High-intensity interval training prevents muscle mass loss in overweight Chilean young adults during a hypocaloric-Mediterranean diet: a randomized trial.

The hypocaloric Mediterranean diet (MD) mainly reduces fat mass but inevitably causes a loss of skeletal muscle mass. High-intensity interval training (HIIT) seems to have advantages in preserving muscle mass during a hypocaloric regime. Our study compares body composition and metabolic changes in overweight and obese Chilean women and men after 3 months of weight loss treatment with a Mediterranean-type hypocaloric diet, HIIT, or a combination of both. The study included 83 overweight or obese women and men between the ages of 25 and 50. The subjects were randomly assigned to one of the three intervention groups: (1) MD, (2) EX, and (3) MD + EX. Baseline and post-intervention measurements included: (a) body composition by dual-beam densitometry, muscle, and fat measurements by thigh ultrasound and computed tomography; (b) handgrip and quadriceps muscle strength; (c) exercise performance by peak oxygen consumption, peak load, work efficiency, and exercise energy expenditure; and (d) metabolic parameters. Out of 83 participants, the retention rate was 49% due to low compliance with the interventions. As expected, the MD group resulted in significantly greater weight loss (MD -7%, EX -0.6% and MD + EX -5.3%) and appendicular fat mass loss (MD -11.1%, EX -2.9, MD + EX -10.2%) but was associated with significant lean tissue loss (2.8%), which was prevented by HIIT (EX -0.1 and MD + EX -0.6%). Metabolic and glycoxidative parameters remained unchanged, irrespective of changes in body composition. Hypocaloric diets remain the most effective means to lose weight and body fat. However, it induces a loss of lean body mass when not accompanied by exercise training. This study shows that HIIT prevents the loss of muscle mass caused by a hypocaloric Mediterranean diet.

Nutritional assessment by subjective methods versus computed tomography to predict survival in oncology patients.

OBJECTIVES: The aim of this study was to analyze the association between survival and two validated methods of nutritional assessment: body composition through computed tomography (CT) scans and Patient-Generated Subjective Global Assessment (PG-SGA). METHODS: Cancer-bearing patients (n = 103) hospitalized in the Oncology Ward of Clínica Alemana in Santiago, Chile, for palliative or curative treatment were assessed by both methods. Images from abdominal CT scans at the L3 level were analyzed by SliceOmatic (version 5.0), to measure muscle and fat areas and densities. Skeletal muscle mass index (MMI) was calculated using total abdominal mass area (psoas + rest of muscles)/ height2. These were compared with those obtained for assessment of trauma of 130 healthy young adults (18-40 y of age), as reference control values. Sarcopenia was established as MMI<1 SD compared with control participants. RESULTS: Patients with cancer had less muscle and higher abdominal fat areas compared with controls (P < 0.05). According to the PG-SGA, ~50% were classified as malnourished. Patients were followed for 38 mo, when 53% had died. Survival time was significantly and negatively correlated with PG-SGA score, cancer stage, and sarcopenia, independent of age and sex. Multivariate analysis included both cancer stage and nutritional assessment variables. CONCLUSIONS: Together with cancer stage, both CT measurements and subjective assessment of nutritional status through PG-SGA can adequately identify cancer patients with a higher mortality risk, independent of age and sex. However, the latter is less costly and simple to use; it should be included as a valuable tool during management of patients with cancer.

Sarcopenia: The need to establish different cutoff points of fat-free mass for the Chilean population.

