Measuring voluntary dietary change in response to exercise : a focus on dietary fat

Traditional treatments for weight management have focussed on prescribed dietary restriction or regular exercise, or a combination of both. However recidivism for such prescribed treatments remains high, particularly among the overweight and obese. The aim of this thesis was to investigate voluntary dietary changes in the presence of prescribed mixed-mode exercise, conducted over 16 weeks. With the implementation of a single lifestyle change (exercise) it was postulated that the onerous burden of concomitant dietary and exercise compliance would be reduced, leading to voluntary lifestyle changes in such areas as diet. In addition, the failure of exercise as a single weight loss treatment has been reported to be due to compensatory energy intakes, although much of the evidence is from acute exercise studies, necessitating investigation of compensatory intakes during a long-term exercise intervention. Following 16 weeks of moderate intensity exercise, 30 overweight and obese (BMI≥25.00 kg.m-2) men and women showed small but statistically significant decreases in mean dietary fat intakes, without compensatory increases in other macronutrient or total energy intakes. Indeed total energy intakes were significantly lower for men and women following the exercise intervention, due to the decreases in dietary fat intakes. There was a risk that acceptance of the statistical validity of the small changes to dietary fat intakes may have constituted a Type 1 error, with false rejection of the Null hypothesis. Oro-sensory perceptions to changes in fat loads were therefore investigated to determine whether the measured dietary fat changes were detectable by the human palate. The ability to detect small changes in dietary fat provides sensory feedback for self-initiated dietary changes, but lean and overweight participants were unable to distinguish changes to fat loads of similar magnitudes to that measured in the exercise intervention study. Accuracy of the dietary measurement instrument was improved with the effects of random error (day-to-day variability) minimised with the use of a statistically validated 8-day, multiple-pass, 24 hour dietary recall instrument. However systematic error (underreporting) may have masked the magnitude of dietary change, particularly the reduction in dietary fat intakes. A purported biomarker (plasma Apolipoprotein A-IV) (apoA-IV) was subsequently investigated, to monitor systematic error in self-reported dietary intakes. Changes in plasma apoA-IV concentrations were directly correlated with increased and decreased changes to dietary fat intakes, suggesting that this objective marker may be a useful tool to improve the accuracy of dietary measurement in overweight and obese populations, who are susceptible to dietary underreporting.

The effects of dietary fish oil on inflammation, fibrosis and oxidative stress associated with obstructive renal injury in rats.

Scope: We examined whether dietary supplementation with fish oil modulates inflammation, fibrosis and oxidative stress following obstructive renal injury. Methods and results: Three groups of Sprague-Dawley rats (n = 16 per group) were fed for 4 wk on normal rat chow (oleic acid), chow containing fish oil (33 g eicosapentaenoic acid and 26 g docosahexaenoic acid per kg diet), or chow containing safflower oil (60 g linoleic acid per kg diet). All diets contained 7% fat. After 4 wk, the rats were further subdivided into four smaller groups (n = 4 per group). Unilateral ureteral obstruction was induced in three groups (for 4, 7 and 14 days). The fourth group for each diet did not undergo surgery, and was sacrificed as controls at 14 days. When rats were sacrificed, plasma and portions of the kidneys were removed and frozen; other portions of kidney tissue were fixed and prepared for histology. Compared with normal chow and safflower oil, fish oil attenuated collagen deposition, macrophage infiltration, TGF-beta expression, apoptosis, and tissue levels of arachidonic acid, MIP-1 alpha, IL-1 beta, MCP-1 and leukotriene B(4). Compared with normal chow, fish oil increased the expression of HO-1 protein in kidney tissue. Conclusions: Fish oil intake reduced inflammation, fibrosis and oxidative stress following obstructive renal injury.

