[Insulin resistance frecuency in women's with polycystic ovary syndrome using hyperinsulinemic-euglycemic clamp]. / Frecuencia de resistencia a la insulina en pacientes con síndrome de ovario poliqulstico con el clamp hiperinsulinémico euglucémico.

OBJECTIVE: To assess IR in PCOS patients, using the HE-clamp as the IR gold standard. MATERIAL AND METHODS: A transversal design was done. All patients who accepted to participate provided written informed consent. PCOS was diagnosed according to the 2003 Rotterdam criteria. IR was assessed using the H-clamp, and other IR surrogates such as; fasting plasma insulin (FPI), homeostasis model assessment (HOMA) index and insulin/ glucose rate (I/G rate). Statistical analysis was performed using measures of location and spread was used according to data distribution. RESULTS: 21 patients were included. The mean age of the total group studied was 29.5 +/- 4.8 years, and the body mass index (BMI) was 27.2 +/- 3.08 kg/m2. The 85.7% of the patients met the three Rotterdam criteria for the diagnosis of PCOS. According to the HE clamp 95.2% were IR (M/I value < 6 mg/Kg/min), in contrast the prevalence of IR using sur- rogates was 47.6%, 33.3%, and 66.6% for FPI, G/I rate, and HOMA index respectively. CONCLUSIONS: Our findings show that IR is highly prevalent in patients with PCOS, and that this prevalence is even higher when insulin sensitivity is assessed using the glucose clamp technique. This evidence suggests that IR could be considered diagnostic criteria for PCOS.

[TNF-alpha, C-reactive protein and serum adiponectin modified in infertile patients with insulin resistance]. / Alteración del factor de necrosis tumoral-alpha, proteína C reactiva y adiponectina séricas en pacientes infértiles con resistencia a la insulina.

BACKGROUND: Women's reproductive potential is closely related to nutritional status. Some of the molecules that participate in ovarian regulation are produced in the adipose tissue, and therefore their production is associated with adiposity. OBJECTIVE: To determine serum leptin, adiponectin, C-reactive protein, interleukin-6, and tumor necrosis factor alpha in infertile women with or without insulin resistance; and to associate these molecules with adiposity. METHODS: Thirty-one infertile women were included. Nutritional status was evaluated through clinical and biochemical parameters. Patients were stratified according with their body mass index and the presence of insulin resistance. For statistics, parametric analyses were conducted. RESULTS: The prevalence of overweight was 67.5%; high adiposity was present in 92.3% and central distribution of fat in 96.2% of studied women. Hypercholesterolemia was found in 32.3% of patients, hypertriglyceridemia in 25.8%, and 61.3% presented hyperinsulinemia. Overweight women presented lower adiponectin, and higher TNF-alpha and C-reactive protein concentrations, than those with normal body mass index (p < 0.05). Overweight women had also a higher probability for insulin resistance (p = 0.04). These women with insulin resistance presented lower adiponectin and higher C-reactive protein concentrations than non insulin resistance women. Body mass index correlated with leptin (r= 0.41), TNF-alpha (r= 0.41), and C-reactive protein (r= 0.33) concentrations. CONCLUSION: The prevalence of overweight, high adiposity, dislipidemias, and IR was high in our population studied. We conclude that adiposity is closely associated with some of the molecules that participate in the reproductive process and that also regulate inflammatory responses.

Disruptions in energy balance: does nature overcome nurture?

Fat accumulation, in general, is the result of a breakdown in the homeostatic regulation of energy balance. Although, the specific factors influencing the disruption of energy balance and why these factors affect individuals differently are not completely understood, numerous studies have identified multiple contributors. Environmental components influence food acquisition, eating, and lifestyle habits. However, the variability in obesity-related outcomes observed among individuals placed in similar controlled environments supports the notion that genetic components also wield some control. Multiple genetic regions have been associated with measures related to energy balance; however, the replication of these genetic contributors to energy intake and energy expenditure in humans is relatively small perhaps because of the heterogeneity of human populations. Genetic tools such as genetic admixture account for individual's genetic background in gene association studies, reducing the confounding effect of population stratification, and promise to be a relevant tool on the identification of genetic contributions to energy balance, particularly among individuals of diverse racial/ethnic backgrounds. Although it has been recognized that genes are expressed according to environmental influences, the search toward the understanding of nature and nurture in obesity will require the detailed study of the effect of genes under diverse physiologic and behavioral environments. It is evident that more research is needed to elucidate the methodological and statistical issues that underlie the interactions between genes and environments in obesity and its related comorbidities.

