Polyphenols and their anti-obesity role mediated by the gut microbiota: a comprehensive review.

Obesity is a global public health problem that results in chronic pathologies such as diabetes, cardiovascular diseases, and cancer. The treatment approach based on energy restriction and promotion of physical activity is ineffective in the long term. Due to the high prevalence of this pathology, complementary treatments such as brown adipose tissue activation (BAT) and white adipose tissue browning (WAT) have been proposed. Dietary polyphenols are plant secondary metabolites that can stimulate browning and thermogenesis of adipose tissue. They have also been shown to prevent body weight gain, and decrease systemic inflammation produced by high-fat diets. Ingested dietary polyphenols that reach the colon are metabolized by the gut microbiota (GM), regulating its composition and generating a great array of metabolites. GM is involved in the production of short chain fatty acids and secondary bile salts that regulate energetic metabolism. The alteration in the composition of GM observed in metabolic diseases such as obesity and type 2 diabetes can be attenuated by polyphenols. Recent studies support the hypothesis that GM would mediate WAT browning and BAT thermogenesis activation induced by polyphenol administration. Together, these results indicate that GM in the presence of polyphenols plays a fundamental role in the control of obesity possible through BAT activation.

Microencapsulated pomegranate peel extract induces mitochondrial complex IV activity and prevents mitochondrial cristae alteration in brown adipose tissue in mice fed on a high-fat diet.

Pomegranate peel is an agro-industrial residue obtained after fruit processing with high total polyphenol (TP) content, making it an attractive by-product for its reuse. Pomegranate peel extract (PPE) and its bioactive compounds have shown positive effects on obesity models. Effects on favouring mitochondrial biogenesis and function have also been described. However, once phenolic compounds are extracted, their stability can be affected by diverse factors. Microencapsulation could improve PPE stability, allowing its incorporation into functional foods. Nevertheless, studies on the potential biological effects of PPE microparticles (MPPE) in obesity models are lacking. This study aims to evaluate the effect of MPPE on brown adipose tissue (BAT) mitochondrial structure and function and metabolic alterations related to obesity in mice fed a high-fat diet (HFD). PPE was microencapsulated by spray drying using inulin (IN) as a wall material and physically-chemically characterised. Eight-week-old male C57BL/6J mice (n 40) were randomly distributed into five groups: control diet (CD), HFD, HFD + IN, HFD + PPE (50 mg/kg per d TP) and HFD + MPPE (50 mg/kg per d TP), for 14 weeks. A glucose tolerance test and indirect calorimetry were conducted. Blood and adipose tissue samples were obtained. MPPE supplementation prevented HFD-induced body weight gain (P < 0·001), fasting glycaemia (P = 0·007) and total cholesterol rise (P = 0·001). MPPE resulted in higher BAT mitochondrial complex IV activity (P = 0·03) and prevented HFD-induced mitochondrial cristae alteration (P = 0·02). In conclusion, MPPE prevented HFD-induced excessive body weight gain and associated metabolic disturbances, potentially by activating complex IV activity and preserving mitochondrial cristae structure in BAT in mice fed with a HFD.

[High intensity interval training in teenagers]. / Efectividad de ejercicio físico intervalado de alta intensidad en las mejoras del fitness cardiovascular, muscular y composición corporal en adolescentes: una revisión.

This review analyzes the effects of high intensity interval training (HIIT) on muscle and cardiovascular fitness and body composition in teenagers. A search was carried out in international databases, finding 145 papers and selecting five for analysis. In all the reviewed manuscripts, peak oxygen uptake improved after HIIT. In the three manuscripts that measured muscle strength, it also increased. We conclude that HIIT improves muscle strength and cardiovascular fitness in school age children. A 12 weeks protocol with three 12-minute sessions per week would be ideal.

[Exercise and oxidative stress in type 2 diabetes mellitus]. / Efecto del ejercicio físico sobre marcadores de estrés oxidativo en pacientes con diabetes mellitus tipo 2.

