Dietas basadas en plantas y factores de riesgo cardio-metabólicos. ¿Qué dice la evidencia?

RESUMEN Las dietas basadas en plantas (DBP) se caracterizan por una alta ingesta de alimentos de origen vegetal y evitan parcial o totalmente los productos animales. El objetivo de esta revisión fue recopilar evidencia sobre DBP, sus tipos y su efecto en principales factores de riesgo cardio-metabólicos (FRCM) modificables. Se encontró que existen DBP saludables y no saludables. Algunas DBP saludables son: vegetariana, mediterránea y DASH (sigla en inglés de la dieta Enfoques Alimenticios para Detener la Hipertensión). Estas promueven la ingesta de alimentos de origen vegetal "saludables" (frutas, verduras, legumbres, semillas, frutos secos, cereales integrales, palta, aceite de oliva y/o canola) y, una reducción gradual de todos los alimentos de origen animal, especialmente carnes rojas y procesadas; evitando alimentos de origen vegetal "menos saludables" (cereales refinados, fritos, productos de pastelería, alimentos con azúcar añadido). Las DBP no saludables, se caracterizan por una alta ingesta de estos alimentos "menos saludables", y se asocian con mayor riesgo cardiovascular, por el bajo aporte de antioxidantes, micronutrientes, fibra dietética y grasas insaturadas. DBP saludables pueden disminuir el riesgo de diabetes tipo 2, hipertensión arterial, sobrepeso y obesidad. Han mostrado mayores beneficios cardiovasculares en comparación con dietas tradicionales, reduciendo significativamente: HbA1c y glicemia en ayunas en diabéticos; presión arterial sistólica y diastólica en hipertensos y prehipertensos; índice de masa corporal en sujetos con sobrepeso/obesidad y mejorando el perfil lipídico en sujetos con dislipidemia. Patrones de DBP saludables, como el tipo vegetariano, mediterráneo y DASH son recomendadas para prevenir y tratar los FRCM.

ABSTRACT Plant-based diets (PBD) are characterized by a high intake of foods of plant origin and the partial or total avoidance of animal products. The objective of the current study was to compile the evidence on types of PBD and its effect on the main modifiable cardio-metabolic risk factors (CMRF). Healthy and unhealthy PBD were found to exist. Some healthy PBDs were: vegetarian, mediterranean and DASH (Dietary Approaches to Stop Hypertension). These promote the intake of "healthy" plant-based foods (fruits, vegetables, legumes, seeds, nuts, whole grains, avocado, olive oil and / or canola) and a gradual reduction of all foods of animal origin, especially red and processed meats; avoiding "less healthy" plant-based foods (refined, fried cereals, pastry products, foods with added sugar). Unhealthy PBDs were characterized by a high intake of these "less healthy" foods, and are associated with greater cardiovascular risk, due to the low contribution of antioxidants, micronutrients, dietary fiber and unsaturated fats. Healthy PBDs can lower the risk of type 2 diabetes, high blood pressure, being overweight, and obesity. They have shown greater cardiovascular benefits compared to traditional diets, significantly reducing: HbA1c and fasting glycemia in diabetics; systolic and diastolic blood pressure in hypertensive and prehypertensive patients; body mass index in overweight / obese subjects and improves lipid profile in subjects with dyslipidemia. Healthy PBD patterns, such as vegetarian, Mediterranean, and DASH are recommended to prevent and treat CMRF.

Validación y generación de ecuaciones para estimar masa grasa corporal en adultos chilenos, formuladas a partir de bioimpedanciometría, en un amplio rango de edad e índice de masa corporal

Background: Equations for the evaluation of fat-free mass (FFM) and fat mass (FM) with Bioelectrical impedance analysis (BIA) were formulated in Caucasian populations. International recommendations suggest that population-specific equations should be formulated. Aim: To validate an equation previously formulated in Chileans adults and compare it to a new equation generated on an independent sample. Material and Methods: In 108 adult volunteers aged 38.1±14.1 years (44% males), with a body mass index (BMI) of 25.1± 4.1 kg/m2, body composition was measured by BIA (Bodystat) and dual X-ray absorptiometry (DXA: Lunar Prodigy). Body composition estimated using Schifferli equation and BIA were compared with DEXA, by the Bland-Altman method and simple linear regression. Results: FFM and FM measured by DXA were 45.2 ± 9.8 kg and 29.6 ± 11.7 % respectively. Resistance was 467.7 ± 76.3 ohm. Schifferli equation and BIA significantly overestimated FFM by 7.3 and 7.4 kg, respectively. The error was higher for high levels of FFM (slope β < 1, p < 0.01). Both equations underestimated FM measured by DXA (averages of 7.5 and 7.8%, respectively, p < 0.01), without a differential bias for Schifferli equation, but with a bias in low levels of FM measured with BIA (slope β < 1, p < 0.01). Estimation biases could be eliminated using the regression coefficients. Conclusions: Both equations behave similarly and have biases, although less with Schifferli. Statistically correcting for biases, the new adjusted equations provide clinically valid estimates of FFM and FM. Equations should not only be population-specific, but also device-specific.

