Thesis (M. Phil.)--University of Hong Kong, 1987.

published_or_final_version / Biochemistry / Master / Master of Philosophy

Introduction: Gastric cancer (GC) is ranked as the second most common fatal malignancy worldwide. Although Helicobacter pylori is recognized as a major predisposing factor for non-cardia GC, infection alone is not sufficient to cause cancer. This thesis aimed to determine the variation in host genetic polymorphisms in subjects from Malaysia and Singapore and to examine the role of H. pylori infection, host genetic factors and dietary factors in the etiology of non-cardia GC in Chinese subjects resident in Malaysia. Methods: Functional dyspepsia (FD) controls from three ethnic groups in Malaysia, Chinese (123), Indian (110) and Malay (84) and Singaporean Chinese (127) plus Malaysian Chinese gastric cancer cases (55)were examined. Polymorphisms in IL-1B-511, IL-1RN, IL-10 cluster, TNFA-308 and TLR5+1174 were determined by PCR-RFLP or PCR; H. pylori status by serology, dietary intake by questionnaire and gastric IL-1b levels by real time PCR. Results: 1) Significant differences existed in the frequency of all polymorphisms, except IL-1B-1473 and TNFA-308, in the three Malaysian ethnic groups and in the IL-1B-511 polymorphism in Malaysian and Singaporean Chinese FD 2) Globally, two distinct patterns of IL-1B-511, IL-1RN, IL-10-1082, IL-10-592 and TNFA-308 exist, Western and East-Asian 3) In Malaysian Malays, the IL-10 ATA haplotype was associated with H. pylori susceptibility 4) In Malaysian Chinese an increased risk of GC was associated with carriage of the IL-1B-1473 G allele {OR=4.4(1.3-15.3)} and the IL-1B-511 C allele {OR=1.8(0.8-4.1)} 5) Increased levels of IL-1b were observed in Singaporean and Malaysian Chinese FD subjects carrying the IL-1-511C and IL-1-1473G alleles 6) Malaysian Chinese not consuming fresh fruit and vegetables had the highest risk of GC {OR=10.2 (3.4-30.6)} 7) The highest risk of GC {OR=37.3(3.3-424.8)} was observed in H. pylori positive Malaysian Chinese who carried both the IL-1B-511C and IL-1B-1473G alleles and did not consume fresh fruit and vegetables. Conclusions: In Malaysian Chinese, H. pylori infection, host genetic and dietary factors all contribute to the risk of GC. However the significant difference observed in the frequency of host genetic polymorphisms within and between ethnic groups suggests that a single group of risk factors cannot be used to determine GC risk across all populations.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Anthropology, 2008. / Includes bibliographical references.

Thesis (MNutr (Human Nutrition))--University of Stellenbosch, 2005. / A diet high in fat results in dietary-related diseases, which have reached epidemic proportions in South Africa. Nutritional labelling has the potential to alter consumers’ knowledge of attitude and behaviour towards their fat intake. The purpose of the study was to investigate the effects of nutritional labelling on the population’s fat-intake through a systematic literature review. Electronic databases, reference lists of relevant studies and the Internet were searched, to identify studies that could help to answer the problem statement. Relevant citations were independently identified by two investigators based on the established inclusion-criteria. After this the full text of the selected citations were obtained and filtered independently by each investigator based on the inclusion- and exclusion criteria. The characteristics of each study was recorded in specially developed data extraction forms by the investigator herself and was checked by a second investigator. The primary objective of the study was to investigate nutritional labelling on food packaging. Two other forms of labelling were included to gain a more concise perception of consumers’ knowledge and practices regarding information on fat. These other forms were point-of-sale labelling (in supermarkets, in restaurants, by vending machines) and experimental labelling (labels spesifically designed to indicate the fat-content of a food item). A total of 59 relevant studies were included based on the inclusion-criteria. Although only a few studies assessed the effect of labelling on diet, there was evidence that the use of labels resulted in lower fat intake. Women older than 35 years with higher education levels, who used nutritional supplements, and who were in the maintenance stage of change to a lower fat diet, and who believed in the importance of nutrition, were between 50% to 80% higher users of information about fat than their counterparts. Fat is the food component which was most looked at on the food label (50% to 80%). Small changes in fat intake occured due to point-of-sale labelling, but labelling programmes which combined labelling with additional information on fat (e.g. pamphlets), increased visibility and nutrition education programmes, were more successful. People generally perceived products lower in fat as less pleasant, but sensory judgement of the products labelled with a low fat content were related to a person’s beliefs and concerns towards fat. Nutritional labelling can be an effective measure, which can be used to reduce the population’s fat intake; however, more research is needed to assess the effect of labelling on fat content of their diet. Regulations and education is needed to enhance the consumer’s trust in and capability in the use of labelling to make better food choices and to alter their diet. The success of labelling is dependant on a well-educated and motivated population, as well as the necessary information in a format which is understandable to the consumer.

