Fat intake and adiposity in 8 to 11-year-old obese children.

OBJECTIVE: To investigate the relationships between diet composition, body composition, and macronutrient oxidation at rest in obese and non-obese children. DESIGN: Cross-sectional study on fat intake, adiposity and postabsorptive macronutrients oxidation rates. SUBJECTS: 82 prepubertal (age: 9.1 +/- 1.1 y) children, 30 obese (FM = 32.6 +/- 6.1%) and 52 non-obese (FM = 15.6 +/- 5.1%). MEASUREMENTS: Subcutaneous skinfold thickness for body composition, diet history for energy and nutrient intake, indirect calorimetry for resting metabolic rate (RMR) and RQ measurement. RESULTS: Energy intake (EI) was comparable in obese and non-obese children. Adjusted for RMR by ANCOVA, using RMR as the covariate, EI was significantly lower in obese than in non-obese children indicating either a blunted physical activity or a systematic underestimation of EI. Protein and carbohydrate intakes expressed as a percentage of total energy intake (%EI) were not significantly different in the two groups. Lipid intake (%EI) was slightly but significantly higher in the obese than in the non-obese group either unadjusted or adjusted for RMR by ANCOVA. The postabsorptive RQ was significantly lower in obese than in non-obese children. In the total group, %FM was weakly but significantly correlated to lipid intake (%EI). CONCLUSION: Obese prepubertal children have a higher relative fat intake than non-obese children and their FM is associated with this factor. The lower postabsorptive RQ of obese children may indicate a compensatory mechanism to achieve fat equilibrium by enhanced fat oxidation.

Reproducibility and within-day variability of body fat measurements using segmental bipolar bioelectrical impedance in women

BACKGROUND AND AIMS: little is known regarding the reproducibility of body fat measuring devices; hence, we assessed the between and within-device reproducibility, and the within-day variability of body fat measurements. METHODS: body fat percentage was measured twice on seventeen female students aged between 18 and 20 with a body mass index of 21.9 ± 2.5 kg/m2 (mean ± SD) using seven bipolar bioelectrical impedance devices. Each participant was also measured each hour between 7:00 and 22:00. RESULTS: the correlation between first and second measurements was very high (Spearman r between 0.985 and 1.000, p<0.001), as well as between devices (Spearman r between 0.916 and 0.991, p<0.001). Repeated measurements analysis showed no differences were between devices (p=0.59) or readings (first vs. second: p=0.74). Conversely, significant differences were found between assessment periods throughout the day, measurements made in the morning being lower than those made in the afternoon (F test for repeated values= 6.58, p<0.001). CONCLUSIONS: the between and within-device reproducibility for measuring body fat is high, enabling the use of multiple devices in a single study. Conversely, small but significant changes in body fat measurements occur during the day, urging body fat measurements to be performed at fixed times.

