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    Nitrate-rich beetroot juice and its effects on cardiovascular health and cognition in younger and older adults : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Sport and Exercise Science at Massey University, Auckland, New Zealand
    (Massey University, 2022) Stanaway, Luke
    Background: Evidence suggests supplementation with nitrate-rich beetroot juice (BR) may improve cardiovascular responses and cognition in male and female, younger and older adults. However, there is still limited research in this area, particularly in older adults and with regards to measures of endothelial and cognitive function where equivocal findings have been observed. In addition, it is unclear whether age-related differences impact on the benefits from dietary nitrate supplementation. Older adults tend to have an increase in blood pressure (BP) and decline in cognition with aging, and thus may respond more favourably to BR supplementation compared to younger adults. Additionally, the effects of dose and duration (acute versus chronic) of supplementation with dietary nitrate are still not well known. Overall aims: To 1) investigate the effects of varying doses of nitrate-rich BR on cardiovascular responses and cognition in older adults, and 2) examine the effects of acute and chronic supplementation with BR on cardiovascular responses and cognition in the two age groups. Methods: The “Dose-response study” (Chapter 4) examined the effects of acute supplementation with varying doses of BR (0.15 (placebo; PL), 2.5, 4.9, and 9.8 mmol nitrate) on cardiovascular and cognitive responses in older adults (50-80 years; n=11) in a randomised, double-blind, crossover designed trial. At each visit, resting blood samples for plasma nitrate and nitrite, BP, mean arterial pressure (MAP), systemic vascular resistance (SVR), heart rate (HR), resting metabolic rate, and cognitive function were completed pre- and 2.25 h post-supplementation. The “Acute study” (Chapter 5) was a randomised, double-blind, crossover study. Twenty-four participants, 13 younger (18-30 years) and 11 older (50-70 years), completed resting blood samples, BP, HR, cognitive function, and mood and perceptual measurements pre- and post-supplementation with nitrate-rich BR (10.5 mmol) or placebo (1 mmol). The “Chronic study” (Chapter 6) was a double-blind, randomised control trial investigating acute, acute + chronic, chronic + acute (exercise performance) and chronic supplementation with either nitrate-rich BR (10.5 mmol) or PL (0.15 mmol) over 28 days in 21 younger (18-30 years) and 22 older (50-80 years) adults. On days 0, 14, and 28 resting blood samples, BP, MAP, SVR, HR, and cognitive performance measures were completed pre- and 2.25 h post-supplementation, while oxygen uptake (V̇O₂) and time trial performance were measured 2.5 h post-supplementation. Results: Ingestion of varying doses of dietary nitrate in the Dose-response study increased plasma nitrate and nitrite concentrations in a dose-dependent manner, with a significant difference shown between each treatment for plasma nitrate (p < 0.001). However, plasma nitrite was only significantly increased following consumption of the 9.8 mmol treatment compared to PL (p = 0.004). Systolic blood pressure (SBP), diastolic blood pressure (DBP), and MAP were reduced 2.25 h post-supplementation with the 9.8 mmol treatment compared to the PL, 2.5, and 4.9 mmol treatments (p < 0.05). Following supplementation with the 9.8 mmol dose, Corsi span (cognitive function) was improved during the Corsi block tapering test (CBT) compared to PL (p = 0.013) and 2.5 mmol (p = 0.004) treatments. In the Acute study, supplementation with nitrate-rich BR also significantly increased plasma nitrate (p < 0.001) and nitrite (p = 0.003) concentrations in younger and older adults relative to PL. Systolic BP was reduced in both younger and older adults (p < 0.001) 2.25 h post-supplementation with BR compared to PL, while DBP was only reduced in older adults (p = 0.013). Older adults had a greater increase in plasma nitrite (p = 0.038) and reduction in DBP (p = 0.005) compared to younger adults. Cognitive performance measures were also improved in younger and older adults following acute supplementation with nitrate-rich BR, with a reduction in reaction time observed during the Stroop test (p = 0.045). The Chronic study showed a significant reduction in SBP, DBP, and MAP following acute supplementation with nitrate-rich BR on day 0 in older adults (p < 0.001) and following an acute dose in the context of chronic supplementation (acute + chronic) on day 28 in both older (p < 0.01) and younger (p < 0.05) adults. Fourteen days’ chronic supplementation with nitrate-rich BR, in the absence of an acute dose, also reduced SBP (p = 0.019), DBP (p = 0.004), and MAP (p = 0.005) in older but not younger adults. Older compared to younger adults also had a greater reduction in SBP, DBP, and MAP following acute supplementation with nitrate-rich BR on day 0 (p < 0.05) and following chronic supplementation on day 14 (p < 0.05). Acute + chronic supplementation with nitrate-rich BR reduced SVR in older adults on days 14 (p = 0.032) and 28 (p = 0.016), with a greater reduction in older compared to younger adults observed on day 14 (p = 0.015) and a trend for greater reduction in older adults observed on day 28 (p = 0.056). Acute (on day 0) and acute + chronic (on day 28) consumption of nitrate-rich BR improved reaction time during the Stroop test in older adults (p = 0.042 and 0.006, respectively), while older (relative to younger) adults also showed a greater improvement in reaction time during the Stroop test following chronic supplementation on days 14 (p = 0.016) and 28 (p = 0.02) despite no effect of treatment on these days. Older adults also showed a greater reduction in V̇O2 at 20% completion of the cycle time trial following acute supplementation with BR on day 0 (p = 0.044), despite no effect of treatment at this time point. Conclusion: The results from this PhD project showed that acute and daily supplementation with nitrate-rich BR can improve BP and cognitive function in younger and older adults, with greater benefits observed in the older cohort. Furthermore, chronic supplementation with nitrate-rich BR in older adults can improve BP independent of an acute dose. These results suggest that daily supplementation with nitrate-rich BR may have a role in clinical settings for helping maintain healthy cardiovascular and cognitive function. Future research should investigate the use of nitrate-rich BR as a potential preventative therapy for cardiovascular and cognitive diseases such as hypertension and dementia.
