Metabolic Equivalent in Adolescents, Active Adults and Pregnant Women

Adequacy of energy and macronutrients intake in differently active slovenian adolescents

OBJECTIVE

Evaluate the adequacy of energy/macronutrient intake in adolescents according to the Slovenian national recommendations adopted from the recommendations of the German Nutrition Society and to identify differences in energy/macronutrient intake between differently active adolescents.

METHODS

Data on energy and macronutrient intake (24-hour dietary recall), physical activity (SHAPES questionnaire), and anthropometric characteristics (body mass and height) of adolescents were obtained on a representative sample of first-year secondary school students (average (SD) age: 15.3 (0.5) years; N = 341), who were included in the national survey The Analysis of Children's Development in Slovenia (ACDSi) in 2013/14.

RESULTS

75% of adolescents met the national recommendations for carbohydrates and proteins and 44% for fats, whereas only 10% of adolescents met the recommendations for energy intake. Energy/macronutrient intakes were significantly higher in vigorously physically active (VPA) boys compared to moderately (MPA) and less (LPA) physically active boys. No such differences were observed between girls of different physical activity levels.

CONCLUSION

Adolescents need to be encouraged to meet their energy needs according to gender and physical activity (especially VPA girls) and to reach for higher quality foods in adequate macronutrient proportions.

Microbial profiles and immune responses in seahorse gut and brood pouch under chronic exposure to environmental antibiotics

Ocean antibiotics pose substantial risks to the adaptation and lifespan of marine organisms. Seahorses are unique owing to the occurrence of brood pouches, male pregnancy, and loss of gut-associated lymphatic tissues and spleen, which lead to increased sensitivity to environmental changes. This study evaluated the changes in microbial diversity and immune responses within the gut and brood pouch in the lined seahorse Hippocampus erectus under chronic exposure to environmental levels of triclosan (TCS) and sulfamethoxazole (SMX), which are common antibiotics in coastal regions. The results showed that microbial abundance and diversity within the gut and brood pouch of seahorses were significantly changed following antibiotics treatment, with the expression of core genes involved in immunity, metabolism, and circadian rhythm processes evidently regulated. Notably, the abundance of potential pathogens in brood pouches was considerably increased upon treatment with SMX. Transcriptome analysis revealed that the expression of toll-like receptors, c-type lectins, and inflammatory cytokine genes in brood pouches was significantly upregulated. Notably, some essential genes related to male pregnancy significantly varied after antibiotic treatment, implying potential effects on seahorse reproduction. This study provides insights into the physiological adaptation of marine animals to environmental changes resulting from human activity.

Cinnamaldehyde supplementation acts as an insulin mimetic compound improving glucose metabolism during adolescence, but not during adulthood, in healthy male rats

PURPOSE

Adolescence is a critical period of increased vulnerability to nutritional modifications, and adolescents may respond differently from adults to dietary intake and nutraceuticals. Cinnamaldehyde, a major bioactive compound of cinnamon, improves energy metabolism, as has been shown in studies conducted primarily in adult animals. We hypothesized that cinnamaldehyde treatment may have a higher impact on the glycemic homeostasis of healthy adolescent rats than on healthy adult rats.

METHODS

Male adolescent (30 days) or adult (90 days) Wistar rats received cinnamaldehyde (40 mg/kg) for 28 days by gavage. The oral glucose tolerance test (OGTT), liver glycogen content, serum insulin concentration, serum lipid profile, and hepatic insulin signaling marker expression were evaluated.

RESULTS

Cinnamaldehyde-treated adolescent rats showed less weight gain (P = 0.041), improved OGTT (P = 0.004), increased expression of phosphorylated IRS-1 (P = 0.015), and a trend to increase phosphorylated IRS-1 (P = 0.063) in the liver of adolescent rats in the basal state. None of these parameters was modified after treatment with cinnamaldehyde in the adult group. Cumulative food intake, visceral adiposity, liver weight, serum insulin, serum lipid profile, hepatic glycogen content, and liver protein expression of IRβ, phosphorylated IRβ, AKT, phosphorylated AKT, and PTP-1B in the basal state were similar between both age groups.

CONCLUSION

In a healthy metabolic condition, cinnamaldehyde supplementation affects glycemic metabolism in adolescent rats while promoting no changes in adult rats.

