No evidence of brown adipose tissue activation after 24 weeks of supervised exercise training in young sedentary adults in the ACTIBATE randomized controlled trial.

Exercise modulates both brown adipose tissue (BAT) metabolism and white adipose tissue (WAT) browning in murine models. Whether this is true in humans, however, has remained unknown. An unblinded randomized controlled trial (ClinicalTrials.gov ID: NCT02365129) was therefore conducted to study the effects of a 24-week supervised exercise intervention, combining endurance and resistance training, on BAT volume and activity (primary outcome). The study was carried out in the Sport and Health University Research Institute and the Virgen de las Nieves University Hospital of the University of Granada (Spain). One hundred and forty-five young sedentary adults were assigned to either (i) a control group (no exercise, n = 54), (ii) a moderate intensity exercise group (MOD-EX, n = 48), or (iii) a vigorous intensity exercise group (VIG-EX n = 43) by unrestricted randomization. No relevant adverse events were recorded. 97 participants (34 men, 63 women) were included in the final analysis (Control; n = 35, MOD-EX; n = 31, and VIG-EX; n = 31). We observed no changes in BAT volume (Δ Control: -22.2 ± 52.6 ml; Δ MOD-EX: -15.5 ± 62.1 ml, Δ VIG-EX: -6.8 ± 66.4 ml; P = 0.771) or 18F-fluorodeoxyglucose uptake (SUVpeak Δ Control: -2.6 ± 3.1 ml; Δ MOD-EX: -1.2 ± 4.8, Δ VIG-EX: -2.2 ± 5.1; p = 0.476) in either the control or the exercise groups. Thus, we did not find any evidence of an exercise-induced change on BAT volume or activity in young sedentary adults.

Association between dietary factors and brown adipose tissue volume/18F-FDG uptake in young adults.

OBJECTIVE: To study the association between usual dietary factors (dietary energy density, nutrient intake, food group consumption, and dietary pattern) and brown adipose tissue (BAT) volume/18F-fluorodeoxyglucose (18F-FDG) uptake after personalized cold exposure in young healthy adults. METHODS: A total of 122 young adults (n = 82 women; 22.0 ± 2.1 years old; 24.8 ± 4.8 kg/m2) took part in this cross-sectional study. Dietary factors were measured via a food frequency questionnaire and three non-consecutive 24 h recalls. Dietary energy density (foods and caloric beverages included) and macronutrient intakes were subsequently estimated using EvalFINUT® software, food group consumption was estimated from the food frequency questionnaire, and different dietary patterns and quality indices were determined according to the reference methods. BAT volume, BAT 18F-FDG uptake, and skeletal muscle 18F-FDG uptake were assessed by static 18F-FDG positron-emission tomography and computed tomography (PET-CT) scans after a 2 h personalized exposure to cold. RESULTS: A direct association was detected between dietary energy density and BAT Standardized Uptake Value (SUV)mean (ß = 0.215; R2 = 0.044; P = 0.022), and between ethanol consumption and BAT volume (ß = 0.215; R2 = 0.044; P = 0.022). The a priori Mediterranean dietary pattern was inversely associated with BAT SUVmean and SUVpeak (ß = -0.273; R2 = 0.075; P = 0.003 and ß = -0.255; R2 = 0.066; P = 0.005 respectively). In addition, the diet quality index for a Mediterranean diet and a pro-inflammatory dietary pattern (as determined via the dietary inflammatory index) were directly associated with BAT SUVmean and SUVpeak (SUVmean: ß = 0.238; R2 = 0.053; P = 0.013 and ß = 0.256; R2 = 0.052; P = 0.012 respectively; SUVpeak: ß = 0.278; R2 = 0.073; P = 0.003 and ß = 0.248; R2 = 0.049; P = 0.016 respectively). After controlling for multiplicity and possible confounders (sex, the evaluation wave and BMI), all the detected associations persisted. CONCLUSION: Dietary factors are slightly associated with BAT volume and/or 18F-FDG uptake after a personalized cold exposure in young adults. Our results provide an overall picture of the potential relationships between dietary factors and BAT-related variables in humans.

