Adipose tissue and cardiovascular and metabolic diseases

Obesity is a major contributor to the rising prevalence of cardiovascular and metabolic diseases in both the developed and developing world. Increased adipose tissue mass is associated with changes to the structure and function of the cardiovascular system to ensure circulatory requirements are met. Adipose tissue is a metabolically active endocrine organ that is capable of synthesizing and releasing a variety of signal proteins (adipokines), many of which impact unfavorably on both the cardiovascular system and metabolism. The extent of adiposity, location of fat deposits and variations in the secretion of adipokines, along with other factors, determine whether a particular obese person develops complications, including type 2 diabetes, coronary artery disease, congestive heart failure, hypertension, obstructive sleep apnea syndrome, and non-alcoholic fatty liver disease. This review will discuss the relationship between obesity and cardiovascular and metabolic diseases and will explore how complications of obesity impact on mortality, while healthy lifestyle may prevent them.Biomedical Reviews 2006; 17: 89-104

The Impact of Altered Timing of Eating, Sleep and Work Patterns on Human Health

Some 20% of the population is required to work outside the regular 9:00 a.m.–5:00 p.m. working day, and this number is likely to increase as economic demands push work hours into the night for many companies. These irregular schedules mean workers often have to sleep during the day and be awake at night. This causes a misalignment between normal day-light entrained internal physiological processes, such as metabolism and digestion, and the external environment. As a direct consequence, night workers have poorer health than day workers, even after controlling for lifestyle and socioeconomic status. The purpose of this Special Issue is to highlight the interrelationships between timing of food intake and diet quality with sleep and work patterns in humans with an emphasis on randomized controlled trials or meta-analyses of data from published studies

Relationships between Obesity, Cardiorespiratory Fitness, and Cardiovascular Function

Background. Obesity and low cardiorespiratory fitness (CRF) have been shown to independently increase the risk of CVD mortality. The aim of this study was to investigate the relationship between CRF, body fatness and markers of arterial function. Method and Results. Obese (9 male, 18 female; BMI 35.3 ± 0.9 kg·m−2) and lean (8 male, 18 female; BMI 22.5 ± 0.3 kg·m−2) volunteers were assessed for body composition (DXA), cardiorespiratory fitness (predicted V˙O2max), blood pressure (BP), endothelial vasodilatator function (FMD), and arterial compliance (AC) (via radial artery tonometry). The obese group had more whole body fat and abdominal fat (43.5 ± 1.2% versus 27.2 ± 1.6%; P < .001 and 48.6 ± 0.9% versus 28.9 ± 1.8%; P < .001, resp.), and lower FMD (3.2 ± 0.4% versus 5.7 ± 0.7%; P < .01) than the lean subjects, but there was no difference in AC. AC in large arteries was positively associated with CRF (R = 0.5; P < .01) but not with fatness. Conclusion. These results indicate distinct influences of obesity and CRF on blood vessel health. FMD was impaired with obesity, which may contribute to arterial and metabolic dysfunction. Low CRF was associated with reduced elasticity in large arteries, which could result in augmentation of aortic afterload

Feasibility of omega-3 fatty acid supplementation as an adjunct therapy for people with chronic obstructive pulmonary disease: study protocol for a randomized controlled trial

There is evidence to support the use of supplementation with long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) from oily fish or fish oil for the treatment of various inflammatory diseases such as rheumatoid arthritis. Chronic obstructive pulmonary disease (COPD) is a progressive, terminal disease characterized by persistent airflow limitation, lung and systemic inflammation. To date, one randomized controlled trial has been published that assessed the efficacy of LCn-3PUFA in people with this condition. The aim of this article is to discuss the feasibility of conducting a trial to evaluate fish oil supplementation as adjunct therapy in people with COPD.The study is supported by a University of South Australia, Division of Health Sciences grant (DRDG 2011 (round 2))