Sedentarism, overweight and malnutrition generate an increase in the production of reactive oxygen species leading to a state of chronic oxidative stress. In patients with type 2 diabetes mellitus, oxidative stress alters pancreatic insulin secretion and the actions of the hormone on target cells, contributing to the development of micro and macrovascular complications. During physical exertion a state of transient oxidative stress occurs. As a consequence, the organism generates multiple physiological adaptations to these repetitive stimuli. Physical exercise is beneficial for type 2 diabetes mellitus but there is a paucity of information about the effects of physical exercise on biomarkers of oxidative stress in patients with the disease. We herein try to elucidate if the effects of exercise on oxidative stress can help in the prevention and treatment of type 2 diabetes mellitus and which is the most effective modality of physical exercise to reduce oxidative stress markers.

Acute Administration of Calafate (Berberis microphylla) Extract Induces the Expression of Thermogenic Markers and Modulates Gut Microbiota in Mice Fed a High-Fat Chow Diet.

INTRODUCTION: Obesity, characterized by excess adipose tissue, is a major public health problem worldwide. Brown adipose tissue (BAT) and beige adipose tissue participate in thermogenesis through uncoupling protein 1 (UCP1). Polyphenols including those from Calafate (a native polyphenol-rich Patagonian berry), are considered as potential anti-obesity compounds due to their pro-thermogenic characteristics. However, polyphenols are mainly metabolized by the gut microbiota (GM) that may influence their bioactivity and bioavailability. The aim of this study was to determine the impact of dietary administration with a Calafate polyphenol-rich extract on thermogenic activity of BAT and beige adipose tissue and GM composition. METHODS: Eight-week-old C57BL6 mice (n = 30) were divided into 4 groups to receive for 24 weeks a control diet (C), a high-fat diet alone (HF), or high-fat diet supplemented with Calafate extract (HFC) or the same high-fat diet supplemented with Calafate extract but treated with antibiotics (HFCAB) from week 19-20. Administration with Calafate extract (50 mg/kg per day) was carried out for 3 weeks from week 21-23 in the HFC and HFCAB groups. After euthanasia, gene expression of thermogenic markers was analyzed in BAT and inguinal white adipose tissue (iWAT). Transmission electron microscopy was performed to assess mitochondrial morphology and cristae density in BAT. GM diversity and composition were characterized by deep sequencing with the MiSeq Illumina platform. RESULTS: Calafate extract administration had no effect on weight gain in mice fed a high-fat diet. However, it prevented alterations in mitochondrial cristae induced by HFD and increased Dio2 expression in BAT and iWAT. The intervention also influenced the GM composition, preventing changes in specific bacterial taxa induced by the high-fat diet. However, the antibiotic treatment prevented in part these effects, suggesting the implications of GM. CONCLUSION: These results suggest that the acute administration of a Calafate extract modulates the expression of thermogenic markers, prevents alterations in mitochondrial cristae and intestinal microbiota in preclinical models. The study highlights the complex interaction between polyphenols, thermogenesis, and the GM, providing valuable insights into their potential roles in the treatment of obesity-related metabolic diseases.

Effects of Polyphenols in Aging and Neurodegeneration Associated with Oxidative Stress.

Aging is defined as the functional loss of tissues and organs over time. This is a biological, irreversible, progressive, and universal process that results from genetic and environmental factors, such as diet, physical activity, smoking, harmful alcohol consumption, and exposure to toxins, among others. Aging is a consequence of molecular and cellular damage built up over time. This damage begins with a gradual decrease in physical and mental capacity, thus increasing the risk of neurodegenerative diseases such as Alzheimer's and Parkinson's disease. Neuronal, functional, and structural damage can be explained by an imbalance among free radicals, reactive oxygen species, reactive nitrogen species, and antioxidants, which finally lead to oxidative stress. Due to the key role of free radicals, reactive oxygen species, and reactive nitrogen species, antioxidant therapy may reduce the oxidative damage associated with neurodegeneration. Exogenous antioxidants are molecules that may help maintain the balance between the formation and elimination of free radicals, thus protecting the cell from their toxicity. Among them, polyphenols are a broad group of secondary plant metabolites with potent antioxidant properties. Here, we review several studies that show the potential role of polyphenol consumption to prevent, or slow down, harmful oxidative processes linked to neurodegenerative disorders.

