A randomised crossover trial of nitrate and breakfast on prefrontal cognitive and haemodynamic response functions.

It remains unknown whether dietary nitrate and breakfast may enhance working memory (WM) performance by augmenting physiological mechanisms and subjective psychological well-being. We performed a 3-arm randomised within-subject crossover study, with pretest-posttest comparisons, to test whether nitrate consumption via breakfast with a beetroot juice shot or regular breakfast compared to no breakfast improved WM (measured with n-back tests) and cognitive task-related changes in prefrontal cortical haemodynamic response (oxygenated- and deoxygenated-haemoglobin derived from functional near-infrared spectroscopy). In addition, effects on peripheral vascular function and self-reported psychological factors were assessed.

Short, frequent physical activity breaks improve working memory while preserving cerebral blood flow in adolescents during prolonged sitting - AbbaH teen, a randomized crossover trial.

Purpose: Physical activity (PA) breaks during school lessons have been suggested as a promising strategy to improve working memory performance in children and adolescents. There is a lack of studies investigating the underlying physiological mechanisms of PA on cognition, especially among adolescents. This study aimed to investigate the effects of different types of short frequent PA on adolescents' cognitive task-related changes in cerebral blood flow in the prefrontal cortex (PFC) and working memory performance compared to prolonged sitting.

Acute effects of nitrate and breakfast on working memory, cerebral blood flow, arterial stiffness, and psychological factors in adolescents: Study protocol for a randomised crossover trial.

Background: Inorganic nitrate has been shown to acutely improve working memory in adults, potentially by altering cerebral and peripheral vasculature. However, this remains unknown in adolescents. Furthermore, breakfast is important for overall health and psychological well-being.

Effects of prolonged sitting and physical activity breaks on measures of arterial stiffness and cortisol in adolescents.

Aim: In adults, prolonged periods of sitting have been linked to acute negative effects on vascular structure and function. The aim of this study was to evaluate the acute effects of physical activity (PA) breaks during prolonged sitting on arterial stiffness, cortisol and psychological factors in adolescents.

Methods: Adolescents underwent different short (3-min) breaks starting every 20 min, during 80 min of sitting on three separate days.

ABBaH teens: Activity Breaks for Brain Health in adolescents: study protocol for a randomized crossover trial.

Background: Physical activity breaks are widely being implemented in school settings as a solution to increase academic performance and reduce sitting time. However, the underlying physiological mechanisms suggested to improve cognitive function from physical activity and the frequency, intensity, and duration of the breaks remain unknown. This study will investigate the effects of frequent, short physical activity breaks during prolonged sitting on task-related prefrontal cerebral blood flow, cognitive performance, and psychological factors.

Frequent, Short Physical Activity Breaks Reduce Prefrontal Cortex Activation but Preserve Working Memory in Middle-Aged Adults: ABBaH Study.

Prolonged sitting is increasingly common and may possibly be unfavorable for cognitive function and mood. In this randomized crossover study, the effects of frequent, short physical activity breaks during prolonged sitting on cognitive task-related activation of the prefrontal cortex were investigated. The effects on working memory, psychological factors, and blood glucose were also examined, and whether arterial stiffness moderated prefrontal cortex activation.

Higher Total Physical Activity is Associated with Lower Arterial Stiffness in Swedish, Young Adults: The Cross-Sectional Lifestyle, Biomarkers, and Atherosclerosis Study.

Purpose: Arterial stiffness describes the rigidity of the arterial walls and is associated with risk factors for cardiovascular disease (CVD). Arterial stiffness predicts future events and mortality, and the predictive value is stronger in younger versus older subjects. The aims of the present study were, firstly, to present data on physical activity (PA) and time spent sedentary, in the population of Swedish, young adults.

The importance of cardiorespiratory fitness and sleep duration in early CVD prevention: BMI, resting heart rate and questions about sleep patterns are suggested in risk assessment of young adults, 18-25 years : The cross-sectional lifestyle, biomarkers and atherosclerosis (LBA) study.

Background: Cardiorespiratory fitness (CRF) and sleep habits are lifestyle factors with potential to prevent cardiovascular disease (CVD). CVD is the leading cause of death worldwide. It is therefore important to establish a healthy lifestyle at a young age.

ABBaH: Activity Breaks for Brain Health. A Protocol for a Randomized Crossover Trial.