OBJECTIVES: International cutoff points for the diagnosis of sarcopenia are not applicable to the Chilean population due to previous evidence of a lower lean mass and strength in this population. Dual-energy x-ray absorptiometry is used to establish fat-free mass cutoff points to define sarcopenia in the Chilean population and analyze its association with handgrip strength in older adults. METHODS: Appendicular fat-free mass (AFFM) was calculated from 4062 dual-energy x-ray absorptiometries of healthy Chileans, ages 18 to 99 y. Possible cutoff points for sarcopenia were obtained using four methods: A) Normative, -2 standard deviation (SD) below mean AFFM/height2 (AFFMI) of adults age <40 y; B) normative -1 SD, -1 SD under the average AFFMI of adults age <40 y; C) stratification, 25th percentile of the residual distribution obtained with the regression equation to predict AFFM in the entire sample; and D) percentage, -2 SD under the average skeletal muscle mass/total body mass of individuals age <40 y. Additionally, in a subsample of elderly subjects, the correlation between handgrip strength and the four calculated cutoff points was analyzed. RESULTS: Using the normative method, sarcopenia was defined as an AFFMI <6.4 kg/m2 in men and <4.8 kg/m2 in women and at -1 SD, the cutoff points were <7.5 kg/m2 and <5.6 kg/m2, respectively. With the stratification method, sarcopenia was defined as -1.33 kg and -1.05 kg of AFFM with respect to the expected value according to the regression equation in men and women, respectively. According to the percentage method, the cutoff points for sarcopenia were <30% and <22.9% in men and women, respectively. The concordance of the four methods was slight to moderate. Only the percentage method showed a progressive increase in the proportion of subjects with sarcopenia as age increased. The latter and the normative -1 DS predicted lower handgrip strength in elderly women, unlike the other diagnostic methods. For elderly men, only the normative -1 DS method predicted weaker handgrip strength. CONCLUSIONS: The AFFM of young Chileans is lower than that reported in Western countries but similar to Latin American data; therefore, the use of the traditional normative method would not be appropriate with -2 SD to establish cutoff points, and using -1 DS resulted in values that are higher than Baumgartner's. Stratification is advantageous because this method throws expected values of AFFM for each population; however, overdiagnosis of sarcopenia is a possibility and thus the method requires a representative sample. The percentage method is simple and showed the expected decrease of muscle mass with age, and also correlated well with handgrip strength in elderly women. Thus, this method represented our method of choice to detect sarcopenia.

Association between activity energy expenditure and peak oxygen consumption with sarcopenia.

BACKGROUND: Sedentariness may be an important risk factor for sarcopenia. The aim of this work was to assess the association between muscle mass and strength and markers of usual physical activity such as activity energy expenditure and peak oxygen uptake. METHODS: Young and old participants were assessed measuring body composition by DEXA (double beam X ray absorptiometry), handgrip strength, peak oxygen consumption and workload during an exercise calorimetry in a braked cycle ergometer and a 72 h activity energy expenditure using Actiheart actigraphs. A heart rate/energy expenditure curve derived from the exercise calorimetry was used to calibrate each actigraph. Sarcopenia was defined as having an appendicular fat free mass index below 7.5 kg/m2 and 5.6 kg/m2 in men and women respectively, or a handgrip strength z score below 1, using local normal data or having both parameters below the cutoff points. RESULTS: We analyzed data from 192 assessments performed in participants aged 22 to 88 years (106 women). Sarcopenic participants (as determined by muscle mass, strength or both) had a significantly lower peak oxygen uptake and work load and a significantly lower activity energy expenditure. When analyzing lean mass and strength as continuous variables, peak oxygen consumption was a significant predictor of fat free mass in men. Among women, the association was observed only when percentage of muscle mass was expressed as a z score. CONCLUSIONS: Activity energy expenditure and peak oxygen consumption are associated with a lower muscle mass and the presence of sarcopenia and should be considered as risk factors for this condition.

Maximal expiratory pressure predicts mortality in patients hospitalized in medical and surgical wards.

BACKGROUND: the prognostic value of maximal inspiratory and expiratory pressures on functional capacity and mortality of hospitalized patients are not well established. AIM: to evaluate the prognostic value of respiratory pressures in hospitalized patients. METHODS: patients admitted to a general hospital in Santiago-Chile were prospectively studied. Within 48 hours of admission, handgrip strength and inspiratory and expiratory pressures were measured. Subjective global assessment of nutritional status (SGA) was determined and Apache II score was calculated. Functional status was assessed using the Karnofski index. Patients were followed for a period of 30 days. Mortality and decline in functional capacity, defined as a reduction in at least two stages of the Karnofski index were determined. Normal values for handgrip strength and respiratory pressures were obtained in 366 healthy subjects aged 20 to 89 years, thus the results obtained in patients were expressed as age and sex matched z-scores. RESULTS: one hundred and eight patients were recruited and 18 had to be excluded. Thus, 90 patients aged 58 ± 16 years (46 females) were studied. During the observation period, six patients died and nine experienced a decline in functional status. Patients who died had significantly lower maximal inspiratory and expiratory pressures, hand grip strength and worse SGA. Logistic regression analysis only accepted maximal expiratory pressure expressed as z-score as a predictor of mortality. In addition, it was the only significant predictor of death or functional decline. CONCLUSIONS: maximal expiratory pressure on admission was a predictor of death or functional decline at 30 days.

