Thesis (M.Sc. (Nutrition))--North-West University, Potchefstroom Campus, 2007.

BACKGROUND: Risk factors associated with Metabolic Syndrome (MetS) have been implicated in cardiovascular disease (CVD) development and outcomes. Few studies have investigated relationships between psychological variables, MetS factors, and indices of cardiac structure and function (CSF) among healthy individuals in a single conceptual model. No studies to date have analyzed such relationships in patients with CVD. METHODS: The present study examined associations between cynical hostility (CynHo), MetS factors, and CSF in 186 multi-ethnic post-myocardial infarction (MI) patients. Structural equation modeling was used to test a theory driven model of MetS that had good statistical fit. Primary MetS variables included waist circumference (WC), the homeostatic model of insulin resistance (HOMA-IR), glucose area under the curve (G-AUC), triglycerides (TRIG), high-density lipoprotein cholesterol (HDL-C), and diastolic blood pressures (DBP). Secondary MetS variables included plasminogen activator inhibitor-1 (PAI-1) and a latent inflammation variable comprised of CRP and IL-6. Cardiac function variables were fractional shortening (FS), E/A ratio, and rate-pressure product (RPP). A latent cardiac mass (CM) variable was also created. RESULTS: The final structural model had good model fit (Chi-Square(102)=100.65, p=0.52, CFI=1.00, RMSEA=0.00, and SRMR=0.04). Direct paths were supported between WC and CM and all MetS factors except TRIG and G-AUC. WC was indirectly associated with DBP via CM. The model supported positive direct paths between HOMA-IR and G-AUC, TRIG, and PAI-1, but not inflammation or HDL-C. HOMA-IR demonstrated a direct positive association with RPP and direct inverse associations with FS and E/A ratio. No direct paths were supported between other MetS variables except one between TRIG and HDL-C. CynHo demonstrated a direct positive relationship with HOMA-IR. CONCLUSIONS: Similar to findings in healthy individuals, central adiposity and IR play primary roles in CSF impairment in post-MI patients. Findings suggest that CynHo could promote the progression of metabolic dysfunction and cardiac disease via factors that influence the efficiency of glucose metabolism. Interventions for post-MI patients should take into account both direct and indirect effects of CynHo, central adiposity, and IR on the progression of CVD in this population to reduce adverse outcomes and improve quality of life.