Modulation of fructose metabolism by dietary factors

High fructose consumption is associated with obesity and characteristics of metabolic syndrome. This includes insulin resistance, dyslipidemia, type II diabetes and hepatic steatosis, the hepatic component of metabolic syndrome. Short term high fructose consumption in healthy humans is considered as a study model to increase intrahepatocellular lipids (IHCL). Protein supplementation added to a short term high fructose diet exerts a protective role on hepatic fat accumulation. Fructose disposal after an acute fructose load is well established. However, fructose disposal is usually studied when a high intake of fructose is ingested. Interaction of fructose with other macronutrients on fructose disposal is not clearly established. We wanted to assess how fructose disposal is modulated with nutritional factors. For the first study, we addressed the question of how would essential amino acid (EAA) supplemented to a high fructose diet have an impact on hepatic fat accumulation? We tried to distinguish which metabolic pathways were responsible for the increase in IHCL induced by high fructose intake and how those pathways would be modulated by EAA. After 6 days of hypercaloric high fructose diet, we observed, as expected an increase in IHCL modulated by an increase in VLDL-triglycerides and an increase in VLDL-13C-palmitate production. When adding a supplementation in EAA, we observed a decrease in IHCL but we could not define which mechanism was responsible for this process. With the second study, we were interested to observe fructose disposal after a test meal that contained lipid, protein and a physiologic dose of fructose co-ingested or not with glucose. When ingested with other macronutrients, hepatic fructose disposal is similar as when ingested as pure fructose. It induced oxidation, gluconeogenesis followed by glycogen synthesis, conversion into lactate and to a minor extent by de novo lipogenesis. When co- ingested with glucose decreased fructose oxidation as well as gluconeogenesis and an increased glycogen synthesis without affecting de novo lipogenesis or lactate. We were also able to observe induction of intestinal de novo lipogenesis with both fructose and fructose co- ingested with glucose. In summary, essential amino acids supplementation blunted increase in hepatic fat content induced by a short term chronic fructose overfeeding. However, EAA failed to improve other cardiovascular risk factors. Under isocaloric condition and in the frame of an acute test meal, physiologic dose of fructose associated with other macronutrients led to the same fructose disposal as when fructose is ingested alone. When co-ingested with glucose, we observed a decrease in fructose oxidation and gluconeogenesis as well as an increased in glycogen storage without affecting other metabolic pathways. - Une consommation élevée en fructose est associée à l'obésité et aux caractéristiques du syndrome métabolique. Ces dernières incluent une résistance à l'insuline, une dyslipidémie, un diabète de type II et la stéatose hépatique, composant hépatique du syndrome métabolique. À court terme une forte consommation en fructose chez l'homme sain est considérée comme un modèle d'étude pour augmenter la teneur en graisse hépatique. Une supplémentation en protéines ajoutée à une alimentation riche en fructose de courte durée a un effet protecteur sur l'accumulation des graisses au niveau du foie. Le métabolisme du fructose après une charge de fructose aiguë est bien établi. Toutefois, ce dernier est généralement étudié quand une consommation élevée de fructose est donnée. L'interaction du fructose avec d'autres macronutriments sur le métabolisme du fructose n'est pas connue. Nous voulions évaluer la modulation du métabolisme du fructose par des facteurs nutritionnels. Pour la première étude, nous avons abordé la question de savoir quel impact aurait une supplémentation en acides aminés essentiels (AEE) associé à une alimentation riche en fructose sur l'accumulation des graisses hépatiques. Nous avons essayé de distinguer les voies métaboliques responsables de l'augmentation des graisses hépatiques induite par l'alimentation riche en fructose et comment ces voies étaient modulées par les AEE. Après 6 jours d'une alimentation hypercalorique riche en fructose, nous avons observé, comme attendu, une augmentation des graisses hépatiques modulée par une augmentation des triglycérides-VLDL et une augmentation de la production de VLDL-13C-palmitate. Lors de la supplémentation en AEE, nous avons observé une diminution des graisses hépatiques mais les mécanismes responsables de ce processus n'ont pas pu être mis en évidence. Avec la seconde étude, nous nous sommes intéressés à observer le métabolisme du fructose après un repas test contenant des lipides, des protéines et une dose physiologique de fructose co-ingéré ou non avec du glucose. Lorsque le fructose était ingéré avec les autres macronutriments, le devenir hépatique du fructose était similaire à celui induit par du fructose pur. Il a induit une oxydation, suivie d'une néoglucogenèses, une synthèse de glycogène, une conversion en lactate et dans une moindre mesure une lipogenèse de novo. Lors de la co-ngestion avec du glucose, nous avons observé une diminution de l'oxydation du fructose et de la néoglucogenèse et une augmentation de la synthèse du glycogène, sans effet sur la lipogenèse de novo ni sur le lactate. Nous avons également pu mettre en évidence que le fructose et le fructose ingéré de façon conjointe avec du glucose ont induit une lipogenèse de novo au niveau de l'intestin. En résumé, la supplémentation en acides aminés essentiels a contrecarré l'augmentation de la teneur en graisse hépatique induite par une suralimentation en fructose sur le court terme. Cependant, la supplémentation en AEE a échoué à améliorer d'autres facteurs de risque cardiovasculaires. Dans la condition isocalorique et dans le cadre d'un repas test aiguë, la dose physiologique de fructose associée à d'autres macronutriments a conduit aux mêmes aboutissants du métabolisme du fructose que lorsque le fructose est ingéré seul. Lors de la co-ngestion avec le glucose, une diminution de l'oxydation du fructose est de la néoglucogenèse est observée en parallèle à une augmentation de la synthèse de glycogène sans affecter les autres voies métaboliques.

Long-term measurements of energy expenditure in humans using a respiration chamber.

There is a need to measure energy expenditure in man for a period of 24 h or even several days. The respiration chamber offers a unique opportunity to reach this goal. It allows the study of energy and nutrient balance; from the latter, acute changes in body composition can be obtained. The respiration chamber built in Lausanne is an air-tight room (5 m long, 2.5 m wide, and 2.5 m high) which forms an open circuit ventilated indirect calorimeter. The physical activity of the subject inside the chamber is continuously measured using a radar system based on the Doppler effect. Energy expenditure of obese and lean women was continuously measured over 24 h and diet-induced thermogenesis was assessed by using an approach which allows one to subtract the energy expended for physical activity from the total energy expenditure. Expressed in absolute terms, total energy expenditure was more elevated in the obese than in the lean controls. Basal metabolic rate was also higher in the obese than in the controls, but diet-induced thermogenesis was found to be blunted in the obese. In a second study, the effect of changing the carbohydrate/lipid content of the diet on fuel utilization was assessed in young healthy subjects with the respiration chamber. After a 7-day adaptation to a high-carbohydrate low-fat diet, the fuel mixture oxidized matched the change in nutrient intake. A last example of the use of the respiration chamber is the thermogenic response and changes in body composition due to a 7-day overfeeding of carbohydrate. Diet-induced thermogenesis was found to be 27%; on the last day of overfeeding, carbohydrate balance was reached by oxidation of 50% of the carbohydrate intake, the remaining 50% being converted into lipid.

