Oxidative stress is the major driving force behind the aging process and many age-related diseases. However, direct experimental evidence of whether antioxidants, such as ascorbate (AA) and lipoic acid (LA) can slow the progression of aging process and/or reduce risks of developing degenerative disease is largely absent. This suggests a better understanding of the precise mechanism of how dietary micronutrient affect parameters of involved in cellular redox balance and aging are warranted. In this dissertation, young and old rats were used as our model to understand potential pro-oxidant events that contribute to increases in oxidative stress in various tissues and how antioxidants such as ascorbate and lipoic acid influence these events. Our major findings are that the age-related impairment of mitochondria and increased deposition of iron contribute significantly to heighten levels of oxidative stress, as evidenced by the resultant increases in the rates of oxidant appearance and in the levels of oxidative damage to DNA, lipids and proteins. We find that AA and LA strongly protected against transition metal-ion dependent increases in oxidative stress. AA effectively inhibited transition metal-mediated lipide peroxidation in human plasma. LA in its reduced form effectively binds iron and copper in a redox inactive manner and reversed chronically elevated levels of iron in the brain without removing enzyme bound transition metal ions. LA also significantly attenuated the age-related increase in oxidative stress associated with mitochondrial decay in the heart, as evidenced by the improvements in AA levels and glutathione redox status. The declines in tissue GSH levels in aged rats were strongly associated with the diminished γ-GCL activity (in parallel with decreased expression of the catalytic and modulatory subunits), and lowered Nrf2 expression and binding to ARE sequence in rat liver. Remarkably, all these events were effectively reversed by the administration of LA, modulating the parameters to return to the observed in young animals. The implications of this work open new avenues not only for further understanding of the aging process but also for possible strategies in its modulation by the micronutrients. / Graduation date: 2004

Graduation date: 2004

We investigated the relationship between calcium and protein intake and bone loss over a one-year period in 99 early postmenopausal women (1-36 months) aged 51.3 �� 0.31 years. Bone mineral density (g/cm��) of the left hip (total hip, femoral neck, greater trochanter) and lumbar spine (L1-L4) as well as body composition were assessed using dual energy x-ray absorptiometry. Dietary intake of calcium and protein was assessed using a 100-item Block Food Frequency Questionnaire. A physical activity questionnaire was also completed by the subjects to estimate energy expenditure. Paired t-tests revealed that there were no significant differences between baseline and month 12 physical characteristics except for percent fat which increased from 31.99 �� 0.60% to 32.44 �� 0.61% (p=.009). At month 12, bone mineral density decreased significantly at the femoral neck (-0.97 �� 0.31%) and total hip (-0.55 �� 0.24%). The average calcium, protein and calcium to protein ratio intake for the group was 1129.88 �� 46.22mg/day, 57.88 �� 1.93g/day and 20.10 �� 0.71m/g, respectively. Partial correlation analyses showed no significant relationships between change in bone mineral density and average intakes for calcium, protein, or the calcium to protein ratio. After adjusting for hormone replacement status, lean body mass and months post menopause, analysis of covariance revealed that there were no significant differences between groups when intakes of calcium, protein and the calcium to protein ratio were separated into "above recommended" and "below recommended" categories (above or below 1000/1500mg/day, 50g/day, 20:1 mg/g/day, respectively). Our results suggest that consuming adequate amounts of calcium and protein does not appear to significantly slow bone loss after 12 months in early postmenopausal women. / Graduation date: 2003