Effects of eating fresh lean pork on cardiometabolic health parameters

High protein meat-based diets are commonly promoted for weight loss, supposedly by increasing satiety and energy expenditure. Pork is a good source of protein however little information on the metabolic effects of pork consumption exists. This pilot study aimed to examine whether regular consumption of fresh lean pork could improve body composition and cardiovascular risk factors in a 6 month parallel intervention trial. 164 overweight adults (mean BMI 32) were randomly assigned to incorporate up to 1 kg pork/week by substituting for other foods or maintain their habitual diet (control). Plasma levels of lipids, glucose and insulin, BMI, waist/hip circumference, blood pressure, heart rate and arterial compliance were measured at baseline and 3 and 6 months. Body composition was determined using dual energy X-ray absorptiometry. A total of 144 volunteers completed and volunteers in the pork group increased their intake 10 fold by substituting pork for mainly beef and chicken. After 3 months, there were significant (p ≤ 0.01) reductions in weight, BMI, waist circumference, % body fat, fat mass and abdominal fat in the pork group relative to controls, which persisted for 6 months. There was no change in lean mass, indicating that the reduction in weight was due to loss of fat mass. There were no significant effects on other metabolic parameters. Regular consumption of lean fresh pork may improve body composition

There is no association between the omega-3 index and depressive symptoms in patients with heart disease who are low fish consumers

Background: Long chain Omega-3 polyunsaturated fatty acids (LCn3PUFAs) may improve cardiovascular health and depression. This study investigated the relationships between erythrocyte membrane LCn3PUFA status, depression and angina symptoms in patients with heart disease.  Methods: We recruited 91 patients (65 males and 26 females, mean age 59.2 ± 10.3 years) with heart disease and depressive symptoms (Center for Epidemiological Studies Depression Scale, CES-D ≥ 16) and low fish/fish oil intakes. The Omega-3 Index (EPA+DHA) of erythrocyte membranes (as a percentage of total fatty acids) was assessed by gas chromatography. Depression status was measured by both self-report and clinician-report scales; CES-D and the Hamilton depression scale (HAM-D). Angina symptoms were measured using the Seattle Angina Questionnaire and the Canadian Cardiovascular Society Classification for Angina Pectoris.  Results: The mean Omega-3 Index was 4.8 ± 1.0% (±SD). Depression scores measured by CES-D and HAM-D were 29.2 ± 8.8 (moderate to severe) and 11.0 ± 5.7 (mild) (arbitrary units) respectively reflecting a different perception of depressive symptoms between patients and clinicians. Angina status was inversely associated with depression scores (r > -0.26, P < 0.03). There were no significant relationships between individual LCn3PUFA or the Omega-3 Index and either the depression scores or the angina symptoms.  Conclusion: Worse angina status was associated with worse depression, but the Omega-3 Index was not associated with symptoms of depression or angina in patients with heart disease

Self-management for obesity and cardio-metabolic fitness: Description and evaluation of the lifestyle modification program of a randomised controlled trial

Background: Sustainable lifestyle modification strategies are needed to address obesity and cardiovascular risk factors. Intensive, individualised programs have been successful, but are limited by time and resources. We have formulated a group-based lifestyle education program based upon national diet and physical activity (PA) recommendations to manage obesity and cardio-metabolic risk factors. This article describes the content and delivery of this program, with information on compliance and acceptability. Methods: Overweight/obese adults (n = 153) with metabolic syndrome were recruited from the community and randomly allocated to intervention (INT) or control (CON). Written copies of Australian national dietary and PA guidelines were provided to all participants. INT took part in a 16-week lifestyle program which provided a curriculum and practical strategies on 1) dietary and PA information based on national guidelines, 2) behavioural self-management tools, 3) food-label reading, supermarkets tour and cooking, 4) exercise sessions, and 5) peer-group support. Compliance was assessed using attendance records and weekly food/PA logs. Participants' motivations, perceived benefits and goals were assessed through facilitated discussion. Program acceptability feedback was collected through structured focus groups. Results: Although completion of weekly food/PA records was poor, attendance at information/education sessions (77% overall) and exercise participation (66% overall) was high, and compared with CON, multiple markers of body composition and cardio-metabolic health improved in INT. Participants reported that the most useful program components included food-label reading, cooking sessions, and learning new and different physical exercises, including home-based options. Participants also reported finding self-management techniques helpful, namely problem solving and short-term goal setting. The use of a group setting and supportive 'peer' leaders were found to be supportive. More frequent clinical assessment was suggested for future programs. Conclusion: This group-based lifestyle program achieved improvements in body composition and cardio-metabolic and physical fitness similar to individualised interventions which are more resource intensive to deliver. It confirmed that active training in lifestyle modification is more effective than passive provision of guidelines. Such programs should include social support and self-management techniques. Continued clinical follow up may be required for long-term maintenance in individuals attempting lifestyle behaviour change. Program facilitation by peers may help and should be further investigated in a community-based model.Tahna L Pettman, Gary MH Misan, Katherine Owen, Kate Warren, Alison M Coates, Jonathan D Buckley and Peter RC How