Das Metabolische Syndrom stellt eine Kombination verschiedener metabolischer Anomalien in einem Individuum dar. Starkes Übergewicht gilt als maßgebende Größe in der Genese des Syndroms, welches mit einem enormen Risiko für kardiovaskuläre Erkrankungen einhergeht. Um die stark steigende Prävalenz des Metabolischen Syndroms einzudämmen, sind dringend Konzepte für die Behandlung, vor allem jedoch für die Prävention von Übergewicht erforderlich. Einen wichtigen Beitrag leisten diesbezüglich Ballaststoffe in der Ernährung. Sie tragen auf unterschiedlichen Wegen zur Gewichtskontrolle bei und beeinflussen zudem verschiedene mit dem Metabolischen Syndrom assoziierte Blutparameter. Ebenso werden protektive Effekte von Polyphenolen, welche zur Gruppe der sekundären Pflanzenstoffe zählen, beschrieben. Diese wirken u. a. auf den Glukose- sowie den Insulinhaushalt und greifen darüber hinaus in die Regulation der Fettverbrennung sowie des Energieverbrauches ein. Die Kombination beider Substanzgruppen verspricht bedeutendes gesundheitsförderndes Potential; dieses wurde gegenwärtig jedoch kaum untersucht. Carobballaststoff ist ein polyphenolreicher und vorwiegend unlöslicher Extrakt der Frucht des Johannisbrotbaumes (Ceratonia siliqua L). Bislang publizierte Studien zur physiologischen Wirksamkeit dieses Ballaststoffpräparates weisen sowohl beim Tier als auch beim Menschen bemerkenswerte hypocholesterinämische Eigenschaften nach. Inwiefern sich der Verzehr des Carobballaststoffes ebenso auf die Entwicklung von Übergewicht sowie anderen Messgrößen des Metabolischen Syndroms auswirkt, ist allerdings nicht bekannt. Die Zielstellung der Promotionsarbeit bestand darin, die postprandialen Wirkungen des Carobballaststoffverzehrs mit Hilfe einer Humanstudie aufzuzeigen. In die randomisierten, einfach verblindeten Untersuchungen im cross-over-Design wurden 20 gesunde Erwachsene im Alter zwischen 22 und 62 Jahren eingeschlossen. Unter Verwendung variierender Begleitmahlzeiten wurden die postprandialen Effekte verschiedener Mengen des Carobballaststoffes untersucht. Hierbei standen die Veränderungen der Plasmakonzentrationen von Glukose, Triglyceriden (TG), totalem und acyliertem Ghrelin sowie der Serumkonzentrationen von Insulin und nicht-veresterten Fettsäuren (NEFA) im Mittelpunkt der Betrachtungen. Der Verzehr des Carobballaststoffes in Kombination mit 200 ml Wasser und 50 g Glukose erhöhte die postprandialen Glukose- und Insulinkonzentrationen gegenüber der Glukoselösung ohne Ballaststoffzusatz. In Kombination mit 400 ml einer Flüssigmahlzeit verzehrt, senkte Carobballaststoff die postprandialen TG-, NEFA- und Ghrelin- (acyliert) Antworten. Die Untersuchung des respiratorischen Quotienten nach Zusatz von Carobballaststoff zur Flüssigmahlzeit mittels indirekter Respirationskalorimetrie bekräftigte die bereits bekannten Effekte auf den Lipidmetabolismus und wies zudem eine Steigerung der Fettverwertung unter Verminderung der Glukoseoxidation nach. Wurde Carobballaststoff schließlich in Lebensmittel eingebracht, sanken nach dem Verzehr dieser Lebensmittel erneut die postprandialen Konzentrationen an TG und NEFA. Gleichzeitig erhöhten sich die Glukose-, Insulin- sowie Ghrelin- (acyliert) Antworten. Carobballaststoff löst in Abhängigkeit von der jeweils verzehrten Begleitmatrix unterschiedliche Effekte aus. Das Präparat weist beachtliche Wirkungen auf die Blutlipide sowie den Energieverbrauch auf, hat indes ungünstige Wirkungen auf die Blutglukose, sofern er in Kombination mit einer veränderten Nährstoffmatrix aufgenommen wird. Carobballaststoff besitzt starkes gesundheitsförderndes Potential; jedoch sind weitere Studien notwendig, um seine Wirkungen sowie deren Voraussetzungen besser zu verstehen. Ferner sollten Untersuchungen über einen längeren Zeitraum vorgenommen werden, um die langfristige Relevanz der gewonnenen Ergebnisse darzulegen. Danach stellt die Anreicherung spezieller Lebensmittel mit Carobballaststoff einen geeigneten Weg dar, um von den viel versprechenden protektiven Wirkungen des Präparates zu profitieren. / The metabolic syndrome is a clustering of metabolic abnormalities and cardiovascular risk factors that occur in one individual. Since many individuals suffering of the metabolic syndrome are overweight, dietary treatment should primarily focus on weight reduction and control to handle and, much more importantly, to prevent the genesis of the syndrome. Dietary fiber could play a role in the management of the metabolic syndrome through its ability to control body weight as well as several parameters associated to the syndrome. Beside this, dietary polyphenols have been shown to influence glucose and insulin metabolism. Furthermore, studies in mice and men showed that polyphenols might increase fat oxidation and energy expenditure. The combination of both, dietary fiber and polyphenols, may exert beneficial health effects, which are not known up to now. A polyphenol-rich insoluble dietary fiber preparation from carob pulp (Ceratonia siliqua L; carob fiber) showed significant hypocholesterolemic activity in different animal trails and two human studies indicating that carob fiber may have potent health effects. However, short term effects on parameters associated with the control of the metabolic syndrome are not known. Therefore, a study was conducted to investigate the postprandial effects of carob fiber in healthy humans using different background food matrices. The study was designed as a randomized single-blind cross-over study in 20 subjects, aged 22 to 62 years. During several examinations plasma glucose, triglycerides (TG), total and acylated ghrelin, cholecystokinin (CCK) and peptide YY (PYY) as well as serum insulin and non-esterified fatty acids (NEFA) were repeatedly assessed before and after ingestion of carob fiber in combination with different test meals. The study results showed that carob fiber, consumed within a glucose load, increased plasma glucose and serum insulin compared to control. Plasma PYY increased after consumption of carob-enriched glucose solution. In a second part of the study, postprandial changes were assessed before and after ingestion of an isocaloric standardized liquid meal with or without carob fiber. Carob fiber intake lowered acylated ghrelin, triglycerides, and NEFA compared to control meal. Postprandial energy expenditure was increased and RQ was reduced after liquid meal with carob fiber compared to control meal. Finally, effects of the consumption of carob fiber-enriched foods were investigated at the subsequent day. Enrichment of foods increased plasma glucose and acylated ghrelin responses. Plasma triglycerides and serum NEFA responses were lower after bread ingestion compared to control. These results indicate that the effects of polyphenol-rich carob fiber on different blood parameters depend on the meal composition. Carob fiber showed beneficial effects on blood lipids as well as energy homeostasis, but also a deteriorated glycemic control when administered within a different food matrix. Further studies are needed to clarify observed effects and the mechanisms behind. Additionally, present study shows only short-term effects of carob fiber consumption, which might be less pronounced after long-term consumption due to adaptation mechanisms. Thus, future studies should elucidate the relevance of observed effects in long-term.