There is a paucity of South African data concerning the cross-cultural incidence of attitudes and behaviours associated with eating disorders. Research in this area has recognised that acculturation to a Western value system appears to have a pathogenic impact on the prevalence of disordered eating among non-Western ethnic groups. This study aimed to explore the relationship between acculturation and disordered eating, and to compare the level of disordered eating (as measured by the Eating Disorders Inventory [EDI]) among black and white female university students in KwaZulu-Natal. The roles of Body Mass Index (BMI) and socioeconomic status were also examined. The sample consisted of one hundred and twenty-two white female undergraduate students from the University of Natal (Pietermaritzburg), fifteen black female undergraduate students from the University of Natal (Pietermaritzburg), and one hundred and fifty-four black female undergraduate students from the University of Zululand. It was found that although black subjects obtained significantly higher scores on the Drive for Thinness subscale of the EDI, white subjects obtained significantly higher scores on a combination of the three subscales designated to assess disordered eating attitudes and behaviours. Black subjects obtained significantly higher BMI scores than white subjects, and BMI was positively correlated with Body Dissatisfaction in both groups, and with Drive for Thinness in the white group only. No relationship was found between socioeconomic status and disordered eating. Similarly, no relationship was found between acculturation and disordered eating. This latter result is partly a function of problems experienced with the measures of acculturation. A comparison of black subjects from the two universities suggests that greater contact with white students is influential in terms of the development of disordered eating. The above results are discussed in terms of the available literature, and recommendations for future research are made on the basis of the limitations of this study. The data from this study is included in a nation wide cross-cultural study of eating disorders initiated by the Eating Disorders Co-ordinating Committee. / Thesis (M.A.)-University of Natal, Pietermaritzburg, 1996.

A total sample of 1,105 students from the universities of Natal, Witwatersrand and the North participated in this study. The Eating Attitude Test (EAT) and the Bulimic Investigatory Test, Edinburgh (BITE) were administered to three female and three male student samples. Subjects also provided biographic, demographic and weight-related information. The majority of subjects fell within the average weight range of the Body Mass Index (BMI), with the percentage of underweight Indian subjects being higher than the corresponding percentages of the black and white student groups. The majority of males in each race group have accurate weight perceptions. In contrast, the minority of females (fewer than a third) of Indian and white females and under half of black females have accurate weight perceptions. However, all overweight white females assessed themselves as such and 89% of overweight black women assessed themselves as overweight. In terms of exaggerated weight perceptions, more white and Indian females (72% and 70% respectively) consider themselves as overweight or very overweight when they were actually of average weight, than black females (47%). Females in each race group scored consistently higher on all scales assessed than their male counterparts. White females exhibited the most disturbed eating behaviours and attitudes in terms of the categorised percentage scores obtained on all scales of the BITE and EAT. No Indian males obtained scores in the pathological range. On the EAT scale, 19% of white females, 17% of black females and 9% of Indian females, 7% of black males and 1% of white males obtained scores which were categorised as pathological. The more stringent criteria of the BITE showed a lower percentage of all subjects in the pathological range, albeit still retaining the gender discrepancy. Thirteen percent of white female students, 8% of black females, 3% of Indian females, 2% of white males and 1% of black males obtained a pathological score on the BITE scale. The Indian female and male sample exhibited the healthiest eating behaviours and attitudes relative to the other two racial groups examined. In terms of mean scores a general trend emerged in which black males obtained higher mean scores than white and Indian males, and black females obtained mean scores (which were overall) similar in magnitude to those of white females. The majority of black females who obtained pathological scores were urban raised and were from the upper socio-economic stratum. The majority of white females who obtained pathological scores were from urban backgrounds, had exaggerated weight perceptions and expressed a desire to lose at least 10 kilograms of weight. / Thesis (M.A.)-University of Natal, Pietermaritzburg, 1996.

The aim of this study was to assess the performance of the children in the study on some psychometric tests and to find out whether iron deficiency had any effect on cognitive skills as measured by the selected psychometric tests. The study also wanted to find out if there would be any gender differences on the psychometric tests. A sample of 810 children was selected from eleven schools from the rural Southern part of KwaZulu-Natal. The children were of ages eight to ten years old, were all Zulu speaking and in standard one. Blood samples were taken from all the children to determine iron levels. Psychometric tests viz., the Symbol Digit Modalities Test, Raven's Coloured Progressive Matrices, Rey's Auditory Verbal Learning Test and Young's Group Mathematics Test, were all administered to measure cognitive performance. The results showed no significant iron level effects on most of the measured cognitive skills. There were some significant gender effects on all the psychometric tests except for the Maths test. There was general low performance on all the psychometric tests. Therefore, the results highlighted the importance of designing more tests that can be standardized and thus be applicable to Zulu speaking children and other children with similar backgrounds. The tests should also be able to tap into the cognitive skills that may be affected by iron levels. There is also a great need for studies looking at the lower end of iron deficiency. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1998.

