To examine the effect of diet fat type on rates of cholesterol synthesis and esterification during feeding and fasting, nine healthy male subjects were fed solid-food diets of 40% fat as predominantly either olive oil (MONO), safflower-oil margarine (POLY), or butter (SAT). At the end of each two-week diet trial, subjects were given deuterium (D) oxide orally and de novo synthesis was measured from D incorporation into cholesterol and interpreted as rates of fractional synthesis (FSR) (pools/day) into the rapidly exchangeable free cholesterol (FC) pool. Absolute synthesis rates (ASR) were calculated as the product of FSR and the FC pool. Pool size for each subject was obtained from analysis of the specific activity decay curve of an intravenous injection of 4-14C-cholesterol over nine months. Synthesis was measured over two consecutive 12-h fed periods followed by two consecutive 12-h fasted periods. Serum samples were also assayed for lathosterol concentration, an index of cholesterol synthesis. Serum cholesterol and non-HDL cholesterol concentrations were highest on the SAT diet, lowest (P<0.001) on the POLY diet and intermediate on the MONO diet, triglyceride levels were greater (P<0.03) on the SAT diet than on the POLY diet, and HDL levels were lowest (P<0.05) on the SAT diet and highest on the MONO diet. Cholesterol D enrichment and FSR during each 12-h period were greater (P<0.014) on the POLY diet than on the SAT diet; MONO enrichment and FSR were not significantly different from those on the other two diets. Similar results were obtained for rates of cholesterol esterification (P<0.001). Deuterium enrichment data suggested, and lathosterol data confirmed, that free cholesterol synthesis was greater during the fed period than during the fasted period (P<0.01); however, this could not be confirmed for rates of cholesterol esterification. Results suggest that POLY fat feeding augments de novo cholesterol synthesis without adverse effects on total serum cholesterol concentrations, and that the deleterious effects of SAT fat on serum cholesterol are not brought about by augmented de novo synthesis. Finally, the combination of deuterium incorporation and mathematical modelling produces estimates of daily cholesterol synthesis which are compatible with those invoked by more laborious techniques.

To examine the effect of diet fat type on rates of cholesterol synthesis and esterification during feeding and fasting, nine healthy male subjects were fed solid-food diets of 40% fat as predominantly either olive oil (MONO), safflower-oil margarine (POLY), or butter (SAT). At the end of each two-week diet trial, subjects were given deuterium (D) oxide orally and de novo synthesis was measured from D incorporation into cholesterol and interpreted as rates of fractional synthesis (FSR) (pools/day) into the rapidly exchangeable free cholesterol (FC) pool. Absolute synthesis rates (ASR) were calculated as the product of FSR and the FC pool. Pool size for each subject was obtained from analysis of the specific activity decay curve of an intravenous injection of 4-14C-cholesterol over nine months. Synthesis was measured over two consecutive 12-h fed periods followed by two consecutive 12-h fasted periods. Serum samples were also assayed for lathosterol concentration, an index of cholesterol synthesis. Serum cholesterol and non-HDL cholesterol concentrations were highest on the SAT diet, lowest (P<0.001) on the POLY diet and intermediate on the MONO diet, triglyceride levels were greater (P<0.03) on the SAT diet than on the POLY diet, and HDL levels were lowest (P<0.05) on the SAT diet and highest on the MONO diet. Cholesterol D enrichment and FSR during each 12-h period were greater (P<0.014) on the POLY diet than on the SAT diet; MONO enrichment and FSR were not significantly different from those on the other two diets. Similar results were obtained for rates of cholesterol esterification (P<0.001). Deuterium enrichment data suggested, and lathosterol data confirmed, that free cholesterol synthesis was greater during the fed period than during the fasted period (P<0.01); however, this could not be confirmed for rates of cholesterol esterification. Results suggest that POLY fat feeding augments de novo cholesterol synthesis without adverse effects on total serum cholesterol concentrations, and that the deleterious effects of SAT fat on serum cholesterol are not brought about by augmented de novo synthesis. Finally, the combination of deuterium incorporation and mathematical modelling produces estimates of daily cholesterol synthesis which are compatible with those invoked by more laborious techniques. / Land and Food Systems, Faculty of / Graduate

