La suplementación con zinc reduce la concentración de ácidos grasos libres en pacientes con diabetes tipo 2

RESUMEN Elevadas concentraciones de ácidos grasos libres (AGL) han sido asociadas con la patogénesis de resistencia a la insulina y diabetes tipo 2 (DT2), por lo que la regulación de la lipólisis resulta prioritaria en estos pacientes. El zinc mediante sus acciones insulinomiméticas e inducción de fosfodiesterasas podría regular la liberación de AGL desde el tejido adiposo. El objetivo de esta investigación fue evaluar en pacientes con DT2 el efecto de 24 meses de suplementación con zinc sobre las concentraciones séricas de AGL en ayuno. Para este propósito: se realizó la determinación de AGL en ayuno por colorimetría enzimática, zinc plasmático por espectrofotometría de absorción atómica, y parámetros bioquímicos y antropométricos de interés en 60 pacientes con DT2 que fueron asignados aleatoriamente para recibir suplementación con 30 mg/día de zinc (n= 30) o placebo (n= 30) por 24 meses. El grupo zinc presentó menor concentración sérica de AGL al mes 24 (p = 0,034). El cambio en el índice de masa corporal, el sexo y la suplementación con zinc contribuyeron significativamente como predictores de la concentración sérica de AGL al mes 24 (R= 0,493, R2= 0,243, p= 0,001). Conclusión: la suplementación con 30 mg/día de zinc en pacientes con DT2 tuvo un efecto significativo en reducir la concentración sérica de AGL en ayuno tras 24 meses de tratamiento. Estos resultados apoyan los beneficios del zinc como coadyuvante en el tratamiento de DT2.

ABSTRACT High concentrations of free fatty acids (FFA) have been associated with the pathogenesis of insulin resistance and type 2 diabetes (T2D), making lipolysis regulation a priority in these patients. Through its insulin-mimetic actions and phosphodiesterase induction, zinc could regulate FFA release from adipose tissue. The objective of this research was to evaluate the effect of 24 months of zinc supplementation on fasting serum FFA concentrations in patients with T2D. For this purpose: fasting FFA by enzymatic colorimetric, plasma zinc by atomic absorption spectrophotometry, and biochemical and anthropometric parameter of interest were determined in 60 T2D patients who were randomly assigned to 30 mg/day of zinc supplementation (n= 30) or placebo (n= 30) for 24 months. The zinc group had lower serum FFA concentration at month 24 (p= 0.034). Body mass index change, gender, and zinc supplementation contributed significantly as predictors of serum FFA concentration at month 24 (R= 0.493, R2= 0.243, p= 0.001). Conclusion: Supplementation with 30 mg/day of zinc in patients with T2D had a significant effect in reducing serum fasting FFA concentration after 24 months of treatment. These results support the benefits of zinc as coadjutant in T2D treatment.

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.

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.

Calidad de la alimentación de mujeres con obesidad severa y mórbida sometidas a bypass gastrico y gastrectomia vertical en manga

El objetivo de este estudio fue comparar la ingesta de energía y nutrientes y la calidad de la alimentación, en pacientes sometidos a bypass gástrico en Y de Roux y (BPGYR) y gastrectomía vertical en manga (GVM). En 36 mujeres con obesidad severa y mórbida se estudió la alimentación previa y a los 6 meses posteriores a la cirugía, mediante encuesta de registro de tres días, se analizó el grado de adecuación e índice de calidad nutricional (ICN). Se controló estrictamente el consumo de suplementos de vitaminas y minerales. El consumo de energía y nutrientes fue significativamente menor al sexto mes post cirugía comparado con el preoperatorio, sin diferencias significativas entre grupos, excepto calcio y vitamina C. El ICN fue similar entre grupos. La ingesta dietética de calcio, hierro, zinc, cobre, ácido fólico, vitamina C y E fue menor al 100% de adecuación al 6º mes. Sin embargo, al considerar en conjunto el aporte de la dieta como de los suplementos, la adecuación de prácticamente todos los nutrientes estudiados sobrepasa el 100% en ambos grupos, logrando una mayor adecuación el grupo sometido a BPGYR. Las excepciones las constituyen el calcio, el cual no alcanza a cubrir el 100% en ningún grupo y el ácido fólico en el grupo sometido a GVM. En conclusión, estos pacientes presentan reducciones importantes de la ingesta dietética de energía y micronutrientes, sin mayores diferencias dependientes del tipo de cirugía. Las características de los suplementos son críticos para lograr la cobertura de las necesidades.