Anthropometric Indicators of the Cardiometabolic Risk, Muscle Strength, and Functional Capacity of Schoolchildren with Intellectual Disabilities during Lockdown in Chile.

Lockdown due to the COVID-19 pandemic has negatively impacted the social, psychological, and physical well-being of the world population. In the case of people with intellectual disabilities, the impact of lockdown on their physical condition and functionality is not completely clear. This study aimed to determine the effects of COVID-19 lockdown on the anthropometric indicators of cardiometabolic risk, muscle strength, and functionality on schoolchildren with intellectual disabilities. The sample was composed of 132 students of both sexes (n = 74 pre-lockdown; n = 58 lockdown) belonging to two special education centers from the Metropolitan Region of Santiago, Chile. Our results showed significant reductions (p ≤ 0.05) in absolute and relative handgrip strength, as well as in functionality, when comparing pre-lockdown and lockdown measurements, with a greater loss in girls than boys. The design and implementation of physical exercise programs centered on strength training are necessary for the physical and functional reconditioning of this population. These programs need to be implemented in special education centers considering the general well-being, quality of life and work needs of people with intellectual disabilities.

The potential role of apigenin in the enhancement of the antioxidant adaptation to exercise by bioactive dietary compounds

Oxidative stress (OS) occurs when the antioxidant defense system is overwhelmed by the predominance of reactive oxygen species (ROS) and pro-oxidant factors. Several diseases such as hypertension, insulin resistance, type 2 diabetes mellitus and neurodegenerative diseases are characterized by chronic OS. Physical exercise constitutes an affordable tool to prevent or ameliorate these conditions. However, during physical activity, acute ROS are produced inducing an activation in peroxisome proliferator activated receptor-Gamma Coactivator-1alpha (PGC-1α), and nuclear factor erythroid-2 related factor 2 (Nrf2), PGC-1α/Nrf2 pathway. This signaling pathway facilitates interaction with antioxidant response elements (ARE), thereby initiating an upregulation in the expression of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and mitochondrial biogenesis. In both cases, whether involving healthy animals or individuals engaged in physical exercise, supplementation with antioxidant scavengers leads to a reduction in the expression and activity of PGC-1α, SOD, CAT, and GPX across various tissues, which is not observed with indirect antioxidants. The preventive role of physical exercise against chronic OS is avoided when executed in conjunction with supplementation of scavenger antioxidants. However, similar to exercise, the indirect antioxidant apigenin can activate the PGC1-α/Nrf2 signaling pathway. Here, we summarize evidence supporting apigenin as a non-nutritional supplement that could enhance the adaptive effects of exercise, improving the endogenous antioxidant defense. Therefore, apigenin could be an interesting supplement to enhance the endogenous antioxidant adaptation induced by exercise in healthy subjects, but also to improve the effectiveness of exercise to prevent oxidative stress-associated diseases.