Comparative evaluation of three different ELISA assays and HPLC-ESI-ITMS/MS for the analysis of Nε-carboxymethyl lysine in food samples.

Nε-carboxymethyl-lysine (CML) is measured in food, but there is a controversy concerning the most convenient yet reliable method(s) for this task. This work compares three different ELISA assays and HPLC-ESI-ITMS/MS for the analysis of CML in several food items. The four methods showed the same decreasing order of CML concentration: beef, bacon>chicken > fish>dairy products>grain products>fruits/vegetables. HPLC-ESI-ITMS/MS results highly correlated with those obtained by ELISA performed with monoclonal CML-antibody (ß=0.98, p<0.0001) whereas My Bio Source® kit results were not correlated with those provided by Lamider®. Small differences of CML concentrations in food items prepared by different culinary treatment were clearly distinguished by HPLC-ESI-ITMS/MS, but could not always be detected by ELISA. This work demonstrates a reasonable relationship between CM determined by ELISA and HPLC-ESI-ITMS/MS and therefore supports the implementation of ELISA in food CML/AGEs screening.

Effects of Two Training Modalities on Body Fat and Insulin Resistance in Postmenopausal Women.

Henríquez, S, Monsalves-Alvarez, M, Jimenez, T, Barrera, G, Hirsch, S, de la Maza, MP, Leiva, L, Rodriguez, JM, Silva, C, and Bunout, D. Effects of two training modalities on body fat and insulin resistance in postmenopausal women. J Strength Cond Res 31(11): 2955-2964, 2017-Our objective was to compare the effects of a low-load circuit resistance training protocol and usual aerobic training in postmenopausal women. Postmenopausal women with at least 1 feature of the metabolic syndrome were randomly allocated to a low-load circuit resistance training protocol or traditional aerobic training in a braked cycle ergometer. The intervention consisted in supervised sessions lasting 40 minutes, 3 times per week, during 6 months. At baseline and at the end of the intervention, fasting serum lipid levels, serum interleukin 6, C-reactive protein, 8 isoprostanes, and insulin resistance (assessed through QUICKI and HOMA-IR) were measured. Body fat was measured by double-beam X-ray absorptiometry and by computed tomography densitometric quantification at lumbar 3 vertebral level. Twenty-one women aged 58 (54-59) years were allocated to aerobic training and 21 women aged 55 (52-61) years were allocated to the low-load circuit resistance training protocol. Eighteen and 16 women in each group completed the 6 months training period. Women in both groups experienced significant reductions in blood pressure, total body, subcutaneous, and intraabdominal body fat. Reductions in total cholesterol and triacylglycerol levels were also observed. No changes in insulin resistance indexes, 8 isoprostanes, C-reactive protein, or interleukin 6 were observed in either group. No significant differences between treatment groups were observed in any of the measured parameters. We conclude that low-load circuit resistance training and aerobic training resulted in the same reductions in body fat and serum lipid levels.

Irisin is weakly associated with usual physical activity in young overweight women

PURPOSE: To determine if irisin plasma levels are associated with regular physical activity, body composition and metabolic parameters in women subjected to calorie restriction. SUBJECTS AND METHODS: We studied 42 women aged 34 ± 13 years with a body mass index of 27.7 ± 1.8 kg/m2, who were subjected to a calorie restriction for three months. At baseline and at the end of the study, weight, waist and hip circumference, laboratory parameters, body composition by DEXA, resting and activity energy expenditure by indirect calorimetry and 72 hours actigraphy were measured. Fasting serum irisin was quantified using an ELISA kit. RESULTS: After the intervention period, participants lost 1.5 (0.4-3.4) kg and irisin levels did not change. Irisin baseline levels were positively but weakly correlated with the level of physical activity. This association was lost at the end of the intervention. No association was found between irisin levels and body composition or insulin sensitivity or their changes after calorie restriction. No association between serum irisin levels and PGC-1αexpression in peripheral blood mononuclear cells and serum irisin was observed. CONCLUSIONS: Fasting serum irisin was weakly associated with usual physical activity and did not change after calorie restriction.

