My thesis research has examined the fatty acid composition of serum triacylglycerol, phospholipid and cholesterol ester in 2793 participants who took part in the 1997 National Nutrition Survey - a national population-based survey of New Zealand adolescents and adults aged or [greater than or equal to]̲15 y. Differences in serum fatty acids by sex, age, ethnicity, body mass index and smoking - independent of dietary fat intake - were determined. Serum fatty acids were used as biomarkers of saturated and polyunsaturated fat intake to predict population serum total cholesterol concentrations. The association between n-3 long-chain polyunsaturated fatty acids in serum phospholipid and mental and physical wellbeing, as assessed by the short form-36, was determined. Serum fatty acids have been used as biological markers of fat intake and to predict the risk of disease. The fatty acid composition of serum triacylglycerol, phospholipid and cholesterol ester is subject to alteration by dietary fat but overall, is largely controlled by metabolic enzymes. Non-dietary variables - sex, age, body mass index or cigarette smoking - may influence the activity of these enzymes, which will subsequently alter the fatty acid composition but the extent to which these affect serum fatty acid composition in the general population is poorly understood. Our results showed that the proportion of docosahexaenoic acid in serum phospholipid and cholesterol ester was significantly greater in women by 0.15 and 0.02 mol%, respectively in comparison to men whereas, the proportion of eicosapentaenoic acid was significantly greater in men by 0.08 and 0.1 mol%, respectively, after adjusting for age, ethnicity, body mass index and smoking. A number of differences in the proportion of palmitoleic acid in serum triacylglycerol, phospholipid and cholesterol ester were detected; palmitoleic acid increased across the age categories in women (15-24, 25-44, 45-64 65+ y), was higher in women compared to men, New Zealand Europeans compared to New Zealand Maori and Pacific People, those with a body mass index or [greater than or equal to] 30 kg/m� compared to those with a body mass index < 25 kg/m� and in current smokers in comparison to non-smokers. In women, there was an inverse trend in the proportion of linoleic acid in serum phospholipid and cholesterol ester across the age categories. The proportion of linoleic acid in serum triacylglycerol, phospholipid and cholesterol ester was lower in smokers by 2.19, 1.04 and 0.75 mol%, respectively in comparison to non-smokers. None of these differences could be explained by a difference in dietary fat intake. Consequently, sex appears to affect the metabolism of n-3 long-chain polyunsaturated fatty acids independent of dietary fat intake and metabolic differences associated with age, body mass index and smoking may be at play for a number of other serum fatty acids notably, palmitoleic and linoleic acids. Evidence for a role of dietary fat as a predictor of serum cholesterol concentrations in the general population is conflicting. On one hand, results from cholesterol-lowering dietary intervention trials show unequivocally that decreasing saturated fat intake produces a meaningful reduction in serum cholesterol concentrations. On the other hand, the results of large observational studies show little association between saturated fat intake and cholesterol concentrations. The lack of association in the latter studies may result from errors in dietary assessment and therefore, using serum fatty acids as biomarkers of fat intake may overcome the limitations associated with typical dietary assessment techniques. Participants were divided into quintiles of increasing proportion of serum fatty acids. Each one SD increase in the myristic acid composition of serum cholesterol ester, triacylglycerol and phospholipid was associated with an increase in cholesterol of 0.19, 0.10 and 0.13 mmol/L, respectively after adjusting for confounding variables. The difference in cholesterol concentrations between those categorised into the highest and lowest quintiles of serum cholesterol ester myristate was 0.48 mmol/L. A one SD increase in the linoleic acid composition of serum cholesterol ester, triacylglycerol and phospholipid corresponded to a decrease in cholesterol of 0.07, 0.05 and 0.07 mmol/L, respectively. The difference in cholesterol concentrations between the 1st and 5th quintiles of serum cholesterol linoleate was 0.18 mmol/L. Intake of saturated and polyunsaturated fats, as measured using serum fatty acids, are important determinants of cholesterol concentrations in New Zealanders. It has been hypothesised that a lower intake of n-3 long-chain polyunsaturated fatty acids, largely of marine origin, is implicated in the aetiology of depressive disorder. Results from the majority of observational studies have shown that depressed participants have a lower proportion of eicosapentaenoic or docosahexaenoic acid in phospholipids compared to controls but evidence for an improvement in depressive symptoms after supplementation with n-3 long-chain polyunsaturated fatty acids is conflicting. There is little known about the role that n-3 long-chain polyunsaturated fatty acids may have as predictors of mental wellbeing in the general population. Participants were categorised into quintiles of increasing n-3 long-chain polyunsaturated fatty acids in serum phospholipid. There was no significant trend in self-reported mental wellbeing - the mental component score - across the quintiles of eicosapentaenoic, docosapentaenoic and docosahexaenoic acids or the sum of these three fatty acids after adjusting for confounding variables. There was a significant trend in the mental component score across the quintiles of the ratio of eicosapentaenoic/arachidonic acid; the difference between the highest and the lowest quintile was 6.6 points. There were significant positive trends in self-reported physical health - the physical component score - across the quintiles of eicosapentaenoic and docosapentaenoic acids as well as the ratio of eicosapentaenoic/arachidonic acid ratio; the difference between the 1st and 5th quintiles were 8.6, 6.0 and 8.9 points, respectively. Overall, there appears to be little association between the n-3 long-chain polyunsaturated fatty acid composition of serum phospholipid and self-reported mental health in a population of low fish consumers; however, the proportion of n-3 long-chain polyunsaturated fatty acids may be an important predictor of physical wellbeing in New Zealanders.

