Déficits dans les apports nutritionnels chez les candidats a la chirurgie bariatrique [Nutritional deficiencies in candidates for bariatric surgery]

98% of patients who have undergone a gastric bypass for treating severe obesity develop multiple micronutrient deficits. However, prior to surgery, it isn't rare to find nutrient deficiencies. Indeed, the dietary intakes of surgery candidates are often unbalanced, lacking in variety especially in high vitamin and mineral nutrients. We present the preliminary results concerning the qualitative and quantitative analysis in a group of patients waiting for a gastric bypass. The recommended daily amounts in vitamin B9, vitamin D and iron are insufficient in the majority of the patients. The correction of nutritional intakes is advisable, even before the surgery, in order to reduce the risks of developing biological deficiencies.

Concept of fat balance in human obesity revisited with particular reference to de novo lipogenesis.

The measurement of fat balance (fat input minus fat output) involves the accurate estimation of both metabolizable fat intake and total fat oxidation. This is possible mostly under laboratory conditions and not yet in free-living conditions. In the latter situation, net fat retention/mobilization can be estimated based on precise and accurate sequential body composition measurements. In case of positive balance, lipids stored in adipose tissue can originate from dietary (exogenous) lipids or from nonlipid precursors, mainly from carbohydrates (CHOs) but also from ethanol, through a process known as de novo lipogenesis (DNL). Basic equations are provided in this review to facilitate the interpretation of the different subcomponents of fat balance (endogenous vs exogenous) under different nutritional circumstances. One difficulty is methodological: total DNL is difficult to measure quantitatively in man; for example, indirect calorimetry only tracks net DNL, not total DNL. Although the numerous factors (mostly exogenous) influencing DNL have been studied, in particular the effect of CHO overfeeding, there is little information on the rate of DNL in habitual conditions of life, that is, large day-to-day fluctuations of CHO intakes, different types of CHO ingested with different glycemic indexes, alcohol combined with excess CHO intakes, etc. Three issues, which are still controversial today, will be addressed: (1) Is the increase of fat mass induced by CHO overfeeding explained by DNL only, or by decreased endogenous fat oxidation, or both? (2) Is DNL different in overweight and obese individuals as compared to their lean counterparts? (3) Does DNL occur both in the liver and in adipose tissue? Recent studies have demonstrated that acute CHO overfeeding influences adipose tissue lipogenic gene expression and that CHO may stimulate DNL in skeletal muscles, at least in vitro. The role of DNL and its importance in health and disease remain to be further clarified, in particular the putative effect of DNL on the control of energy intake and energy expenditure, as well as the occurrence of DNL in other tissues (such as in myocytes) in addition to hepatocytes and adipocytes.

Parametrial adipose tissue and metabolic dysfunctions induced by fructose-rich diet in normal and neonatal-androgenized adult female rats.

Hyperandrogenemia predisposes an organism toward developing impaired insulin sensitivity. The aim of our study was to evaluate endocrine and metabolic effects during early allostasis induced by a fructose-rich diet (FRD) in normal (control; CT) and neonatal-androgenized (testosterone propionate; TP) female adult rats. CT and TP rats were fed either a normal diet (ND) or an FRD for 3 weeks immediately before the day of study, which was at age 100 days. Energy intake, body weight (BW), parametrial (PM) fat characteristics, and endocrine/metabolic biomarkers were then evaluated. Daily energy intake was similar in CT and TP rats regardless of the differences in diet. When compared with CT-ND rats, the TP-ND rats were heavier, had larger PM fat, and were characterized by basal hypoadiponectinemia and enhanced plasma levels of non-esterified fatty acid (NEFA), plasminogen activator inhibitor-1 (PAI-1), and leptin. FRD-fed CT rats, when compared with CT-ND rats, had high plasma levels of NEFA, triglyceride (TG), PAI-1, leptin, and adiponectin. The TP-FRD rats, when compared with TP-ND rats, displayed enhanced leptinemia and triglyceridemia, and were hyperinsulinemic, with glucose intolerance. The PM fat taken from TP rats displayed increase in the size of adipocytes, decrease in adiponectin (protein/gene), and a greater abundance of the leptin gene. PM adipocyte response to insulin was impaired in CT-FRD, TP-ND, and TP-FRD rats. A very short duration of isocaloric FRD intake in TP rats induced severe metabolic dysfunction at the reproductive age. Our study supports the hypothesis that the early-androgenized female rat phenotype is highly susceptible to developing endocrine/metabolic dysfunction. In turn, these abnormalities enhance the risk of metabolic syndrome, obesity, type 2 diabetes, and cardiovascular disease.