Admission handgrip strength predicts functional decline in hospitalized patients.

PROBLEM: Up to 35% of hospitalized patients may experience functional decline during or after hospitalization. Subjective Global Assessment (SGA) and handgrip strength at admission, have been proposed as simple and accessible tools to predict functional decline, but there are few studies in hospitalized patients to confirm these findings. OBJECTIVE: To assess the predictive value of handgrip strength at hospital admission, on functional decline after 30 days. METHODS: 125 non-critical patients hospitalized for medical and surgical conditions, were studied in El Pino hospital in Santiago, Chile. Upon admission, nutritional status was assessed by SGA, functional status through the Karnofsky index (KI), and handgrip strength by dynamometry. Change in functionality was assessed by the difference between KI at admission and 30 days later. Multivariate logistic regression models were used to establish associations between the variables at hospital admission, and subsequent functional decline. RESULTS: Thirty days post-hospital admission, 28.8% of the sample showed functional decline. In a multivariate analysis, only handgrip strength was associated with this decline (ß = -0.025, OR = 0.974 (CI 0.956-0.992), p = 0.007). CONCLUSIONS: Handgrip strength upon hospital admission can be a useful independent and early method to predict deterioration of functional status during hospitalization.

Associations between socioeconomic status, aging and functionality among older women.

To assess if there is an association between socioeconomic status and quality of life, functional status and markers of aging, we studied 86 women aged 73 ± 7 years, who answered the WHO Qol Bref quality of life survey. Mini mental state examination, timed up and go test, 12 minutes' walk, hand grip and quadriceps strength, dual X-ray absorptiometry (DEXA), carotid intima-media thickness and telomere length in peripheral leukocytes were measured. Successful aging was defined as a walking speed, handgrip strength, appendicular lean body mass, timed up and go and minimental values above cutoff points for disability. Participants with successful aging had a higher quality of life score and were more likely to live in rich municipalities. There was a positive correlation between telomere length, right handgrip strength and total fat free mass. Therefore, there is an association between socioeconomic status, successful aging and quality of life.

FACTORS RELATED TO TOTAL ENERGY EXPENDITURE IN OLDER ADULTS (CHILE).

AIM: to asses Total Energy Expenditure (TEE) in healthy Chilean institutionalized or independently older people Methods: twenty seven young (27-30 years), 27 institutionalized (> 65 years old) and 27 free-living older (> 65 years old) participants were studied. Body composition was estimated by dual energy X-ray absorptiometry. Physical activity energy expenditure (AEE) and TEE were assessed using Actiheart accelerometers. The Mini Nutritional Assessment (MNA) was applied and Timed Up and Go (TUG) was measured. RESULTS: AEE was 171, 320 and 497 kcal/day in institutionalized, free living older and young participants, respectively (p < 0.01 between young and older participants). Both absolute TEE and TEE/RMR was higher in young people. Multiple regression analysis accepted age, MNA and TUG as significant predictors of AEE (r2 = 0.24 p < 0.01). CONCLUSION: AEE and PAL were lower among older people, with no differences by institutionalization.

Objetivo: evaluar el Gasto Energético Total (GET) en ancianos sanos que viven institucionalizados o independientes en Chile. Método: se evaluaron veintisiete jovenes (27-30 años), 27 adultos mayores institucionalizados (> 65 años ) y 27 ancianos independientes (> 65 años). Se midió la composición corporal utilizando absorciometría bifotónica de rayos X. Se calculó el gasto energético por actividad física (GEAF) y el gasto energético total (GET) utilizando acelerómetros Actiheart; se aplicó Mini Nutritional Assessment (MNA) y se midió el Timed Up and Go (TUG). Resultados: el GEAF fue 171, 320 y 497 kcal/día en ancianos institucionalizados, independientes y jóvenes, respectivamente (p.

Dietary advanced glycation end products and their role in health and disease.