A quart of the of the adult population worldwide have metabolic syndrome. A sedentary lifestyle, low physical activity, combined with wrong eating habits, stress, smoking and psychosocial factors, are the main causes of development of the metabolic syndrome. The purpose of the literature review was to illuminate the physical activity in persons who have the metabolic syndrome, and what sort of advice a nurse use in the promotion of physical activity. The study was conducted as a literature review, including 15 scientific quantitative articles. In ten articles, the focus was on physical activity at the metabolic syndrome, and five articles focused on various forms of counselling for physical activity. The results showed that there is a strong correlation between level of physical activity and risk of developing metabolic syndrome. Increased physical activity reduces the risk of developing metabolic syndrome and has positive effects on metabolic risk factors. Physical activity may be crucial for the prevention of metabolic syndrome. Advice via telephone, e-mail and physical activity on prescription is effective method for the promotion of physical activity. This study also showed that the nurse has an important role in promoting physical activity. Promotion of physical activity should be given a clearer place in health care.

Mit dem Beginn der Industrialisierung stieg in den westlichen Kulturen rasant die Prävalenz von Krankheitsbildern wie Adipositas, arterieller Hypertonie, Typ-2-Diabetes Mellitus und Hyperlipidämie, die als Cluster eines multifaktoriellen Krankheitsbildes namens „Metabolisches Syndrom“ (MTS) verstanden werden. Tierstudien, in denen durch die Inhibition der Fettsäuresynthase (FASN) ein rapider Abfall des Körpergewichts in Mäusen erzeilt wurden, bestätigen zunehmend genetische Prädispositionen als ursächlich für die Ausbildung des MTS. Um herauszufinden ob und in welchem Ausmaß das FASN-Gen mit humanen Merkmalen des MTS assoziiert ist, wurde das Gen in 48 nicht verwandten ostdeutschen Probanden sequenziert. Acht repräsentative tagging-SNPs wurden dabei identifiziert, anschließend in 1311 deutschen Probanden (Erwachsene) genotypisiert und in Fall-Kontroll-Studien zwischen 389 schlanken Probanden (BMI ≤ 25kg/m²) vs. 446 adipösen Teilnehmern (BMI ≥ 30kg/m²) sowie zwischen 502 glukosetoleranten Probanden (NGT) vs. 640 Probanden mit Typ-2-Diabetes (T2D) miteinader verglichen. Für den Polymorphismus rs2229422 (P = 1.3x10-5 adjustiert auf Alter, Geschlecht und Diabetes-status) konnten die stärksten Assoziationen mit BMI und weiteren Merkmalen der Fettleibigkeit identifiziert werden (adjustiert P < 0.05). Des Weiteren wurde der zuvor in der Literatur beschriebene protektive Einfluss der Val1483Ile Substitution (rs2228305) gegenüber Adipositas, sowie der geschlechts-spezifische Effekt auf den BMI bestätigt (adjustiert, P = 0.03).