IGF-I polymorphism is associated with lean mass, exercise economy, and exercise performance among premenopausal women.

BACKGROUND: We undertook this study to investigate the association of a genetic polymorphism of the insulin-like growth factor, IGF-I(189), on body composition, exercise performance and exercise economy, after controlling for the independent effect of race as assessed by African genetic admixture (AFADM). METHODS: A total of 114 premenopausal sedentary women were genotyped for IGF-I189, obtaining measures of fat mass, lean body mass, VO2 during cycling and stairclimbing, time on treadmill and leg strength. A quantitative value for AFADM was derived from genotypic information of approximately 40 ancestry informative markers and used as covariate in statistical models. RESULTS: After adjusting for AFADM, IGF-I189 was negatively associated with lean body mass (p = 0.029) and lean leg mass (p = 0.050). Leg strength was not associated with the presence/absence of IGF-I189 (p = 0.380), but carriers of the allele demonstrated a longer time on the treadmill (p = 0.015) after adjusting for AFADM. There was also a negative relationship between oxygen uptake during cycling and presence of the IGF-I189 independent of AFADM (p = 0.010). CONCLUSIONS: Independent of AFADM, individuals with IGF-I189 are more likely to have low leg lean mass and to perform better in activities requiring exercise economy and endurance performance.

Docosahexaenoic acid administered in the acute phase protects the nutritional status of septic neonates.

OBJECTIVE: We tested the hypothesis of whether a pharmacologic, orogastric dose of docosahexaenoic acid (DHA) administered during the acute phase of sepsis protects the nutritional status of neonates. METHODS: A randomized, placebo-controlled trial was conducted. Neonates who developed sepsis after a surgical procedure were randomly assigned to receive daily 100 mg of DHA or 100 mg of olive oil as placebo for 14 d. At selection, illness severity was evaluated and a blood sample was obtained to measure erythrocyte fatty acid composition. Energy intake and type of feeding were recorded daily. Body composition was also determined at selection and after 14 d of follow-up with the deuterium dilution technique. Body composition differences between d 14 and baseline were calculated and compared between groups. Confounders were analyzed in a multiple regression model. RESULTS: In all, 16 DHA and 11 placebo cases were followed up. Both groups showed an increase in length and head circumference, but length gain tended to be greater in neonates with DHA (P = 0.07). The DHA group presented increases in body mass (50 g, P = 0.03) and fat mass (70 g, P = 0.03), whereas infants in the placebo group did not show an increase in any body composition components. Gain in fat mass was positively related with the DHA of erythrocytes and whether or not infants received DHA. CONCLUSIONS: Orogastric DHA administered in the acute phase of infection likely protects the nutritional status of neonates with sepsis.

Cooking and Fe fortification have different effects on Fe bioavailability of bread and tortillas.

OBJECTIVE: To identify iron sources for wheat- (WF) and corn-flour (CF) fortification taking into account the effect of cooking. METHODS: Sixty-six Fe-depleted rats were replete with various Fe sources. Fe bioavailability and utilization in wheat bread (WB) and corn tortillas (CT) fortified with various Fe sources was assessed after the depletion and repletion periods. RESULTS: Baking decreased the phytates content of WF by 97%. Improvements in Hb and FeHb were greater in rats fed unfortified WB than in those fed unfortified WF. Fe fortification had no benefit. In contrast, phytates content was unchanged by tortilla preparation, but fortification improved iron availability. Iron bioavailability indicators were best in rats fed CT fortified with ferrous sulfate and NaFe(III)EDTA than in those fed unfortified CT or CT plus reduced Fe. CONCLUSION: We concluded that baking WF bread improved the bioavailability of native Fe with no further effect of fortification. Pan-cooking of lime-treated CF did not improve Fe bioavailability, but addition of Ferrous sulfate or NaFe(III)EDTA did it, despite the high phytate and calcium content of tortillas.

