Marion Brandolini

Daily protein intakes and eating patterns in young and elderly French

An adequate level of protein intake is required to limit the gradual body protein loss observed during ageing. Different factors (cohort age, sex, life conditions) may modify protein intake and distribution. However the precise amounts, as well as their daily distribution which affects protein utilisation and N retention, are unknown in both young and elderly individuals. The hypothesis was tested that protein intake and its distribution over daily meals could be different between the young and elderly. The consumption of six different protein-rich food groups by 292 healthy individuals aged 20-30 and 65-75 years was determined throughout each day for 1 week. The data of the total protein intake and protein intakes at each meal were analysed by ANOVA for each sex separately, using age group as the independent factor. The average protein intake of men was lower in the older age group whilst the opposite trend was seen in women. The distribution of protein intake was different between the two age groups: 56.5 % of the daily protein was eaten at lunch by the elderly but only 47 % (P<0.0001) by the younger subjects. In the elderly subjects, those eating larger amounts consumed a greater proportion of protein-rich foods at dinner than those eating small amounts (30.4 v. 26.2 %, P=0.05). A high level of protein intake was related to a higher meat-product consumption in both the elderly and young individuals. In conclusion, the pattern of protein intake differs significantly between age groups and sexes.

Alterations of Sensory Perceptions in Healthy Elderly Subjects during Fasting and Refeeding

Background: Sensory perception losses may contribute to age-related malnutrition by affecting food selection and consumption. Objective: To determine the effects of a 36-hour fast followed by a 6-hour refeeding period on sensory perceptions in 7 healthy elderly subjects (65–80 years of age) and 6 healthy young subjects (18–35 years of age). Methods: Self-perceived hunger and olfactory ratings were recorded on visual analogue scales in response to three different classes of odorant stimuli (salt, sweet and sour). Odorant stimuli were administered three times during the study, twice during the fasting period (12 and 24 h fasted) and once at the end of the re-nutrition period. Results: A significant difference was found between the two groups for the self-perceived hunger ratings in response to the sour stimuli. A significant difference was observed between the two groups for olfactory ratings as regards the salt and sour odorant stimuli. Among the metabolic changes associated with fasting and refeeding, blood glucose was significantly related (r2 = 0.97, p = 0.001) to the perception of hunger in the control group subjects, but no such relationship was found for the elderly subjects (r2 = 0.16, p = NS). Conclusion: (1) Self-perceived hunger and olfactory ratings are specifically affected in healthy elderly. (2) Nutritional status can modulate sensory perceptions in elderly and young during the transition from fasting to refeeding.

Higher calcium urinary loss induced by a calcium sulphate-rich mineral water intake than by milk in young women

It is well known that the intestinal availability of Ca from Ca-rich mineral waters is equivalent to that of milk Ca. However, the effect of associated anions on Ca urinary loss needs to be addressed. The aim of the current study was to compare, under ordinary conditions of consumption, milk and a SO4-rich mineral water as the Ca provider in a large number of subjects consuming the same quantity of Ca from the two sources in a crossover study lasting for an extended period. Thirty-seven healthy women completed a 12-week protocol, divided into four periods of 3 weeks (W). In the first (W1-3) and third (W6-9) periods, dietary Ca intake was restricted to 600 mg/d. In the second (W4-6) and final (W10-12) periods, either 400 ml/d medium-fat milk or 1 litre of a Ca- and SO4-rich mineral water, each providing about 480 mg Ca/d, was added to the diet in a random manner. Dietary evaluation, blood and urinary measures were performed during the last week (W6 and W12) of each Ca supplementation period. The urinary excretion of Ca was higher (0.5 mmol/d more) with water than with milk (P<0.001). An examination of all the dietary factors known to influence calciuria suggested that the acidogenic action of SO4 was responsible for this increased calciuria. Thus, despite an equal Ca intake and assuming an unchanged intestinal absorption, these results suggest that Ca balance is better with milk consumption than with CaSO4-rich water.