Over the past 2 decades there has been increasing evidence supporting an important contribution from food-derived advanced glycation end products (AGEs) to the body pool of AGEs and therefore increased oxidative stress and inflammation, processes that play a major role in the causation of chronic diseases. A 3-d symposium (1st Latin American Symposium of AGEs) to discuss this subject took place in Guanajuato, Mexico, on 1-3 October 2014 with the participation of researchers from several countries. This review is a summary of the different presentations and subjects discussed, and it is divided into 4 sections. The first section deals with current general knowledge about AGEs. The second section dwells on mechanisms of action of AGEs, with special emphasis on the receptor for advanced glycation end products and the potential role of AGEs in neurodegenerative diseases. The third section discusses different approaches to decrease the AGE burden. The last section discusses current methodologic problems with measurement of AGEs in different samples. The subject under discussion is complex and extensive and cannot be completely covered in a short review. Therefore, some areas of interest have been left out because of space. However, we hope this review illustrates currently known facts about dietary AGEs as well as pointing out areas that require further research.

Rectus femoris (RF) ultrasound for the assessment of muscle mass in older people.

BACKGROUND: Simple and reliable methods to evaluate muscle mass in older people are lacking. AIM: To evaluate ultrasound as a measure of RF muscle mass and quality in healthy subjects of different ages and gender, assessing its concordance with dual energy X-ray densitometry (DEXA) and association with muscle strength and walking capacity. METHODS: We selected 54 adults of both genders, aged 20-55 years and 51 adults older than 60 years. Ultrasound images of the RF were obtained at the mid-thigh to measure its thickness and ultrasonographic density using a GE Logiq e equipment. Body composition was assessed by DEXA. Quadriceps isometric strength and 12 minutes' walk were also measured and gender specific t scores for older adults were calculated using the values obtained in adults. RESULTS: RF ultrasound measurements correlated significantly with lean body mass assessed by DEXA (Double energy X-ray absorptiometry). The concordance between both measures was also adequate. Older people had lower muscle mass and worse ultrasound parameters than adults. Older males with a t score for quadriceps strength of -2 or less, had a significantly higher RF grayscale density. Older males with a 12 minutes' walk t score of -2 or less and old males and females with a walking speed of 1m/s or less had a lower RF thickness. DISCUSSION: There is a good concordance between RF ultrasound and DEXA. CONCLUSIONS: Assessment of RF using ultrasound appears to be a reliable and accurate method to evaluate muscle mass in older people.

Folates Induce Colorectal Carcinoma HT29 Cell Line Proliferation Through Notch1 Signaling.

Folic acid (FA) consumption at high levels has been associated with colon cancer risk. Several mechanisms have been proposed to explain this association. The Notch signal pathway has been implicated in the regulation of cellular proliferation. Our aim was to demonstrate that high concentrations of FA or its reduced form, 5-methyltetrahydrofolic acid (5-MTHF), increase colorectal carcinoma HT29 cell proliferation through an increase of Notch1 activation and to prove if the inhibition of Notch1 activation by gamma secretase inhibitor, reduce the effect of folic acid. HT29 cells were cultured in high (400 nM), low (20 nM), or 0 nM FA or 5-MTHF concentrations during 96 h with or without DAPT (gamma secretase inhibitor). Cell proliferation was determined by the methylthiazole tetrazolium method, and Notch1-intracellular domain (NICD) was analyzed by flow cytometry. HT29 cells exposed to 400 nM FA or 5-MTHF showed higher proliferation rate than those exposed to 20 nM of FA or 5-MTHF (P < 0.01) during 96 h. NICD expression increased at higher FA or 5-MTHF concentrations compared with lower concentrations (P < 0.01). This effect on proliferation was partially reversible when we blocked Notch1 activation with the inhibitor of γ-secretase (P < 0.05).These data suggest that high concentration of FA and 5-MTHF induce HT29 cell proliferation activating Notch1 pathway.