The main aim of this thesis was to examine the hypothesis that the A/J strain variant of H55N substitution affects citrate synthase (CS) enzyme activity and metabolic health in mice fed a high fat diet (HFD). C57BL/6J (B6) mice and congenic B6.A-(rs3676616-D10Utsw1)/KjnB6 (B6.A) mice, a strain which carries the A/J allele of Cs on the B6 strain background, were fed a HFD (45% kcal from fat) for 12 weeks. CS activity, but not that of ß-hydroxyacyl-coenzyme dehydrogenase was lower in the gastrocnemius muscle of B6.A mice compared to B6 mice (P< 0.001). During HFD feeding the glucose tolerance of mice decreased progressively and to a greater extent in B6.A females compared to B6 females, with males showing a similar trend. Interestingly, after 12 weeks of HFD feeding only B6.A males showed increases (P< 0.05) in their resting metabolic rate; moreover; core body temperature were also increased (P< 0.05) for congenic B6.A of both sexes by the end of the study. However, body weight and fat gain did not differ between B6.A and B6 mice. The second aim of the thesis was to test the hypothesis that low CS activity promotes palmitate-induced lipotoxicity in muscle cells. After 18 hours of incubation in 0.8 mM palmitate, C2C12 muscle cells with a ~50% reduction in CS activity showed low (P< 0.001) viability, increased (P< 0.001) levels of cleaved Caspase-3, high levels of AMP-activated protein kinase and acetyl-CoA carboxylase phosphorylation (P< 0.05), low levels of protein kinase B phosphorylation, high mitogen-activated protein kinases activation (P< 0.001) compared to the control shRNA cells. This was coupled with higher levels of mitochondrial proteins (P< 0.05), which are involved in oxidative phosphorylation. C2C12 cells with reduced CS activity also showed high reactive oxygen species production (P< 0.05), low intracellular ATP levels (P< 0.05), and lower basal mitochondrial respiration (P< 0.001). In summary, the A/J strain variant of H55N is associated with low CS enzyme activity and impaired metabolic health when fed HFD. Palmitate has a lipotoxic effect on Cs shRNA transfected cells and can lead to cell death.