Food insecurity among adults residing in disadvantaged urban areas : potential health and dietary consequences

Objective: Food insecurity is the limited or uncertain availability or access to nutritionally-adequate, culturally-appropriate and safe foods. Food insecurity may result in inadequate dietary intakes, overweight or obesity and the development of chronic disease. Internationally, few studies have focused on the range of potential health outcomes related to food insecurity among adults residing in disadvantaged locations and no such Australian studies exist. The objective of this study was to investigate associations between food insecurity, socio-demographic and health factors and dietary intakes among adults residing in disadvantaged urban areas. Design: Data were collected by mail survey (n= 505, 53% response rate), which ascertained information about food security status, demographic characteristics (such as age, gender, household income, education) fruit and vegetable intakes, take-away and meat consumption, general health, depression and chronic disease. Setting: Disadvantaged suburbs of Brisbane city, Australia, 2009. Subjects: Individuals aged ≥ 20 years. Results: Approximately one-in-four households (25%) were food insecure. Food insecurity was associated with lower household income, poorer general health, increased healthcare utilisation and depression. These associations remained after adjustment for age, gender and household income. Conclusion: Food insecurity is prevalent in urbanised disadvantaged areas in developed countries such as Australia. Low-income households are at high risk of experiencing food insecurity. Food insecurity may result in significant health burdens among the population, and this may be concentrated in socioeconomically-disadvantaged suburbs.

Potential dietary consquences of food insecurity among Australian adults residing in urbanised disadvantaged areas

Introduction: Food insecurity is the limited/uncertain availability, access to or ability to acquire nutritionally-adequate, culturallyrelevant and safe foods. Adults suffering from food insecurity are at risk of inadequate nutrient intakes or, paradoxically, overweight/ obesity and the development of chronic disease. Despite the global financial crisis and rising costs of living, there are few studies investigating the potential dietary consequences of food insecurity among the Australian population. This study examined whether food insecurity was associated with weight status and poorer intakes of fruits, vegetable and takeaway foods among adults residing in socioeconomically-disadvantaged urbanised areas. Methods: In this cross-sectional study, a random sample of residents (n=1000) were selected from the most disadvantaged suburbs of Brisbane city (response rate 51%). Data were collected by postal questionnaire which ascertained information on sociodemographic information, household food security status, height, weight, fruit and vegetable intakes and takeaway consumption. Data were analysed using chi-square and logistic regression. Results: The overall prevalence of food insecurity was 31%. Food insecurity was not associated with weight status among men or women. Associations between food security status and potential dietary consequences differed for men and women. Among women, food security was not associated with intakes of fruit, vegetable or takeaway consumption. Contrastingly, among men food security was associated with vegetable intakes and consumption of takeaway food: men reporting food insecurity had lower intakes of vegetables and were more likely to consume takeaway foods compared to those that were food secure. Conclusion: Food security is an important public health issue in Australia and has potential dietary consequences that may adversely affect the health of food-insecure groups, most notably men residing in food-insecure households.

Potential health and dietary consequences of food insecurity among Australian adults residing in urbanised disadvantaged areas

Purpose: Food insecurity is the limited/uncertain availability or ability to acquire nutritionally-adequate, culturally-relevant and safe foods. Adults suffering from food insecurity are at risk of inadequate nutrient intakes or, paradoxically, overweight/obesity and the development of chronic disease. Despite the global financial crisis and rising costs of living, few studies have investigated the potential dietary and health consequences of food insecurity among the Australian population. This study examined whether food insecurity was associated with health behaviours and dietary intakes among adults residing in socioeconomically-disadvantaged urbanised areas. Methods: In this cross-sectional study, a random sample of residents (n = 1000) were selected from the most disadvantaged suburbs of Brisbane city (response rate 51%). Data were collected by postal questionnaire which ascertained information on socio-demographic information, household food security, height, weight, frequency of healthcare utilisation, presence of chronic disease and intakes of fruit, vegetables and take-away. Data were analysed using logistic regression. Results/Findings: The prevalence of food insecurity was 25%. Those reporting food insecurity were two-to-three times more likely to have seen a general practitioner or been hospitalised within the previous 6 months. Furthermore, food insecurity was associated with a three-to-six-fold increase in the likelihood of experiencing depression. Food insecurity was associated with higher intakes of some take-away foods, however was not significantly associated with weight status or intakes of fruits or vegetables among this disadvantaged sample. Conclusion: Food insecurity has potential adverse health consequences that may result in significant health burdens among the population, and this may be concentrated in socioeconomically-disadvantaged suburbs.