Relación entre estado nutricional y evolución postoperatoria, en cirugía oncológica digestiva / Nutritional status and postoperative complications in patients with digestive cancer

Background: Risk of malnutrition is elevated among oncologic patients, and this increases postoperative morbidity and mortality. Aim: To study the association between nutritional status and postoperative outcomes in a group of patients with gastrointestinal cancers. Patients and Methods: We studied 129 patients with diagnosis of digestive cancer, previous to potentially curative surgery. Nutritional status was evaluated through anthropometric measures, Subjective Global Assessment (SGA), dietary intake recalls and routine biochemical parameters. Functional performance was assessed by the Karnofsky index (KI). Cancer stage was classified according to TNM4. During the postoperative period, complications, length of stay at the critical care ward and duration of hospitalization were registered. Thirty days after discharge, patients were contacted, and the appearance of new complications was listed. Results: According to SGA 14.7% of patients were classified as well nourished (A), 57.3% as moderately undernourished or at risk of malnutrition (B) and 27.9% as severely malnourished (C). The incidence of total complications was 25.5%. Nutritional status was not associated with cancer stage. The frequency of complications among patients classified as A, B and C were 5.5, 25.3 and 37.1% respectively (p = 0.03). Conclusions: We detected a high frequency of malnutrition in this group of patients. Overall the frequency of postoperative complications was low, however malnourished patients exhibited a higher rate of surgical complications.

Carotid ultrasound examination as an aging and disability marker.

AIM: To explore the usefulness of carotid ultrasound examination as a marker of aging and predictor of disability among older people. METHODS: Carotid ultrasound, measuring carotid intima media thickness (CIMT) and recording the presence of plaques, was carried out in 152 adults aged 29-59 years (47 women) and in 107 older adults aged 61-88 years (86 women). In all, clinical routine laboratory parameters and lymphocyte telomere length as T/S ratio were measured. Among older adults, 12-min walk, timed up and go, hand grip and quadriceps strength were determined. RESULTS: CIMT was significantly higher among older people and T/S ratio was significantly higher in young women. Carotid plaques were found in one adult and 17 older people. A multiple regression analysis accepted age, systolic blood pressure and T/S ratios as independent predictors of CIMT (R(2) = 0.51). Among older people, a logistic regression accepted age and the presence of carotid plaques as significant predictors of a 12-min walk speed below 1 m/s. CONCLUSIONS: An abnormal 12-min walk as an indicator of functional decline among older people is associated with the presence of carotid artery plaques. CIMT is independently associated with age.

[Nutritional status and postoperative complications in patients with digestive cancer]. / Relación entre estado nutricional y evolución postoperatoria, en cirugía oncológica digestiva.

BACKGROUND: Risk of malnutrition is elevated among oncologic patients, and this increases postoperative morbidity and mortality. AIM: To study the association between nutritional status and postoperative outcomes in a group of patients with gastrointestinal cancers. PATIENTS AND METHODS: We studied 129 patients with diagnosis of digestive cancer, previous to potentially curative surgery. Nutritional status was evaluated through anthropometric measures, Subjective Global Assessment (SGA), dietary intake recalls and routine biochemical parameters. Functional performance was assessed by the Karnofsky index (KI). Cancer stage was classified according to TNM4. During the postoperative period, complications, length of stay at the critical care ward and duration of hospitalization were registered. Thirty days after discharge, patients were contacted, and the appearance of new complications was listed. RESULTS: According to SGA 14.7% of patients were classified as well nourished (A), 57.3% as moderately undernourished or at risk of malnutrition (B) and 27.9% as severely malnourished (C). The incidence of total complications was 25.5%. Nutritional status was not associated with cancer stage. The frequency of complications among patients classified as A, B and C were 5.5, 25.3 and 37.1% respectively (p = 0.03). CONCLUSIONS: We detected a high frequency of malnutrition in this group of patients. Overall the frequency of postoperative complications was low, however malnourished patients exhibited a higher rate of surgical complications.

Central obesity and not age increases skeletal muscle lipids, without influencing lean body mass and strength.