The time course of this increase in muscle n-3 PUFA composition and anabolic protein expression is currently unknown. In Chapter 2 of this thesis ten healthy male participants consumed 5g.d-1 of n-3 PUFA-enriched fish oil for 4 weeks. Muscle biopsies samples were collected in the fasted, rested state 2 weeks prior, immediately before (Week 0), at Week 1, Week 2 and Week 4 after initiation of fish oil supplementation for assessment of changes in lipid composition and expression of anabolic signalling proteins over time. Muscle lipid profile, (% total n-3 PUFA/total fatty acids) increased from W0 to W2 (3.8 ± 0.2 to 5.1 ± 0.3 %) and continued to rise at W4 (6.7 ± 0.4 %). Total protein content of FAK increased from W0 to W4 (3.9 ± 1.5 fold) whereas total mTOR was increased from W0 at W1 (2.4 ± 0.6 fold) with no further significant increases at W2 and W4. For the first time this study demonstrates that oral fish oil consumption results in an increase of n-3 PUFA levels in human skeletal muscle that is associated with increases in the expression of anabolic signalling proteins. Our understanding of the anabolic signalling process that underpins muscle protein synthesis has been advanced by the application of the WB technique. However, the semi-quantitative nature and poor dynamic range associated with the WB technique may lead to incongruence regarding the molecular response of skeletal muscle to anabolic stimulation. Chapter 3 of this thesis developed and applied a quantitative in vitro [γ-32P] ATP kinase assay (KA) alongside a traditional WB methodology to assess p70S6K1 signalling responses in human skeletal muscle to RE and protein feeding. Following validation in tissue culture with rapamycin and optimization of the assay in human skeletal muscle, this methodology was tested in a physiologically relevant context. In this regard, six males performed unilateral resistance exercise (RE) followed by the consumption of 20 g of protein. Skeletal muscle biopsies were obtained at pre-RE, at 1 h and 3 h post-RE. In response to RE and protein consumption, p70S6K1 activity was significantly increased from pre-RE at 1 h and 3 h post-RE (8.84 ± 0.78 to 17.18 ± 2.62 and 15.62 ± 3.12 µU/mg). However, phosphorylated p70S6K1thr389 was not significantly elevated. To assess if a combined stimulus of RE and feeding can influence AMPK activity we directly measured AMPK activity. AMPK activity was suppressed from pre-RE at 3 h post-RE (24.15 ± 1.6 to 15.64 ± 1.07 mU/mg), whereas phosphorylated ACCser79 was unchanged. These data therefore highlight the utility of the KA to study skeletal muscle plasticity. Previous studies have shown that ingestion of n-3 PUFA potentiates the phosphorylation of mTORC1 and associated kinases in response to nutrition. However, no study has identified whether n-3 PUFA supplementation potentiates anabolic kinase activity when RE is performed prior to nutrient provision. In Chapter 4 of this thesis, twenty healthy males consumed 5g.d-1 of either fish oil (FO) or coconut oil (CO) capsules for 8 weeks. Muscle biopsy samples were collected in the fasted, rested state before and after 8 weeks of supplementation for assessment of changes in lipid composition. Following 8 weeks of supplementation muscle samples also were obtained at rest (Rest), post RE in both the exercise leg (Post-RE) and the rested leg (Pre-FED) and also at 3 h post RE and protein feeding from both the exercise leg (3 h post-REF) and rested leg (3 h post-FED). There was a 2-fold increase in muscle (5.53 ± 0.3 to 11.16 ± 0.45 % of total fatty acids) n-3 PUFA composition after supplementation in the FO group but no change in the CO group. Following supplementation there was an increase in p70S6K1 activity at 3 h post-REF from Rest in the CO group (5.6 ± 1.4 to 12.2 ± 2.1 µU/mg) but no change in the FO group. In the CO group, AMPKα2 was significantly increased at Post-RE from Rest (3.7 ± 0.7 to 9.9 ± 2.0 mU/mg). These data show that 8 weeks of n-3 PUFA enriched fish oil supplementation suppresses the activity of p70S6K1 in response to RE and protein feeding.