Is there a place for pixels in our practice? Dietitians' attitudes towards the use of photographic dietary records within the nutrition care process

Photographic records of dietary intake (PhDRs) are an innovative method for the dietary assessment and may alleviate the burden of recording intake compared to traditional methods of recording intake. While the performance of PhDRs has been evaluated, no investigation into the application of this method had occurre within dietetic practice. This study examined the attitudes of dietitians towards the use of PhDRs in the provision of nutrition care. A web-based survey on the practices and beliefs with regards to technology use among Dietitians Association of Australia members was conducted in August 2011. Of the 87 dietitians who responded, 86% assessed the intakes of clients as part of individualised medical nutrition therapy, with the diet history the most common method used. The majority (91%) of dietitians surveyed believed that a PhDR would be of use in their current practice to estimate intake. Information contained in the PhDR would primarily be used to obtain a qualitative evaluation of diet (84%) or to supplement an existing assessment method (69%), as opposed to deriving an absolute measure of nutrient intake (31%). Most (87%) indicated that a PhDR would also be beneficial in both the delivery of the intervention and to evaluate and monitor goals and outcomes, while only 46% felt that a PhDR would assist in determining the nutrition diagnosis. This survey highlights the potential for the use of PhDRs within practice. Future endeavours lie in establishing resources which support the inclusion of PhDRs within the nutrition care process.

Nutritional status and dietary intake of acute care patients : results from the Nutrition Care Day Survey 2010

Background & aims: One aim of the Australasian Nutrition Care Day Survey was to determine the nutritional status and dietary intake of acute care hospital patients. Methods: Dietitians from 56 hospitals in Australia and New Zealand completed a 24-h survey of nutritional status and dietary intake of adult hospitalised patients. Nutritional risk was evaluated using the Malnutrition Screening Tool. Participants ‘at risk’ underwent nutritional assessment using Subjective Global Assessment. Based on the International Classification of Diseases (Australian modification), participants were also deemed malnourished if their body mass index was <18.5 kg/m2. Dietitians recorded participants’ dietary intake at each main meal and snacks as 0%, 25%, 50%, 75%, or 100% of that offered. Results: 3122 patients (mean age: 64.6 ± 18 years) participated in the study. Forty-one percent of the participants were “at risk” of malnutrition. Overall malnutrition prevalence was 32%. Fifty-five percent of malnourished participants and 35% of well-nourished participants consumed ≤50% of the food during the 24-h audit. “Not hungry” was the most common reason for not consuming everything offered during the audit. Conclusion: Malnutrition and sub-optimal food intake is prevalent in acute care patients across hospitals in Australia and New Zealand and warrants appropriate interventions.

Raman and infrared spectroscopic characterization of beryllonite, a sodium and beryllium phosphate mineral : implications for mineral collectors

The mineral beryllonite has been characterized by the combination of Raman spectroscopy and infrared spectroscopy. SEM–EDX was used for the chemical analysis of the mineral. The intense sharp Raman band at 1011 cm-1, was assigned to the phosphate symmetric stretching mode. Raman bands at 1046, 1053, 1068 and the low intensity bands at 1147, 1160 and 1175 cm-1 are attributed to the phosphate antisymmetric stretching vibrations. The number of bands in the antisymmetric stretching region supports the concept of symmetry reduction of the phosphate anion in the beryllonite structure. This concept is supported by the number of bands found in the out-of-plane bending region. Multiple bands are also found in the in-plane bending region with Raman bands at 399, 418, 431 and 466 cm-1. Strong Raman bands at 304 and 354 cm-1 are attributed to metal oxygen vibrations. Vibrational spectroscopy served to determine the molecular structure of the mineral. The pegmatitic phosphate minerals such as beryllonite are more readily studied by Raman spectroscopy than infrared spectroscopy.