Eat well plate

This poster shows graphically how much of each of the following food groups we should eat for a healthy, balanced diet: fruit and vegetables; bread, rice, potatoes, pasta and other starchy foods; milk and dairy foods; meat, fish, eggs, beans and other non-dairy sources of protein; and foods and drinks high in fat and/or sugar.��

Effect of acute and chronic exercise on fat oxidation and hormonal and plasma metabolite kinetics in obese and severely obese men

Acute exercise increases energy expenditure (EE) during exercise and post-exercise recovery [excess post-exercise oxygen consumption (EPOC)] and therefore may be recommended as part of the multidisciplinary management of obesity. Moreover, chronic exercise (training) effectively promotes an increase in insulin sensitivity, which seems to be associated with increased fat oxidation rates (FORs). The main purpose of this thesis is to investigate 1) FORs and extra-muscular factors (hormones and plasma metabolites) that regulate fat metabolism during acute and chronic exercise; and 2) EPOC during acute post-exercise recovery in obese and severely obese men (class II and III). In the first study, we showed that obese and severely obese men present a lower exercise intensity (Fatmax) eliciting maximal fat oxidation and a lower reliance on fat oxidation at high, but not at low and moderate, exercise intensities compared to lean men. This was most likely related to an impaired muscular capacity to oxidize non-esterified fatty acids (NEFA) rather than decreased plasma NEFA availability or a change in the hormonal milieu during exercise. In the second study, we developed an accurate maximal incremental test to correctly and simultaneously evaluate aerobic fitness and fat oxidation kinetics during exercise in this population. This test may be used for the prescription of an appropriate exercise training intensity. In the third study, we demonstrated that only 2 wk of exercise training [continuous training at Fatmax and adapted high-intensity interval training (HIIT)], matched with respect to mechanical work, may be effective to improve aerobic fitness, FORs during exercise and insulin sensitivity, which suggest that FORs might be rapidly improved and that adapted HIIT is feasible in this population. The increased FORs concomitant with the lack of changes in lipolysis during exercise suggest an improvement in the mismatching between NEFA availability and oxidation, highlighting the importance of muscular (oxidative capacity) rather than extra-muscular (hormones and plasma metabolites) factors in the regulation of fat metabolism after a training program. In the fourth study, we observed a positive correlation between EE during exercise and EPOC, suggesting that a chronic increase in the volume or intensity of exercise may increase EE during exercise and during recovery. This may have an impact in weight management in obesity. In conclusion, these findings might have practical implications for exercise training prescriptions in order to improve the therapeutic approaches in obesity and severe obesity. -- L'exercice aigu augmente la dépense énergétique (DE) pendant l'exercice et la récupération post-exercice [excès de consommation d'oxygène post-exercise (EPOC)] et peut être utilisé dans la gestion multidisciplinaire de l'obésité. Quant à l'exercice chronique (entraînement), il est efficace pour augmenter la sensibilité à l'insuline, ce qui semble être associé à une amélioration du débit d'oxydation lipidique (DOL). Le but de cette thèse est d'étudier 1) le DOL et les facteurs extra-musculaires (hormones et métabolites plasmatiques) qui régulent le métabolisme lipidique pendant l'exercice aigu et chronique et 2) l'EPOC lors de la récupération aiguë post-exercice chez des hommes obèses et sévèrement obèses (classe II et III). Dans la première étude nous avons montré que les hommes obèses et sévèrement obèses présentent une plus basse intensité d'exercice (Fatmax) correspondant au débit d'oxydation lipidique maximale et un plus bas DOL à hautes, mais pas à faibles et modérées, intensités d'exercice comparé aux sujets normo-poids, ce qui est probablement lié à une incapacité musculaire à oxyder les acides gras non-estérifiés (AGNE) plutôt qu'à une diminution de leur disponibilité ou à un changement du milieu hormonal pendant l'exercice. Dans la deuxième étude nous avons développé un test maximal incrémental pour évaluer simultanément l'aptitude physique aérobie et la cinétique d'oxydation des lipides pendant l'exercice chez cette population. Dans la troisième étude nous avons montré que seulement deux semaines d'entraînement (continu à Fatmax et intermittent à haute intensité), appariés par la charge de travail, sont efficaces pour améliorer l'aptitude physique aérobie, le DOL pendant l'exercice et la sensibilité à l'insuline, ce qui suggère que le DOL peut être rapidement amélioré chez cette population. Ceci, en absence de changements de la lipolyse pendant l'exercice, suggère une amélioration de la balance entre la disponibilité et l'oxydation des AGNE, ce qui souligne l'importance des facteurs musculaires (capacité oxydative) plutôt que extra-musculaires (hormones et métabolites plasmatiques) dans la régulation du métabolisme lipidique après un entraînement. Dans la quatrième étude nous avons observé une corrélation positive entre la DE pendant l'exercice et l'EPOC, ce qui suggère qu'une augmentation chronique du volume ou de l'intensité de l'exercice pourrait augmenter la DE lors de l'exercice et lors de la récupération post-exercice. Ceci pourrait avoir un impact sur la gestion du poids chez cette population. En conclusion, ces résultats pourraient avoir des implications pratiques lors de la prescription des entraînements dans le but d'améliorer les approches thérapeutiques de l'obésité et de l'obésité sévère.