This thesis evaluated supplementation with two components of flaxseed during exercise training on inflammation in older adults.<P>Experiment 1: This experiment assessed secoisolariciresinol diglucoside (SDG) supplementation during aerobic exercise training on inflammation in older adults. Methods: One hundred subjects aged 50y or older were randomized to receive either SDG or placebo before completing a 6-month walking program. Fasting concentrations of interleukin-6 and tumor necrosis factor-á, glucose, triacylglycerol (TAG), high density lipoprotein (HDL), low density lipoprotein, and total cholesterol as well as leukocyte cell count were measured every two months while body composition, resting blood pressure, and a composite Z-score of six metabolic syndrome risk factors were assessed at baseline and 6 months. Results: Men on placebo increased metabolic syndrome composite Z-score (p<0.05). TAG increased (p=0.017) in men on placebo relative to men on SDG and men on SDG decreased (p=0.045) DBP relative to men on placebo. Conclusions: SDG had no effect on inflammation while it is effective in attenuating risk factors associated with metabolic syndrome in older males but not females.<p>Experiment 2: This experiment evaluated alpha-linolenic acid (ALA) supplementation during strength exercise training on inflammation in older adults. Methods: Fifty-one healthy older adults (65.4±0.8y) were randomized to receive ALA or a placebo before completing a 12 wk strength training program. Subjects were evaluated at baseline and 12 weeks for TNF-á and IL-6, muscle strength, body composition, and muscle thickness. Results: Males supplementing with ALA decreased IL-6 concentration (p=0.003). The female placebo and male ALA group had a significant increase in knee flexor thickness (p<0.05). Chest and leg press strength, lean tissue mass, and muscle thickness significantly increased, while percent fat and total body mass decreased with training (p<0.05), with no difference between ALA and placebo. Conclusions: ALA lowers IL-6 in older men, but has minimal effect on muscle mass and strength during resistance training.<p>General Conclusion: A composite score of metabolic syndrome is attenuated in males supplementing with SDG. ALA reduces IL-6 in older men. Older men, but not older women, derive specific health benefits from increased consumption of components of flaxseed consumed during an exercise program.

Chronic low-grade inflammation is associated the Metabolic Syndrome (MetS) and may contribute to its development. A diet high in saturated fat (SFA) has been associated with increased inflammation and development of the MetS. SFAs have been shown to elicit pro-inflammatory signaling through proteins of innate immunity, TLR4 and Nods 1 and 2. We determined whether common polymorphisms in the genes of these proteins could modify the association between fat intake and biomarkers of the MetS. Fat intake was measured using a food frequency questionnaire and genotyping was completed using real-time PCR. The TLR4 Asp299Gly (rs4986790) polymorphism was associated with decreased insulin sensitivity while an intronic polymorphism (rs5030728) modified the association between dietary SFA and HDL-cholesterol. The Nod1 Glu266Lys polymorphism modified the association between dietary SFA and HOMA-IR. These results suggest a role for innate immunity in mediating some of the effects of dietary SFAs on factors associated with the MetS.