El estrés oxidativo (OS) ocurre cuando el sistema de defensa antioxidante es sobrepasado por el predominio de especies reactivas de oxígeno (ROS) y factores prooxidantes. Varias enfermedades como la hipertensión, la resistencia a la insulina, la diabetes mellitus tipo 2 y enfermedades neurodegenerativas se caracterizan por un OS crónico. El ejercicio físico constituye una herramienta asequible para prevenir o mejorar estas enfermedades. Sin embargo, durante la actividad física, se producen ROS agudas que inducen una activación en la vía PGC-1α/Nrf2. Esta vía de señalización facilita la interacción con los elementos de respuesta antioxidante (ARE), iniciando así una regulación que permite la expresión de enzimas antioxidantes, incluidas SOD, CAT, GPX y biogénesis mitocondrial. En ambos casos, ya sea que se trate de animales sanos o de individuos que practican ejercicio físico, la suplementación con antioxidantes "scavengers" conduce a una reducción en la expresión y actividad de PGC-1α, SOD, CAT y GPX en varios tejidos, lo que no se observa con antioxidantes "indirectos". El papel preventivo del ejercicio físico contra el OS crónico se atenúa cuando se realiza en conjunto con la suplementación de antioxidantes "scavengers". Sin embargo, de manera similar al ejercicio, la apigenina es un antioxidante "indirecto" que puede activar la vía de señalización PGC1-α/Nrf2. Aquí, resumimos la evidencia que respalda a apigenina como un suplemento no-nutricional que podría mejorar los efectos adaptativos del ejercicio, mejorando la defensa antioxidante endógena de sujetos sanos que no tienen suficiente tiempo para hacer ejercicio.

Effects of high intensity interval training versus moderate intensity continuous training on the reduction of oxidative stress in type 2 diabetic adult patients: CAT.

INTRODUCTION: Oxidative stress is caused by an imbalance between an excessive production of reactive oxygen species and/or a deficiency in the level of endogenous and exogenous antioxidant defenses. The presence of reactive oxygen species in large concentrations and for long periods is associated with the occurrence of various diseases, including type 2 diabetes mellitus. Exercise represents an effective means for the prevention and treatment of type 2 diabetes mellitus, and is also able to reduce long-term oxidative stress levels. High-intensity interval training has shown to be an efficient and viable option for type 2 diabetes mellitus control. In turn, high-intensity interval training seems to have positive effects on oxidative stress levels by increasing levels of endogenous antioxidants. OBJECTIVE: To assess the validity and applicability of the results regarding the effectiveness of high-intensity interval training compared to moderate intensity continuous training to reduce oxidative stress in patients with type 2 diabetes mellitus and to answer the following question: In adults with type 2 diabetes mellitus, can the method of high-intensity interval training, compared to moderate intensity continuous training reduce oxidative stress levels? METHODS: We performed a critical analysis of the article "Continuous training vs Interval training in glycemic control and macro and microvascular reactivity in patients with type 2 diabetes". RESULTS: No statistically significant differences were observed in concentrations of superoxide dismutase in any of the experimental groups. Only in the interval group a decrease in malondialdehyde regarding control group and baseline (p<0.05) was observed. In addition, only in the interval group there was an increase in glutathione peroxidase compared to the group of continuous aerobic training and baseline (p<0.05). Nitric oxide showed a significant increase regarding the control, continuous aerobic group and baseline (p<0.05) in the interval training group. CONCLUSIONS: Despite the fact that both training groups show improvements over markers of lipid profile and fitness, high intensity interval training has shown to be more effective in the normalization of oxidative stress, impacting positively on the concentration of pro-oxidant markers and antioxidants.