BACKGROUND/AIMS: To measure skeletal muscle lipid infiltration, its association with insulin resistance (IR) lean mass and function, in Chilean men differing in age and body composition. Our hypothesis was that muscle lipid accumulation would be higher among older and heavier individuals and this would deteriorate insulin sensitivity (IS) and decrease muscle mass and function, both features of the ageing process. METHODS: Healthy men (38 < 55 and 18 > 65 years), underwent anthropometric measurements, body composition assessment through radiologic densitometry, Nuclear Magnetic Resonance spectroscopy at the tibialis anterioris muscle to measure intra (IMCL) and extramyocellular lipids (EMCL), quadriceps and handgrip strength, 12 minute walking distance and serum biochemistry (haemoglobin, lipoproteins, creatinine, ultrasensitive C Reactive Protein, fasting and post glucose insulin and glucose concentrations, to assess IS). Physical activity was estimated by actigraphy. RESULTS: 23 men were eutrophic, 26 were overweight and 7 were obese and mostly sedentary, independent of age. Both IMCL and EMCL were higher in overweight/ obese men. Abdominal fat was negatively associated with IS and positively correlated with muscle lipid accretion (both IMCL and EMCL), but not with age. As expected, older individuals had lower muscle mass and strength, but not more adipose tissue nor intramyocellular lipids, yet were more glucose intolerant. CONCLUSIONS: central obesity was associated with IMCL and EMCL infiltration and IR. This type of lipid accretion was not related with ageing nor age-related sarcopenia. Older individuals were more glucose intolerant, which was explained by a decrease of insulin secretion more than adiposity-related IR.

Introducción/Objetivos: medir la infiltracion grasa en el musculo esqueletico, su asociacion con resistencia a la insulina (RI) y con masa y funcion muscular, en hombres chilenos de diferente edad y composicion corporal. Nuestra hipotesis era que habria mas acumulacion de grasa en el tejido muscular entre las personas de mayor edad y peso, lo cual deterioraria la sensibilidad a la insulina (SI) y afectaria negativamente la masa y la funcion muscular, ambas caracteristicas del proceso de envejecimiento. Métodos: se estudiaron hombres sanos (38 < 55 anos y 18 > 65 anos), que fueron sometidos a mediciones antropometricas, evaluacion de la composicion corporal mediante densitometria radiologica (DEXA), espectroscopia de resonancia nuclear magnetica en el musculo tibial anterior para medir lipidos intra (LIM) y extramiocelulares (LEM), fuerza de mano y cuadriceps, test de 12 minutos y bioquimica serica (glicemia, hemoglobina, lipoproteinas, creatinina y proteina C reactiva ultrasensible en ayunas, ademas de glucosa e insulina post carga de glucosa para evaluar SI). La actividad fisica se estimo mediante actigrafia. Resultados: 23 hombres eran eutroficos, 26 tenian sobrepeso y 7 eran obesos, todos eran sedentarios segun el registro actigrafico, independiente de la edad. Tanto LIM como LEM resultaron mas altos entre los hombres con sobrepeso / obesidad. La grasa abdominal se asocio negativamente con la SI y se correlaciono positivamente con la acumulacion de grasa en el musculo (tanto LIM como LEM), pero no con la edad. Como era de esperar, las personas mayores tenian menor masa magra y fuerza, pero no mas tejido adiposo ni lipidos intramiocelulares, aunque eran mas intolerantes a la glucosa. Conclusiones: La obesidad central se asocio con infiltracion de grasa intramuscular y con RI. Esta distribucion adiposa no se relaciono con edad ni con sarcopenia asociada al envejecimiento. Las personas mayores resultaron mas intolerantes a la glucosa, explicable por una disminucion de la secrecion de insulina mas que por RI relacionada con mayor adiposidad.

Variability of formulas to assess insulin sensitivity and their association with the Matsuda index.

OBJECTIVE: To assess the individual variability of HOMA and QUICKI indexes for the assessment of insulin resistance, using three fasting blood samples obtained within 30 minutes. RESEARCH METHODS & PROCEDURES: Data from 80 participants aged 41.5 ± 15 years (26 females), who underwent an oral glucose tolerance test to calculate Matsuda index, were used. Every participant had three fasting blood samples obtained within 30 minutes and four blood samples obtained at 30, 60, 90 and 120 minutes after a 75 g oral glucose load. Insulin and glucose were measured in each sample. HOMA and QUICKI indexes were calculated using the nine possible combinations of the three fasting blood samples. Matsuda index was calculated with all samples obtained. RESULTS: Median values of HOMA-IR, HOMA-ß, QUICKI and Matsuda indexes were 1.9, 117.9, 0.35 and 3.71 arbitrary units, respectively. The individual variation coefficients of HOMA-IR, HOMA-ß and QUICKI were 11.8 (7.8-18.9), 15 (10.2-22.9) and 1.8 (8.8-21.9) % respectively. When compared with Matsuda index, the R squared values of HOMA-IR, HOMA-ß and QUICKI were 0.46, 0.2 and 0.71, respectively. CONCLUSIONS: Among fasting indexes for insulin resistance, QUICKI had the lower variation coefficient and the higher correlation with Matsuda index.