The soil-borne fungi Rhizoctonia solani Kuhn and Sclerotinia sclerotiorum De Bary are ubiquitous plant pathogens with a wide host range. They are among the most widespread and destructive diseases of many crops, including sunflowers. Although in many cases, the use of chemicals appears to be the most economical and efficient means of controlling plant pathogens, their environmental concerns and the development of tolerance in pathogen populations have led to drastic reduction in their usage and increased the need to find alternative means of disease control. The potential benefits of applying Trichoderma harzianum Rifai and silicon (Si) nutrition to plants have been extensively reviewed. In this study, the ability of T. harzianum (Eco-T®), soluble silicon, and their combination was evaluated on sunflower (Helianthus annuus L.), for their potential to suppress pathogenic strains of R. solani and S. sclerotiorum. The ability of this crop to take up and accumulate Si in different plant parts was also investigated. In vitro assessment of fungal responses to Si in PDA showed that both R. solani and S. sclerotiorum were inhibited in the presence of Si. More inhibition was observed as the Si concentration increased with a relative increase in pH. Maximum growth inhibition was observed at 3000 mg ;-1 – 6000 mg ;-1 of PDA. No difference in inhibition between the two pathogens was observed, thus confirming the fungitoxic/suppressive ability of high Si concentrations to fungal growth. In addition, in vivo trials showed that the Si concentration of 200 mg ;-1 applied weekly significantly increased the dry weight of plants inoculated with R. solani and S. sclerotiorum and was therefore considered the optimum concentration. Assessments on in vitro antifungal activities of Eco-T® on R. solani and S. sclerotiorum, showed that Eco-T® significantly inhibited mycelial growth, in both dual culture methods and volatile and non-volatile compounds produced by Eco-T®. In addition, the combination of Eco-T® and Si was most effective in suppressing damping-off and increasing plant dry weight of sunflower seedlings in the greenhouse. The combination of Si and Eco-T® significantly increased percentage germination, number of leaves and head dry weight of the sunflower cultivars tested. Silicon alone increased growth but was unable to control R. solani and S. sclerotiorum effectively. Rhizotron studies showed that S. sclerotiorum infected the host through the roots and the stem, whereas R. solani only infected the host through the roots. A study on Si uptake and distribution showed that sunflower accumulates Si in various plant tissues. Analysis of plant tissues revealed that more Si was accumulated in leaves > stems > roots, with the Si levels in leaves being significantly higher than in stems and roots. In conclusion, Si alone could be used to increase growth but was unable to control R. solani and S. sclerotiorum. However, Si together with Eco-T® provides an environmentally friendly alternative for the control of R. solani and S. sclerotiorum, and enhanced plant growth and yield. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