Does metabolic compensation explain the majority of less-than-expected weight loss in obese adults during a short-term severe diet and exercise intervention?

Objective:We investigated to what extent changes in metabolic rate and composition of weight loss explained the less-than-expected weight loss in obese men and women during a diet-plus-exercise intervention.Design:In all, 16 obese men and women (41±9 years; body mass index (BMI) 39±6 kg m(-2)) were investigated in energy balance before, after and twice during a 12-week very-low-energy diet(565-650 kcal per day) plus exercise (aerobic plus resistance training) intervention. The relative energy deficit (EDef) from baseline requirements was severe (74%-87%). Body composition was measured by deuterium dilution and dual energy X-ray absorptiometry, and resting metabolic rate (RMR) was measured by indirect calorimetry. Fat mass (FM) and fat-free mass (FFM) were converted into energy equivalents using constants 9.45 kcal per g FM and 1.13 kcal per g FFM. Predicted weight loss was calculated from the EDef using the '7700 kcal kg(-1) rule'.Results:Changes in weight (-18.6±5.0 kg), FM (-15.5±4.3 kg) and FFM (-3.1±1.9 kg) did not differ between genders. Measured weight loss was on average 67% of the predicted value, but ranged from 39% to 94%. Relative EDef was correlated with the decrease in RMR (R=0.70, P<0.01), and the decrease in RMR correlated with the difference between actual and expected weight loss (R=0.51, P<0.01). Changes in metabolic rate explained on average 67% of the less-than-expected weight loss, and variability in the proportion of weight lost as FM accounted for a further 5%. On average, after adjustment for changes in metabolic rate and body composition of weight lost, actual weight loss reached 90% of the predicted values.Conclusion:Although weight loss was 33% lower than predicted at baseline from standard energy equivalents, the majority of this differential was explained by physiological variables. Although lower-than-expected weight loss is often attributed to incomplete adherence to prescribed interventions, the influence of baseline calculation errors and metabolic downregulation should not be discounted.