Nutritional influences on lipogenesis and thermogenesis after a carbohydrate meal.

In vivo lipogenesis and thermogenesis were studied for 24 h after ingestion of 500 g of carbohydrate (CHO) in subjects who had consumed either a high-fat, a mixed, or a high-CHO diet during the 3-6 days preceding the test. CHO oxidation and conversion to fat was significantly less in the high-fat diet group (222 +/- 5 g) than in the mixed (300 +/- 13 g) or high-CHO diet (331 +/- 7 g) groups, resulting in a greater glycogen storage in the high-fat (278 +/- 6 g) than in the other two groups (197 +/- 11 and 170 +/- 2 g). Net lipogenesis occurred sooner and lasted longer in the high-CHO group, amounting to 0.8 +/- 0.5, 3.4 +/- 0.6, and 9 +/- 1 g of lipid synthesized in the high-fat, mixed, and high-CHO groups, respectively. The thermic effect of the CHO load was 5.2 +/- 0.5% on the high-fat, 6.5 +/- 0.4% on the mixed diet, and 8.6 +/- 0.4% on the high-CHO diet. Significant relationships were demonstrated between the postabsorptive nonprotein respiratory quotient and net lipogenesis after the CHO load (r = 0.82) and between net lipogenesis and the increase in energy expenditure (r = 0.71). It is concluded that the antecedent diet influences the amount of net lipogenesis and the magnitude of thermogenesis after a large CHO test meal. However, lipogenesis remains too limited even after such large CHO intakes to cause an increase in the body's fat content.

The brain tracks the energetic value in food images.

Do our brains implicitly track the energetic content of the foods we see? Using electrical neuroimaging of visual evoked potentials (VEPs) we show that the human brain can rapidly discern food's energetic value, vis à vis its fat content, solely from its visual presentation. Responses to images of high-energy and low-energy food differed over two distinct time periods. The first period, starting at approximately 165 ms post-stimulus onset, followed from modulations in VEP topography and by extension in the configuration of the underlying brain network. Statistical comparison of source estimations identified differences distributed across a wide network including both posterior occipital regions and temporo-parietal cortices typically associated with object processing, and also inferior frontal cortices typically associated with decision-making. During a successive processing stage (starting at approximately 300 ms), responses differed both topographically and in terms of strength, with source estimations differing predominantly within prefrontal cortical regions implicated in reward assessment and decision-making. These effects occur orthogonally to the task that is actually being performed and suggest that reward properties such as a food's energetic content are treated rapidly and in parallel by a distributed network of brain regions involved in object categorization, reward assessment, and decision-making.

Prospective study of the barriers to nutritional support in a paediatric intensive care unit : P16

Introduction and aim: Children hospitalised in a paediatric intensive care unit (PICU) are mainly fed by nutritional support (NS) which may often be interrupted. The aims of the study were to verify the relationship between prescribed (PEI) and actual energy intake (AEI) and to identify the reasons for NS interruption. Methods: Prospective study in a PICU. PEI and AEI from day 1 to 15, type of NS (enteral, parenteral, mixed), position of the feeding tube, interruptions in NS and reasons for these were noted. Inter - ruptions were classified in categories of barriers and their frequency and duration were analysed. Results: Fifteen children (24 ± 25.2 months) were studied for 84 days. The NS was exclusively enteral (69%) or mixed (31%). PEI were significantly higher than AEI (54.7 ± 32.9 vs 49.2 ± 33.6 kcal/kg, p = 0.0011). AEI represented 93% of the PEI. Ninety-eight interruptions were noted and lasted 189 h, i.e. 9.4% of the evaluated time. The most frequent barriers were nursing procedures, respiratory physiotherapy and unavailability of intravenous access. The longest were caused by the necessity to stop NS for surgery or diagnostic studies, to treat burns or to carry out medical procedures. Conclusion: AEI in PICU were inferior by 7% to PEI, considerably lower than in adult studies. Making these results available to medical staff for greater anticipation and compensation could reduce NS interruptions. Starving protocols should be reconsidered.

A whole body transportable indirect calorimeter for human use in the tropics.