Mass Spectrometric Metabolic Fingerprinting of 2-Deoxy-D-Glucose (2-DG)-Induced Inhibition of Glycolysis and Comparative Analysis of Methionine Restriction versus Glucose Restriction under Perfusion Culture in the Murine L929 Model System

All forms of restriction, from caloric to amino acid to glucose restriction, have been established in recent years as therapeutic options for various diseases, including cancer. However, usually there is no direct comparison between the different restriction forms. Additionally, many cell culture experiments take place under static conditions. In this work, we used a closed perfusion culture in murine L929 cells over a period of 7 days to compare methionine restriction (MetR) and glucose restriction (LowCarb) in the same system and analysed the metabolome by liquid chromatography mass spectrometry (LC-MS). In addition, we analysed the inhibition of glycolysis by 2-deoxy-D-glucose (2-DG) over a period of 72 h. 2-DG induced very fast a low-energy situation by a reduced glycolysis metabolite flow rate resulting in pyruvate, lactate, and ATP depletion. Under perfusion culture, both MetR and LowCarb were established on the metabolic level. Interestingly, over the period of 7 days, the metabolome of MetR and LowCarb showed more similarities than differences. This leads to the conclusion that the conditioned medium, in addition to the different restriction forms, substantially reprogramm the cells on the metabolic level.

Low Energy Status under Methionine Restriction Is Essentially Independent of Proliferation or Cell Contact Inhibition

Nonlimited proliferation is one of the most striking features of neoplastic cells. The basis of cell division is the sufficient presence of mass (amino acids) and energy (ATP and NADH). A sophisticated intracellular network permanently measures the mass and energy levels. Thus, in vivo restrictions in the form of amino acid, protein, or caloric restrictions strongly affect absolute lifespan and age-associated diseases such as cancer. The induction of permanent low energy metabolism (LEM) is essential in this process. The murine cell line L929 responds to methionine restriction (MetR) for a short time period with LEM at the metabolic level defined by a characteristic fingerprint consisting of the molecules acetoacetate, creatine, spermidine, GSSG, UDP-glucose, pantothenate, and ATP. Here, we used mass spectrometry (LC/MS) to investigate the influence of proliferation and contact inhibition on the energy status of cells. Interestingly, the energy status was essentially independent of proliferation or contact inhibition. LC/MS analyses showed that in full medium, the cells maintain active and energetic metabolism for optional proliferation. In contrast, MetR induced LEM independently of proliferation or contact inhibition. These results are important for cell behaviour under MetR and for the optional application of restrictions in cancer therapy.

Comparison of the Validity and Generalizability of Machine Learning Algorithms for the Prediction of Energy Expenditure: Validation Study

Background

Accurate solutions for the estimation of physical activity and energy expenditure at scale are needed for a range of medical and health research fields. Machine learning techniques show promise in research-grade accelerometers, and some evidence indicates that these techniques can be applied to more scalable commercial devices.

Objective

This study aims to test the validity and out-of-sample generalizability of algorithms for the prediction of energy expenditure in several wearables (ie, Fitbit Charge 2, ActiGraph GT3-x, SenseWear Armband Mini, and Polar H7) using two laboratory data sets comprising different activities.

Methods

Two laboratory studies (study 1: n=59, age 44.4 years, weight 75.7 kg; study 2: n=30, age=31.9 years, weight=70.6 kg), in which adult participants performed a sequential lab-based activity protocol consisting of resting, household, ambulatory, and nonambulatory tasks, were combined in this study. In both studies, accelerometer and physiological data were collected from the wearables alongside energy expenditure using indirect calorimetry. Three regression algorithms were used to predict metabolic equivalents (METs; ie, random forest, gradient boosting, and neural networks), and five classification algorithms (ie, k-nearest neighbor, support vector machine, random forest, gradient boosting, and neural networks) were used for physical activity intensity classification as sedentary, light, or moderate to vigorous. Algorithms were evaluated using leave-one-subject-out cross-validations and out-of-sample validations.

Results

The root mean square error (RMSE) was lowest for gradient boosting applied to SenseWear and Polar H7 data (0.91 METs), and in the classification task, gradient boost applied to SenseWear and Polar H7 was the most accurate (85.5%). Fitbit models achieved an RMSE of 1.36 METs and 78.2% accuracy for classification. Errors tended to increase in out-of-sample validations with the SenseWear neural network achieving RMSE values of 1.22 METs in the regression tasks and the SenseWear gradient boost and random forest achieving an accuracy of 80% in classification tasks.