Metabolic effects of fructose in humans

Abstract : Fructose is a simple sugar, whose consumption has increased over the past decades. In rodents, a high-fructose diet (HFrD) induces several features of the metabolic syndrome. The aim of the studies included in this thesis was to investigate the metabolic effects of a HFrD in humans, with a focus on insulin sensitivity and ectopic fat deposition. Moreover, we addressed the question whether these effects may differ between individuals according to gender and the genetic background. The first study was designed to evaluate the impact of a 4-week HFrD on insulin sensitivity and lipid metabolism in 7 healthy men. Insulin sensitivity, intrahepatocellular lipids (IHCL) and intramyocellular lipids (IMCL) contents were measured before and after 1 and 4 weeks of HFrD (1.5 g fructose/kg body weight/day). Insulin sensitivity was assessed by a 2-step hyperinsulinemic euglycemic clamp. IHCL and IMCL were measured by 1H-magnetic resonance spectroscopy (MRS). Fructose caused significant (P<0.05) increases in fasting plasma concentrations of triacylglycerol (TG) (+36%), VLDL-TG (+72%) and glucose (+6%) without any change in body weight, IHCL, IMCL, and insulin sensitivity. In the second study, muscle biopsies were taken from five of these healthy male subjects before and after 4 weeks of HFrD. mRNA concentrations of 18 genes involved in lipid and carbohydrate metabolism were quantified by real-time quantitative PCR. We found that a 4-week HFrD increased the expression of genes involved in lipid synthesis, while it decreased those involved in insulin sensitivity and lipid oxidation; these molecular changes maybe early markers of insulin resistance and altered lipid metabolism. The third study aimed at delineating whether male and females equally respond to a HFrD. For this purpose, higher doses of fructose (twice the dose of the previous study) were provided to 8 healthy young males and 8 healthy young females over 6 days. HFrD significantly increased fasting TG in males (+71 %), whereas this increase was markedly blunted in females (+16%). Males also developed hepatic insulin resistance, characterized by increased hepatic glucose output (+12%), and showed higher alanine aminotransferase concentration (+38%), but none of these effect was observed in females. This study suggests that short-term HFrD leads to hypertriglyceridemia and hepatic insulin resistance in men, but premenopausal women seem protected against these effects. Finally, the fourth study investigated whether healthy offspring of type 2 diabetic patients (OffT2D), a subgroup of individuals prone to metabolic disorders due to their genetic background, may have exacerbated response to HFrD. Eight healthy males (Ctrl) and 16 OffT2D received a HFrD and isocaloric diet in a randomized order. In both groups, HFrD significantly increased IHCL (Ctrl: +76%; OffT2D: +79%) and fasting plasma VLDL-TG (Ctrl: +51 %; OffT2D: +110%). In absolute values, these increments were significantly higher in OffT2D, suggesting that these individuals may be more prone to developing metabolic disorders when challenged by high fructose intake. In order to better delineate the specific effects of fructose vs the hypercaloric energy content, we repeated the complete metabolic investigations after an isocaloric high glucose diet in four of the eight Ctrl volunteers. After a high glucose diet, TG and IHCL concentrations remained similar to the control values, in contrast to the marked increases observed after the HFrD. In conclusion, the studies included in this thesis provided novel insights into the metabolic effects of fructose in humans. They showed that fructose may rapidly increase fasting VLDL-TG, IHCL and lead to hepatic insulin resistance; these effects seem specific to fructose, and potential mechanisms may involve both stimulation of hepatic de novo lipogenesis and decreased lipid oxidation. Moreover, the results suggest that women seem protected against such deleterious effects, while OffT2D displayed exacerbated response. Résumé : Le fructose est un sucre simple, dont la consommation a augmenté durant les dernières décennies. Dans les modèles animaux, un régime riche en fructose (RRFru) peut induire plusieurs composantes du syndrome métabolique. Le but de cette thèse était d'étudier les effets d'un régime riche en fructose sur la sensibilité à l'insuline et la déposition de lipides ectopiques chez l'humain, et si ces effets variaient selon le genre ou le background génétique. La première étude avait pour but d'évaluer l'effet d'un RRFru d'une durée de 4 semaines sur la sensibilité à l'insuline et le métabolisme des lipides chez des hommes sains. La sensibilité à l'insuline, les lipides intrahépatiques (IHCL) et intramusculaires (IMCL) ont été mesurés avant, et après 1 et 4 semaines du RRFru (1.5 g fructose/kg/jour). La sensibilité à l'insuline a été déterminée par un clamp hyperinsulinémique euglycémique, et les IHCL/IMCL par spectroscopie à résonnance magnétique. Le fructose a augmenté les concentrations plasmatiques à jeun des VLDL- triglycérides (TG) (+72%) et de glucose (+6%), sans induire de changement au niveau de la sensibilité à l'insuline, IHCL ou IMCL. Dans la deuxième étude, des biopsies de muscle squelettique ont été prélevées chez cinq de ces volontaires avant et après les 4 semaines de RRFru. Les concentrations de mRNA de 18 gènes impliqués dans le métabolisme des lipides et des hydrates de carbone ont été mesurées par RT-PCR quantitative. Le RRFru a augmenté l'expression de gènes impliqués dans la synthèse de lipides, et diminué celles de gènes impliqués dans la sensibilité à l'insuline et l'oxydation de lipides. Ces changements pourraient constituer des altérations précoces de la sensibilité à l'insuline et du métabolisme lipidique en réponse au fructose. La troisième étude avait pour but de définir si les réponses au RRFru étaient semblables entre les hommes et les femmes. Pour ceci, des doses plus