[Truncated abstract] This thesis examines the potential role of dietary intake in the development of two common conditions affecting the prostate gland; prostate cancer and benign prostatic hyperplasia (BPH). Diet is of interest as a potential risk factor for prostate cancer because of geographical variations in prostate cancer incidence and increased prostate cancer risks associated with migration from Asian to western countries. Some geographical variation has been suggested for BPH, but this is less certain. However, both prostate cancer and BPH have potential links with diet through their positive associations with sex hormone levels, metabolic syndrome, increased insulin levels and chronic inflammation. In addition, zinc is an essential dietary micronutrient required for semen production in the prostate gland. The original work for this thesis is presented in six manuscripts of which, four have been published in peer-reviewed journals (at the time of thesis completion). BPH investigated in this thesis is defined as surgically-treated BPH. The following hypotheses were investigated. Regarding foods, nutrients and the risk of prostate cancer and BPH: 1. Increasing intakes of fruits, vegetables and zinc are inversely associated with the risk of prostate cancer and BPH 2. Increasing intakes of total fat and calcium are positively associated with the risk of prostate cancer and BPH. 3. Dietary patterns characterised by high meat, processed meat, calcium and fat content are positively associated with the risk of prostate cancer and BPH. 4. Dietary patterns characterised by high fruit and vegetable and low meat content are inversely associated with the risk of prostate cancer and BPH. v Regarding methodological issues related to the study of diet-disease relationships: 5. Dietary patterns (overall diet) elicited from principal components analysis yield stronger diet-disease associations than when studying isolated nutrients. 6. Remotely recalled dietary intake is reliable enough to be used in studies of chronic disease with long latency periods, such as prostate cancer and BPH. Methods: Data from two studies was used to address the hypotheses above. ... Based on the literature reviewed and the original work for this thesis, the most important dietary risk factors for prostate cancer and BPH appear to be those common to western style diets, i.e. diets high in red meat, processed meat, refined grains, dairy products, and low in fruit and vegetables. This type of diet is likely to result in marginal intakes of antioxidants and fibre, excess intakes of fat and possibly, moderate intakes of carcinogens associated with processed meat and meat cooked at high temperatures. These dietary factors have been linked with biomarkers of inflammation, and they support the hypotheses that chronic inflammation is involved in the development of both prostate cancer and BPH. In addition, this work builds on evidence that zinc is an important factor in prostate health. There is scope for more investigation into the reliability of dietary patterns and the use of nutrient patterns as an alternative to focussing on single food components. Further studies on the reliability of remote dietary intake would also be useful. Because of the latency of chronic disease, it can be theorised that remote dietary recall may uncover more robust diet-disease relationships.