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    Metabolic flexibility and endurance performance : a thesis submitted for the degree of Doctor of Philosophy, School of Sport and Exercise, College of Health, Massey University
    (Massey University, 2017) O'Connor, William James
    This thesis examined the sex-specific biochemical, physiological and physical performance responses of highly-trained endurance athletes to chronic moderate and low carbohydrate (CHO) training diets. In addition, a novel exogenous ketone supplement was studied to examine its effects on participants’ physiology and performance during the two contrasting diets. STUDY ONE: This study was designed to test whether adaptation to a low CHO diet affects physical capacity during prolonged exercise. Thirteen highly-trained endurance athletes (eight males, VO₂max = 66.0 ± 9.5 mL·kg⁻¹·min⁻¹ ; five females, VO₂max = 50.6 ± 8.4 mL·kg⁻¹·min⁻¹) consumed a moderate (>5 g CHO·kg⁻¹·day⁻¹) or low (<2 g CHO·kg⁻¹·day⁻¹) CHO training diet for four weeks, in a randomised cross-over design. Performance was measured, after a 24 h moderate CHO “loading” regime, through a self-paced time trial to complete a fixed workload, equivalent to five hours at a workload calculated to elicit 55% VO₂max. Although time-to-complete was not significantly different between diets, the average absolute (watts) and relative (W/kg) power outputs were significantly better on the low CHO diet (p = 0.03 and 0.02 respectively). Both sexes responded similarly in terms of performance, whilst only women significantly improved body composition when CHO was restricted (p = 0.02). It was concluded that when CHO is restricted during training, trained endurance athletes show improved ultra-endurance performance relative to their body mass. STUDY TWO: This study was designed to test the sex specific response to a low CHO diet during fasted endurance exercise. The participants and dietary restrictions were the same as outlined in Study One. Physiological measures were collected before, during and after a two-hour ride at a fixed power output, equivalent to 60 % VO₂max. The ride was undertaken after an overnight (>12 hours) fast and completed at three points throughout each dietary intervention (baseline, week two, week four). As expected there were a significant main effect of diet and time on substrate oxidation rates during fasted exercise (p < 0.05). The low CHO diet resulted in lower CHO oxidation and higher fat oxidation (FATox) in both sexes throughout the exercise. The degree of ‘adaptation’ to low CHO intake increased from baseline to week four, with significant interactions between trial and diet (p < 0.05). There was a sex specific negative correlation between the rate of CHO oxidation and perceived exertion (RPE) at the end of the fasted exercise (p = 0.001). Women consistently had a higher RPE at the end of the exercise (p = 0.04). These data show that both men and women can increase their rates of FATox, in a time-dependent manner, when CHO is restricted in the training diet. STUDY THREE: This study was designed to examine the differences in the blood metabolome of highly-trained male endurance athletes (VO₂max = 6.0 ± 9.5 mL·kg⁻¹·min⁻¹)who each underwent two contrasting dietary interventions, in a randomised crossover design as follows: four weeks moderate (> 5 g CHO·kg⁻¹·day⁻¹) or low (< 2 g CHO·kg⁻¹·day⁻¹) CHO. Exercise training was controlled during both conditions. Fasting venous blood samples were collected before and after exercise at 60% VO₂max and the plasma metabolome was analysed using 700 Hz H1 nuclear magnetic resonance (NMR) spectroscopy. Unsupervised (PCA) and supervised (PLSA-DA & OPLS-DA) multivariate statistical analysis models failed to statistically separate the sample groups in regards to the dietary intervention. However, both methods of supervised discriminant analysis (PLS-DA and OPLS-DA) could separate groups based on time (i.e. pre–post exercise). The variable influence on projection (VIP) was used to identify the individual metabolites causing the group separation within the discriminant analysis. Metabolites were analysed using two-way ANOVA and paired t-tests, with the only significant difference being the blood glucose response to exercise at the end of each dietary intervention (p = 0.006). In conclusion, neither the resting nor exercising metabolome is significantly influenced by the CHO content of the diet. This indicates that endurance-trained individuals possess the metabolic flexibility to counter changes in dietary CHO availability and maintain a normal circulating metabolic profile. STUDY FOUR: The aim of this case study was two-fold: to test the effectiveness of a proposed study, and to explore the validity of reports which have claimed that ingesting a ketone supplement can improve endurance performance. One highly-trained male triathlete (VO₂max = 73.0 mL·kg⁻¹·min⁻¹) completed four time-to-exhaustion (TTE) cycling bouts, each preceded by two hours of cycling at 60% VO₂max (power = 213 W). The exercise bouts were completed in a crossover design as follows: ketogenic diet (< 1.5 g CHO·kg⁻¹·day⁻¹) and regular (non-ketogenic) sports drink (K), ketogenic diet with ketone-containing drink (K+KS), high CHO diet (> 5 g CHO·kg⁻¹·day⁻¹) and regular sports drink (CHO), moderate CHO diet and ketone-containing drink (CHO+KS). Ketosis was confirmed with sustained resting blood β – hydroxybutyrate (β-HB) levels of >0.2 mM. Ketone supplementation was associated with better performance following both dietary interventions, with CHO+KS being better than K+KS (12:54 minutes vs 13:32 minutes, respectively). Ketone supplementation resulted in higher [β-HB] during exercise relative to the sports drink (0.63 & 0.78 mM vs 0.20 & 0.25 mM, respectively). VO₂ and blood lactate did not noticeably differ during the fixed intensity ride, but differed greatly during the TTE, with VO₂ beginning higher on the high CHO diet. The results from this study show the potential benefits of ingesting a ketone supplement on endurance performance and suggest that the moderate CHO status of the individual may have an additive effect. Based on these results, it was suggested that a full scientific study be carried out to further test the effectiveness of ketone supplementation on endurance performance. STUDY FIVE: The aim of this study was to test the effects of ingesting a ketone supplement on endurance performance in two different metabolic states, induced by dietary interventions. Six well-trained male endurance athletes (age: 29 ± 9 yrs, mass: 74.1 ± 7.7 kg, VO₂max: 64.1 ± 5.8 mL·kg⁻¹·min⁻¹) underwent a randomised, double-blinded, placebo-controlled protocol, consisting of two dietary interventions, completed as a cross-over design. Following each dietary intervention, a performance session was carried out, during which, participants drank either a ketone-containing (KS) or placebo (PLB) drink. Thus, the performance session was carried out a total of six times; habitual diet (BASE1, BASE2), moderate-CHO diet + PLB (PLB+CHO), moderate-CHO diet + KS (KS+CHO), ketogenic diet + PLB (PLB+K), ketogenic diet + KS (KS+K). Physiological measures were taken during each performance session, which consisted of a 40-minute fixed intensity ride, followed by a self-paced time trial (TT), to complete a fixed workload equivalent to 20 minutes at 75% VO₂ max. There were no main effects or interactions between diet and KS on TT performance or body mass. The KS significantly increased the beta-hydroxybutyrate concentration [β-HB] in the blood at rest and during exercise (peak = 1.1 mM) (p = 0.001). The KS caused an attenuated blood lactate response during the TT compared to baseline and PLB. The respiratory exchange ratio (RER) was significantly lower on the ketogenic diet at rest and throughout fixed intensity exercise but did not differ during the TT. It is concluded that the circulating [β-HB] attained were not high enough to significantly contribute to muscular energy provision via oxidative phosphorylation and that future research into ketone supplements and exercise performance should ensure that a minimum of 2 mM [β-HB] is obtained. Further, the CHO status of the individual can be largely ignored as supplementation appears to be equally effective irrespective of the CHO status.