Variability in estimation of self-reported dietary intake data from elite athletes resulting from coding by different sports dietitians

A routine activity for a sports dietitian is to estimate energy and nutrient intake from an athlete's self-reported food intake. Decisions made by the dietitian when coding a food record are a source of variability in the data. The aim of the present study was to determine the variability in estimation of the daily energy and key nutrient intakes of elite athletes, when experienced coders analyzed the same food record using the same database and software package. Seven-day food records from a dietary survey of athletes in the 1996 Australian Olympic team were randomly selected to provide 13 sets of records, each set representing the self-reported food intake of an endurance, team, weight restricted, and sprint/power athlete. Each set was coded by 3-5 members of Sports Dietitians Australia, making a total of 52 athletes, 53 dietitians, and 1456 athlete-days of data. We estimated within- and between- athlete and dietitian variances for each dietary nutrient using mixed modeling, and we combined the variances to express variability as a coefficient of variation (typical variation as a percent of the mean). Variability in the mean of 7-day estimates of a nutrient was 2- to 3-fold less than that of a single day. The variability contributed by the coder was less than the true athlete variability for a 1-day record but was of similar magnitude for a 7-day record. The most variable nutrients (e.g., vitamin C, vitamin A, cholesterol) had approximately 3-fold more variability than least variable nutrients (e.g., energy, carbohydrate, magnesium). These athlete and coder variabilities need to be taken into account in dietary assessment of athletes for counseling and research.

The location of Ti atom in sodium alanate : an ab initio spin-polarised study

In this work, ab initio spin-polarised Density Functional Theory (DFT) calculations are performed to study the interaction of a Ti atom with a NaAlH4(001) surface. We confirm that an interstitially located Ti atom in the NaAlH4 subsurface is the most energetically favoured configuration as recently reported (Chem. Comm. (17) 2006, 1822). On the NaAlH4(001) surface, the Ti atom is most stable when adsorbed between two sodium atoms with an AlH4 unit beneath. A Ti atom on top of an Al atom is also found to be an important structure at low temperatures. The diffusion of Ti from the Al-top site to the Na-bridging site has a low activation barrier of 0.20 eV and may be activated at the experimental temperatures (∼323 K). The diffusion of a Ti atom into the energetically favoured subsurface interstitial site occurs via the Na-bridging surface site and is essentially barrierless.

Vacancy mediated desorption of hydrogen from a sodium alanate surface : An ab initio spin-polarized study

Ab initio spin-polarized density functional theory calculations are performed to explore the effect of single Na vacancy on NaAlH4(001) surface on the initial dehydrogenation kinetics. The authors found that two Al–H bond lengths become elongated and weakened due to the presence of a Na vacancy on the NaAlH4(001) surface. Spontaneous recombination from the surface to form molecular hydrogen is observed in the spin-polarized ab initio molecular dynamics simulation. The authors’ results indicate that surface Na vacancies play a critical role in accelerating the dehydrogenation kinetics in sodium alanate. The understanding gained here will aid in the rational design and development of complex hydride materials for hydrogen storage

Effects of soluble dietary cellulose on specific growth rate, survival and digestive enzyme activities in three freshwater crayfish (Cherax) species