A transportable, whole body indirect calorimeter, designed for use in the tropics, is described. The calorimeter was built to study energy expenditure of people having chronically or acutely low levels of food intake, and it will help to determine energy adaptations made by individuals with restricted food intake. The calorimeter comprises two units: a 27 m3 ventilated chamber connected to an office housing control and monitoring equipment. The system also allows the experimenter to assess the rate of energy expenditure by means of a ventilated hood or a baby respiration chamber. The incoming air flow rate is variable and is typically set at approximately 30 l/min. Carbon dioxide production (VCO2) and oxygen consumption (VO2) are continuously monitored by means of differential gas analysers via a computerized data acquisition unit. Gas production/consumption rates are measured with a delay of 80 s, the complete response to step changes in VCO2 or VO2 consumption being calculated over 15 min using the rate of change terms in the gas exchange equations. The total electrical power required for the whole system is 12 kW. The calorimeter has been functioning for nearly 4 years in a rural village of The Gambia during which ambient temperatures have ranged from 16 to 44 degrees C and dewpoints from -8 to 24 degrees C. The performance and accuracy of the calorimeter were tested using 20 per cent CO2 in N2 infusion and butane burning. Agreement between the theoretical and the measured values was found to be 99 per cent for VO2 and 100 per cent for VCO2 with a precision for both gases of +/- 10 ml/min over a 1-h period.

Fructose overconsumption causes dyslipidemia and ectopic lipid deposition in healthy subjects with and without a family history of type 2 diabetes.

BACKGROUND: Both nutritional and genetic factors are involved in the pathogenesis of nonalcoholic fatty liver disease and insulin resistance. OBJECTIVE: The aim was to assess the effects of fructose, a potent stimulator of hepatic de novo lipogenesis, on intrahepatocellular lipids (IHCLs) and insulin sensitivity in healthy offspring of patients with type 2 diabetes (OffT2D)--a subgroup of individuals prone to metabolic disorders. DESIGN: Sixteen male OffT2D and 8 control subjects were studied in a crossover design after either a 7-d isocaloric diet or a hypercaloric high-fructose diet (3.5 g x kg FFM(-1) x d(-1), +35% energy intake). Hepatic and whole-body insulin sensitivity were assessed with a 2-step hyperinsulinemic euglycemic clamp (0.3 and 1.0 mU x kg(-1) x min(-1)), together with 6,6-[2H2]glucose. IHCLs and intramyocellular lipids (IMCLs) were measured by 1H-magnetic resonance spectroscopy. RESULTS: The OffT2D group had significantly (P < 0.05) higher IHCLs (+94%), total triacylglycerols (+35%), and lower whole-body insulin sensitivity (-27%) than did the control group. The high-fructose diet significantly increased IHCLs (control: +76%; OffT2D: +79%), IMCLs (control: +47%; OffT2D: +24%), VLDL-triacylglycerols (control: +51%; OffT2D: +110%), and fasting hepatic glucose output (control: +4%; OffT2D: +5%). Furthermore, the effects of fructose on VLDL-triacylglycerols were higher in the OffT2D group (group x diet interaction: P < 0.05). CONCLUSIONS: A 7-d high-fructose diet increased ectopic lipid deposition in liver and muscle and fasting VLDL-triacylglycerols and decreased hepatic insulin sensitivity. Fructose-induced alterations in VLDL-triacylglycerols appeared to be of greater magnitude in the OffT2D group, which suggests that these individuals may be more prone to developing dyslipidemia when challenged by high fructose intakes. This trial was registered at clinicaltrials.gov as NCT00523562.

L'insuffisance rénale chronique: quelle est la diète optimale

The optimal diet for chronic kidney disease (CKD) is an issue frequently brought up by patients and/or their relatives during outpatient visits. For patients without malnutrition who are motivated and supported by an experienced multidisciplinary team, the optimal protein intake of 0,6 g/kg of ideal body weight/day is recommended to halt the progression of CKD. A calorie intake of 30 to 35 kcal/kg of ideal body weight/day is necessary to reduce the risk of malnutrition from a low protein diet and to maintain a neutral nitrogen balance. A low-salt diet, namely 5 to 6 g/d, is useful to optimize the treatment of hypertension associated with CKD and to limit fluid overload. At the advanced stage of CKD, it is also necessary to restrict the intake of phosphorus and sometimes potassium. Given the complexity of optimal renal diet, coordination between general practitioners, nephrologists and dietitians is essential to foster optimal care.

Metabolic and nutritional support of critically ill patients: consensus and controversies.