BACKGROUND: Cystic fibrosis (CF) patients grow poorly and tend to be malnourished. They frequently suffer from lung infections necessitating the repeated use of antibiotics. AIM: This study was conducted to determine whether supplementation with a probiotic Lactobacillus reuteri (L. reuteri) could reduce the incidence and duration of lung infections, and whether this would impact on their anthropometric data. The secondary purpose was to compare the nutritional status of the CF patients attending CF clinics in Kwazulu-Natal (KZN) with CF patients attending CF clinics in Cape Town (CT). METHODS: Twenty three CF patients 6-31 years of age from 2 CF clinics in Kwazulu-Natal started the study although only 16 patients completed it. The study was a randomized, double blind, placebo controlled crossover trial with six months on placebo and six months on probiotic. Weight, height, mid arm circumference (MAC), triceps skin fold thickness (TSF), forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were measured, sputum collected and a symptom diary completed over the 12 month period. Anthropometric data of CF patients attending CF clinics in CT was obtained from the publication by Westwood & Saitowitz (1999). RESULTS: Compliance with taking the L. reuteri was poor. Most took only 50% of the required daily dose. Probiotic supplementation showed a slight (non significant) trend to improve FEV1 and FVC, while no significant difference could be seen in the number and duration of the lung infections. Sputum analysis showed a non significant trend towards the probiotic reducing the number of bacteria in the sputum. There was a significant reduction of symptoms for fever, running nose, sore throat and ear ache while on placebo. There was a significant increase in weight gained off probiotic compared to the probiotic period. The changes in height, weight for age (WFA) percentiles, height for age (HFA) percentiles, WFA and HFA Z-scores, percentage expected weight for age and percentage expected height for age all showed no difference whether on or off probiotic. Over half the CF children in the KZN clinics were underweight for their actual height compared to one third in the CT clinics with a higher number of subjects below the 5th percentile for MAC and TSF readings compared to CT. CONCLUSION: Due to a small sample size and poor compliance no firm conclusions could be drawn. However a slight (non significant) improvement could be seen in favour of the probiotic for FEV1, FVC, and sputum analysis. Although all other findings were not significantly different it would be of benefit to carry out further investigation with improved compliance with the probiotic to see if the parameters set out above could be improved. The KZN and CT CF groups were comparable and the nutritional status of CF patients on KZN was well below that of the CT CF clinics and further monitoring would need to be carried out.

Adolescent athletes of this era are more pressurized than adolescents of previous generations to perform at an optimum level (Micheli & Jenkins 2001, p49). The importance of winning can result in adolescent athletes developing inappropriate nutritional practices such as neglecting hydration and consuming insufficient carbohydrate (Micheli & Jenkins 2001, p57). Consuming insufficient fluid leads to dehydration which reduces a soccer player’s ability to continue training. Consuming inadequate carbohydrate reduces performance and blood glucose levels during training. This study aimed to determine the hydration status, fluid and carbohydrate intake of male, adolescent soccer players during training. A cross-sectional study was conducted among 122 amateur male, adolescent soccer players (mean age = 15.8 ± 0.8 years; mean BMI = 20.4 ± 2.0 kg/m2). The players’ hydration status before and after training, was measured using urine specific gravity and percent loss of body weight. Their carbohydrate intake, as well as the type and amount of fluid consumed, were assessed before, during and after training. A questionnaire was administered to determine the players’ knowledge regarding the importance of fluid and carbohydrate for soccer training. The study had an 87.1% response rate. The mean environmental conditions did not predispose players to heat illness. However, the players were at risk of developing heat illness during six of the 14 training sessions. Although the mean urine specific gravity indicated that players were slightly dehydrated before and after training, 43.8% of players were very or extremely dehydrated before training and 53.6% after training. A few (3.3%) were extremely hyperhydrated before training and after training (7.0%). On average players lost less than 1% of body weight during training and less than 3% of players dehydrated more than 2%. Players consumed mainly water before (289.17 ± 206.37 ml), during (183.20 ± 158.35 ml) and after (259.09 ± 192.29 ml) training. More than 90% stated that water was the most important fluid to consume before, during and after training. Very few (4.7%) correctly stated that carbohydrate should be consumed before, during and after training. Players were found to be slightly dehydrated before and after training and therefore were not consuming enough fluids during training. Players consumed inadequate amounts and types of fluid and carbohydrate. This not only compromises their performance but also health. Players were not aware of the importance of fluid and carbohydrate for soccer training. This study is unique in that it focused on the carbohydrate and hydration practices of socioeconomically disadvantaged adolescent soccer players during training. The study sample therefore represents a high risk group about which there is limited published data both locally and internationally. This study generated important baseline information which was lacking before on the hydration status, fluid and carbohydrate intake of adolescent soccer players in South Africa. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

Bibliography: v. 2, leaves [410]-464 / 2 v. : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Community Medicine, 1986?