Critical analysis on the use of the homeostasis hodel assessment (HOMA) indexes in the evaluation of the insulin resistance and the pancreatic beta cells functional capacity

Beta-cell dysfunction and insulin resistance are interrelated metabolic abnormalities in the aetiology of Type 2 Diabetes. In several countries, increases in the prevalence of obesity and diabetes have been observed in association with the presence of insulin resistance. In this context, measurement of insulin resistance and beta-cell function is useful. The HOMA indexes (Homeostasis Model Assessment) have been widely used, representing an alternative for the evaluation of these parameters, particularly as a fast, easy and cheap method. This review discusses the origin and evolution of the HOMA index, as well as details of the method, analyzing features related to its validation and the cutoff limits for its interpretation.A disfunção das células-beta e a resistência insulínica são anormalidades metabólicas inter-relacionadas na etiologia do diabetes tipo 2. Em diversos países, tem sido observado o aumento da prevalência de obesidade e diabetes em associação com a presença da resistência insulínica. Nesse contexto, é útil a mensuração da resistência insulínica e da capacidade funcional das células-beta nos indivíduos. Os índices Homeostasis Model Assessment (HOMA) têm sido amplamente utilizados, representando uma das alternativas para avaliação desses parâmetros, principalmente por figurarem um método rápido, de fácil aplicação e de menor custo. Esta revisão discute sobre a origem e a evolução dos índices HOMA, bem como as particularidades do método, abordando aspectos relacionados à sua validação e aos pontos de corte existentes para sua interpretação.323

Efeitos do índice glicêmico no balanço energético

A prevalência da obesidade vem crescendo nas últimas décadas. Associado a este fato, tem-se observado uma mudança no padrão dietético da população em geral, no que diz respeito a um maior consumo de carboidratos. Segundo alguns autores, o índice glicêmico (IG) dos alimentos afeta a composição e o peso corporal. A presente revisão de literatura teve como objetivo avaliar os efeitos do IG sobre apetite, saciedade e composição corporal. A partir das evidências científicas analisadas, foi possível constatar que a maioria dos estudos que atribuem efeitos positivos ao IG é cercada de limitações metodológicas. Estudos bem delineados não observaram benefícios do IG sobre os parâmetros citados acima. Diante disso, conclui-se que o IG apresenta pouca aplicabilidade na prática clínica, como uma ferramenta capaz de controlar a saciedade, reduzir o apetite e, conseqüentemente, a prevalência de obesidade.The prevalence of obesity has increased over the last decades. Associated to this, there has been observed a chance in the dietetic pattern of the population in general, related to the increase in carbohydrate consumption. According to some authors, the glycemic index (GI) of food may affect body composition and body weight. The purpose of this review was to evaluate the effects of GI on appetite, satiety, and body composition. Based on the scientific evidences reviewed, it was possible to verify that the majority of the studies that observed a positive effect of GI in that matter have a lot of methodological limitations. Well-designed studies have not observed any benefit of GI on these parameters. Therefore, it is concluded that GI has little application in clinical practice, as a useful tool to control satiety, reduce appetite, and consequently, to reduce the prevalence of obesity

Consumption of yacon flour improves body composition and intestinal function in overweight adults: A randomized, double-blind, placebo-controlled clinical trial

Yacon root is a natural source of fructooligosaccharides (FOS), and it has been studied for its potential effect as a functional food. However, FOS in the in naturaroot are rapidly hydrolyzed. Thus, the use of dehydrated products such as flour ensures stability of FOS. The effect of chronic consumption of yacon flour on body composition, food intake and of biochemical variables concentration has not yet been evaluated in humans. Thus, we evaluated the effects of yacon flour consumption on these variables associated with excess body weight. Twenty-six adults (31.3 ± 8.5 years) with excess weight (30.4 ± 2.4 kg/m2, 40.16 ± 6.7% body fat) participated in this randomized, double-blind, six-week study. Subjects were randomly allocated to one of the experimental groups (control (n = 13) or yacon flour (n = 13)), received the prescription of energy-restricted diets (- 500 kcal/day) and daily consumed a breakfast drink not containing or containing 25 g of yacon flour (0.1 g of FOS/kg body weight). At the beginning and at the end of the study, biochemical analyses (glycemia, insulinemia, lipid profile and liver function markers), anthropometrics (weight, waist, hip and neck circumference and sagittal abdominal diameter), body composition (lean mass, total body fat, trunk fat, android fat and gynoid fat), blood pressure, intestinal function, and food intake were assessed. Daily yacon flour consumption was well tolerated, did not cause adverse gastrointestinal effects, increased dietary fiber consumption, promoted greater body weight, waist circumference, waist to height index, sagittal abdominal diameter, and body fat reduction, besides improving bowel function in comparison to the control group. Yacon flour served as a natural fiber supplement and proved to be an effective adjuvant to be used in nutritional strategies to control excess body weight

Análise crítica do uso dos índices do Homeostasis Model Assessment (HOMA) na avaliação da resistência à insulina e capacidade funcional das células-b pancreáticas