The results of recent large-scale clinical trials have led us to review our understanding of the metabolic response to stress and the most appropriate means of managing nutrition in critically ill patients. This review presents an update in this field, identifying and discussing a number of areas for which consensus has been reached and others where controversy remains and presenting areas for future research. We discuss optimal calorie and protein intake, the incidence and management of re-feeding syndrome, the role of gastric residual volume monitoring, the place of supplemental parenteral nutrition when enteral feeding is deemed insufficient, the role of indirect calorimetry, and potential indications for several pharmaconutrients.

Physiologie et biomécanique du ski-alpinisme

Introduction: Ski mountaineering is an increasingly popular winter sport and leisure activity. Elite athletes practice this sport with a high level of professionalism, but so far little scientific evidence was available to support their approach. The main aim of this work was to develop a specific knowledge about ski mountaineering, allowing providing specific recommendations for the practice. Methods: First we investigated energy cost (EC) and vertical energy cost (ECv). These two parameters were estimated with oxygen uptake, at different gradients (7 to 33%) and different speeds (2 to 7 km·∙h-­‐1) on treadmill with roller skis and on snow with ski mountaineering gear. Then we assessed energy expenditure (EE) during a long duration ski mountaineering event by measuring heart rate and altitude all along the race and associating them with an EE. The EE was compared with the energy intake during the race. Hydration level was estimated by comparing body weight immediately before and after the race. The energy intake during the 4 days preceding the race was estimated with food diaries and compared with the guidelines. Results/discussion: EC and ECv of ski mountaineering were very high and varied with gradient and speed. ECv decreased between 7 and 33% and with increasing speed at steep gradients. For a 5 h 51 ± 53 min race, the mean EE was 22.6 ± 2.6 MJ. The energy intake covered 20 ± 7% of the EE and was about 14% lower than the recommendations. No significant dehydration was observed. For the longest (53 km) race, we can extrapolate the EE as about 40 MJ. Before the race the energy intake and especially the carbohydrate intake were far under the guidelines (83 ± 17% and 46 ± 13% of the recommendations). Conclusions: EC and EE of ski mountaineering are very high. To minimize the EE to reach the top of a mountain and optimize the performance, the skier should choose a steep gradient and combine this steep gradient with a fast speed. The CHO intake should be increased during but, also before the race while the fluid intake seemed to be adequate. -- Introduction : Le ski-­‐alpinisme est un sport d'hiver qui s'est particulièrement développé durant les dernières décennies : de plus en plus de personnes pratiquent cette activité dans un cadre de loisirs et de plus en plus d'athlètes d'élite prennent part à des compétitions qu'ils préparent avec un haut degré de professionnalisme. Cependant, les connaissances scientifiques restent limitées et les athlètes ne disposent pas de recommandations précises et spécifiques. Le but principal de ce travail est donc de développer un savoir spécifique sur le ski-­‐alpinisme, ce qui devrait permettre d'établir des recommandations pour la pratique. Méthode : Le coût énergétique (CE) et le coût énergétique vertical (CEv) du ski-­‐alpinisme ont été calculés en mesurant la consommation d'oxygène à différentes pentes (7 à 33%) et vitesses (2 à 6.8 km·∙h-­‐1) sur tapis roulant avec des skis à roulettes et sur le terrain avec des skis de randonnée. Ensuite, la dépense énergétique (DE) d'une course de ski-­‐alpinisme de longue durée a été évaluée en mesurant la fréquence cardiaque et l'altitude en continu. La DE a été comparée à l'énergie consommée par les ravitaillements. Des carnets alimentaires ont permis d'estimer la consommation d'énergie (boissons et nourriture) pendant les 4 jours précédant la course. Résultats/discussion : Le CE du ski-­‐alpinisme est très élevé. Le CEv diminue entre 2 et 6 km·∙h-­‐1 et entre 7 et 33%. Pour une course de 5 h 51 ± 53 min (26 km), la DE était de 22.6 ± 2.6 MJ, alors que, pour le grand parcours de la Patrouille des Glaciers (53 km), elle serait d'environ 40 MJ. La consommation d'énergie, pendant le parcours de 26 km, couvrait 20 ± 7% de la DE et était inférieure de 14% aux recommandations, alors qu'aucune déshydratation significative n'était constatée. Les jours précédant la course, la consommation d'énergie et surtout d'hydrates de carbone était bien inférieure aux quantités recommandées (83 ± 17% et 46 ± 13% des recommandations). Conclusion : Le CE et la DE étaient très élevés. Pour minimiser la dépense lors d'une ascension, il faut combiner pente et vitesse élevées. La consommation d'hydrates de carbone devrait être massivement augmentée avant et pendant la course, alors que l'hydratation semble adéquate.

