Les glucocorticoïdes (GC) sont des substances très utilisées en thérapeutique, mais parfois détournées de leur utilisation première par les sportifs en raison de leurs effets ergogéniques. Si les effets secondaires d’une prise chronique de GC sont bien connus, les répercussions d’un traitement court restent controversées. Nous nous sommes tout d’abord intéressés aux effets d’un traitement d’1 semaine de GC (50-60 mg/j de prednisone/prednisolone) sur la prise alimentaire, la composition corporelle, la glycémie, l’insulinémie et la sécrétion d’adipokines chez des sujets masculins et féminins sportifs de loisir. Pour des raisons éthiques, cette étude n’a pu être conduite chez des sportifs de haut-niveau. Les adipokines (i.e., leptine et adiponectine) apparaissent significativement augmentées chez tous les sujets par le traitement de GC, mais celui-ci n’entraîne aucune modification de la prise alimentaire, de la composition corporelle ou de l’insulinémie. Il n’existe pas d’effet genre à l’exception de l’hyperglycémie mise en évidence sous GC uniquement chez les sujets de sexe masculin. Il apparait également qu’un traitement d’une semaine de prednisone per os n’altère que de manière très transitoire l’axe hypothalamo-hypophyso-surrénalien, avec un retour à des concentrations basales de cortisol et de DHEA seulement 3 jours après la fin du traitement. / Glucocorticoids (GC) are substances widely used in therapy, but sometimes diverted from their primary use by athletes for their ergogenic effects. Whereas the side effects of chronic use of GC are well known, the impact of short treatment remains controversial. We first investigated the effects of 1 week treatment of GC (50-60 mg/day of prednisone/prednisolone) on food intake, body composition, blood glucose, insulinemia, and adipokine secretion in male and female recreationally-trained athletes. For ethical reasons, this study could not be conducted in elite athletes. The adipokines (ie, leptin and adiponectin) appear significantly increased in all subjects after the GC treatment, but the treatment does not induce any change in food intake, body composition or insulin concentrations. There is no gender effect with the exception of hyperglycemia demonstrated with GC only in males. It also appears that the short-term treatment of oral prednisone alters the hypothalamic-pituitary-adrenal axis only very transient, with a return to basal levels of cortisol and DHEA only 3 days after of treatment.

Leucine injections directly into the brain decrease food intake whereas supplementation of this amino acid in a diet has a negligible effect on food intake. We sought to investigate why orally supplemented leucine is ineffective as an anorexigen. We found that mice consuming leucine exhibited increased cFos immunoreactivity in the ARC and PVN of hypothalamus, areas controlling energy balance. However, real time- PCR analysis of the hypothalamic tissue in mice that were exposed to oral leucine showed changes in expression of genes involved in the regulation of energy balance as well as those mediating feeding reward (TMEM18, MC4R, CRH, FTO, SLC6A15, DOR). This suggests that leucine consumption affects activity of not only brain pathways that control calorie intake, but also those that mediate eating for pleasure. Hence the lack of feeding response to leucine supplementation in a diet may stem from the simultaneous action of this amino acid at brain circuit promoting reward and energy homeostasis.

This study was conducted to determine water intake. Forty-four Holstein bull calves were evaluated to investigate the effects of starter intake, body weight, temperature and time to predict water intake. A model was developed using PROC GLM in SAS. Least square means separation were used to identify significant effects. Starter intake was a significant variable (P < 0.05) in predicting the water intake of a calf, especially after day 21 when starter intake and water intake were both increasing. Water intake was increased by calves with fecal scores of 1 and 2. However, water intake was significantly different for calves with fecal scores of 3 or 4 with a (P < 0.05) which had decreased water intake. The interaction between scours and fecal score were not significant. Water intakes significantly differ in calves that had scour and in calves not experimented scours.