élevées de fructose ont été administrées à 8 jeunes hommes et 8 jeunes femmes durant 6 jours. Le RRFru a augmenté les TG chez les hommes (+71 %), et de manière nettement plus modeste chez les femmes (+16%). Les hommes ont développé une résistance hépatique à l'insuline, ainsi qu'une augmentation des concentrations d'alanine aminotransférase (+38%), mais aucun de ces effets n'a été observé chez les femmes. Cette étude suggère qu'à court terme, un RRFru mène à une hypertriglycéridémie et résistance hépatique à l'insuline chez l'homme, tandis que les femmes semblent en être protégées. Finalement, la 4ème étude a investigué si des personnes apparentées à des patients diabétiques de type 2 (AppDT2), qui constituent un groupe d'individus à risque de développer des maladies métaboliques en raison de leur background génétique, avaient des réponses plus marquées au RRFru. Huit hommes sains (Ctrl) et 16 AppDT2 on reçu dans un ordre randomisé un RRFru et une diète isocalorique durant 6 jours. Dans les deux groupes, le RRFru a augmenté significativement les IHCL (Ctrl: +76%; AppDT2: +79%) et les VLDL-TG plasmatiques à jeun (Ctrl: +51%; AppDT2: +110%). En valeurs absolues, ces deux augmentations étaient plus importantes dans le groupe des AppDT2, suggérant que ces individus sont plus à risque de développer des problèmes métaboliques suite à un apport de fructose. Afin de définir les effets spécifiques du fructose, quatre des huit sujets Ctrl ont été soumis à un régime riche en glucose. Après le régime riche en glucose, les concentrations de TG et d'IHCL étaient semblables aux valeurs obtenues après une diète isocalorique, contrairement aux nombreux effets observés après le RRFru. En conclusion, ces différentes études ont démontré que chez l'humain, le fructose peut rapidement induire une augmentation des VLDL-TG à jeun, des IHCL et une résistance hépatique à l'insuline ; ces effets semblent être spécifiques au fructose. De plus, les différents résultats obtenus montrent que les femmes développent des effets moindres en réponse au fructose, contrairement aux AppDT2, chez qui les effets du fructose semblent plus marqués. Résumé grand public : Le fructose est un sucre simple, présent naturellement et en faibles quantités dans les fruits, mais également constituant du sucrose - appelé aussi sucre de table. Depuis les années 1970, la consommation de fructose a augmenté dans les pays industrialisés et émergents, principalement par le biais d'une hausse de consommation de boissons sucrées de type soda. Dans des modèles animaux tels que les rongeurs, un régime riche en fructose mène au développement de plusieurs facteurs de risques étroitement liés aux maladies cardiovasculaires, à l'obésité et au diabète de type 2; ceux-ci sont caractérisés par une augmentation des concentrations de glucose et de lipides sanguins, ainsi qu'une accumulation de lipides dits « ectopiques », à savoir dans le foie et les muscles. Le but de cette thèse était de définir les effets d'un régime riche en fructose chez l'être humain. De plus, nous nous sommes intéressés à savoir si ces effets étaient semblables entre différents groupes d'individus, à savoir des personnes de sexe masculin / féminin, ou des personnes dont au moins un des parents est diabétique de type 2. Pour ceci, différents groupes de volontaires (hommes, femmes, avec histoire familiale de diabète de type 2) âgés de 18-30 ans se sont soumis à une alimentation enrichie en fructose, d'une durée allant de 6 à 28 jours, suivant l'étude à laquelle ils participaient. La quantité de fructose consommée en plus de l'alimentation normale durant ces périodes équivalait au contenu en fructose de 2-4 litres de boissons sucrées par jour. Des prises de sang ont été effectuées au terme de chacun de ces différents régimes, ainsi que des mesures de sensibilité à l'insuline et de concentrations de lipides dans le foie et le muscle par résonnance magnétique nucléaire, en collaboration avec l'Hôpital de l'Ile de Berne. Les résultats montrent qu'après 6 jours de régime riche en fructose, les volontaires sains de sexe masculin ont presque doublé leurs concentrations de lipides sanguins et hépatiques. De plus, le foie de ces volontaires réagissait moins bien à l'insuline, ce qui pourrait mener à long terme à des maladies métaboliques comme le diabète de type 2. Un des mécanismes postulés est que le fructose pourrait stimuler la formation de lipides dans le foie, contribuant ainsi à un dysfonctionnement de cet organe. De manière surprenante, des femmes d'âge et d'IMC (Indice de Masse Corporelle) comparables aux hommes étudiés n'ont pas développé ces différents effets en réponse au régime riche en fructose. Il semblerait donc qu'elles possèdent certaines propriétés pouvant les «protéger », du moins à court terme, des problèmes métaboliques induits par le fructose. De tels mécanismes sont pour l'heure inconnus, mais il est possible que des différences hormonales, ou de répartition de la masse graisseuse dans le corps, puissent jouer un rôle. Enfin, nous avons également démontré que chez certaines personnes ayant au moins un parent (père ou mère) diabétique de type 2, les augmentations de lipides sanguins et hépatiques induits par le fructose étaient plus marquées que chez des volontaires sans parents diabétiques. Ceci est néanmoins à tempérer par le fait que nous avons observé une grande hétérogénéité des réponses parmi ces individus, découlant certainement d'interactions complexes entre différents facteurs tels que la génétique, le mode de vie, l'alimentation et l'activité physique. Ces différents résultats donnent lieu à une meilleure compréhension du rôle de facteurs alimentaires dans le développement de problèmes métaboliques tels que le diabète de type 2. Ils vont également permettre de tester différentes approches thérapeutiques. Bien qu'ayant été obtenus avec des doses de fructose importantes, ces études soulignent l'effet potentiellement dangereux pour la santé d'une alimentation riche en sucres.