Thesis (Mnutr)--Stellenbosch University,2003. / ENGLISH ABSTRACT: Most of the risk factors for coronary heart disease (CHD) such as hypertension, dyslipidaemia, smoking, non-insulin dependent diabetes mellitus (NIDDM), obesity, physical inactivity and heredity are common in South African populations, with Indians ranking among those with the highest prevalence in the country. Little published literature is available on eating patterns in pre-school children in the Indian population. Therefore, this study a ims to assess the nutritional status of a group of Indian pre-school children in Howick West (a small suburb in the Kwa-Zulu Natal Midlands). Methods: This was a cross-sectional study of 50 Indian pre-school children between the ages of 1-5 years, randomly selected from a total of 632 available Indian households in Howick West. Written, informed consent was obtained from the mother/caregiver of each child that participated in the study. Standardized and validated 24-hour-recall (24-H-R) and quantitative food frequency questionnaires (QFFQ), used in the National Food Consumption Survey (NFCS) of 1999, were adapted and used to assess habitual intake and eating patterns of the 50 Indian pre-school children. Height and weight measurements using standardized methodology were used to assess the anthropometric status of the children. Results: The prevalence of underweight was 14%. Stunting affected only 8% of the children, and 2% were at risk of overweight. The mean energy intakes of the children were above that recommended for age. A high fat intake was observed, with total fat contributing 42% to the daily total energy (TE) intake. The contributions of total carbohydrate and protein to TE intake were 45% and 10%, respectively. Low mean intakes of the following micronutrients were observed (less than 67% of the RDA): Calcium (22% of the children), Vitamin D (90%), Zinc (56%) and Iodine (90%), respectively. Based on the 24-H-R, the intakes of the remaining micronutrients were either above or equivalent to that recommended for age when compared to the 1989 RDAs. Conclusions: Despite a relatively high prevalence of underweight compared to overweight in these preschoolers, dietary analysis has indicated adequate dietary intakes in terms of total energy recommended for the age groups studied. However, total fat intake which represented 42% of TE, was high, with saturated fat (SF) contributing 15% to TE intake. This finding is cause for concern as excessive consumption of dietary fat has been implicated in the aetiology of CVD, obesity and some forms of cancer, and CHD is one of the main causes of morbidity and mortality in South Africa, especially among the Indian segment of the population. / AFRIKAANSE OPSOMMING: Meeste van die risikofaktore vir koronêre hartsiektes (KHS) soos hipertensie, dislipidemie, rook, nie-insulien afhanklike diabetes (NIADM), vetsug, fisiese onaktiwiteit en oorerflikheid, kom algemeen onder Suid-Afrikaanse bevolkingsgroepe voor, met Indiërs onder dié met die hoogste voorkoms in die land. Min gepubliseerde inligting is beskikbaar oor die eetgewoontes van voorskoolse kinders onder die Indiër bevolking. Die doel van hierdie studie was dus 0 m die voedingstatus van 'n groep Indiër voorskoolse kinders in Howick Wes ('n klein voorstad in die Kwa-Zulu Natal Middellande) te bepaal. Metodes: Dit was 'n dwarssnit studie van 50 voorskoolse Indiër kinders tussen die ouderdomme van 1-5 jaar, ewekansig geselekteer uit 632 beskikbare Indiër huishoudings in Howick Wes. Geskrewe en ingeligte toestemming is ontvang van die moeder/versorger van elke kind wat aan die studie deelgeneem het. Gestandaardiseerde en gevalideerde 24-uur herroep (24-H-R) en voedsel frekwensie vraelyste (QFFQ) soos gebruik in die Nasionale Voedsel Inname Studie (NFCS) van 1999, is aangepas en gebruik om gewoontelike inname en eetgewoontes van die 50 Indiër voorskoolse kinders te bepaal. Lengte en gewig is m.b.v. standaad tegnieke bepaal om die antropometriese status van die kinders te evalueer. Resultate: Die voorkoms van ondergewig was 14%. Dwerggroei het slegs 8% van die kinders geaffekteer en 2% het 'n risiko vir oorgewig getoon. Die gemiddelde energie inname van die kinders was hoër as wat aanbeveel word vir hierdie ouderdomsgroep. 'n Hoë vetinname is gevind, met 'n totale vet bydrae van 42% tot die daaglikse totale energie (TE) inname. Die bydrae van koolhidrate en proteïen tot TE was 45% en 10% respektiewelik. Lae gemiddelde innames van die volgende mikrovoedingstowwe is gevind (minder as 67% van die RDA): kalsium (22% van die kinders), vitamien D (90%), sink (56%) en jodium (90%), respektiewelik. Gebasseer op die 24-H-R, was die inname van die oorblywende mikrovoedingstowwe óf hoër óf gelyk aan wat aanbeveel word vir die betrokke ouderdomsgroep wanneer vergelyk word met die 1989 RDA. Gevolgtrekkings: Ten spyte van 'n relatiewe hoë voorkoms van ondergewig in vergelyking met oorgewig in hierdie voorskoolse kinders, was dieetinname voldoende in terme van totale aanbevole energie vir die ouderdomsgroep. Totale vetinname, wat 42% van TE uitgemaak het, was egter hoog en versadigde vette het 15% van TE bedra. Hierdie verskynsel is 'n rede tot kommer aangesien oormatige vetinname reeds geïmpliseer is in die etiologie van KHS, vetsug en sommige vorms van kanker, en KHS is een van die belangrikste oorsake van morbiditeit en mortaliteit in Suid Afrika, veralonder die Indiër bevolking.

A dissertation submitted in partial fulfilment of the requirements for the degree of Bachelor of Arts Masters (Industrial/ Organisational Psychology) in the Faculty of Humanities, University of the Witwatersrand, Johannesburg. March, 2016 / This study investigated whether the lifestyle behaviours and psychological well-being of women executives and managers predicted their ten-year risk of developing cardiovascular disease. The sample of South African women executives and managers work in a variety of industries in the cities of Johannesburg, Durban and Cape Town. The study sought to determine the predictability of the women executives and managers’ risk of developing cardiovascular disease through examining their level of alcohol consumption, level of physical exercise and the nutritional and dietary choices that they made as well as their level of depression, anxiety and stress. The data was gathered through an executive health and wellness programme and logistic regression and Chi-squared tests of association were used in conducting the analyses. The results suggested that the level of alcohol consumption and the nutritional and dietary choices made were predictive of the individual’s ten-year risk of developing cardiovascular disease. Additionally, the level of anxiety was found to be associated with the risk of developing cardiovascular disease. The results suggest that both individuals and organisations should prioritise the changing of unhealthy lifestyle behaviours, specifically excessive alcohol consumption and daily dietary choices, in order to lower their risk of developing cardiovascular disease. / MT2017