Three native freshwater crayfish Cherax species are farmed in Australia namely; Redclaw (Cherax quadricarinatus), Marron (C. tenuimanus), and Yabby (C. destructor). Lack of appropriate data on specific nutrient requirements for each of these species, however, has constrained development of specific formulated diets and hence current use of over-formulated feeds or expensive marine shrimp feeds, limit their profitability. A number of studies have investigated nutritional requirements in redclaw that have focused on replacing expensive fish meal in formulated feeds with non-protein, less expensive substitutes including plant based ingredients. Confirmation that freshwater crayfish possess endogenous cellulase genes, suggests their potential ability to utilize complex carbohydrates like cellulose as nutrient sources in their diet. To date, studies have been limited to only C. quadricarinatus and C. destructor and no studies have compared the relative ability of each species to utilize soluble cellulose in their diets. Individual feeding trials of late-juveniles of each species were conducted separately in an automated recirculating culture system over 12 week cycles. Animals were fed either a test diet (TD) that contained 20% soluble cellulose or a reference diet (RD) substituted with the same amount of corn starch. Water temperature, conductivity and pH were maintained at constant and optimum levels for each species. Animals were fed at 3% of their body weight twice daily and wet body weight was recorded bi-weekly. At the end of experiment, all animals were harvested, measured and midgut gland extracts assayed for alpha-amylase, total protease and cellulase activity levels. After the trial period, redclaw fed with RD showed significantly higher (p<0.05) specific growth rate (SGR) compare with animals fed the TD while SGR of marron and yabby fed the two diets were not significantly different (p<0.05). Cellulase expression levels in redclaw were not significantly different between diets. Marron and yabby showed significantly higher cellulase activity when fed the RD. Amylase and protease activity in all three species were significantly higher in the animals fed with RD (Table 1). These results indicate that test animals of all species can utilize starch better than dietary soluble cellulose in their diet and inclusion of 20% soluble cellulose in diets does not appear to have any significant negative effect on their growth rate but survival was impacted in C. quadricarinatus while not in C. tenuimanus or C. destructor.

Effects of soluble dietary cellulose on specific growth rate, survival and digestive enzyme activities in three freshwater crayfish (Cherax) species

The current study evaluated the effect of soluble dietary cellulose on growth, survival and digestive enzyme activity in three endemic, Australian freshwater crayfish species (redclaw: Cherax quadricarinatus, marron: C. tenuimanus, yabby: C. destructor). Separate individual feeding trials were conducted for late-stage juveniles from each species in an automated recirculating freshwater, culture system. Animals were fed either a test diet (TD) that contained 20% soluble cellulose or a reference diet (RD) substituted with the same amount of corn starch, over a 12 week period. Redclaw fed with RD showed significantly higher (p<0.05) specific growth rates (SGR) compared with animals fed the TD, while SGR of marron and yabby fed the two diets were not significantly different. Expressed cellulase activity levels in redclaw were not significantly different between diets. Marron and yabby showed significantly higher cellulase activity when fed the RD (p<0.05). Amylase and protease activity in all three species were significantly higher in the animals fed with RD (p<0.05). These results indicate that test animals of all three species appear to utilize starch more efficiently than soluble dietary cellulose in their diet. The inclusion of 20% soluble cellulose in diets did not appear, however, to have a significant negative effect on growth rates.

trans-Polyacetylene on sodium and cesium mordenites: a resonance Raman spectroscopic study

Sodium and cesium mordenite (denoted NaM and CsM, respectively) were investigated as potential catalysts for the synthesis of polyacetylene ((CH) x). Both were successful in initiating polymerization of purified gaseous acetylene at room temperature as evidenced by Raman spectroscopic studies. The polyacetylene synthesised in this way exhibited resonance enhancement of the polyene skeletal vibrations. trans-Polyacetylene, but no cis-(CH) x, was detected. As no apparent coloration of the NaM and CsM substrates accompanied the formation of trans-(CH) x it was concluded that only small quantities of the polymer were present. The number of conjugated double bonds was estimated from the frequencies of the Raman active C-C and C=C stretching vibrations, and it was shown that the trans-(CH) x formed on CsM has a distribution of conjugation lengths ranging from less than 6 to at least 30 double bonds. The polyacetylene formed on NaM was significantly shorter and was produced in lower yields than that synthesized on CsM. "Sliced" resonance excitation profiles of polyacetylene formed on CsM were obtained using nearly 40 different excitation wavelengths and these confirmed that the adsorbed trans-(CH) x was composed of segments having a distribution of conjugated lengths. The architecture of the mordenite pore system permitted only a single polymer molecule per channel, thereby preventing cross-linking. Raman spectroscopic studies of the effects of exposure to air revealed that progressive oxidative degradation occurred with a reduction in the number of conjugated double bond