[The effect of docosahexaenoic acid on the loss of appetite in pediatric patients with pneumonia]. / Efecto del ácido docosahexaenoico sobre la pérdida del apetito en pacientes pediátricos con neumonía.

OBJECTIVE: To evaluate the role of docosahexaenoic acid (DHA) administered during the acute phase of pneumonia in infants, on appetite, cytokines and leptin concentrations. METHODS: Seventeen children between three months and 12 years of age were followed from hospitalization to discharge. Children were randomly assigned to receive DHA or placebo. The effect of treatment was evaluated on energy intake, cytokines, and leptin concentrations. RESULTS: Cytokine concentrations tended to decrease earlier in DHA children. By day 4, concentrations of IL-1beta and TNFalpha had decreased by 12%, while such concentrations increased by 12% and 250% in placebo children. Energy intake recovered in DHA children at discharge, but placebo children were still consuming only 60% of their requirements. CONCLUSIONS: Our results suggest that DHA administered in the acute phase of infection could modulate IL-1 and TNF production, and secondarily, decrease the effect of infection on appetite.

Reproducibility and reliability of the 13C-acetate breath test to measure gastric emptying of liquid meal in infants.

OBJECTIVE: This study assessed the noninvasive 13C-acetate breath test (13C-ABT) as a reliable and reproducible method to evaluate gastric emptying in infants METHODS: Gastric emptying was measured simultaneously by scintigraphy and 13C-ABT in 11 infants with clinical symptoms of gastroesophageal reflux to validate the method compared with the gold standard. Gastric emptying was also measured with 13C-ABT in a separate group of 14 healthy infants on 2 consecutive days to evaluate reproducibility of the method. Half-emptying times obtained with scintigraphy and 13C-ABT were correlated with Pearson's analysis. The variability of the half-emptying times obtained on 2 consecutive days was analyzed with paired t test and by the coefficient of variation as proposed by Bland and Altman. RESULTS: The mean emptying times obtained with scintigraphy and 13C-ABT were not different (89 +/- 27 min and 70 +/- 39 min, respectively, P = 0.22). Both methods correlated significantly (r = 0.75, P < 0.05). Half-emptying times measured on 2 consecutive days with 13C-ABT were 69 +/- 31 min and 68 +/- 30 min, respectively (mean difference = 1.4 +/- 12.4 min, P = 0.67). Intraindividual coefficient of variation was 6.3%. CONCLUSIONS: This study supports the 13C-ABT method as a useful tool to evaluate gastric emptying of liquids in healthy infants and in infants with gastroesophageal reflux in the field of research and in clinical evaluations.

[Serum levels of antioxidants and vitamins related to the homocystein's metabolism during postmenopause]. / Concentraciones séricas de vitaminas antioxidantes y vitaminas relacionadas con el metabolismo de la homocisteína durante la posmenopausia.

OBJECTIVE: To describe nutritional status, B6, B12, and antioxidant vitamins, as well as homocysteine concentrations in postmenopausal women. PATIENTS AND METHODS: A cross-sectional study was conducted in Mexico City. One hundred twenty-five women were selected if they were healthy and were in their first five years after menopause onset. Women were spontaneously divided in two groups: women who did not receive any hormonal treatment for at least six months before the study (n = 66), and those who received hormonal treatment at the moment of the study (n = 59). Anthropometry was measured and a fasting blood sample from a peripheral vein was obtained to determine homocysteine, vitamins A, C, E, B6, B12, and folic acid. Results were compared with Student t-test, and a logistic regression model was used to calculate the risk of hyperhomocystinemia after adjusting by some potential confounders. RESULTS: Women who did not receive hormone replacement therapy presented higher body mass index and waist-hip ratio than those who received such treatment. In contrast, this group presented higher prevalence of folic acid deficiency and hyperhomocystinemia, despite they consumed higher amounts of folic acid in the diet. This high risk of hyperhomocystinemia was independent of vitamin serum concentrations and the level of physical activity (OR = 15.1, IC95 = 1.60,141.9). CONCLUSIONS: These results suggest that hormone replacement therapy may protect against overweight and central fat distribution that occur after menopause, but increases the risk of hyperhomocystinemia.

Ability of the actiwatch accelerometer to predict free-living energy expenditure in young children.