Conclusions

Algorithms trained on combined data sets demonstrated high predictive accuracy, with a tendency for superior performance of random forests and gradient boosting for most but not all wearable devices. Predictions were poorer in the between-study validations, which creates uncertainty regarding the generalizability of the tested algorithms.

Absolute Accelerometer-Based Intensity Prescription Compared to Physiological Variables in Pregnant and Nonpregnant Women

Estimation of the intensity of physical activity (PA) based on absolute accelerometer cut points (Cp) likely over- or underestimates intensity for a specific individual. The purpose of this study was to investigate the relationship between absolute moderate intensity Cp and the first ventilatory threshold (VT₁). A group of 24 pregnant and 15 nonpregnant women who performed a submaximal incremental walking test with measures of ventilatory parameters and accelerations from three different accelerometers on the wrist (ActiGraph wGT3X-BT, GENEActiv, Axivity AX3) and one on the hip (Actigraph wGT3X-BT) were analyzed. Cp were determined corresponding to 3 metabolic equivalents of task (MET), using the conventional MET definition (Cp_3.5) (3.5 mL/kg×min) and individual resting metabolic rate (Cp_ind). The ventilatory equivalent (VE/VO₂) was used to determine VT₁. Accelerations at VT₁ were significantly higher (p < 0.01) compared to Cp_3.5 and Cp_ind in both groups. Cp_3.5 and Cp_ind were significantly different in nonpregnant (p < 0.01) but not in pregnant women. Walking speed at VT₁ (5.7 ± 0.5/6.2 ± 0.8 km/h) was significantly lower (p < 0.01) in pregnant compared to nonpregnant women and correspondent to 3.8 ± 0.7/4.9 ± 1.4 conventional METs. Intensity at absolute Cp was lower compared to the intensity at VT₁ independent of the device or placement in pregnant and nonpregnant women. Therefore, we recommend individually tailored cut points such as the VT₁ to better assess the effect of the intensity of PA.

Comparison of Conventional and Individualized 1-MET Values for Expressing Maximum Aerobic Metabolic Rate and Habitual Activity Related Energy Expenditure

The maximum aerobic metabolic rate can be expressed in multiple metabolically equivalent tasks (MET), i.e., METmax. The purpose was to quantify the error when the conventional (3.5 mL∙kg⁻¹∙min⁻¹) compared to an individualized 1-MET-value is used for calculating METmax and estimating activity energy expenditure (AEE) in endurance-trained athletes (END) and active healthy controls (CON). The resting metabolic rate (RMR, indirect calorimetry) and aerobic metabolic capacity (spiroergometry) were assessed in 52 END (46% male, 27.9 ± 5.7 years) and 53 CON (45% male, 27.3 ± 4.6 years). METmax was calculated as the ratio of VO₂max over VO₂ during RMR (METmax_ind), and VO₂max over the conventional 1-MET-value (METmax_fix). AEE was estimated by multiplying published MET values with the individual and conventional 1-MET-values. Dependent t-tests were used to compare the different modes for calculating METmax and AEE (α = 0.05). In women and men CON, men END METmax_fix was significantly higher than METmax_ind (p < 0.01), whereas, in women END, no difference was found (p > 0.05). The conventional 1-MET-value significantly underestimated AEE in men and women CON, and men END (p < 0.05), but not in women END (p > 0.05). The conventional 1-MET-value appears inappropriate for determining the aerobic metabolic capacity and AEE in active and endurance-trained persons.

Exercising the hepatobiliary-gut axis. The impact of physical activity performance

BACKGROUND

Physical inactivity puts the populations at risk of several health problems, while regular physical activity brings beneficial effects on cardiovascular disease, mortality and other health outcomes, including obesity, glycaemic control and insulin resistance. The hepatobiliary tract is greatly involved in several metabolic aspects which include digestion and absorption of nutrients in concert with intestinal motility, bile acid secretion and flow across the enterohepatic circulation and intestinal microbiota. Several metabolic abnormalities, including nonalcoholic fatty liver as well as cholesterol cholelithiasis, represent two conditions explained by changes of the aforementioned pathways.

