with their use in a sample of Western Australian pregnant women. MATERIALS AND METHODS: A cross-sectional study was conducted on pregnant women attending antenatal clinics in a public tertiary hospital for women and neonates in Perth during 2012 and 2013 (n = 425). Women completed a self-administered questionnaire. Frequencies and percentages were obtained for categorical variables and χ2 tests conducted to assess associations between iodine-containing supplement use and sociodemographic and pregnancy-related factors. RESULTS: A total of 24% of pregnant women reported using iodine-containing supplements prior to pregnancy compared to 66% during the previous two months. Age and maternal income were associated with use prior to pregnancy only (P = 0.004 and P = 0.031) and first pregnancy was associated with use during pregnancy only (P = 0.006). Ethnicity and reporting use in the first two trimesters were associated with the use of iodine supplements both in the year prior to pregnancy (P = 0.002 and P = 0.020, respectively) and during pregnancy (P < 0.001 and P = 0.001, respectively). CONCLUSIONS: Two-thirds of women reported use of iodine-containing supplements during pregnancy, within the range reported for other Australian states. One-quarter reported use prior to pregnancy. Public health strategies are required to promote awareness of the importance of iodine and supplementation both before and during the entire pregnancy.

The Prevalence and Predictors of Dietary Supplement Use in the Australian Population.

Current dietary supplement use in Australia is not well described. We investigated the prevalence and predictors of supplement use in the Australian population (n = 19,257) using data from the 2014-2015 National Health Survey. We reported the prevalence of supplement use by sex and age group and investigated the independent predictors of supplement use in adults, adolescents, and children using multiple logistic regression models. A total of 43.2% of adults (34.9% of males, 50.3% of females), 20.1% of adolescents (19.7% of males, 20.6% of females), and 23.5% of children (24.4% of males, 22.5% of females) used at least one dietary supplement in the previous two weeks. The most commonly used supplements were multivitamins and/or multiminerals and fish oil preparations. In adults, independent predictors of supplement use included being female, increasing age, being born outside Australia and other main English-speaking countries, having a higher education level, having a healthy BMI compared to those who were obese, being physically active, and being a non-smoker. To our knowledge, this is the first detailed investigation of dietary supplement use in a nationally-representative sample of the Australian population. Future studies investigating the contribution of supplements to overall dietary intakes of vitamins, minerals, and omega-3 fatty acids are warranted.

In Pursuit of Vitamin D in Plants.

Vitamin D deficiency is a global concern. Much research has concentrated on the endogenous synthesis of vitamin D in human skin following exposure to ultraviolet-B radiation (UV-B, 280-315 nm). In many regions of the world there is insufficient UV-B radiation during winter months for adequate vitamin D production, and even when there is sufficient UV-B radiation, lifestyles and concerns about the risks of sun exposure may lead to insufficient exposure and to vitamin D deficiency. In these situations, dietary intake of vitamin D from foods or supplements is important for maintaining optimal vitamin D status. Some foods, such as fatty fish and fish liveroils, certain meats, eggs, mushrooms, dairy, and fortified foods, can provide significant amounts of vitamin D when considered cumulatively across the diet. However, little research has focussed on assessing edible plant foods for potential vitamin D content. The biosynthesis of vitamin D in animals, fungi and yeasts is well established; it is less well known that vitamin D is also biosynthesised in plants. Research dates back to the early 1900s, beginning with in vivo experiments showing the anti-rachitic activity of plants consumed by animals with induced rickets, and in vitro experiments using analytical methods with limited sensitivity. The most sensitive, specific and reliable method for measuring vitamin D and its metabolites is by liquid chromatography tandem mass spectrometry (LC-MS/MS). These assays have only recently been customised to allow measurement in foods, including plant materials. This commentary focuses on the current knowledge and research gaps around vitamin D in plants, and the potential of edible plants as an additional source of vitamin D for humans.

Comparing the effects of sun exposure and vitamin D supplementation on vitamin D insufficiency, and immune and cardio-metabolic function: the Sun Exposure and Vitamin D Supplementation (SEDS) Study.

BACKGROUND: Adults living in the sunny Australian climate are at high risk of skin cancer, but vitamin D deficiency (defined here as a serum 25-hydroxyvitamin D (25(OH)D) concentration of less than 50 nmol/L) is also common. Vitamin D deficiency may be a risk factor for a range of diseases. However, the optimal strategies to achieve and maintain vitamin D adequacy (sun exposure, vitamin D supplementation or both), and whether sun exposure itself has benefits over and above initiating synthesis of vitamin D, remain unclear. The Sun Exposure and Vitamin D Supplementation (SEDS) Study aims to compare the effectiveness of sun exposure and vitamin D supplementation for the management of vitamin D insufficiency, and to test whether these management strategies differentially affect markers of immune and cardio-metabolic function. METHODS/DESIGN: The SEDS Study is a multi-centre, randomised controlled trial of two different daily doses of vitamin D supplementation, and placebo, in conjunction with guidance on two different patterns of sun exposure. Participants recruited from across Australia are aged 18-64 years and have a recent vitamin D test result showing a serum 25(OH)D level of 40-60 nmol/L. DISCUSSION: This paper discusses the rationale behind the study design, and considers the challenges but necessity of data collection within a non-institutionalised adult population, in order to address the study aims. We also discuss the challenges of participant recruitment and retention, ongoing engagement of referring medical practitioners and address issues of compliance and participant retention. TRIAL REGISTRATION: Australia New Zealand Clinical Trials Registry: ACTRN12613000290796 Registered 14 March 2013.

Developing a self-administered questionnaire as a guide to consultations with women treated for breast cancer.

Background. Health professionals, including general practitioners involved in followup of breast cancer patients, need to systematically assess opportunities to offer patients support with ongoing or new problems. Methods. A self-administered needs assessment questionnaire was developed with reference to a multidisciplinary team. Short, evidence-based, readable questions were emphasized, and questions were tested for face validity. The questions flowed across three domains: physical, social, and psychological. Content validity and user friendliness were assessed. Results. A final set of 30 questions was rated as easy to read and comprehend (Flesch Reading Ease score 65.8 and Flesch-Kincaid Grade Level 6.9). When piloted with twenty-one patients the self-administered questionnaire detected 121 items of unmet need encompassing all three domains. Conclusions. This self-administered questionnaire has the potential to assist in the holistic assessment of breast cancer patient after treatment. The clinical value of the self-administered questionnaire will need to be further tested before it can be widely adopted.