Current dietary recommendations have placed increasing emphasis on dietary fat as an important element to decrease risk of cardiovascular disease (CVD). Although total fat and the fatty acid composition of diets influence the risk of CVD, the optimal amounts of different fatty acids are not well defined, especially if n-6 and n-3 fatty acids are considered. Despite the fact that postmenopausal women are at increased risk of CVD, few studies have investigated the influence of dietary fatty acids on this risk. Therefore, this study was designed to determine the effect of supplementation with different fatty acids on risk factors of CVD in postmenopausal women. Sixteen healthy, postmenopausal women were randomly assigned in a three-period crossover trial to treatments of 15 g/d supplements of oleic acid-rich sunflower oil (TS), linoleic acid-rich safflower oil (SO), and eicosapentaenoic acid- and docosahexaenoic acid-rich fish oil (FO). Each treatment period lasted 5 weeks followed by a 7-week washout interval. When the women were supplemented with FO compared to supplementation with either TS or SO, the concentration of high density lipoprotein cholesterol tended to increase (p=0.07 and 0.05, respectively) as did the size of the low density lipoprotein (LDL) particle (P=0.03 in both instances) while the concentration of triacylglycerol (p=0.0001 and 0.02, respectively) and apolipoprotein B (apo B) (P=0.005 and P=0.01, respectively) decreased. The concentration , i.e., total cholesterol, cholesterol ester, free cholesterol, phospholipids, α- and γ-tocopherol, of the two LDL subfractions was not influenced by any of the oil supplements but was greater in the large (L) subfraction than the small (S). When the oxidation of the two subfractions was measured by monitoring the formation of conjugated dienes, the lag time was shorter in both fractions after supplementation with FO compared to supplementation with SO (P=0.0001) or TS (P=0.0001) but the effect was greater in the L subfraction. The rate of formation of conjugated dienes, which was slower after FO supplementation than supplementation with either TS (P=0.02) or SO (P=0.001), was faster in the L compared to the S subfraction. When oxidation was measured by monitoring the increase in negative charge on apo B over 23 hr, only the 1 hr time point differed. The increase was greater in the FO-supplemented group than either the TS- or SO-supplemented groups (P=0.001 in both instances). The change was greater in S LDL (P=0.007). These findings demonstrate a greater potential antiatherogenic property of dietary n-3-rich oil than n-6- or n-9-rich ones as indicated by changes to plasma lipids, lipoproteins, apo B, and particle size but the influence of the oxidative susceptibility of L and S subfractions is less conclusive. / Graduation date: 2000

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

Thesis (Ph. D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Vita. "December 2006" Includes bibliographical references.