Chronic low-grade inflammation is associated the Metabolic Syndrome (MetS) and may contribute to its development. A diet high in saturated fat (SFA) has been associated with increased inflammation and development of the MetS. SFAs have been shown to elicit pro-inflammatory signaling through proteins of innate immunity, TLR4 and Nods 1 and 2. We determined whether common polymorphisms in the genes of these proteins could modify the association between fat intake and biomarkers of the MetS. Fat intake was measured using a food frequency questionnaire and genotyping was completed using real-time PCR. The TLR4 Asp299Gly (rs4986790) polymorphism was associated with decreased insulin sensitivity while an intronic polymorphism (rs5030728) modified the association between dietary SFA and HDL-cholesterol. The Nod1 Glu266Lys polymorphism modified the association between dietary SFA and HOMA-IR. These results suggest a role for innate immunity in mediating some of the effects of dietary SFAs on factors associated with the MetS.

Vitamins are readily available in the modern diet due to liberalized fortification and supplementation policies. This research tested the hypothesis that high multi-vitamin intake by Wistar rats during pregnancy leads to the development of obesity and characteristics of the metabolic syndrome in the offspring. Pregnant Wistar rats were fed the AIN-93G diet containing either the recommended (RV) or 10-fold increase (HV) in vitamin content. Pups were weaned to the RV diet (Study 1), an obesogenic liquid diet (Ob, Study 2), low vitamin diets (1/3RV or 1/6RV, Study 3), or a nutrient selection paradigm (NSP) with 10% and 60% casein diets (Study 4). Body weight (BW), food intake (FI), glucose and insulin responses, appetite hormones, abdominal fat pad mass (FPM) and systolic blood pressure (SBP) was measured. Expressions of mRNA for hypothalamic serotonin (5-HT) receptors and proopiomelanocortin (POMC) were measured in Study 4. Males, but not females, born to HV dams had higher post-weaning BW and FI when weaned to the RV or 1/3RV diet, and exhibited components of metabolic syndrome, including higher FPM, hyperglycemia, insulin resistance and elevated SBP compared with those born to RV dams. The Ob diet led to exaggerated weight gain and expressions of components of metabolic syndrome in both sexes born to dams fed the HV diet. Female pups on the 1/6RV diet from HV dams had two-fold higher glucose response and lower insulin response, but no difference in post-weaning BW and daily FI compared to those from RV dams. In contrast to the pups born to HV dams and fed a single diet, those from the HV dams and on the NSP gained less weight and ate less, and had lower hypothalamic mRNA expressions of 5-HT receptors and POMC. In conclusion, high multi-vitamin intake during pregnancy may lead to obesity, and result in a higher risk of developing characteristics of metabolic syndrome in the offspring. However, sex, weaning diet composition, and the presence of diet choice alter the outcomes.

The hypothesis that source of protein in a nutritionally adequate diet during gestation, lactation and weaning alters food intake and characteristics of metabolic syndrome in the offspring was investigated. Pregnant Wistar rats were randomized to either the AIN 93-G casein (C) or soy protein (S) diets (n=12/group) during gestation only or during gestation and lactation. Male offspring in each dams’ diet group were weaned to either C or S diets (n=12/group). Food intake, body weight (BW), fat pad mass, systolic (SBP) and diastolic (DBP) blood pressure, and plasma homocysteine (p<0.05) were higher in offspring born to dams fed the S diet. Fasting blood glucose (BG), BG in response to a glucose gavage and Homeostatic Model of Assessment of Insulin Resistance (HOMA-IR) index were higher only in male offspring born to dams fed the S diet. Moreover, gene expression of Agouti Related Protein (AgRP) was higher in offspring born to dams fed the S diet at weaning. Extending the dams’ diet during gestation and lactation magnified the effect of the gestational S diet on BW and composition and glucose metabolism in male offspring. Although composition of the weaning diets interacted with that of the dams’ diets, the latter was the dominant factor in determining metabolic outcomes in the offspring. In conclusion, the soy protein diet, compared to the casein diet when consumed during gestation or throughout gestation and lactation increased food intake and the presence of characteristics of metabolic syndrome in the offspring.