: Extended periods of sitting may have detrimental effects on brain health. However, the effects of breaking up prolonged sedentary periods with frequent, short physical activity bouts on mechanisms to improve brain health remain unclear. Therefore, this study aims to investigate the immediate effects of uninterrupted sitting and frequent, short bouts of physical activity on cerebral blood flow and cognitive function in the prefrontal cortex in middle-aged adults.

Insulin resistance (HOMA-IR) and body fat (%) are associated to low intake of fruit and vegetables in Swedish, young adults: the cross-sectional lifestyle, biomarkers and atherosclerosis study.

Background: In the cross-sectional Lifestyle, Biomarkers, and Atherosclerosis study (LBA study) we have previously reported a high prevalence (15%) of homeostasis model assessment of insulin resistance (HOMA-IR) in Swedish, young adults. The aim of the present study was to report the dietary habits of subjects 18.0-25.

Body composition is a strong predictor of local carotid stiffness in Swedish, young adults - the cross sectional Lifestyle, biomarkers, and atherosclerosis study.

Background: Obesity has nearly tripled worldwide during the last four decades, especially in young adults, and is of growing concern since it is a risk factor for cardiovascular diseases (CVD). We explored how different body composition measurements are associated with intima media thickness (cIMT) and local stiffness in the common carotid artery, in a subsample of healthy, young women and men, from the Swedish Lifestyle, Biomarkers, and Atherosclerosis (LBA) Study.

Methods: From the LBA study, a subsample of 220 randomly selected, self-reported healthy individuals, 18-25 years old, were collected for the automatized local stiffness measurements; arterial distensibility, Young's elastic modulus, and β stiffness index.

Individual variations in platelet reactivity towards ADP, epinephrine, collagen and nitric oxide, and the association to arterial function in young, healthy adults.

Introduction: Platelet aggregation and secretion can be induced by a large number of endogenous activators, such as collagen, adenosine diphosphate (ADP) and epinephrine. Conversely, the blood vessel endothelium constitutively release platelet inhibitors including nitric oxide (NO) and prostacyclin. NO and prostacyclin are also well-known vasodilators and contribute to alterations in local blood flow and systemic blood pressure.

Arterial stiffness is associated to cardiorespiratory fitness and body mass index in young Swedish adults: The Lifestyle, Biomarkers, and Atherosclerosis study.

Background Early changes in the large muscular arteries are already associated with risk factors as hypertension and obesity in adolescence and young adulthood. The present study examines the association between arterial stiffness measurements, pulse wave velocity and augmentation index and lifestyle-related factors, body composition and cardiorespiratory fitness, in young, healthy, Swedish adults. Design This study used a population-based cross-sectional sample.

Aerobic fitness is associated with low cardiovascular disease risk: the impact of lifestyle on early risk factors for atherosclerosis in young healthy Swedish individuals - the Lifestyle, Biomarker, and Atherosclerosis study.

Background: The progression of cardiovascular disease (CVD) and atherosclerosis is slow and develops over decades. In the cross-sectional Swedish Lifestyle, Biomarker, and Atherosclerosis study, 834 young, self-reported healthy adults aged 18.0-25.

Improved Muscle Mitochondrial Capacity Following Gastric Bypass Surgery in Obese Subjects.

Background: Weight loss resulting from low-calorie diets is often less than expected. We hypothesized that energy restriction would influence proton leakage and improve mitochondrial efficiency, leading to reduced energy expenditure, partly explaining the difficulties in weight loss maintenance.

Methods: Eleven women with a median BMI of 38.

Oral branched-chain amino acid supplements that reduce brain serotonin during exercise in rats also lower brain catecholamines.

Exercise raises brain serotonin release and is postulated to cause fatigue in athletes; ingestion of branched-chain amino acids (BCAA), by competitively inhibiting tryptophan transport into brain, lowers brain tryptophan uptake and serotonin synthesis and release in rats, and reputedly in humans prevents exercise-induced increases in serotonin and fatigue. This latter effect in humans is disputed. But BCAA also competitively inhibit tyrosine uptake into brain, and thus catecholamine synthesis and release.

The ingestion of different dietary proteins by humans induces large changes in the plasma tryptophan ratio, a predictor of brain tryptophan uptake and serotonin synthesis.