The first objective was to estimate total internal fat in beef cattle based on a technique that measures kidney fat (uKFd) using real-time ultrasound (RTU). Data were obtained from 109 cattle from four studies, and animals were scanned 7 d preslaughter for uKFd and ultrasound backfat thickness. At slaughter carcass kidney fat depth (cKFd), KPH weight, and total internal fat were measured. The second objective was to characterize residual feed intake (RFI) in finishing cattle fed high grain diets and to examine the relationships with growth, ultrasound, carcass, non-carcass, and tenderness traits in two studies involving Santa Gertrudis (n = 114) steers, and Angus bulls (n = 16) and heifers (n = 16). In both experiments, RFI was calculated as the difference between actual DMI and predicted DMI. Results for the first objective indicated that RTU can be used to estimate cKFd, KPH weight and total internal fat (IFAT). Prediction equations developed to predict IFAT had R2 that ranged from 0.65 to 0.97 (P < 0.05). Results for the second objective indicate that RFI was not correlated with ADG, but was positively correlated with DMI and feed conversion ratio. Carcass 12th-rib fat depth was positively correlated with RFI in Santa Gertudis steers, such that steers with low RFI were leaner than steers with high RFI. Residual feed intake was not correlated with carcass or non-carcass composition traits in Angus bulls and heifers. Marbling and tenderness traits were not associated with RFI. Results from these studies indicate that we are able to measure IFAT with RTU, and that beef cattle producers can utilize RFI to identify animals that are more efficient with minimal impacts on growth, carcass composition and tenderness.

Abstract Objective: To measure dietary intakes of young children aged 12–24 months and to determine the impact of poor diets on stunting. Design: A quantitative food-frequency questionnaire was adapted, tested and standardised. Trained enumerators conducted in-depth interviews with the mothers/caregivers of the children. Forty stunted children in urban informal settlements and 30 stunted children in rural areas were selected and pair-matched with controls. The data were captured on the Food Finder Program of the Medical Research Council. Results: In both urban and rural areas, the diet of stunted and non-stunted groups did differ significantly and all diets were of poor nutritional quality. Conclusion: Diets in both areas resembled the recommended prudent diet, i.e. low in fat and high in carbohydrates. Poor quality diets were not the primary cause of stunting.

No description available.

Cockroaches apparently select balanced diets using simple. but robust rules (Geissler & Rollo 1987). These rules are general enough to deal with a complex habitat yet sufficiently specific to contribute a balanced diet, thus leading to the successful maintenance of fitness. Both internal and external stimuli are integrated to elicit the appropriate responses. Feedback information concerning nutritional status may be short-term (e.g. immediate physiological state or sensory input) or long-term (e.g. storage reserves. hormones or learning) so that both coarse and fine-tuning mechanisms are involved in the choice of nutritious and non-toxic foods. The insects' ability to evaluate palatability (scent and taste cues) and nutritional value are essential aspects of the decision-making process. This study investigated the general mechanisms governing changes in preferences with respect to tradeoffs between short and long-term stimuli. On a short-term scale, animals should prefer foods that present immediate positive stimuli according to their innate disposition. However, if a food does not meet long-term physiological needs. the animal should develop an aversion and learning may override a decision based upon a short-term stimulus, or alter innate preferences entirely. The experimental protocol involved measuring amounts and time spent eating. Where appropriate, these values were related to female reproductive productivity to show the link between nutrition and reproductive capacity (fitness). Investigations demonstrated the ability of cockroaches to use coarse controls to compensate for long term general starvation as well as specifically depleted nutrients such as carbohydrates and protein. Cockroaches also showed discrimination between the quality of carbohydrate diets. The ranking of palatability among foods was not a fixed attribute but varied relative to the items available. With large nutritional imbalances that required time to correct, dietary management was less discriminatory with respect to food quality and was largely concerned with increased quantity. Relatively well nourished animals showed much greater selectivity with regard to quality. Thus, the coarse and fine-tuned control systems stressed different strategic tactics. Reproductive success was linked to responses to malnourishment. Reproductive output was increased even over control levels when animals compensated for energy depletion by switching to alternate resources. This contradicted the prediction of maximization of reproductive output (fitness) by maximization of energy intake from optimality theory. The results were interpreted with respect to optimal foraging theory, the currently accepted paradigm for ecological feeding relations. The results not only conflicted with the predictions of optimal foraging theory in most respects, they suggest a completely different paradigm that is incompatible with a hypothesis of maximization of net energy gain. Instead. cockroaches appear to regulate feeding with respect to evolutionarily determined set points related to innate growth and production rates. Moreover, the criteria for decisions are a multiplicity of nutritional requirements, not simply energy, as proposed by optimal foraging theory. Some of the decisions made with respect to nutritional balancing result from direct response to external or internal stimuli, and others are a learned association between long-term benefits and correlated sensory cues. / Thesis / Master of Science (MS)