A disfunção das células-b e a resistência insulínica são anormalidades metabólicas inter-relacionadas na etiologia do diabetes tipo 2. Em diversos países, tem sido observado o aumento da prevalência de obesidade e diabetes em associação com a presença da resistência insulínica. Nesse contexto, é útil a mensuração da resistência insulínica e da capacidade funcional das células-b nos indivíduos. Os índices Homeostasis Model Assessment (HOMA) têm sido amplamente utilizados, representando uma das alternativas para avaliação desses parâmetros, principalmente por figurarem um método rápido, de fácil aplicação e de menor custo. Esta revisão discute sobre a origem e a evolução dos índices HOMA, bem como as particularidades do método, abordando aspectos relacionados à sua validação e aos pontos de corte existentes para sua interpretação.Beta-cell dysfunction and insulin resistance are interrelated metabolic abnormalities in the aetiology of Type 2 Diabetes. In several countries, increases in the prevalence of obesity and diabetes have been observed in association with the presence of insulin resistance. In this context, measurement of insulin resistance and beta-cell function is useful. The HOMA indexes (Homeostasis Model Assessment) have been widely used, representing an alternative for the evaluation of these parameters, particularly as a fast, easy and cheap method. This review discusses the origin and evolution of the HOMA index, as well as details of the method, analyzing features related to its validation and the cutoff limits for its interpretation

Capacidade dos biomarcadores inflamatórios em predizer a síndrome metabólica

O processo inflamatório é o elo entre a síndrome metabólica e as doenças cardiovasculares. Para medir o grau da inflamação subclínica, vários biomarcadores inflamatórios têm sido propostos. Este trabalho tem como objetivo revisar as recentes pesquisas das associações entre os biomarcadores inflamatórios e a síndrome metabólica, bem como a capacidade daqueles em predizer a síndrome metabólica. Estes biomarcadores incluem as citocinas pró-inflamatórias, citocinas antiinflamatórias, adipocinas, chemocinas, marcadores de inflamação derivados de hepatócitos, marcadores de conseqüência da inflamação e enzimas. Com esta revisão pode-se integrar o novo conhecimento referente às interações possíveis de mediadores inflamatórios com a síndrome metabólica, visto que estes biomarcadores desempenham vários papéis e seguem diversos caminhos metabólicos.The inflammatory process is the link between metabolic syndrome and cardiovascular diseases. To measure the degree of subclinical inflammation some inflammatory biomarkers have been considered. This work reviews the recent researches of the associations between inflammatory biomarkers and metabolic syndrome, as well as the capacity in predicting the metabolic syndrome. These biomarkers include pro-inflammatory cytokines, anti-inflammatory cytokines, adipokines, chemokines, inflammation markers derived from hepatocites, the consequence markers of inflammation and enzymes. This review integrates the new knowledge of inflammatory mediators interactions with metabolic syndrome, since these biomarkers play different roles and follow diverse metabolic ways

Addition of pooled pumpkin seed to mixed meals reduced postprandial glycemia: a randomized placebo-controlled clinical trial

We investigated if pumpkin and flaxseeds could improve postprandial glycemic, food intake, and appetitive responses. Herein, we hypothesize based on the literature that pumpkin seed has potential to lower postprandial glycemic effects. Therefore, we conducted a randomized, single-blind, placebo-controlled, crossover design study involving normoglycemic adults (food intake: n = 25; glycemia: n = 15). Three high-carbohydrate mixed meals presenting no seed (control [C]) or 65 g of the tested seeds (pumpkin seed [P] or flaxseed [F]) were consumed in 3 nonconsecutive days. Test meals had similar nutritional composition. Blood glucose was measured by capillary finger blood at 0 (immediately before), 15, 30, 45, 60, 90, and 120 minutes after the ingestion of each meal, and the incremental area under glycemic response curves (iAUC) were calculated. Appetitive responses were assessed, and dietary records were used to evaluate food intake on testing days. Glucose iAUC was significantly lower in P compared with C (reduction of ~35%, P = .025). There was no significant differences in glucose iAUC between F and C (P = .257). Glycemic response at each time point did not differ between C, P, and F (Pgroup × time = .238). Fiber consumption was higher in F (P = .009) than in C, but there were no differences in appetitive responses, energy, or macronutrient consumptions between dietary interventions. Acute consumption of 65 g of pumpkin seed markedly reduced postprandial glycemia. Pumpkin seed has potential as a hypoglycemic food, which now deserves to be confirmed in long-term studies

Benefits and relationship of steps walked per day to cardiometabolic risk factor in Brazilian middle-aged men

We evaluated the benefits and relationship of the number of steps per day to the cardiometabolic risk factors: adiposity indicators; insulin resistance; and metabolic syndrome(MetS) in apparently healthy Brazilian middle-aged men. Design Cross-sectional. Apparently healthy men (age: 50 ± 5 years; n = 299) were studied. The number of steps per day was measured by pedometer. The adiposity indicators (waist circumference, total body fat, android and gynoid body fat), serum insulin, glucose and triglycerides, triglycerides/high-density lipoprotein cholesterol (HDL-c) ratio, homeostasis model assessment of insulin resistance (HOMA-IR) and MetS were assessed. Subjects were placed in groups to reflect different levels of steps per day (average of 7 consecutive days): Group 1 < 10,000 and Group 2 ≥ 10,000. Relationships among variables were measured by multiple linear regressions and the Spearman correlation coefficient as appropriate (p < 0.05). The cardiometabolic risk factors were lower (p < 0.05) in Group 2 than in Group 1. The number of steps per day was a negative predictive factor for total body fat, android and gynoid body fat and HOMA-IR independent of age, working position, android fat, overweight/obesity prevalence, and triglycerides/HDL-c ratio. Moreover, there was a negative correlation between the number of steps and total body fat, android and gynoid body fat, HOMA-IR and MetS. Brazilian middle-aged men performing more than 10,000 steps per day have better cardiometabolic conditions than those walking fewer than 10,000 steps. The number of steps per day is inversely related to the indicators of total and regional adiposity, insulin resistance and MetS