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    The effect of 10 weeks of peri-training whey protein supplementation on systemic, metabolic, and skeletal muscle molecular responses in Type-2 diabetes : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy (Sport and Exercise Science), Massey University, Wellington, New Zealand
    (Massey University, 2017) Gaffney, Kim
    Introduction: Type-2 diabetes (T2D) is a modern global epidemic associated with multiple health complications and economic burden. Exercise improves glycaemic control in populations with T2D with greater insulin sensitivity, muscle hypertrophy, and reduced emotional distress as possible mediators. Milk protein supplementation has been shown to produce similar benefits, raising the potential of an adjunct therapy. Therefore, the primary purpose of the thesis was to determine if whey-protein supplementation can promote skeletal muscle plasticity associated with improved glycaemic control in exercising men with T2D. Secondary aims were to determine if improvements in functional capacity and glycaemic control led to better mood and quality of life. Methods: In a randomized, double blind clinical trial, 24 non-insulin dependent middle-aged men with T2D were allocated to a pre- and post-training whey-carbohydrate (20 grams-10 grams) supplement or isocaloric carbohydrate-only control. Participants completed 45 high-intensity endurance and resistance exercise sessions over 10 weeks. Insulin sensitivity was determined from glucose disposal rates (GDR) during a euglycaemic insulin clamp, with fasting blood glucose concentration (FBG) and the homeostatic model of assessment of insulin resistance (HOMA-IR) providing secondary measures of glycaemic control. Insulin-mediated haemodynamics; microvascular blood flow (mBF) and microvascular blood volume (mBV) were assessed at the vastus lateralis (VL) muscle via near-infrared spectroscopy. VL muscle biopsies were used to determine capillarity, intramyofibrillar mitochondrial and lipid density, citrate synthase (CS) and cytochrome c oxidase (COX) activity, and mRNA content of angiogenic and mitochondrial markers: eNOS, VEGFA, VEGFR2, PGC1-α, CS, NRF1. Aerobic capacity (VO2peak), strength (1-repetition maximum), VL muscle and subcutaneous adipose thickness, and survey-rated mood and quality of life (DASS42; SF-36) were also assessed. Results: There were substantial increases in GDR (27.5%; 90%CI 1.2%, 60.7% and 24.8%; -5.4%, 64.8%), capillarisation (24.5%; -0.1%, 55.0 and 26.3%; 1.9%, 56.6%), and mitochondrial density (24.3%; 13.8%, 35.8% and 26.7%; 16.8%, 37.5%) in the control and whey groups respectively, with no group differences. Lipid density, COX enzyme activity, VL muscle thickness, VO2peak, 1RM strength, mood, and quality of life were also substantially increased with no group differences. Exercise training had no effect on microvascular haemodynamics; however, whey supplementation produced likely and possible improvements in mBV (16.8%; -4.3%, 42.6%) and mBF (5.9%; -3.7%, 16.3%) respectively at rest and likely improvements in both mBV (17.5%; -3.7%, 43.5%) and mBF (10.2%; 0.3%, 21.1%) under insulin-stimulated conditions. Regression analysis of the pooled 10-week change outcomes showed a positive relationship between the change in lipid density and the change in GDR (r = 0.29); negative associations between basal mBV and FBG (r=.27) and HOMA-IR (r=.30); a negative association between basal mBF and HOMA-IR (r=.48); and a positive association (r = 0.39) between the total DASS score and the change in FBG. Conclusion: Peri-training whey protein supplementation elevated microvascular blood kinetics in middle-aged men with T2D; but did not accentuate the substantial improvements produced by the intense mixed-mode exercise training on tissue and cellular remodelling, insulin sensitivity, glycaemia, exercise capacity, mood or quality of life. The findings support the use of adjunct whey protein supplementation for elevating microvascular blood kinetics in populations with T2D, an outcome that could potentially improve the treatment of vascular diseases where microcirculation contributes to disease pathology and therefore warrants further exploration. The observation that myocellular lipid density was increased by intense exercise training and not detrimental to insulin sensitivity supports recent evidence that lipid accrual may be a favourable adaptation to exercise in populations with T2D.