Background: African Americans have disproportionately higher burden of prostate cancer compared to European Americans. However, the cause of prostate cancer disparities is still unclear. Several roles have been proposed for calcium and vitamin D in prostate cancer pathogenesis and progression, but epidemiologic studies have been conducted mainly in European descent populations. Here we investigated the association of calcium and vitamin D intake with prostate cancer in multiethnic samples. Methods: A total of 1,657 prostate cancer patients who underwent screening and healthy controls (888 African Americans, 620 European Americans, 111 Hispanic Americans, and 38 others) from Chicago, IL and Washington, D.C. were included in this study. Calcium and vitamin D intake were evaluated using food frequency questionnaire. We performed unconditional logistic regression analyses adjusting for relevant variables. Results: In the pooled data set, high calcium intake was significantly associated with higher odds for aggressive prostate cancer (ORQuartile (1 vs. Quartile) (4) = 1.98, 95% C.I.: 1.01-3.91), while high vitamin D intake was associated with lower odds of aggressive prostate cancer (ORQuartile 1 vs. Quartile (4) = 0.38, 95% C.I.: 0.18-0.79). In African Americans, the association between high calcium intake and aggressive prostate cancer was statistically significant (ORQuartile 1 vs. Quartile 4 = 4.28, 95% C.I.: 1.70-10.80). We also observed a strong inverse association between total vitamin D intake and prostate cancer in African Americans (ORQuartile 1 vs. Quartile 4 = 0.06, 95% C.I.: 0.02-0.54). In European Americas, we did not observe any significant associations between either calcium or vitamin D intake and prostate cancer. In analyses stratifying participants based on Body Mass Index (BMI), we observed a strong positive association between calcium and aggressive prostate cancer and a strong inverse association between vitamin D intake and aggressive prostate cancer among men with low BMI (<27.8 kg/m(2)), but not among men with high BMI (>= 27.8 kg/m(2)). Interactions of race and BMI with vitamin D intake were significant (P-Interaction < 0.05). Conclusion: Calcium intake was positively associated with aggressive prostate cancer, while vitamin D intake exhibited an inverse relationship. However, these associations varied by race/ethnicity and BMI. The findings from this study may help develop better prostate cancer prevention and management strategies.

The micronutrient intake of the average South African is not optimal. National fortification of staple foods does not solve all micronutrient deficiencies. Furthermore, urbanisation causes a shift in food intake, increasing the availability of cheaper and more energy dense food and drinks that are often lacking in micronutrients. It is unclear whether the current literature provides sufficient evidence of nutrient dilution by the moderate consumption of alcohol and/or added sugar. The aim of the present study was to evaluate the dietary intakes of a population in nutrition transition and determine the effect of intake of alcohol and added sugars on intakes of micronutrients and food groups to provide information for the development of preventive strategies in public health. A number of countries, including South Africa, suggest limited alcohol and sugar intakes in the Food Based Dietary Guidelines but do not quantify this recommendation. Data from the "Transition and Health during Urbanisation in South Africa" survey (THUSA) were analysed for dietary intakes (as determined by a validated quantified food frequency questionnaire), age and body mass index (BMI). The THUSA study was conducted during 1996 and 1998 in the North West Province and included 1854 "apparently healthy". Respondents aged 15 years and older from 37 randomly selected sites from rural and urban areas. Alcohol intake (absolute intake and percentage of energy) was the highest for men living in middle class urban areas. With increased urbanisation, the type of beer shifted from sorghum based to commercial beer. Sixty-one percent of men and 25% of women reported that they consumed alcohol at the time of the survey. Eighteen percent of men and 11.7% of women consumed more than 30g and 15g alcohol per day, respectively (intakes which are regarded as moderate). Men and women consuming the most alcohol had significantly higher mean intakes of most macro and micronutrients. However, the intake of vitamin Bi2, B6, folate, vitamin E and vitamin C did not meet the recommended dietary intake (RDA) across all levels of alcohol intake. Although the total energy intake increased with increased alcohol intake, there was no significant difference between the mean BMI of men or women with different levels of intake. One third of the population consumed more than a 100g of added sugar daily. Intake of sugar was the highest in the farm dwellers but the intake of sweets, cakes, cookies and cold drinks was the highest in the urban areas. As sugar intake increased so did energy, carbohydrates and most micronutrients. However, the intake of vitamin B12, folate, vitamin C and calcium did not meet the RDA across all levels of sugar intake. BMI did not differ between respondents with the highest and lowest sugar intake and no association was found between BMI and sugar intake. The THUSA study was conducted before fortification of staple food became law in October 2003. Maize meal and wheat flour are nowadays fortified with certain vitamins and minerals which may alleviate some micronutrient deficiencies. For future research it is imperative to establish the reasons for low intake of certain micronutrients rather than to look at a single food item in the diets of the South African adult population. Proper education on the intake of cheaper food sources of micronutrients needs to be highlighted at all levels of the health sector. / Thesis (M.Sc. (Dietetics)--North-West University, Potchefstroom Campus, 2009.