INTRODUCCIÓN : El estrés oxidativo es causado por un desequilibrio entre una excesiva producción de especies reactivas de oxígeno y/o un déficit en el nivel de defensas antioxidantes endógenas y exógenas. La presencia de especies reactivas de oxígeno en grandes cantidades y por tiempos prolongados, se asocia a la aparición de diversas patologías, entre ellas la diabetes mellitus tipo 2. El ejercicio físico representa un medio efectivo para la prevención y el tratamiento de la diabetes mellitus tipo 2, también es capaz de reducir los niveles de estrés oxidativo a largo plazo. El entrenamiento interválico de alta intensidad ha mostrado ser una opción eficaz y viable en el control de la diabetes mellitus tipo 2. A su vez, el entrenamiento interválico de alta intensidad parece tener efectos positivos sobre los niveles de estrés oxidativo, aumentando los niveles de antioxidantes endógenos. OBJETIVO: Comprobar la validez y aplicabilidad de los resultados en la efectividad que presenta el entrenamiento interválico de alta intensidad, en comparación con el entrenamiento continuo de moderada intensidad en la reducción del estrés oxidativo de pacientes con diabetes mellitus tipo 2. También se busca responder a la siguiente interrogante: en pacientes adultos con diabetes mellitus tipo 2, ¿puede el entrenamiento interválico de alta intensidad, en comparación con el entrenamiento continuo de moderada intensidad, reducir los niveles de estrés oxidativo? MÉTODOS: Se analizó críticamente el artículo “Entrenamiento continuo versus interválico en el control glicémico y la reactividad macro y microvascular en pacientes con diabetes tipo 2”. RESULTADOS: No se observaron cambios estadísticamente significativos en las concentraciones de superóxido dismutasa en ninguno de los grupos experimentales. Sólo en el grupo de entrenamiento interválico se observa una disminución significativa de malondialdehído en comparación al grupo control y a los niveles basales (p<0,05). Respecto a la enzima glutatión peroxidasa sólo en el grupo de entrenamiento interválico se observaron cambios significativos en comparación al grupo de entrenamiento aeróbico continuo y a los niveles basales (p<0,05). El óxido nítrico aumentó significativamente en el grupo de entrenamiento interválico respecto del grupo control, del grupo aeróbico continuo y del inicio del estudio (p<0,05). CONCLUSIÓN: Si bien en ambos grupos de entrenamiento se observaron mejoras respecto de marcadores de perfil lipídico y de la condición física general, el entrenamiento interválico de alta intensidad mostró ser más efectivo en la normalización del estrés oxidativo, incidiendo de forma positiva en la concentración de marcadores pro-oxidantes y antioxidantes.

[Effect of high-intensity interval training on the reduction of glycosylated hemoglobin in type-2 diabetic adult patients]. / Efectividad del entrenamiento interválico de alta intensidad en la reducción de la hemoglobina glicosilada en pacientes adultos con diabetes mellitus tipo 2.

INTRODUCTION: Type 2 diabetes mellitus is one of the major non-communicable chronic diseases in the world. Its prevalence in Chile is significant, and complications associated with this disease involve great costs, which is why prevention and treatment of this condition are essential. Physical exercise is an effective means for prevention and treatment of type 2 diabetes mellitus. The emergence of new forms of physical training, such as "high intensity interval training", presents novel therapeutic alternatives for patients and health care professionals. OBJECTIVE: To assess the validity and applicability of the results regarding the effectiveness of high intensity interval training in reducing glycosylated hemoglobin in adult patients with type 2 diabetes mellitus and answer the following question: In subjects with type 2 diabetes, can the method of high intensity interval training compared to moderate intensity exercise decrease glycosylated hemoglobin? METHODS: We performed a critical analysis of the article "Feasibility and preliminary effectiveness of high intensity interval training in type 2 diabetes". RESULTS: We found no significant differences in the amount of glycosylated hemoglobin between groups of high intensity interval training and moderate-intensity exercise upon completion of the study (p>0.05). CONCLUSION: In adult patients with type 2 diabetes mellitus, high intensity interval training does not significantly improve glycosylated hemoglobin levels. Despite this, the high intensity interval training method shows as much improvement in body composition and physical condition as the moderate intensity exercise program.