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    Effect of various whey protein supplements on recovery from prolonged endurance exercise in trained cyclists : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutritional Science at Massey University, Palmerston North, New Zealand
    (Massey University, 2005) Rankin, Dean Mathew
    Background: Protein-containing recovery beverages are proposed to support an athlete's recovery from exercise through stimulation of insulin release, promoting the restoration of muscle glycogen stores, and stimulation of protein synthesis and muscle protein restoration. Objective: The present study aimed to determine, (1) whether there is an insulinotropic effect of whey proteins, when consumed in addition to carbohydrate, which is assumed to enhance muscle glycogen resynthesis and (2) whether a blend of hydrolysate and intact protein, when consumed in addition to carbohydrate, will enhance the athlete's recovery from exercise. Design: Twelve trained top level cyclists repeated a protocol on four consecutive weeks, during which either a control beverage (Carb) or three beverages containing whey protein (carbohydrate and intact protein (Carb + I); carbohydrate and protein hydrolysate (Carb + H; carbohydrate and intact protein : protein hydrolysate mix (Carb + M)) were consumed during recovery from exhaustive endurance exercise. The beverages were formulated to supply 1.2 g/kg/hour carbohydrate and 0.4 g/kg/hour protein. Subjects followed a controlled diet two days before each experimental day. On the experimental day the athletes each performed a glycogen-depleting exercise programme, then received the designated dietary beverage every 30 minutes for the first two hours post-exercise. The progress of recovery was monitored via the measurement of cardiovascular recovery, and the appearance and relative concentration of metabolites in blood (15 samples over a four hour period, obtained via an indwelling cannula) and urine samples (13 samples over a seven hour period) collected sequentially during the post-exercise recovery period. Results: Plasma albumin concentrations were significantly lower following consumption of beverages containing whey protein (Carb + H, p<0.01; Carb + M, p<0.05) compared to that observed with the Carb beverage. Urine output was significantly higher after consumption of the Carb beverage than with any of the three-protein containing beverages (Carb + I, p<0.01; Carb + H, p<0.05; Carb + M, p<0.05) during the period of controlled fluid consumption. Heart rate recovery was found to be significantly greater following consumption of the three protein-containing beverages (Carb + I, p<0.001; Carb + M, p<0.001, Carb + H, p<0.01) than following consumption of the Carb beverage. The Carb + M beverage produced increased heart rate recovery (p<0.001) compared to that observed following consumption of the other two protein-containing beverages (Carb + I, Carb + H). Following correction of the data for haematocrit, to account for the hydration status of the athletes, a significant difference (p<0.05) in the ratio of plasma insulin to plasma glucose concentrations was found following consumption of any of beverages containing whey protein (Carb + I, Carb + H, Carb + M) compared to that observed for the Carb beverage. Consumption of the Carb + I beverage resulted in significantly higher concentrations of urinary nitrogen excretion as urea (p<0.05) and ammonia (p<0.01), and significantly higher plasma concentrations of the amino acids Valine, Leucine, Isoleucine, Phenylalanine, Tryptophan, and Tyrosine (p<0.05). Conclusions: The addition of whey protein to a carbohydrate-containing beverage stimulated enhanced recovery from exercise. A major factor in the improved recovery was increased rehydration following consumption of the protein-containing beverages, mainly due to the high sodium content of these beverages. This increased rehydration was shown to influence results for plasma insulin and plasma glucose concentrations where, after accounting for the hydration status of athletes, a difference between consumption of the Carb beverage and that observed for any of the three protein-containing beverages was observed. The results also allude to a potential benefit of protein hydrolysates over intact protein on protein recovery. Consuming a protein mix (Carb + M) also appears to improve heart rate recovery compared to consuming either intact (Carb + I) or hydrolysed (Carb + H) proteins individually. The results of this study highlight the importance of dietary protein on enhancing recovery from endurance exercise.