The micronutrient intake of the average South African is not optimal. National fortification of staple foods does not solve all micronutrient deficiencies. Furthermore, urbanisation causes a shift in food intake, increasing the availability of cheaper and more energy dense food and drinks that are often lacking in micronutrients. It is unclear whether the current literature provides sufficient evidence of nutrient dilution by the moderate consumption of alcohol and/or added sugar. The aim of the present study was to evaluate the dietary intakes of a population in nutrition transition and determine the effect of intake of alcohol and added sugars on intakes of micronutrients and food groups to provide information for the development of preventive strategies in public health. A number of countries, including South Africa, suggest limited alcohol and sugar intakes in the Food Based Dietary Guidelines but do not quantify this recommendation. Data from the "Transition and Health during Urbanisation in South Africa" survey (THUSA) were analysed for dietary intakes (as determined by a validated quantified food frequency questionnaire), age and body mass index (BMI). The THUSA study was conducted during 1996 and 1998 in the North West Province and included 1854 "apparently healthy". Respondents aged 15 years and older from 37 randomly selected sites from rural and urban areas. Alcohol intake (absolute intake and percentage of energy) was the highest for men living in middle class urban areas. With increased urbanisation, the type of beer shifted from sorghum based to commercial beer. Sixty-one percent of men and 25% of women reported that they consumed alcohol at the time of the survey. Eighteen percent of men and 11.7% of women consumed more than 30g and 15g alcohol per day, respectively (intakes which are regarded as moderate). Men and women consuming the most alcohol had significantly higher mean intakes of most macro and micronutrients. However, the intake of vitamin Bi2, B6, folate, vitamin E and vitamin C did not meet the recommended dietary intake (RDA) across all levels of alcohol intake. Although the total energy intake increased with increased alcohol intake, there was no significant difference between the mean BMI of men or women with different levels of intake. One third of the population consumed more than a 100g of added sugar daily. Intake of sugar was the highest in the farm dwellers but the intake of sweets, cakes, cookies and cold drinks was the highest in the urban areas. As sugar intake increased so did energy, carbohydrates and most micronutrients. However, the intake of vitamin B12, folate, vitamin C and calcium did not meet the RDA across all levels of sugar intake. BMI did not differ between respondents with the highest and lowest sugar intake and no association was found between BMI and sugar intake. The THUSA study was conducted before fortification of staple food became law in October 2003. Maize meal and wheat flour are nowadays fortified with certain vitamins and minerals which may alleviate some micronutrient deficiencies. For future research it is imperative to establish the reasons for low intake of certain micronutrients rather than to look at a single food item in the diets of the South African adult population. Proper education on the intake of cheaper food sources of micronutrients needs to be highlighted at all levels of the health sector. / Thesis (M.Sc. (Dietetics)--North-West University, Potchefstroom Campus, 2009.