Association of Neck Circumference with Anthropometric Indicators and Body Composition Measured by DXA in Young Spanish Adults.

BACKGROUND: Due to a clinical and public health interest of neck circumference (NC), a better understanding of this simple anthropometric measurement, as a valid marker of body composition is necessary. METHODS: A total of 119 young healthy adults participated in this study. NC was measured over the thyroid cartilage and perpendicular to the longitudinal axis of the neck. Body weight, height, waist circumference (WC), and hip circumference were measured. A Dual X-ray absorptiometry (DXA) scan was used to determine fat mass, lean mass, and visceral adipose tissue (VAT). Additionally, body mass index (BMI) and triponderal mass index (TMI), the waist to hip and waist to height ratios, and the fat mass and lean mass indexes (FMI and LMI, respectively) were calculated. RESULTS: NC was positively associated in women (W) and men (M), with BMI (rW = 0.70 and rM = 0.84, respectively), TMI (rW = 0.63 and rM = 0.80, respectively), WC (rW = 0.75 and rM = 0.86, respectively), VAT (rW = 0.74 and rM = 0.82, respectively), Waist/hip (rW = 0.51 and rM = 0.67, respectively), Waist/height (rW = 0.68 and rM = 0.83, respectively) and FMI (rW = 0.61 and rM = 0.81, respectively). The association between NC and indicators of body composition was however weaker than that observed by BMI, TMI, WC and Waist/height in both women and men. It is of note that in women, NC was associated with FMI, VAT and LMI independently of BMI. In men, adding NC to anthropometric variables did not improve the prediction of body composition, while slight improvements were observed in women. CONCLUSIONS: Taken together, the present study provides no indication for NC as a useful proxy of body composition parameters in young adults, yet future studies should explore its usefulness as a measure to use in combination with BMI, especially in women.

Associations of dietary energy density with body composition and cardiometabolic risk in children with overweight and obesity: role of energy density calculations, under-reporting energy intake and physical activity.

This study examined (1) the association of dietary energy density from solid (EDS) and solid plus liquids (EDSL) with adiposity and cardiometabolic risk factors (CRF) in children with overweight and obesity, (2) the effect of under-reporting on the mentioned associations and (3) whether the association between ED and body composition and CRF is influenced by levels of physical activity. In a cross-sectional design, 208 overweight and obese children (8-12-year-old; 111 boys) completed two non-consecutive 24 h recalls. ED was calculated using two different approaches: EDS and EDSL. Under-reporters were determined with the Goldberg method. Body composition, anthropometry and fasting blood sample measurements were performed. Moderate to vigorous physical activity (MVPA) was registered with accelerometers (7-d-register). Linear regressions were performed to evaluate the association of ED with the previously mentioned variables. Neither EDS nor EDSL were associated with body composition or CRF. However, when under-reporters were excluded, EDS was positively associated with BMI (P=0·019), body fat percentage (P=0·005), abdominal fat (P=0·008) and fat mass index (P=0·018), while EDSL was positively associated with body fat percentage (P=0·008) and fat mass index (P=0·026). When stratifying the group according to physical activity recommendations, the aforementioned associations were only maintained for non-compliers. Cluster analysis showed that the low-ED and high-MVPA group presented the healthiest profile for all adiposity and CRF. These findings could partly explain inconsistencies in literature, as we found that different ED calculations entail distinct results. Physical activity levels and excluding under-reporters greatly influence the associations between ED and adiposity in children with overweight and obesity.

Congruent Validity of Resting Energy Expenditure Predictive Equations in Young Adults.

Having valid and reliable resting energy expenditure (REE) estimations is crucial to establish reachable goals for dietary and exercise interventions. However, most of the REE predictive equations were developed some time ago and, as the body composition of the current population has changed, it is highly relevant to assess the validity of REE predictive equations in contemporary young adults. In addition, little is known about the role of sex and weight status on the validity of these predictive equations. Therefore, this study aimed to investigate the role of sex and weight status in congruent validity of REE predictive equations in young adults. A total of 132 young healthy adults (67.4% women, 18⁻26 years old) participated in the study. We measured REE by indirect calorimetry strictly following the standard procedures, and we compared it to 45 predictive equations. The most accurate equations were the following: (i) the Schofield and the "Food and Agriculture Organization of the United Nations/World Health Organization/United Nations" (FAO/WHO/UNU) equations in normal weight men; (ii) the Mifflin and FAO/WHO/UNU equations in normal weight women; (iii) the Livingston and Korth equations in overweight men; (iv) the Johnstone and Frankenfield equations in overweight women; (v) the Owen and Bernstein equations in obese men; and (vi) the Owen equation in obese women. In conclusion, the results of this study show that the best equation to estimate REE depends on sex and weight status in young healthy adults.