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    [Beta]-hydroxy-[beta]-methylbutyrate (HMB) supplementation of resistance trained men : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Science in Nutritional Science at Massey University
    (Massey University, 2004) Thomson, Jasmine Sarah
    A randomised double-blind placebo controlled study design was used to investigate the effects of supplementing 34 resistance trained men (RTM) with 3g/d of β-hydroxy-β-methylbutyrate or a cornstarch placebo on strength and body composition over a 9 week supplementation period. At the beginning of the study period, questionnaires were given to each participant. Prior to and following the period of supplementation; anthropometric measurements were taken, including 8 skinfold sites, height, and body weight; body composition was measured using bioelectrical impedance analysis: strength was assessed using 1 repetition maximum (1RM) strength testing on the leg extension, bench press, and preacher curl apparatus; and food intakes were assessed using 3-day dietary records. During the supplementation period, all participants completed the same resistance training programme and physical activity was assessed using training log book records. Prior to the supplementation period, a significant difference was found between the two supplementation groups for initial body mass indices (BMI: HMB 26.2 ± 0.8; Placebo 22.8 ± 0.9, P=0.0I4). There was no significant difference found between the HMB and Placebo supplemented groups for any other baseline anthropometric (P>0.056). or strength measurements (P>0.583). Over the study duration there was no significant difference found in number of training sessions between the two supplemented groups (P>0.056). Following the supplementation period there was no significant change in anthropometric measurements (P>0.095). nor actual strength (P>0.086) over the study duration. However, percent change in leg extension strength increased significantly more for the HMB-supplemented group than the placebo group (LE: HMB 14.7 ± 3.69% Placebo 4.84 ± 2.8%, P=0.04l). During the supplementation period there was a significant difference found between the dietary intakes of some nutrients between the supplementation groups.The HMB group tended to consume a greater percent of energy from carbohydrates, and had a higher maltose intake. The HMB group had a lower percent of energy from fats in the diet, and consumed lower average cholesterol intake than the placebo group (P <0.047). Several study participants failed to meet the recommended dietary intakes for adult New Zealanders of certain nutrients. The average intakes of energy front carbohydrates, intakes of vitamin A, vitamin E, vitamin B6. potassium, magnesium, calcium, and selenium were low for some participants. The conclusion of this study was that there was no beneficial effect of HMB supplementation on body composition in resistance trained humans, however there was a significant increase found in leg extension strength with HMB supplementation in response to resistance exercise over the 9 week supplementation period.