Acylation stimulating protein (ASP) is a plasma protein that significantly increases adipose tissue fat storage. In vivo and in vitro studies have suggested a role for plasma ASP in enhancing postprandial plasma triglyceride (TG) clearance. The primary objective of this study was to examine, for the first time, the postprandial response of plasma ASP and the fate of an exogenous fat source in 8 post-obese and 8 matched control women. This was done through following 13C-labeled high fat breakfast meal (1062 Cal, 67% fat) every 2 hours for 8 hours in 3 plasma pools and in expired breath CO2. The 3 plasma pools were: TG fraction in triglyceride rich lipoproteins (TRL) with sedimentation factor Sf > 400 (referred to as chylomicron-TG), TG fraction in TRL with Sf = 20--400 (referred to as VLDL-TG), and plasma free fatty acid (FFA). The secondary objective was to examine fasting and postprandial resting energy expenditure (REE), thermic effect of food (TEF), carbohydrate to fat oxidation rate and insulin sensitivity, which are factors that have been implicated in the tendency of post-obese women to regain weight. (Abstract shortened by UMI.)

The purpose of this investigation was to examine the effects of exercise and diet on muscle triglyceride. Seven endurance-trained men completed a 120min cycling bout at 65% of V O2max in an attempt to lower muscle glycogen and triglyceride. Each subject then ingested an isocaloric, high-carbohydrate (HI-CHO; 83% of kcal) or high-fat (HI-FAT; 68% of kcal) diet for the ensuing 24 h. A 1600 kJ cycling time trial was completed following this 24-h dietary period. Muscle glycogen concentration before (571±38 vs. 599±41 mmol•kg dw-1) and after (241±36 vs. 285±41 mmol•kg dw-1) the 120-min cycling bout was not different (P>0.05) between the HI-CHO and HI-FAT trials, respectively. Muscle triglyceride concentration before (33.0±2.3 vs. 37.0±2.1 mmol•kg dw-1) and after (30.9±2.4 vs. 32.8±1.6 mmol•kg dw-1) the 120-min cycling bout was also not different between the HI-CHO and HI-FAT trials, respectively. In addition, muscle triglyceride did not decrease significantly during the cycling bout for the HI-CHO (2.1±2.1 mmol•kg dw-1) or HI-FAT (4.2±1.8 mmol•kg dw-1) trial. Over the 24-h dietary period, a significantly greater amount of glycogen was resynthesized during the HI-CHO (308±41 mmol•kg dw-1) versus the HI-FAT trial (42±23 mmol•kg dw-1). Muscle triglyceride concentration increased 11.9±1.6 mmol•kg dw-1 (P<0.05) and decreased 3.4±1.8 mmol•kg dw-1 (P>0.05) during the 24-h dietary period for the HI-FAT and HI-CHO trials, respectively. Cycling performance time was significantly greater during the HI-FAT (139.3±7.1 min) compared to the HICHO (117.1±3.2) trial. The average V02 (3.40±0.12 vs. 2.96±0.17 L•min-1) and RER (0.89±0.01 vs. 0.82±0.01) during the time trial were higher for the HI-CHO than the HI-FAT trial, respectively. These data demonstrate that a small, insignificant amount of muscle triglyceride is utilized during prolonged, moderate-intensity cycling. Furthermore, 24 h of a high-fat diet increased muscle triglyceride concentration and reduced endurance performance. / Human Performance Laboratory

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Typescript (photocopy). / Digitized by Kansas Correctional Industries

The purpose of this study was to analyze the effect of fatty acid chain length and quantity on the bioavailability of calcium. Thirteen healthy subjects were randomly assigned to a series of 5 test meals containing varying types and levels of fat and calciumconsumed over a three week time period. The test meals included 10 grams MCT oil (MCT 10), 20 grams MCT oil (MCT 20), 10 grams beef fat (BT 10), 20 grams beef fat (BT 20), and calcium only (Ca). Calcium absorption was assessed using timed urine collections following a specified calcium load. Three day food records were obtained to assess typical nutrient intakes of the subjects coming into and during the study. MCT oil provided better absorption of the calcium supplement than did the beef tallow. A difference was also noted in the absorption of calcium based on the amount of fat consumed. A higher intake of MCT oil (10 g vs. 20 g) appeared to favor the absorption of calcium. Urine calcium excretion was significantly greater (p < .009) during the MCT oil treatments (MCT 10, MCT 20) compared to the beef fat treatments (BT 10, BT 20), suggesting reduced calcium absorption during the beef fat treatments. There were no differences in mean calcium excretion based on quantity of fat consumed ( 10 g vs. 20 g), nor any interaction between type of fat and amount. Tests for detecting differences between individual treatments indicated a significance difference (p < .05) in calcium excretion between MCT 20 and BT 10 treatments. Urine calcium excretion was corrected for body size using urine calcium/creatinine ratio (Ca/Cr). There was a significant time effect between the 0 - 2, 2 - 4 hour time periods (p < .005) and the various treatments for Ca/Cr. Though not significant, mean Ca/Cr was highest for the calcium treatment (0.42), compared to the MCT oil treatments (36, z of MCT 10 & MCT 20), and beef fat treatments (28, x of BT 10 & BT 20). The beef fat treatments significantly decreased the absorption of calcium compared to the MCT oil treatments. It appears that beef fat, when compared to the calcium only treatment, decreased calcium absorption. / Department of Home Economics