Skin temperature response to a liquid meal intake is different in men than in women.

BACKGROUND & AIM: The thermic effect of food (TEF) refers to the increase of the metabolic rate and body temperature in response to a single meal. To date, most of the studies have focused to determine the TEF in terms of energy expenditure, but little is known about which is the response in terms of skin temperature. The aim of this study was to analyze whether the thermic effect of food (TEF) on the skin temperature with a standardized and individualized liquid meal test is different in young adult men than in young adult women. METHODS: A total of 104 young adults (36 men and 68 women, age: 18-25 years old) consumed a standardized and individualized liquid meal (energy intake: 50% of measured basal metabolic rate, 50% carbohydrates, 35% fat, 15% protein). The skin temperature was measured by means of 17 iButtons during 3 h and 20 min. The mean, proximal, distal, and supraclavicular skin temperature, as well as the peripheral gradient, were determined as a proxy of a peripheral vasoconstriction. The participants reported the thermal sensation of the whole body, clavicular, feet, and hands zones. The body composition was measured by dual X-ray absorptiometry. RESULTS: The overall, mean, proximal, and supraclavicular skin temperature significantly increased after the meal intake (all P < 0.05 vs. the baseline temperature). There was a postprandial peripheral vasoconstriction right after the meal intake and over the first hour and a peripheral vasodilatation during the second and third hour. Women had a higher increase in all skin temperature parameters in comparison to men (all, P < 0.05), whereas there were no sex differences in the proximal skin temperature (P = 0.279). The pattern of thermal sensation was similar between sexes, but women always felt colder than men. All of the results persisted after adjusting the analyses for body composition or menstrual cycle. CONCLUSION: A standardized and individualized liquid meal test increases the skin temperature in young adults, being the thermic effect higher in women than in men.

Association of Breakfast Quality and Energy Density with Cardiometabolic Risk Factors in Overweight/Obese Children: Role of Physical Activity.

There is a general belief that having breakfast is an important healthy lifestyle factor; however, there is scarce evidence on the influence of breakfast quality and energy density on cardiometabolic risk in children, as well as on the role of physical activity in this association. The aims of this paper were (i) to examine the associations of breakfast quality and energy density from both solids and beverages with cardiometabolic risk factors, and (ii) to explore whether physical activity levels may attenuate these relationships in children with overweight/obesity from two projects carried out in the north and south of Spain. Breakfast consumption, breakfast quality index (BQI) score, BEDs/BEDb (24 h-recalls and the KIDMED questionnaire), and physical activity (PA; accelerometry) were assessed, in 203 children aged 8⁻12 years who were overweight or obese. We measured body composition (Dual X-ray Absorptiometry), uric acid, blood pressure, lipid profile, gamma-glutamyl-transferase (GGT), glucose, and insulin, and calculated the HOMA and metabolic syndrome z-score. The BQI score was inversely associated with serum uric acid independently of a set of relevant confounders (ß = -0.172, p = 0.028), but the relationship was attenuated after further controlling for total PA (p < 0.07). BEDs was positively associated with total and HDL cholesterol, and systolic blood pressure regardless of confounders (all p < 0.05), while BEDb was positively associated with HOMA in either active/inactive children (all p < 0.03). In conclusion, higher breakfast quality and lower breakfast energy density should be promoted in overweight/obesity children to improve their cardiometabolic health.

Influence of Physical Activity on Bone Mineral Content and Density in Overweight and Obese Children with Low Adherence to the Mediterranean Dietary Pattern.