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    The use of dietary supplements in two groups of New Zealand children and adolescents : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Philosophy in Nutritional Science, Massey University
    (Massey University, 2001) Crowley, Jennifer
    In Western societies, personal responsibility for health has become an important pre-occupation during the latter part of the 20th century, with guidelines issued by governments as part of encouraging a healthy lifestyle. Many sectors of any given society have embraced this issue, but often in different ways. Dietary supplementation, as part of general self-medication, is particularly prevalent among women, but not exclusively so. Supplementation reflects concerns about dietary adequacy and an attempt to manage nutritional status. It may also be that by virtue of the roles which many women occupy, including as shopper and health care dispenser, they may be more exposed to dietary and health information that encourages a degree of dissatisfaction with existing diets and makes supplementation more attractive. The consumption of supplements by children suggests that supplementation reflects a range of group or social influences. Communication between family members and external sources of health information, for example, friends, the family doctor and the media, may also encourage the adoption and maintenance of supplementation patterns. The purpose of this study was to determine the use of dietary supplements in two different groups of New Zealand children and adolescents. The first group consisted of children between 1 and 14 years of age from rural and urban areas who were targeted for the pilot study for the Children's Nutrition Survey. The pilot study consisted of a pre-testing and validation component. In the pre-testing component, there were 428 children, 137 of whom were Maori, 147 were Pacific peoples and 148 European/Pakeha. In the validation component, there were 183 children, with 60 Maori, 63 Pacific and 60 European/Pakeha. Questionnaires were used to provide demographic data and information on food and dietary supplement use. The pilot study found that 12.8% of the children of 1 to 14 years of age consumed dietary supplements. Supplement use was highest in children in the age range of 1 to 5 years (52.3%) and decreased to 47.6% in children 6 to 14 years. Maori and Pacific children were less likely to consume supplements than European/Pakeha children. The most popular supplements consumed were vitamin C, either alone or in combination with vitamins A and D, or echinacia (49.9%), and multi-vitamins (30.9%). Herbal combinations were consumed by 16.5% of the children. Most of the children who consumed supplements took them daily. Further study of the prevalence of dietary supplement use by children in New Zealand will take place in the proposed Children's National Nutrition Survey. The athletes' study provided the second set of data. One hundred year 9 and 10 children (67 males and 23 females), who were identified as having potential in their respective sports, were recruited from two decile one North Shore secondary schools. Questionnaires were used to provide demographic data, information on the use of dietary supplements, influences on dietary supplement use and the perceived benefits of dietary supplement use. The mean age of the athletes was 13.5 years. Twenty-eight sports were represented. Seventy percent of the athletes took dietary supplements. Supplement use was higher in females (84.8%) than males (62.5%). Energy products, the most popular dietary supplement, were consumed by 43.1% of the athletes. These were followed by vitamins (28.7%) and recovery products (7.1%). Meal replacers, herbal supplements and "other" (12.2%) were the least popular supplements. Vitamin C and multivitamins were the most popular vitamins consumed, while minerals were consumed only by a few athletes. Parents and coaches were found to be the most important sources of information amongst those who took dietary supplements (59.5%) and they were also found to be the most likely to be the person(s) who suggested taking dietary supplements (66.39%). Dietary supplements were perceived to benefit athletes' performances in a variety of ways, from providing more energy, to improving fitness, or to preventing illness. The findings from the athletes study suggests that sports organisations need to adopt a pro-active stance to ensure that young athletes understand the importance of nutrition for both their sporting performance and their long-term health.
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    Does the use of a wheat dextrin fibre supplement improve bowel performance in renal dialysis patients? : a pilot study : a thesis submitted in partial fulfillment of the requirements for a degree of Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand
    (Massey University, 2015) Edwards, Chester
    Background: Constipation is common within renal dialysis patients. Current practice for the management of constipation in renal dialysis patients in Northland DHB involves prescribing laxatives and attempting to alter dietary fibre intake through dietary measures. These methods are however often ineffective and laxatives can have unwanted side effects. The use of a fibre supplement for the treatment of constipation within this patient group would be ideal; however, the currently subsidised fibre supplement in New Zealand needs to be consumed with fluid and is therefore not suitable for renal dialysis patients with severe fluid restrictions. A wheat dextrin fibre supplement is available in New Zealand and this product can be mixed into food, therefore requiring no water. This makes a wheat dextrin fibre supplement ideal for renal dialysis patients as a way to increase their fibre intake in an attempt to improve bowel performance. Aim: To examine the effectiveness of a wheat dextrin fibre supplement on bowel performance in free living end stage renal failure patients who are currently receiving either peritoneal or haemodialysis within the Northland DHB. Methods: Haemodialysis (HD) or peritoneal dialysis (PD) patients who were currently taking laxatives were recruited for this cross-over, single blind intervention study (n =7). After a two week observation stage (OBS), subjects consumed up to 22 g of wheat dextrin fibre supplement (WD) per day or the equivalent of a maltodextrin placebo (PB) for four weeks. Patients then switched treatments after a two week washout period. In all three study stages, subjects completed a prospective patient held record measuring stool frequency, stool form, laxative use, and the quantity of supplement consumed in the WD and OBS stages. During the final three days of each stage, subjects completed a 28 question quality of life (QOL) questionnaire designed to assess QOL with reference to constipation over the two weeks immediately prior. Results: No significant differences were found between the OBS, WD or PB stage for laxative use (p =0.299), stool frequency (p =0.653), stool form (p =0.549), percentage of ideal stools formed (p =0.253), or QOL measures (p =0.181). When determining if WD had an effect in some individuals, it was found that one subject showed a clear increase from 4 stools/week in the OBS stage to 14 stool/week in the WD stage and five stools/week in the PB stage. Another subject managed to decrease their laxative use by 31% in the WD stage compared to the OBS and PB stage. The percentage of stools that were ideal increased by 20% or more from the OBS to WD and/or PB stage in 67% of subjects. Conclusion: This pilot study found the use of wheat dextrin to improve bowel performance in some individuals. Due to low subject numbers in the analysis (n =6), it was not surprising that no significant results were found between any stages of the study for any objectives, however individual subjects showed WD improving stool frequency, stool form and reducing laxative use compared to placebo. Overall, this pilot study has highlighted the difficulties in carrying out such a trial in renal dialysis patients, and these should be taken into account when designing future trial in this population.