Objetivo: Evaluar la variabilidad individual de los índices HOMA y QUICKI para resistencia a insulina, utilizando tres muestras de sangre en ayunas obtenidas en un período de 30 minutos. Material y métodos: Se utilizaron datos provenientes de 80 participantes de 41.5 ± 15 años de edad (26 mujeres) a quienes se les efectuó una prueba de tolerancia a glucosa oral para calcular el índice de Matsuda. A cada participante se le tomaron tres muestras de sangre en ayunas en un período de 30 minutos y cuatro muestras a los 30, 60, 90 y 120 minutos después de una carga oral de 75 g de glucosa. En cada muestra se midieron los niveles de insulina y glucosa. Los índices HOMA y QUICKI se calcularon utilizando las nueve combinaciones posibles con las tres muestras obtenidas en ayunas. El índice de Matsuda se calculó utilizando todas las muestras. Resultados: Las medianas de los índices HOMA-IR, HOMA-?, QUICKI y Matsuda fueron 1,9, 117,9, 0,35 and 3,71 unidades arbitrarias, respectivamente. Los coeficientes de variación individual del HOMA-IR, HOMA-??y QUICKI fueron 11,8 (7,8-18,9), 15 (10,2-22,9) and 1,8 (8,8-21,9) %, respectivamente. Comparados con el índice de Matsuda, los valores de R2 para el HOMA-IR, HOMA-??y QUICKI fueron 0,46, 0,2 y 0,71, respectivamente. Conclusiones: De los índices que utilizan muestras en ayunas para determinar resistencia a insulina, el QUICKI es el que tiene el menor coeficiente de variación y la mejor correlación con el índice de Matsuda.

Variability of glycemic and insulin response to a standard meal, within and between healthy subjects.

AIM: To test the variability within and between subject of glycemic response test following the ingestion of a standard food. MATERIAL AND METHODS: Glucose and insulin response of a standard meal (white bread) was performed in ten healthy volunteers and repeated under identical conditions for 6 times. Blood glucose and insulin levels were measured in the fasted state and over the 180 min following commencement of consumption of the foods The Area Under the Curve (AUC) for glucose and insulin was calculated for the values above baseline for the 3-hour period following the standard meal. Within and between coefficient of variation was calculated. RESULTS: The total intra-individual variation of the gAUC was 51.8% range 24.9 to 91.4%. The inter-individual variation of the gAUC in the complete study was 75.2% . The total intra-individual variation of the iAUC was 51.9%. ranged: 7.7 to 103%. The inter-individual variation in the complete study was 86%. CONCLUSION: Glucose and insulin response to a reference food has low reliability, therefore limits its clinical utility for individual dietary prescription.

Objetivo: Evaluar la variabilidad inter e intra individual de la respuesta glicémica frente a la ingestión de un alimento estándar en sujetos sanos. Material y métodos: Se midió en 6 oportunidades la respuesta glicémica e insulínica de un alimento estándar (pan batido blanco) en 10 voluntarios sanos. A cada sujeto se le midió la glicemia e insulina en ayuno a los 15, 45, 60, 90, 120, 150 y 180 minutos, después de ingerir el alimento estándar. Posteriormente se calculó el área bajo la curva (ABC) de glicemia e insulina en cada sujeto. Se calculó el coeficiente de variación intra e inter individual del ABC de glucosa e insulina. Resultados: La variación intra-individual total del ABC de glucosa fue de 51,8% (rango: 24,9%-91,4%). La variación inter-individual del ABC de glucosa total fue 75,2%. La variación intra-individual del ABC de insulina fue de 51,9% (rango: 7,7%-103%). La variación inter-individual del ABC de insulina total fue de 86%. Conclusión: La respuesta glicémica e insulínica a un alimento estándar tiene poca reproducibilidad, tanto intra e inter individual. En consecuencia, su utilidad clínica para la prescripción dietaria individual, está limitada.