Net energy value of two low-digestible carbohydrates, Lycasin HBC and the hydrogenated polysaccharide fraction of Lycasin HBC in healthy human subjects and their impact on nutrient digestive utilization.

The metabolizable energy content of low-digestible carbohydrates does not correspond with their true energy value. The aim of the present study was to determine the tolerance and effects of two polyols on digestion and energy expenditure in healthy men, as well as their digestible, metabolizable and net energy values. Nine healthy men were fed for 32 d periods a maintenance diet supplemented either with dextrose, Lycasin HBC (Roquette Frères, Lestrem, France), or the hydrogenated polysaccharide fraction of Lycasin HBC, at a level of 100 g DM/d in six equal doses per d according to a 3 x 3 Latin square design with three repetitions. After a 20 d progressive adaptation period, food intake was determined for 12d using the duplicate meal method and faeces and urine were collected for 10 d for further analyses. Subjects spent 36 h in one of two open-circuit whole-body calorimeters with measurements during the last 24h. Ingestion of the polyols did not cause severe digestive disorders, except excessive gas emission, and flatulence and gurgling in some subjects. The polyols induced significant increases in wet (+45 and +66% respectively, P<0.01) and dry (+53 and +75 % respectively, P<0.002) stool weight, resulting in a 2% decrease in dietary energy digestibility (P<0.001). They resulted also in significant increases in sleeping (+4.1%, P<0.03) and daily energy expenditure (+2.7 and +2.9% respectively, P<0.02) compared with dextrose ingestion. The apparent energy digestibility of the two polyols was 0.82 and 0.79 respectively, their metabolizable energy value averaged 14.1 kJ/g DM, and their net energy value averaged 10.8 kJ/g DM, that is, 35 % less than those of sucrose and starch.

Age-related changes in plasma lycopene concentrations, but not in vitamin E, are associated with fat mass.

The aim of the present study was to assess the influence of age on plasma concentration of alpha-tocopherol, retinol and carotenoids with a special attention paid to natural differences in body composition. Forty healthy subjects were recruited: twenty were less than 35 years old and twenty above 60 years old. Males and females were equally represented in each age group. Subjects were kept in energy balance and received controlled diets for 36 h. Fat mass and fat-free mass were determined with the (18)0-enriched water dilution technique. Plasma vitamins A and E, and carotenoid levels were determined after 12 h fasting and were shown to be similar in women and men. Plasma alpha-tocopherol concentration increased with age (+44 % elderly v. young), and correlated with % fat mass and plasma cholesterol. After adjustment for plasma cholesterol, the effect of age and % fat mass disappeared. In contrast, plasma lycopene level was 2-fold lower in the elderly than in the young group, and was inversely correlated with fat mass. When lycopene values were adjusted for fat mass, the effect of age disappeared. These results suggest that plasma levels of vitamin E and lycopene differed in the two age groups and that differences in plasma cholesterol and fat mass might participate in such an effect. Short-term vitamin intake did not appear to influence plasma vitamin concentrations.

Feature Selection Methods for Early Predictive Biomarker Discovery Using Untargeted Metabolomic Data