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    Effects of orally administered ovine serum immunoglobulin in the normal and Salmonella enteritidis-challenged growing rat. : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Nutrition at Massey University, Palmerston North, New Zealand
    (Massey University, 2011) Balan, Prabhu; Balan, Prabhu
    Immunoglobulins (Ig) are the primary anti-infective component of plasma, colostrum and breast milk. They are the specialized glycoproteins that protect the body from harmful bacteria, viruses and other environmental pathogens by either binding to them or by forming an encapsulating barrier. The development of antimicrobial and immunomodulatory products from natural sources for dietary supplementation in both animals and humans is an active area of research. Purified Ig from sheep plasma (ovine serum Ig) is one such candidate product. Based on the results of the numerous background growth studies of others, the objectives of this study were to determine whether orally administered ovine serum Ig affected growth performance, digestive organ weights, gut morphology, immunity, the gut microbiota, goblet cell numbers, mucin gene expression and digesta mucin protein contents in the growing rat. The study also sought to understand whether orally administered ovine serum Ig prevented or lessened the negative effects of Salmonella enteritidis ATCC 13076 (a pathogen) in the S. enteritidis−challenged growing rat. The presence of ingested intact Ig in different parts of the digestive tract was also determined. Investigations were undertaken in normal and S. enteritidis−challenged Sprague-Dawley male growing rats. Diets were iso-caloric and had similar protein and amino acid contents. The diets were fed for 21 days (for non-challenged rats) and for 18 days (for the challenged rats). An ovine Ig fraction improved food conversion efficiency, the weights of several digestive organs and gut histology. Compared with spray-drying, a freeze-drying procedure preserved a higher degree of immunological activity. In immunity studies, an ovine Ig fraction selectively enhanced (P < 0.05) various indices of immune function such as phagocytic acitivity, lymphocyte proliferation and gut and plasma antibodies. In microbiolgical studies, the number of lactobacilli in the gut were increased (P < 0.05) by feeding the ovine Ig. Ovine Ig also influenced the transcription and translation of gut mucin protein as evidenced by increased (P < 0.05) mucin gene expression and digesta mucin protein concentrations as well as an increased goblet cell count. After gavaging with S. enteritidis, the rats fed the IOI (inactivated ovine Ig) and BD (basal diet) diets grew considerably more slowly (growth declined) than the challenged rats fed the FDOI (freeze-dried ovine Ig) diet and the latter rats showed no sign of infection. The villus length, crypt depth, villus:crypt ratio and villus surface area (VSA) of the duodenum and jejunum were generally greater (P < 0.05) in rats challenged with S. enteritidis and receiving the FDOI diet compared to either the unchallenged rats fed the BD diet (except duodenal and jejunal VSA) or the challenged rats fed the BD or IOI diets. Several measures of immune modulation were affected as was the bacterial composition of the gut microflora. The ileal and colonic digesta for the FDOI-fed rats had higher (P < 0.05) numbers of goblet cells and higher (P < 0.05) digestive luminal mucin protein concentrations than the challenged rats fed either the BD- or IOI-supplemented diets. Intact ovine Ig were detected in the luminal contents from the stomach through to the colon in the growing rat fed orally with ovine Ig fraction. The amounts (percentages of digesta dry matter) of intact ovine Ig for rats fed the FDOI diet were 2.17%, 3.12%, 5.31%, 2.03% and 5.76% for stomach chyme, duodenal, jejunal, ileal and colonic digesta respectively. Overall, the accumulated amount was 18.4%, which indicates the presence of a high level of active material throughout the digestive tract. In conclusion, purified ovine Ig improves growth of healthy rats and protects against enteric infection by immunomodulation, mucin protein and/or modification of commensal microbial composition. The results contribute to knowledge of how orally administered ovine Ig can modulate and enhance key indicators of gut function and overall growth performance in the growing rat.