Experimental monitoring of nonlinear wave interactions in crab orchard sandstone under uniaxial load

When two waves interact within a rock sample, the interaction strength depends strongly on the sample’s microstructural properties, including the orientation of the sample layering. The study that established this dependence on layering speculated that the differences were caused by cracks aligned with the layers in the sample. To test this, we applied a uniaxial load to similar samples of Crab Orchard Sandstone and measured the nonlinear interaction as a function of the applied load and layer orientation. We show that the dependence of the nonlinear signal changes on applied load is exponential, with a characteristic load of 11.4–12.5 MPa that is independent of sample orientation and probe wavetype (P or S); this value agrees with results from the literature, but does not support the cracks hypothesis

No Effect of a Whey Growth Factor Extract during Resistance Training on Strength, Body Composition, or Hypertrophic Gene Expression in Resistance-Trained Young Men

Growth factors can be isolated from bovine milk to form a whey growth factor extract (WGFE). This study examined whether WGFE promoted activation of the AKT/mTOR pathway enabling increased lean tissue mass and strength in resistance trained men. Forty six men with \u3e6 months of resistance training (RT) experience performed 12 weeks of RT. Participants consumed 20 g/day of whey protein and were randomised to receive either 1.6 g WGFE/day (WGFE; n = 22) or 1.6 g cellulose/day (control, CONT; n = 24). The primary outcome was leg press one-repetition maximum (LP1-RM) which was assessed at baseline, 6 and 12 weeks. At baseline and 12 weeks body composition was assessed by dual energy x-ray absorptiometry, and muscle protein synthesis and gene expression were assessed (vastus lateralis biopsy) in a sub-sample (WGFE n = 10, CONT n = 10) pre- and 3 hr post-training. RT increased LP1-RM (+34.9%) and lean tissue mass (+2.3%; p \u3c 0.05) with no difference between treatments (p \u3e 0.48, treatment x time). Post-exercise P70s6k phosphorylation increased acutely, FOXO3a phosphorylation was unaltered. There were no differences in kinase signalling or gene expression between treatments. Compared with CONT, WGFE did not result in greater increases in lean tissue mass or strength in experienced resistance trained men

Effect of 12 weeks high oleic peanut consumption on cardio-metabolic risk factors and body composition

Epidemiological evidence indicates an inverse association between nut consumption and obesity, inflammation, hyperlipidaemia and glucose intolerance. We investigated effects of high oleic peanut consumption vs. a nut free diet on adiposity and cardio-metabolic risk markers. In a randomised cross-over design, 61 healthy subjects (65 ± 7 years, body mass index (BMI) 31 ± 4 kg/m2) alternated either high oleic peanuts (15%–20% of energy) or a nut free diet for 12 weeks. Body composition and mass, waist circumference, C-reactive protein (CRP), lipids, glucose and insulin were assessed at baseline and after each phase. Repeated measures analysis of variance (ANOVA) compared the two diets. Consistent with other nut studies, there were no differences in lipids, CRP, glucose and insulin with peanut consumption. In contrast, some reports have demonstrated benefits, likely due to differences in the study cohort. Energy intake was 10% higher (853 kJ, p &lt; 0.05), following peanut consumption vs. control, attributed to a 30% increase in fat intake (p &lt; 0.001), predominantly monounsaturated (increase 22 g, p &lt; 0.05). Despite greater energy intake during the peanut phase, there were no differences in body composition, and less than predicted increase (0.5 kg) in body weight for this additional energy intake, possibly due to incomplete nutrient absorption and energy utilisation