Colon cancer is a leading cause of cancer related deaths worldwide. Lifestyle factors such as diet and exercise have been implicated as important agents in colon cancer development and progression. Epidemiological, in vivo and in vitro studies have found that n-3 polyunsaturated fatty acids (PUFAs) reduce colon carcinoma. The role of n-6 PUFAs remains a controversial topic, with studies indicating both promoting and preventing capabilities published. In order to better understand the effects of PUFAs on colon carcinoma, it is important to have an understanding of how they will be broken down in the body. During this study, in silico metabolism of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA) predicted the formation of hydroxy-, di-hydroxy- and epoxy-FAs. A gas chromatography-mass spectrometry method was developed and validated for the detection of these PUFAs and their cytochrome P450 (CYP) metabolites. A human liver microsomal system for the in vitro metabolism of EPA, DHA and AA was optimised in terms of microsomal and PUFA concentration. The system resulted in the metabolism of the positive control, lauric acid, to 12-hydroxy-lauric acid but was unable to metabolise the PUFAs of interest. EPA, DHA and AA reduced cell viability in the colon carcinoma cell lines SW480 and SW620 in the micromolar concentration range (25 – 200 μM). The CYP epoxidation metabolite of EPA, 17, 18-epoxyeicosatetraenoic acid (17, 18-EpETE) resulted in a significant reduction in SW480 cell viability relative to the parent compound at lower concentrations (25 and 50 μM). Annexin V apoptosis analysis revealed that EPA and 17, 18- EpETE did not result in apoptosis in SW480 cells at a concentration of 25 μM and over an incubation period of 24 hours. A significant reduction in reactive oxygen species production was seen in SW480 cells after incubation with 25 μM 17, 18-EpETE for 24 hours. EPA and 17, 18-EpETE were implicated in the reduction of colon cancer metastasis since they were able to reduce SW480 migration and anchorage independent cell growth. These results indicate that the dietary intake of EPA, DHA and AA may be beneficial to one’s health due to the negative effects that these PUFAs had on colon carcinoma. Future studies are needed to confirm these benefits and compare the effects of the PUFAs to their CYP-metabolites.

Numerous dietary factors have been shown to influence the fatty acid profiles (FAP) in breast milk from lactating women. However, few studies have evaluated the effect of trace minerals on milk FAP. Consequently, the purpose of this study was to determine the effect of selenium status on the FAP in breast milk. Subjects were lactating women from three different regions in China; Xichang (n=21), an area where selenium intakes are among the lowest in the world, Beijing (n=20), where there are adequate selenium intakes, and Enshi (n=19), where selenium intakes are among the highest in the world. Plasma and milk samples were obtained from women at birth of their baby and within 10 months postpartum and analyzed for selenium content, glutathione peroxidase (Gpx) activity and FAP. Plasma and breast milk selenium levels were significantly lower in the Xichang women and significantly higher in the Enshi women when compared to Beijing women. Despite the fact that the highest level of plasma selenium was measured in the samples from Enshi, the Gpx activity was greatest in the samples from Beijing; there was no effect of time of sampling on these samples. In breast milk, on the other hand, all the samples obtained at birth had similar activity of Gpx. The samples taken later, however, followed the same trend as plasma with the samples obtained from the women in Beijing having the highest activity. FAP indicated a significant difference in the amount of unsaturated fatty acids in both the plasma and milk for the Beijing women, when compared to the women from Xichang and Enshi. In particular, there were higher levels of linoleic acid, 18:2(n-6), in the plasma and milk of the women whose selenium intake was adequate. / Graduation date: 1997

No description available.