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    Effects of dietary fish oil or other lipids and Sanovite on pig performance and pork quality : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Animal Science at Massey University, Palmerston North, New Zealand
    (Massey University, 2010) Nuijten, Wilhelmina Gerardina Maria
    In this experiment, the effects of (1) lipid type (soy bean oil, tallow and fish oil), (2) the period the fish oil was provided and (3) a dietary supplement containing conjugated linoleic acid (CLA), selenium (Se), vitamin E and vitamin C on pig performance and pork quality were studied. Forty-eight female pigs (PIC hybrids, with a mean live weight of 16.19 kg ± 1.56 SD) were obtained from a single commercial operation in the North Island of New Zealand. The pigs were rank ordered by weight and assigned to one of six dietary treatment groups. The diet base was either a combination of animal and plant feedstuffs (AT and PTS), plant feedstuffs only (PO, POS) or plant feedstuffs combined with fish oil (PFSe and PFSl). The diets also differed depending on the presence or absence of the nutritional supplement SanoviteTM and a vitamin C supplement. SanoviteTM is a trademarked dietary supplement containing CLA (BASF, Auckland, New Zealand), organic Selenium (Alltech Inc., Nicholasville, KY) and vitamin E (Morel et al., 2008). Diets POS, PTS, PFSe, PFSl contained SanoviteTM and a vitamin C supplement. Diets PO and POS were used to establish the effect of the supplementation with SanoviteTM and the vitamin C supplement. Pigs fed diet PFSe received plant feedstuffs and fish oil with supplement between days 1 and 35 and then diet POS up to day 84. Pigs fed diet PFSl received diet POS between days 1 and 35; plant feedstuffs and fish oil with supplement between days 36 and 56 and then diet POS up to day 84. Pigs in group PFSe and PFSl both received the same total amount of fish oil per pig (2.52 l/ 2.31 kg). Between days 1 and 56 of the experiment grower diets were fed, and finisher diets were fed between days 57 and 84 of the experiment. The pigs were kept in pens of six, but fed individually twice daily (at approximately 8 am and 3.30 pm) according to a fixed feeding schedule. Water was available at all times. Individual feed intakes were measured daily and live weight recorded weekly. Faeces were collected once a day during two days in week five of the trail for digestibility determination. Carcass quality characteristics determined at the abattoir included carcass weight and back fat thickness as measured at the end of the slaughter line. Meat quality assessments were performed on the Semimembranosus muscle (SM) from one of the topside cuts of each pig. Measurements of fatty acid profile (loin and backfat) and the Se content (lean meat) were conducted in Singapore by Mrs. J. Leong (MSc). In this study plant or animal feedstuffs, lipid type, SanoviteTM and vitamin C supplementation had no significant effects on growth performance and carcass quality. There were no differences in apparent faecal digestibility characteristics for dry matter (DDM) and organic matter (DOM) in the un-supplemented animal (AT) and plant based (PO) diets. Lipid type had a significant effect on the digestibility of ash (DA), and an increased ratio of unsaturated fatty acid to saturated fatty acid resulted in increases in DDM and DOM. DDM and DOM increased when soybean and linseed oil (POS) were used instead of tallow (PTS) or fish oil (PFS). The main differences in DDM, DOM and DA were observed between diets PO and POS. A positive effect of selenium, vitamin E and CLA supplementation is suggested. Increased cooking temperatures reduced tenderness (higher mean, peak force, yield force and peak force – yield force) and increased cooking loss. There was a significant negative relationship between ultimate pH and relative lightness (L*). There were highly significant positive correlations between all three measurements of expressed juice, and there was a significant positive correlation between cooking loss at 60 and 70oC (P<0.01) but correlations between expressed juice values and cooking loss were not significant. The P-values for the contrasts for cooking loss at 70 0C were significant for all contrasts except for AT vs PO and PFSe vs PFSl. For all other contrasts, the P-values for cooking loss at 70 0C were significantly higher in group POS than for groups PO, PTS and PFSe+PFSl. The P-value for (Peak force – Yield force) at 70°C was significantly higher in samples from group PFSe than for samples from group PFSl. The P-value for the myofibrillar fragmentation index (MFI) was significantly higher for group AT in contrast to group PO. Group POS had a significantly higher P-value for MFI in contrast to groups PO, PTS and PFSe and PFSl. Group POS had a lower P-value for sarcomere length in contrast to groups PFSe and PFSl. Group PFSe had a significantly higher P-value for sarcomere length in contrast to group PFSl. Group PFSe had a significantly higher P-value for expressed juice percentage loss in weight in contrast to group PFSl. Supplementing with SanoviteTM increased the Se content (P = 0.002) in lean meat as analysed by J. Leong (2010, personal communication). In general it was concluded that an increase in the ratio of unsaturated fatty acid to saturated fatty acid (U/S) in the diet resulted in higher levels of unsaturated fatty acids in loin and backfat. The fatty acid profile in the diet reflected the fatty acid profile of pork. Backfat of pigs fed diets including soybean and linseed oil contained higher levels of linoleic and α-linolenic acids. Diets PO and POS were used to establish the effect of the supplementation of CLA. The backfat of pigs fed diet POS contained higher levels of CLA (C18:2-trans-10, cis-12) and α-linolenic acid than pigs fed diet PO. The loin of pigs fed diet POS contained higher levels of palmitoleic and linoleic acid and CLA (C18:2-cis-9, trans-11) and lower levels of oleic acid than pigs fed diet PO. The use of fish-oil as a lipid type resulted in the highest levels of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) in loin and backfat. The loin and backfat of pigs fed fish-oil in the second part of the grower phase (PFSl) contained higher levels of EPA, DPA and DHA than pigs fed fish-oil in the first part of the grower phase (PFSe). By enriching the swine diet with long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) it was possible to increase the EPA, DPA and DHA content of pork. Enriching pork with LC n-3 PUFA will contribute to achieving standards for adequate intake (AI), but might not be suitable to reach suggested dietary targets (SDT). In conclusion, it was possible to change the pork composition by dietary manipulation without compromising pig performance and meat quality. There were a few significant effects from treatments on meat quality characteristics, but differences reported in this study were small and relatively unimportant. A negative influence of the dietary regime on palatability and meat processing was expected, but these issues are beyond the scope of this experiment.