MATERIALS AND METHODS

This review defines different training modalities and discusses the effects of physical activity in two metabolic disorders, that is nonalcoholic fatty liver disease (NAFLD) and cholelithiasis. Emphasis is given to pathogenic mechanisms involving intestinal bile acids, microbiota and inflammatory status.

RESULTS

A full definition of physical activity includes the knowledge of aerobic and endurance exercise, metabolic equivalent tasks, duration, frequency and intensity, beneficial and harmful effects. Physical activity influences the hepatobiliary-gut axis at different levels and brings benefits to fat distribution, liver fat and gallbladder disease while interacting with bile acids as signalling molecules, intestinal microbiota and inflammatory changes in the body.

CONCLUSIONS

Several beneficial effects of physical activity are anticipated on metabolic disorders linking liver steatosis, gallstone disease, gut motility, enterohepatic circulation of signalling bile acids in relation to intestinal microbiota and inflammatory changes.

MET-values of standardised activities in relation to body fat: studies in pregnant and non-pregnant women

Background

Physical activity is associated with health in women. Published MET-values (MET: metabolic equivalent of task) may assess physical activity and energy expenditure but tend to be too low for subjects with a high total body fat (TBF) content and therefore inappropriate for many contemporary women. The MET-value for an activity is the energy expenditure of a subject performing this activity divided by his/her resting energy expenditure, often assumed to be 4.2 kJ/kg/h. Relationships between TBF and MET have been little studied although overweight and obesity is common in women. Available data indicate that MET-values decrease during pregnancy but more studies in pregnant contemporary women are needed.

Subjects and methods

Using indirect calorimetry we measured energy expenditure and assessed MET-values in women, 22 non-pregnant (BMI: 18–34) and 22 in gestational week 32 (non-pregnant BMI: 18–32) when resting, sitting, cycling (30 and 60 watts), walking (3.2 and 5.6 km/h) and running (8 km/h). Relationships between TBF and MET-values were investigated and used to predict modified MET-values. The potential of such values to improve calculations of total energy expenditure of women was investigated.

Results

The resting energy expenditure was below 4.2 kJ/kg/h in both groups of women. Women in gestational week 32 had a higher resting energy metabolism (p < 0.001) and 7–15% lower MET-values (p < 0.05) than non-pregnant women. MET-values of all activities were correlated with TBF (p < 0.05) in non-pregnant women and modified MET-values improved estimates of total energy expenditure in such women. In pregnant women, correlations (p ≤ 0.03) between TBF and MET were found for running (8 km/h) and for walking at 5.6 km/h.

Conclusions

Our results are relevant when attempts are made to modify the MET-system in contemporary pregnant and non-pregnant women. MET-values were decreased in gestational week 32, mainly due to an increased resting energy metabolism and studies describing how body composition affects the one MET-value (i.e. the resting energy metabolism in kJ/kg/h) during pregnancy are warranted. Studies of how pregnancy and TBF affect MET-values of high intensity activities are also needed. Corrections based on TBF may have a potential to improve the MET-system in non-pregnant women.

Physical Activity May Be Associated with Conditioned Pain Modulation in Women but Not Men among Healthy Individuals

Background

Conditioned pain modulation (CPM), a phenomenon also known as diffuse noxious inhibitory control, is thought to be affected by various factors, including sex and level of physical activity. However, the involvement of these factors in CPM remains unclear.

Methods

Eighty-six healthy young subjects (M/F, 43/43) participated in this study. Participants were assessed on the basis of their mechanical pressure pain threshold (PPT), CPM response, body mass index (BMI), basal metabolic rate (BMR), and duration of moderate-to-vigorous physical activity (MVPA) over a week, using a motion counter. Response to CPM was evaluated as PPT during painful cold stimulation relative to baseline PPT.

Results

Men showed significantly higher baseline PPT than women; however, this difference was no longer significant after controlling for confounders. Stepwise multiple linear regression analyses revealed BMR to be a significant contributor towards baseline PPT in the entire study population. In contrast, although there were no significant contributors to CPM response among men and in the overall study group, MVPA was positively associated with CPM response among women (β = 0.397).

Conclusions

These results suggest that, among healthy young individuals, CPM response may be associated with moderate-to-vigorous physical activity in women but not in men.