This thesis consists of a brief description on cancer, carcinogenesis, the changes in the type and level of dietary fat available in our diets over time and association with the development of certain diseases. The main focus of this research was on omega 6 and omega 3 essential fatty acids (EFA) and their interaction with regards to carcinogenesis.

This thesis consists of a brief description on cancer, carcinogenesis, the changes in the type and level of dietary fat available in our diets over time and association with the development of certain diseases. The main focus of this research was on omega 6 and omega 3 essential fatty acids (EFA) and their interaction with regards to carcinogenesis.

The regulation of the serum triglyceride responses to fat ingestion have been examined in normolipidemic men. To evaluate the existing methods for comparing chylomicron-triglyceride clearance, the oral and intravenous fat tolerance tests and a steady state duodenal perfusion method were compared. Good correlations (r > 0.8) were found between each of these methods. Since the intravenous fat tolerance test is independent of fat absorption, these data suggested that the serum triglyceride response to fat feeding was largely determined by the rate of chylomicron-triglyceride clearance. To determine the influence of the quantity and type of meal fat on postprandial serum triglyceride concentrations, the serum triglyceride responses to three different doses of dairy cream, and to standard doses of olive and sunflower oil were examined. For a given type of fat, the magnitude of postprandial lipemia (the integrated serum triglyceride excursion) varied directly with the quantity of fat in the meal. This finding suggested that the chylomicron- triglyceride clearance system(s) did not become saturated even after large fat meals. In addition, it appeared that the hormonal factors released in response to fat ingestion (some of which are known to increase lipoprotein lipase activity in vitro) did not increase the rate of chylomicron-triglyceride clearance. If the quantity of fat in a meal was fixed, then postprandial lipemia increased with increasing saturation of the triglyceride fatty acids. These differences did not appear to reflect differences in triglyceride absorption. Since acute fat feeding per se did not appear to stimulate chylomicron-triglyceride clearance, the effects of dietary proteins and carbohydrates were studied. The addition of up to 35g protein to a standard test meal did not affect postprandial lipemia. These results were supported by the observation that protein ingestion did not affect intravenous fat tolerance. Postprandial serum triglyceride concentrations were significantly influenced by carbohydrate ingestion. Fructose (50g) and sucrose (100g) markedly increased postprandial lipemia, although glucose ingestion did not. In agreement with earlier studies, glucose ingestion decreased serum triglyceride concentrations 2 hours after the meal. This effect was abolished by intraduodenal fat administration and by substituting starch for glucose in the test meal. The effects of glucose could be reproduced by iso-osmotic quantities of urea, however. These findings suggested that glucose ingestion did not increase chylomicron -triglyceride clearance. It is more likely that glucose delayed the absorption of triglycerides by slowing gastric emptying, and that this effect was partly related to the increased osmolarity of glucose- containing meals. The effects of chronic exercise on postprandial lipemia and chylomicron-triglyceride clearance were determined in endurance- adapted athletes. The serum triglyceride responses to large and small fat meals were lower in athletes than in sedentary men with comparable fasting triglyceride concentrations. These differences were not eliminated by a single bout of acute exercise in the sedentary men. The clearance of intravenously administered lntralipid, and chylomicron -triglyceride clearance assessed from steady state chylomicron-triglyceride concentrations during duodenal fat perfusion were faster in athletes than in the sedentary men. These data suggested that the low postprandial lipemia in athletes reflects increased chylomicron-triglyceride clearance caused by increased activity of the triglyceride clearing system(s). Given these considerations. it appears that the pathway(s) for chylomicron triglyceride clearance are extremely efficient in normal men and that these pathways are not subject to acute physiological regulation.