Citrulina plasmática como marcador de pérdida de masa enterocitaria en la enfermedad celíaca en la infancia

Introduction: Plasma citrulline is not incorporated in endogenous or exogenous proteins so it is a theoretical marker of villous atrophy. Our aim was to correlate plasma citrulline levels with severity of villous atrophy inceliac patients. Methods: Observational case-control study longitudinal in children 16 month-old to 14 year-old: 48 with untreated celiac disease, 9 celiac children under gluten free diet and 35 non-celiac healthy children. Plasma amino acids concentration is determined, expressed in μmol/L, and so are other clinical and analytical data. Results: No statistically significative difference found in the referring to BMI, age or renal function. Small increase in fecal fat in celiac children. Citrulline, arginine and glutamine are significantly lower in cases (17.7 μmol/l, 38.7 μmol/l, 479.6 μmol/l respectively) than in controls (28.9 μmol/l, 56.2 μmol/l, 563.7 μmol/l). Citrulline levels are significantly lower in the severe degrees of atrophy than in mild ones (13.8 μmol/l vs. 19.7 μmol/l, p < 0.05), not happening so with rest of amminoacids. Summary: Postabsortive mean of plasma citrulline is a good marker of reduction in enterocyte mass in celiac patients with villous atrophy; secondary reduction in plasma arginine too. Just a small histological alteration in intestinal biopsy is enough to differentiate citrulline in cases and controls and besides it can be seen that high levels of atrophy present with lower plasma citrulline.

Dietoterapia en paciente con linfangiectasia intestinal primaria y ascitis quilosa de repetición.

OBJECTIVES Primary intestinal lymphangiectasia is a lymphatic system's disorder, where lymphatic drainage is blockaged. Clinically it produces malabsorption, protein-losing enteropathy, hypogammaglobulin in blood, and several degrees of malnutrition. Its treatment is not easy and includes dietetic-therapy and drugs. MATERIAL AND METHOD A 35-year-old-woman case report is exposed. She has recurrent chylosa ascites, requiring several admissions and evacuatory paracentesis. After food-fat was replaced by medium-chain triacyl-glicerol-enriched diet, a clinical, analytical and anthropometric improvement was demonstrated. CONCLUSIONS The major way of treatment in intestinal lymphangiectasia in this case is the employement of specific-diet and adaptaded-basic-food. It's difficult and high collaboration of the patient is required, being necessary medical revisions during the whole life, due to the not well known evolution of this long-standing disease.

Guidelines for specialized nutritional and metabolic support in the critically-ill patient. Update. Consensus SEMICYUC-SENPE: Septic patient

Nutritional metabolic management, together with other treatment and support measures used, is one of the mainstays of the treatment of septic patients. Nutritional support should be started early, after initial life support measures, to avoid the consequences of malnutrition, to provide adequate nutritional intake and to prevent the development of secondary complications such as superinfection or multiorgan failure. As in other critically-ill patients, when the enteral route cannot be used to ensure calorie-protein requirements, the association of parenteral nutrition has been shown to be safe in this subgroup of patients. Studies evaluating the effect of specific pharmaconutrients in septic patients are scarce and are insufficient to allow recommendations to be made. To date, enteral diets with a mixture of substrates with distinct pharmaconutrient properties do not seem to be superior to standard diets in altering the course of sepsis, although equally there is no evidence that these diets are harmful. There is insufficient evidence to recommend the use of glutamine in septic patients receiving parenteral nutrition. However, given the good results and absence of glutamine-related adverse effects in the various studies performed in the general population of critically-ill patients, these patients could benefit from the use of this substance. Routine use of omega-3 fatty acids cannot be recommended until further evidence has been gathered, although the use of lipid emulsions with a high omega-6 fatty acid content should be avoided. Septic patients should receive an adequate supply of essential trace elements and vitamins. Further studies are required before the use of high-dose selenium can be recommended.

Intake and home use of olive oil or mixed oils in relation to healthy lifestyles in a Mediterranean population. Findings from the prospective Pizarra study.

Discordances exist in epidemiological studies regarding the association between the intake of nutrients and death and disease. We evaluated the social and health profile of persons who consumed olive oil in a prospective population cohort investigation (Pizarra study) with a 6-year follow-up. A food frequency questionnaire and a 7 d quantitative questionnaire were administered to 538 persons. The type of oil used in food preparation was determined by direct measurement of the fatty acids in samples obtained from the kitchens of the participants at baseline and after follow-up for 6 years. The fatty acid composition of the serum phospholipids was used as an endogenous marker of the type of oil consumed. Total fat intake accounted for a mean 40 % of the energy (at baseline and after follow-up). The concordance in intake of MUFA over the study period was high. The fatty acid composition of the serum phospholipids was significantly associated with the type of oil consumed and with fish intake. The concentration of polar compounds and polymers, indicative of degradation, was greater in oils from the kitchens where sunflower oil or refined olive oil was used, in oils used for deep frying and in oils that had been reused for frying five times or more. Consumption of olive oil was directly associated with educational level. Part of the discordance found in epidemiological studies between diet and health may be due to the handling of oils during food preparation. The intake of olive oil is associated with other healthy habits.

VEGF gene expression in adult human thymus fat: a correlative study with hypoxic induced factor and cyclooxygenase-2.