The objective of this study was to evaluate the changes of dietary intake and quality of the diet in patients undergoing gastric bypass and sleeve surgery. In 36 women with severe and morbid obesity it was assessed their nutrient intakes and dietary quality before and 6 months after bariatric surgery through three-day food records. Vitamin and mineral intakes from supplements were strictly controlled. Energy and nutrient intakes were significantly decreased 6 months after surgery bypass compared to the pre-surgery period, with the exceptions of calcium and vitamin C. No differences were observed between groups. The Dietary quality index was also similar in both groups. Dietary intakes of calcium, iron, zinc, copper, folic acid, vitamin C, and vitamin E were below 100% of adequacy from at the 6th month after the surgery. Nevertheless, by considering both diet and supplements supply, nutrient adequacy of all but calcium and folic acid was above 100% in both groups. Gastric bypass patients presented greater values. In conclusion, these patients present an important reduction of their energy and nutrient intakes, with no major impact of the type of surgery. Supplement characteristics are crucial to cover nutritional needs.

Evolución y calidad de la alimentación de mujeres con obesidad severa y mórbida sometidas a bypass gástrico / Evolution and quality of the diet of women with severe and morbid obesity undergoing gastric bypass

El objetivo de este estudio fue evaluar los cambios en la ingesta energía y nutrientes y el grado de suficiencia de la alimentación en pacientes sometidos a bypass gástrico. En 44 mujeres con obesidad severa y mórbida se estudió la alimentación previa y a los 6, 12 y 18 meses después de realizada la intervención quirúrgica mediante encuesta de registro de tres días. El consumo de suplementos de vitaminas y minerales se controló estrictamente mediante el registro individualizado de su consumo. Con la excepción de la ingesta de calcio y vitamina A, el consumo de energía y nutrientes fue significativamente menor a los 6, 12 y 18 meses post cirugía comparado con el período preoperatorio. La ingesta dietética de calcio, hierro, zinc, cobre, ácido fólico, vitamina C y vitamina E estuvo por debajo del 100 por ciento de adecuación a partir del 6º mes post operatorio, situación que se revierte al considerar el consumo de estos nutrientes a partir de los suplementos. Aun cuando se observó una tendencia a una curva en “U” en la ingesta de micronutrientes durante el período experimental, en la mayoría de ellos las diferencias entre los valores obtenidos a los meses 12 y 18 no fue significativa. En conclusión, estos pacientes presentan reducciones importantes de la ingesta dietética de energía y micronutrientes. El consumo rutinario de suplementos podría revertir esta situación, sin embargo, las alteraciones anatómicas inherentes a esta intervención podrían producir que cifras de adecuación ligeramente superiores al 100 por ciento sean, en la práctica, insuficientes para asegurar que no se desarrollen cuadros de deficiencia.

The objective of this study was to evaluate the changes of dietary intake and quality of the diet in patients undergoing gastric bypass. In fortyfour women with severe and morbid obesity it was assessed their nutrient intakes before and 6, 12, and 18 months after gastric bypass by using three-day food records. Vitamin and mineral intakes from supplements were strictly controlled though personalized records. With the exceptions of calcium and vitamin A, energy and nutrient intakes were significantly decreased at 6, 12, and 18 month after bypass compared to the pre-surgery period. Dietary intakes of calcium, iron, zinc, copper, folic acid, vitamin C, and vitamin E were below 100 percent of adequacy from the 6th month after the surgery and thereafter. This situation is reverted when nutrient intakes supplied by supplements are taken into account. Although a “U” shape trend was observed in the nutrient intakes results during the experimental period, in most cases the differences between the observed values at month 12 and 18 were not significant. In conclusion, these patients had important reductions of their energy and nutrient intakes as result of gastric bypass. Routine supplements may correct this situation, nevertheless, the anatomical alterations inherent to this type of surgery may cause that total nutrient intakes reaching adequacy values slightly above 100 percent, may not necessarily be able to avoid the development of nutritional deficiencies.