Factores de riesgo cardiovascular en universitarios de primer y tercer año / Cardiovascular risk factors among first and third year university students

Background: College students are in a critical stage in their life style due to the transition between high school and university and they may be prone to develop cardiovascular diseases. Aim: To compare the prevalence of cardiovascular risk factors (CVRF) in students from first and third year at the University of La Frontera, Temuco-Chile, according to faculty, gender and socioeconomic status (SES). Material and Methods: Cross-sectional study. Anthropometry, blood pressure, lipid profile, blood glucose, insulin resistance (IR), sedentary lifestyle, tobacco and alcohol consumption were evaluated during 2014 in randomly selected 163 freshmen aged 19.2 ± 1.8 years and 163 third year students aged 21.7 ± 2.5 years (49% females), stratified by faculty, career and gender. Results: 32.4% of students had prehypertension, 30.6% abdominal obesity, 26.3% insulin resistance, 25.7% dyslipidemia and 8.9% metabolic syndrome. Third grade students had higher prevalence of elevated total and LDL cholesterol and higher alcohol consumption, especially among students of middle and high socioeconomic level. Compared with students from the School of Medicine, students from the Education Faculty had 3.9, 3.3 and 2.7 times greater likelihood of being obese, having elevated LDLcholesterol and being smokers, respectively. Women had the highest prevalence of sedentary lifestyles and dyslipidemia. Men had the highest prevalence of prehypertension and smoking. Conclusions: Educational programs are required to promote healthy lifestyles among these students.

Ejercicio físico interválico de alta intensidad mejora el control glicémico y la capacidad aeróbica en pacientes con intolerancia a la glucosa / High intensity interval training improves glycemic control and aerobic capacity in glucose intolerant patients

Background: Proper exercise training modifies intra miocellular energy utilization, glucose transport and mitochondrial biogenesis. Aim: To determine the therapeutic effects of a high intensity intermittent training (HIIT) program on glucose homeostasis, physical fitness and body fat in glucose intolerant patients. Patients and Methods: Eighteen patients with overweight or obesity and glucose intolerance were invited to participate in an exercise program consisting in three sessions per week for 3 months. Ten participants aged 35 ± 13 years who attended > 26 of the planned 36 sessions, were considered as adherent to exercise. The other eight participants aged 37 ± 17 years, who attended to a mean of 13 sessions, were considered as non-adherent. Both groups had similar body weight, body mass index, body fat, plasma glucose 2 h after an oral glucose load and maximal oxygen uptake. All these variables were measured at the end of exercise intervention. Each session consisted of 1 min exercise of cycling at maximal intensity until muscle fatigue followed by 2 min rest, repeated 10 times. Results: Among adherent participants, twelve weeks of HIIT improved signifcantly maximal oxygen uptake (6.1 + 3.6 mL/kg/min or 24.6%), reduced 2 h post load blood glucose (-33.7 + 47.9 mg/dL or -12.5%) and body fat (-4.3 + 5.6 kg). No signifcant changes were observed in the non-adherent group. Conclusions: HIIT exercise reduces blood glucose after an oral load in glucose intolerant patients.

Formulación de una ecuación para predecir la masa grasa corporal a partir de bioimpedanciometría en adultos en un amplio rango de edad e índice de masa corporal / Formulation of an equation to predict fat mass using bioelectrical impedance in adults in a wide range of ages and body mass index

Background: Bioelectrical impedance (BIA) has a good correlation and agreement with reference techniques, such as dual energy X-ray absorptiometry (DEXA), to assess body composition. Aim: To develop and assess the concordance of an equation to predict body fat mass derived from anthropometric data, gender, age and resistance obtained from bioelectrical impedance in adults, using DEXA as the reference method. Patients and Methods: Cross-sectional study of 62 women and 59 men aged 18 to 64 years with a body mass index ranging from 18.5 to 34.8 kg/ m². The equation was constructed using a predictive statistical model, considering sex, age, weight, resistance index (height²(cm)/ resistance (ohms)), as independent variables, and fat mass as the dependent variable. Results: The R² of the regression model was 0.96, and the standard error of estimation was 2.58 kg (p < 0.001). When comparing with DEXA, no significant differences were observed for the estimation of FM, between the equation developed in this work and that proposed by the manufacturer of the BIA equipment. However, the latter equation, underestimated FM by -2.5 ± 9.5% (p > 0.05) and - 4.5 ± 8,9% (p < 0.05) in both genders and in women, respectively. Conclusions: The concordance between estimation of fat mass by the formula developed in this work and by DEXA was better than the estimation obtained using the formula proposed by the manufacturer of the BIA equipment.