Character transformations and their functional significance as a key to the evolution of hystricognath Rodentia

Hystricognathi represent a monophyletic taxon within Rodentia. Since phylogenetically analyzed morphological systems are essential for revealing evolutionary processes, this study identifies evolutionary character transformations on the stem lineage of Hystricognathi as derived from the author's own work and the literature. Data so far indicate that evolutionary transformations in the rostral head region, the loss of tactile ability in the outer nasal skin and the mobile arrangement of the associated cartilage, were allied with a switch from omnivorous to herbivorous and fiber-rich nutrition. Additional character transformations in the skull assist in digesting such food. Structures associated with reproduction and placentation show a remarkable pro portion of derived character conditions: the chorioallantoic placenta has a ring-shaped organization and growth structure which optimizes the capacity for passive diffusion, a subplacenta occurred as a specialized region responsible for placental invasion and the inverted yolk sac facilitates substance exchange with the main placenta. Finally, precocial newborns evolved as a derived condition within Rodentia. All things considered, a mode of reproduction is indicated, which does not demand excessive additional energy intake by the mother and is in accordance with her low energetic diet. Hystricognathi possess major character transformations that represent prerequisites for their successful radiation at the time when more open ecosystems and grasslands evolved during Earth history. The analysis resulted in the reconstruction of a life-near picture of the hystricognath stem species pattern with high explanatory power in terms of changes in space and time and their interdependence with biodiversity.

Swimming training down-regulates plasma leptin levels, but not adipose tissue ob mRNA expression

The aim of the present study was to assess the effects of endurance training on leptin levels and adipose tissue gene expression and their association with insulin, body composition and energy intake. Male Wistar rats were randomly divided into two groups: trained (N = 18) and sedentary controls (N = 20). The trained group underwent swimming training for 9 weeks. Leptin and insulin levels, adiposity and leptin gene expression in epididymal and inguinal adipose tissue were determined after training. There were no differences in energy intake between groups. Trained rats had a decreased final body weight (-10%), relative and total body fat (-36 and -55%, respectively) and insulin levels (-55%) compared with controls (P < 0.05). Although trained animals showed 56% lower leptin levels (2.58 ± 1.05 vs 5.89 ± 2.89 ng/mL in control; P < 0.05), no difference in leptin gene expression in either fat depot was demonstrable between groups. Stepwise multiple regression analysis showed that lower leptin levels in trained rats were due primarily to their lower body fat mass. After adjustment for total body fat, leptin levels were still 20% (P < 0.05) lower in exercised rats. In conclusion, nine weeks of swimming training did not affect leptin gene expression, but did lead to a decrease in leptin levels that was independent of changes in body fat.

Long-term melatonin treatment reduces ovarian mass and enhances tissue antioxidant defenses during ovulation in the rat

Melatonin regulates the reproductive cycle, energy metabolism and may also act as a potential antioxidant indoleamine. The present study was undertaken to investigate whether long-term melatonin treatment can induce reproductive alterations and if it can protect ovarian tissue against lipid peroxidation during ovulation. Twenty-four adult female Wistar rats, 60 days old (± 250-260 g), were randomly divided into two equal groups. The control group received 0.3 mL 0.9% NaCl + 0.04 mL 95% ethanol as vehicle, and the melatonin-treated group received vehicle + melatonin (100 µg·100 g body weight-1·day-1) both intraperitoneally daily for 60 days. All animals were killed by decapitation during the morning estrus at 4:00 am. Body weight gain and body mass index were reduced by melatonin after 10 days of treatment (P < 0.05). Also, a marked loss of appetite was observed with a fall in food intake, energy intake (melatonin 51.41 ± 1.28 vs control 57.35 ± 1.34 kcal/day) and glucose levels (melatonin 80.3 ± 4.49 vs control 103.5 ± 5.47 mg/dL) towards the end of treatment. Melatonin itself and changes in energy balance promoted reductions in ovarian mass (20.2%) and estrous cycle remained extensive (26.7%), arresting at diestrus. Regarding the oxidative profile, lipid hydroperoxide levels decreased after melatonin treatment (6.9%) and total antioxidant substances were enhanced within the ovaries (23.9%). Additionally, melatonin increased superoxide dismutase (21.3%), catalase (23.6%) and glutathione-reductase (14.8%) activities and the reducing power (10.2% GSH/GSSG ratio). We suggest that melatonin alters ovarian mass and estrous cyclicity and protects the ovaries by increasing superoxide dismutase, catalase and glutathione-reductase activities.