OBJECTIVE: To determine whether activity counts obtained with the Actiwatch monitor are associated with total expenditure and body composition in young children. RESEARCH METHODS AND PROCEDURES: Actiwatch activity monitors were tested in 29 children 4 to 6 years old under field conditions over eight days. Total energy expenditure (TEE) was assessed with the doubly labeled water (DLW) technique. Correlation analyses were used to identify variables related to energy expenditure and percentage body fat. Multiple linear regression analyses were used to examine the variance in TEE and percentage body fat explained by activity counts after adjusting for relevant covariates. RESULTS: Both average total daily activity counts (658,816 +/- 201,657) and the pattern of activity were highly variable among subjects. TEE was significantly related to lean body mass (r = 0.45) and age (r = 0.48; p < 0.05 for both). Activity counts alone were not associated with TEE. In multiple linear regression analyses, TEE was independently associated with only lean body mass. Percentage fat mass was independently associated with body weight, being a girl, and being white, but not with average total activity counts. DISCUSSION: Activity counts obtained with the Actiwatch under free-living conditions do not reflect TEE in 4- to 6-year-old children and are not correlated with percentage fat mass. Therefore, average total activity counts obtained with the Actiwatch may be of limited value in identifying children at risk for becoming obese.

Iron bioavailability and utilization in rats are lower from lime-treated corn flour than from wheat flour when they are fortified with different sources of iron.

Although iron bioavailability from wheat flour fortified with iron has been widely studied, the bioavailability of lime-treated corn flour has not been evaluated sufficiently. We compared iron bioavailability and utilization of lime-treated corn flour and wheat flour supplemented with various iron sources. Bioavailability and utilization were determined in Sprague-Dawley rats using the iron balance and hemoglobin depletion-repletion methods. Rats were iron depleted by feeding them a low iron, casein diet for 10 d. During the repletion period, the rats were fed diets based on lime-treated corn flour or wheat flour, both supplemented with ferrous fumarate, ferrous sulfate, ferric citrate and reduced iron for 14 d. Hemoglobin was determined at the end of depletion and repletion periods. The phytate concentration was lower in wheat flour (114 mg/100g) than in lime-treated corn flour (501 mg/100g). Iron bioavailability and utilization by rats were higher from fortified and unfortified wheat flour than from the lime-treated corn flour counterparts. Iron utilization was greater in rats fed wheat flour supplemented with ferrous sulfate, followed by fumarate and citrate than in rats fed reduced iron. In lime-treated corn flour, iron utilization by rats fed unfortified flour and flour fortified with reduced iron did not differ, but utilization was higher in rats fed corn flour fortified with iron sulfate, fumarate and citrate than with reduced iron. We conclude that fortification of lime-treated corn flour with reduced iron has no effect on iron bioavailability or utilization, probably due to the high phytate content. Other iron compounds must be selected to fortify lime-treated corn flour when intended for public nutrition programs.

Breastfeeding attenuates reductions in energy intake induced by a mild immunologic stimulus represented by DPTH immunization: possible roles of interleukin-1beta, tumor necrosis factor-alpha and leptin.

An attenuated severity of infections is among the well-documented benefits of breast-feeding. The degree to which this attenuated severity extends to the amelioration of anorexia is understood incompletely, and possible underlying mechanisms have received limited evaluation. This study was designed to test whether breast-feeding attenuates reductions in energy intake associated with a mild immunologic stimulus and to assess poststimulus relationships among putative reductions in energy intake and serum interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha and leptin concentrations. A quasi-experimental, hospital-based study was conducted in 23 healthy fully breast- (BF) and formula-fed (FF) infants who received the quadruple diphtheria, pertussis, tetanus and hemophilus influenza (DPTH) immunization as an immunologic challenge. Only FF infants had decreased energy intakes (12 +/- 2%, P = 0.001) after immunization. Leptin concentrations increased after immunization only in FF infants (30 +/- 7%, P = 0.03). Correlations between postimmunization increases in IL-beta and reductions in energy intake were of borderline significance (r = -0.56, P = 0.08). These findings support the view that breast-feeding protects against anorectic responses to mild immunologic stimuli. Increases in leptin are associated with reductions in energy consumption in the postimmunization period in FF infants and postimmunization changes in IL-1beta concentrations likely are related to reductions in energy intake in response to immunologic stimuli.