INTRODUCCIÓN: La diabetes mellitus tipo 2 es una de las principales enfermedades crónicas no transmisibles presentes en el mundo. Su prevalencia en Chile es considerable y las complicaciones asociadas a esta patología implican un gran gasto económico, razón por la cual la prevención y el tratamiento de esta afección son fundamentales. El ejercicio físico representa un medio eficaz en la prevención y tratamiento de la diabetes mellitus tipo 2. El surgimiento de nuevas modalidades de entrenamiento, como el entrenamiento interválico de alta intensidad, presenta nuevas alternativas para pacientes y profesionales de la salud en el tratamiento de esta enfermedad. OBJETIVO: Comprobar la validez y aplicabilidad de los resultados con respecto a la efectividad del entrenamiento interválico de alta intensidad en la reducción de la hemoglobina glicosilada en pacientes adultos con diabetes mellitus tipo 2 y responder la siguiente interrogante: en sujetos con diabetes tipo 2, ¿puede el método de entrenamiento interválico de alta intensidad, en comparación al ejercicio de moderada intensidad, disminuir la hemoglobina glicosilada? MÉTODOS: Se analizó críticamente el artículo "Viabilidad y eficacia preliminar de entrenamiento de intervalos de alta intensidad en la diabetes tipo 2". RESULTADOS: No existen diferencias significativas en la cantidad de hemoglobina glicosilada entre los grupos de entrenamiento interválico de alta intensidad y el ejercicio de moderada intensidad al finalizar el estudio (p>0,05). CONCLUSIÓN: En pacientes adultos con diabetes mellitus tipo 2, el entrenamiento interválico de alta intensidad no mejora significativamente los niveles de hemoglobina glicosilada. A pesar de esto, el entrenamiento interválico de alta intensidad muestra mejoras significativas en cuanto a la composición corporal y a la condición física, similares al método continuo de moderada intensidad.

Efectividad de ejercicio físico intervalado de alta intensidad en las mejoras del fitness cardiovascular, muscular y composición corporal en adolescentes: una revisión / High intensity interval training in teenagers

This review analyzes the effects of high intensity interval training (HIIT) on muscle and cardiovascular fitness and body composition in teenagers. A search was carried out in international databases, finding 145 papers and selecting five for analysis. In all the reviewed manuscripts, peak oxygen uptake improved after HIIT. In the three manuscripts that measured muscle strength, it also increased. We conclude that HIIT improves muscle strength and cardiovascular fitness in school age children. A 12 weeks protocol with three 12-minute sessions per week would be ideal.

Efecto del ejercicio físico sobre marcadores de estrés oxidativo en pacientes con diabetes mellitus tipo 2 / Exercise and oxidative stress in type 2 diabetes mellitus

Sedentarism, overweight and malnutrition generate an increase in the production of reactive oxygen species leading to a state of chronic oxidative stress. In patients with type 2 diabetes mellitus, oxidative stress alters pancreatic insulin secretion and the actions of the hormone on target cells, contributing to the development of micro and macrovascular complications. During physical exertion a state of transient oxidative stress occurs. As a consequence, the organism generates multiple physiological adaptations to these repetitive stimuli. Physical exercise is beneficial for type 2 diabetes mellitus but there is a paucity of information about the effects of physical exercise on biomarkers of oxidative stress in patients with the disease. We herein try to elucidate if the effects of exercise on oxidative stress can help in the prevention and treatment of type 2 diabetes mellitus and which is the most effective modality of physical exercise to reduce oxidative stress markers.

[Not Available]. / Patrones alimentarios de ultramaratonistas chilenos.

Objetivo: determinar los patrones alimentarios de ultramaratonistas chilenos. Métodos: estudio descriptivo transversal, con enfoque cuantitativo. La muestra incluyó 20 ultramaratonistas (n = 3 mujeres), quienes promediaban para la edad 33,0 ± 7,8 años, peso 71,1 ± 6,6 kg y estatura 1,72 ± 0,05 m. Se aplicó una encuesta de hábitos alimentarios validada y un punto de significación de p < 0,05. Resultados: los ultramaratonistas chilenos presentan bajo consumo de alimentos de acuerdo a las porciones recomendadas de frutas, verduras, pescado y leguminosas, y el 75% de ellos consume desayuno diariamente. Se observa ingestas moderadas de bebidas azucaradas, snacks dulces y alcohol, mientras que la ingesta de frituras (65%) corresponde al hábito no saludable más frecuente. Conclusión: los ultramaratonistas chilenos presentan un bajo cumplimiento en las porciones recomendadas de alimentos, pese al gran esfuerzo físico que realizan.