It is well known that the adult human thymus degenerates into fat tissue; however, it has never been considered as a potential source of angiogenic factors. Recently, we have described that this fat (TAT) produces angiogenic factors and induces human endothelial cell proliferation and migration, indicating its potential angiogenic properties. DESIGN Adult thymus fat and subcutaneous adipose tissue specimens were obtained from 28 patients undergoing cardiac surgery, making this tissue readily available as a prime source of adipose tissue. We focused our investigation on determining VEGF gene expression and characterizing the different genes, mediators of inflammation and adipogenesis, and which are known to play a relevant role in angiogenesis regulation. RESULTS We found that VEGF-A was the isoform most expressed in TAT. This expression was accompanied by an upregulation of HIF-1alpha, COX-2 and HO-1 proteins, and by increased HIF-1 DNA binding activity, compared to SAT. Furthermore, we observed that TAT contains a high percentage of mature adipocytes, 0.25% of macrophage cells, 15% of endothelial cells and a very low percentage of thymocyte cells, suggesting the cellular variability of TAT, which could explain the differences in gene expression observed in TAT. Subsequently, we showed that the expression of genes known as adipogenic mediators, including PPARgamma1/gamma2, FABP-4 and adiponectin was similar in both TAT and SAT. Moreover the expression of these latter genes presented a significantly positive correlation with VEGF, suggesting the potential association between VEGF and the generation of adipose tissue in adult thymus. CONCLUSION Here we suggest that this fat has a potential angiogenic function related to ongoing adipogenesis, which substitutes immune functions within the adult thymus. The expression of VEGF seems to be associated with COX-2, HO-1 and adipogenesis related genes, suggesting the importance that this new fat has acquired in research in relation to adipogenesis and angiogenesis.

Progression from high insulin resistance to type 2 diabetes does not entail additional visceral adipose tissue inflammation.

Obesity is associated with a low-grade chronic inflammation state. As a consequence, adipose tissue expresses pro-inflammatory cytokines that propagate inflammatory responses systemically elsewhere, promoting whole-body insulin resistance and consequential islet β-cell exhaustation. Thus, insulin resistance is considered the early stage of type 2 diabetes. However, there is evidence of obese individuals that never develop diabetes indicating that the mechanisms governing the association between the increase of inflammatory factors and type 2 diabetes are much more complex and deserve further investigation. We studied for the first time the differences in insulin signalling and inflammatory pathways in blood and visceral adipose tissue (VAT) of 20 lean healthy donors and 40 equal morbidly obese (MO) patients classified in high insulin resistance (high IR) degree and diabetes state. We studied the changes in proinflammatory markers and lipid content from serum; macrophage infiltration, mRNA expression of inflammatory cytokines and transcription factors, activation of kinases involved in inflammation and expression of insulin signalling molecules in VAT. VAT comparison of these experimental groups revealed that type 2 diabetic-MO subjects exhibit the same pro-inflammatory profile than the high IR-MO patients, characterized by elevated levels of IL-1β, IL-6, TNFα, JNK1/2, ERK1/2, STAT3 and NFκB. Our work rules out the assumption that the inflammation should be increased in obese people with type 2 diabetes compared to high IR obese. These findings indicate that some mechanisms, other than systemic and VAT inflammation must be involved in the development of type 2 diabetes in obesity.

Impact of dietary betaine and conjugated linoleic acid on insulin sensitivity, protein and fat metabolism of obese pigs.

To determine possible mechanisms of action that might explain the nutrient partitioning effect of betaine and conjugated linoleic acid (CLA) in Iberian pigs and to address potential adverse effects, twenty gilts were restrictively fed from 20 to 50 kg BW Control, 0.5% betaine, 1% CLA or 0.5% betaine + 1% CLA diets. Serum hormones and metabolites profile were determined at 30 kg BW and an oral glucose test was performed before slaughter. Pigs were slaughtered at 50 kg BW and livers were obtained for chemical and histological analysis. Decreased serum urea in pigs fed betaine and betaine + CLA diets (11%; P = 0.0001) indicated a more efficient N utilization. The increase in serum triacylglycerol (58% and 28%, respectively; P = 0.0098) indicated that CLA and betaine + CLA could have reduced adipose tissue triacylglycerol synthesis from preformed fatty acids. Serum glucose, low-density lipoprotein (LDL) cholesterol and non-esterified fatty acids were unaffected. CLA and betaine + CLA altered serum lipids profile, although liver of pigs fed CLA diet presented no histopathological changes and triglyceride content was not different from Control pigs. Compared with controls, serum growth hormone decreased (20% to 23%; P = 0.0209) for all treatments. Although serum insulin increased in CLA, and especially in betaine + CLA pigs (28% and 83%; P = 0.0001), indices of insulin resistance were unaffected. In conclusion, CLA, and especially betaine + CLA, induced changes in biochemical parameters and hormones that may partially explain a nutrient partitioning effect in young pigs. Nevertheless, they exhibited weak, although detrimental, effects on blood lipids. Moreover, although livers were chemically and histologically normal, pigs fed CLA diet challenged with a glucose load had higher serum glucose than controls.