The objective of the present cross-sectional study was to examine the associations of physical activity and the adherence to the Mediterranean dietary pattern (MDP) with bone mineral content (BMC) and density (BMD) in children with overweight and obesity. A total of 177 (n = 80 girls) children with overweight and obesity aged 8 to 12 years old participated in the study. Both BMC and BMD were assessed by Dual-Energy X-ray absorptiometry. Dietary patterns were assessed by the KIDMED questionnaire and two 24-hour recalls. Physical activity was assessed by accelerometers for 7 consecutive days (24 hours/day). Low adherence to the MDP was observed in 82.4% of participants. Higher physical activity levels (of at least moderate intensity) and lower sedentary time were significantly associated with BMC and BMD in children with low adherence to the MDP (all p < 0.05). No associations were observed between physical activity and BMC and BMD in children with high adherence to the MDP. In conclusion, engaging in moderate to vigorous physical activity and reducing the time spent in sedentary behavior might be particularly beneficial for improving bone health in overweight or obese children with poor adherence to the Mediterranean dietary pattern.

An exercise-based randomized controlled trial on brain, cognition, physical health and mental health in overweight/obese children (ActiveBrains project): Rationale, design and methods.

The new and recent advances in neuroelectric and neuroimaging technologies provide a new era for further exploring and understanding how brain and cognition function can be stimulated by environmental factors, such as exercise, and particularly to study whether physical exercise influences brain development in early ages. The present study, namely the ActiveBrains project, aims to examine the effects of a physical exercise programme on brain and cognition, as well as on selected physical and mental health outcomes in overweight/obese children. A total of 100 participants aged 8 to 11 years are randomized into an exercise group (N=50) or a control group (N=50). The intervention lasts 20-weeks, with 3-5 sessions per week of 90 min each, and is mainly focused on high-intensity aerobic exercise yet also includes muscle-strengthening exercises. The extent to what the intervention effect remains 8-months after the exercise programme finishes is also studied in a subsample. Brain structure and function and cognitive performance are assessed using structural and functional magnetic resonance imaging and electroencephalographic recordings. Secondary outcomes include physical health outcomes (e.g. physical fitness, body fatness, bone mass and lipid-metabolic factors) and mental health outcomes (e.g. chronic stress indicators and overall behavioural and personality measurements such as anxiety or depression). This project will substantially contribute to the existing knowledge and will have an impact on societies, since early stimulation of brain development might have long lasting consequences on cognitive performance, academic achievement and in the prevention of behavioural problems and the promotion of psychological adjustment and mental health. Clinical trials. Gov identifier: NCT02295072.

Activating brown adipose tissue through exercise (ACTIBATE) in young adults: Rationale, design and methodology.

AIMS: The energy expenditure capacity of brown adipose tissue (BAT) makes it an attractive target as a therapy against obesity and type 2 diabetes. BAT activators namely catecholamines, natriuretic peptides and certain myokines, are secreted in response to exercise. ACTIBATE will determine the effect of exercise on BAT activity and mass measured by positron emission tomography/computed tomography (PET/CT, primary outcome) in young adults. ACTIBATE will also investigate the physiological consequences of activating BAT (secondary outcomes). METHODS: ACTIBATE will recruit 150 sedentary, healthy, young adults (50% women) aged 18-25 years. Eligible participants will be randomly assigned to a non-exercise group (n ≈ 50) or one of two exercise groups (n=50 each). Participants in the exercise groups will perform aerobic and strength training 3-4 days/week at a heart rate equivalent to 60% of heart rate reserve (HRres), and at 50% of 1 repetition maximum (RM) for the moderate-intensity group, and at 80% of HRres and 70% RM for the vigorous-intensity group. Laboratory measures completed at baseline and 6 months include BAT activity and mass, resting energy expenditure, meal and cold-induced thermogenesis, body temperature regulation and shivering threshold, body composition and cardiovascular disease risk factors. We will also obtain biopsies from abdominal subcutaneous white adipose tissue and skeletal muscle to analyse the expression of genes encoding proteins involved in the thermogenic machinery. DISCUSSION: Findings from ACTIBATE will have significant implications for our understanding of exercise and its protective effects against the development of type 2 diabetes, obesity and related metabolic diseases. ClinicalTrials.gov ID: NCT02365129.