Background & Aims: The ingestion by rats of different proteins causes large differences in the plasma ratio of tryptophan to other large neutral amino acids, which predicts brain tryptophan uptake and serotonin synthesis. We evaluated in humans whether ingesting these proteins also produces large excursions in the tryptophan ratio.

Methods: Fasting males (n = 6) ingested V-8 Juice containing 40 g of α-lactalbumin, gluten, zein or starch.

Communication strategies to help reduce the prevalence of non-communicable diseases: proceedings from the inaugural IFIC Foundation Global Diet and Physical Activity Communications Summit.

Non-communicable diseases (NCDs), which include cardiovascular disease, cancer, and diabetes, all of which are associated with the common risk factors of poor diet and insufficient physical activity, caused 63% of all deaths globally in 2008. The increasing discussion of global NCDs, including at the 2011 United Nations General Assembly High-level Meeting on the Prevention and Control of Non-communicable Diseases, and a request for multi-stakeholder engagement, prompted the International Food Information Council Foundation to sponsor the Global Diet and Physical Activity Communications Summit: "Insights to Motivate Healthful, Active Lifestyles" on September 19, 2011, in New York City. The Summit brought together a diverse group of stakeholders, representing 34 nations from governments; communication, health, nutrition, and fitness professions; civil society; nonprofits; academia; and the private sector.

Imaged based estimation of food volume using circular referents in dietary assessment.

Measuring food volume (portion size) is a critical component in both clinical and research dietary studies. With the wide availability of cell phones and other camera-ready mobile devices, food pictures can be taken, stored or transmitted easily to form an image based dietary record. Although this record enables a more accurate dietary recall, a digital image of food usually cannot be used to estimate portion size directly due to the lack of information about the scale and orientation of the food within the image.

Effect of chronic protein ingestion on tyrosine and tryptophan levels and catecholamine and serotonin synthesis in rat brain.

Objectives: Previous studies have shown that brain tyrosine (TYR) levels and catecholamine synthesis rate increase in rats as chronic dietary protein content increases from 2 to 10% (% weight). A single protein, casein, was examined. The present study explores how TYR levels and catecholamine synthesis (and tryptophan (TRP) levels and serotonin synthesis) change when different proteins are ingested chronically over the same range of dietary protein contents.

The chronic ingestion of diets containing different proteins produces marked variations in brain tryptophan levels and serotonin synthesis in the rat.

Serotonin (5HT) synthesis in brain is influenced by precursor (tryptophan (TRP)) concentrations, which are modified by food ingestion. Hence, in rats, a carbohydrate meal raises brain TRP and 5HT; a protein-containing meal does not, but little attention has focused on differences among dietary proteins. Recently, single meals containing different proteins have been shown to produce marked changes in TRP and 5HT.

Reduced respiratory capacity in muscle mitochondria of obese subjects.

Background/aims: The extent of weight gain varies among individuals despite equal calorie overconsumption. Furthermore, weight gain is often less than expected from energy excess. This suggests differences in metabolic efficiency and basal metabolism.

Nutritional assessment of bariatric surgery patients presenting for plastic surgery: a prospective analysis.

Background: Assessment of nutritional status in the growing postbariatric patient population remains controversial. Previous literature suggests that these patients have poor nutrition that may have adverse effects on surgical outcomes. The authors sought to determine the optimal method of nutritional assessment in postbariatric patients.

Effect of physical training on mitochondrial respiration and reactive oxygen species release in skeletal muscle in patients with obesity and type 2 diabetes.

Aim/hypothesis: Studies have suggested a link between insulin resistance and mitochondrial dysfunction in skeletal muscles. Our primary aim was to investigate the effect of aerobic training on mitochondrial respiration and mitochondrial reactive oxygen species (ROS) release in skeletal muscle of obese participants with and without type 2 diabetes.

Methods: Type 2 diabetic men (n = 13) and control (n = 14) participants matched for age, BMI and physical activity completed 10 weeks of aerobic training.

Ultraendurance exercise increases the production of reactive oxygen species in isolated mitochondria from human skeletal muscle.

Exercise-induced oxidative stress is important for the muscular adaptation to training but may also cause muscle damage. We hypothesized that prolonged exercise would increase mitochondrial production of reactive oxygen species (ROS) measured in vitro and that this correlates with oxidative damage. Eight male athletes (24-32 yr) performed ultraendurance exercise (kayaking/running/cycling) with an average work intensity of 55% V(O(2peak)) for 24 h.