Thesis (PhD (Food Science))--University of Stellenbosch, 2006. / Long-chain polyunsaturated fatty acids (LCPUFA), especially the n-3 LCPUFA metabolic products eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) play an important role as regulators in many biological processes. To date hake (Merluccius capensis) heads, a rich source of EPA and DHA, have been discarded at sea. The South African Fisheries Policy Development Committee concerned with the environmental impact of this practice has rendered it undesirable. The high prevalence of under-nutrition amongst children in South Africa can be addressed by the supplementation of their diet with this unexploited fish source. The aim of the current study was to develop a microbiologically safe and sensory acceptable sandwich spread using fish flour prepared from fish heads, as a prime ingredient. The intervention trial aimed to compare the effects of an increased dietary intake of n-3 LCPUFA, specifically DHA, on the blood fatty acid levels and absenteeism (as indicator of immune function), as well as the cognitive status, of the subjects. The microbiological content of the sandwich spread was determined after storage for 20 d at 5°C and 15 d at 25°C. Sensory evaluation was performed by consumers (n = 95; M:F = 44:51; 6 – 9 yr) to determine acceptance of the five different flavours individually incorporated into the sandwich spread to mask the fishy note and to provide different flavour options. For the intervention trial subjects (n = 351) were stratified within class group (A - E) and gender and randomly assigned to two treatment categories, an experimental group (EG; n = 174) receiving 25 g sandwich spread.d-1 (191.66 mg DHA. d-1) and a control group (CG; n = 177) receiving an analogous placebo. On school days (104 d), each subject received two sandwiches consisting of two slices of bread (ca. 60 g), spread with 25 g of either the placebo or the experimental spread. Blood samples were drawn at baseline and post intervention. Plasma fatty acid and red blood cell (RBC) membrane status, C-reactive protein levels, as well as vitamin and micronutrient status, were determined. Trained test administrators conducted a battery of cognitive tests. According to South African Government health standards, the sandwich spread remained microbiologically safe after storage. Male and female consumer respondents revealed a significant difference between gender preferences of the five different spread flavours (p <0.05). Significant treatment effects (p <0.05) were observed in n-3 LCPUFA status of the EG, as well as for their absenteeism from school. The two subtests of the Hopkins Verbal Learning test, Recognition and Discrimination Index, showed significant differences between the EG and CG (p <0.05) post intervention in the Grade 2 subjects. The Spelling tests also showed a significant difference between the two groups (p <0.05). In the current study a microbiologically safe and sensory acceptable sandwich spread was developed and tested during an intervention trial, and could possibly in future, provide a healthier option in the School Nutritional Programme. This study proved that supplementation of children (6 - 9 yr) with n-3 LCPUFA, with specific reference to EPA and DHA from a marine source, could have a beneficial effect on their fatty acid status and absenteeism from school. Based on the outcomes of the Hopkins Verbal Learning test and Spelling test, the current study proved that an n-3 fatty acid-rich spread improved the learning ability and memory of children.

Fish meal (FM) and fish oil (FO) have traditionally been central in aquaculture feed formulation but the finite global supply situation limiting future use along with issues of contaminant levels in these feed ingredients have become critical issues. The objectives of the present study were to investigate alternative feed ingredients as substitutes for both FM and FO in feeds for Atlantic salmon (Salmo salar) to ensure optimal growth, feed efficiency and health of the fish as well as maintaining the nutritional quality of the fish product to the human consumer, especially the levels of n-3 highly unsaturated fatty acid (HUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in the flesh. The results of the present study revealed that there were no negative effects on growth performance, feed utilisation and apparent digestibility in Atlantic salmon when FO was substituted with vegetable oil (VO) but these parameters were affected when FM was replaced with alternative protein sources from plants and animals at high levels, despite dietary supplementation with crystalline amino acids and lecithin. Reduction in feed intake was a factor affecting growth retardation when FM inclusion decreased. However, replacing FM with alternative plant and animal proteins along with partial replacement of FO had no major effect on nutritional quality, particularly n-3 HUFA content of salmon tissues. Replacing Northern FO with decontaminated FO or blends of southern hemisphere FO and VOs strategies to reduce POP contaminants and retain high nutritional values in flesh were very successful. Dietary treatments and genetic origin of fish both had effects on tissue compositions and gene expression. All fish groups (strain/family), consist of CAL, LEAN and FAT strains, fed a diet containing VO showed significant differential expression of lipid metabolism-related genes compared to fish fed a FO diet with LEAN strain appearing to adapt to VO inclusion better than FAT strain. This thesis has demonstrated dual replacement of FM and FO with alternative raw materials in salmon feeds without a major negative impact on nutritional quality.