Untargeted metabolomics is a powerful phenotyping tool for better understanding biological mechanisms involved in human pathology development and identifying early predictive biomarkers. This approach, based on multiple analytical platforms, such as mass spectrometry (MS), chemometrics and bioinformatics, generates massive and complex data that need appropriate analyses to extract the biologically meaningful information. Despite various tools available, it is still a challenge to handle such large and noisy datasets with limited number of individuals without risking overfitting. Moreover, when the objective is focused on the identification of early predictive markers of clinical outcome, few years before occurrence, it becomes essential to use the appropriate algorithms and workflow to be able to discover subtle effects among this large amount of data. In this context, this work consists in studying a workflow describing the general feature selection process, using knowledge discovery and data mining methodologies to propose advanced solutions for predictive biomarker discovery. The strategy was focused on evaluating a combination of numeric-symbolic approaches for feature selection with the objective of obtaining the best combination of metabolites producing an effective and accurate predictive model. Relying first on numerical approaches, and especially on machine learning methods (SVM-RFE, RF, RF-RFE) and on univariate statistical analyses (ANOVA), a comparative study was performed on an original metabolomic dataset and reduced subsets. As resampling method, LOOCV was applied to minimize the risk of overfitting. The best k-features obtained with different scores of importance from the combination of these different approaches were compared and allowed determining the variable stabilities using Formal Concept Analysis. The results revealed the interest of RF-Gini combined with ANOVA for feature selection as these two complementary methods allowed selecting the 48 best candidates for prediction. Using linear logistic regression on this reduced dataset enabled us to obtain the best performances in terms of prediction accuracy and number of false positive with a model including 5 top variables. Therefore, these results highlighted the interest of feature selection methods and the importance of working on reduced datasets for the identification of predictive biomarkers issued from untargeted metabolomics data.

Back to the Future: The European Academy for the Medicine of Ageing Revisited

It was around a decade ago that several heads of geriatric departments (Group of European Professors in Medical Gerontology [1, 2]) envisioned the need for younger colleagues to get an adequate postgraduate training in geriatrics under the auspices of an international faculty. This ‘nucleus group’ consisted of E. Beregi, S. Duursma, J. Grimley Evans, J.P. Michel, A. Ruiz-Torres, H.B. Stähelin and B. Steen. The product of these discussions was the inauguration of the ‘European Academy for the Medicine of Ageing’ (EAMA) [3, 4]. The importance of training an ample future geriatric faculty has certainly not diminished since then. Indeed, the cross-talk and the delineation of specific tasks between internists and geriatricians is still a question of debate [5, 6]. One of the major tasks from the beginning was the creation of a network of past and present students. Meanwhile, three courses (each course lasting for 4 weeks spread over a 2-year period) have been completed and the fourth one has just started, in January 2001. Besides a devoted faculty, two ‘critical success factors’ seem to make up the success of the EAMA: (1) the unique site in Sion (Switzerland) in the well-equipped ‘Institut Universitaire Kurt Bösch’ where the courses are held, and (2) the generous support of the Novartis Foundation for Gerontological Research, which enables the recruitment of highclass international teachers. ‘Flashback’ to the Third Course

Systems Metabolomics for Prediction of Metabolic Syndrome

The evolution of human health is a continuum of transitions, involving multifaceted processes at multiple levels, and there is an urgent need for integrative biomarkers that can characterize and predict progression toward disease development. The objective of this work was to perform a systems metabolomics approach to predict metabolic syndrome (MetS) development. A case-control design was used within the French occupational GAZEL cohort (n = 112 males: discovery study; n = 94: replication/validation study). Our integrative strategy was to combine untargeted metabolomics with clinical, sociodemographic, and food habit parameters to describe early phenotypes and build multidimensional predictive models. Different models were built from the discriminant variables, and prediction performances were optimized either when reducing the number of metabolites used or when keeping the associated signature. We illustrated that a selected reduced metabolic profile was able to reveal subtle phenotypic differences 5 years before MetS occurrence. Moreover, resulting metabolomic markers, when combined with clinical characteristics, allowed improving the disease development prediction. The validation study showed that this predictive performance was specific to the MetS component. This work also demonstrates the interest of such an approach to discover subphenotypes that will need further characterization to be able to shift to molecular reclassification and targeting of MetS.

Évaluation des apports alimentaires d’adolescents obèses et post-obèses : comparaison de la méthode iconographique SU.VI.MAX à la méthode de pesée des aliments

Resume Les objectifs de cette etude etaient 1) de comparer la methode iconographique SU.VI.MAX a la methode de pesee des aliments pour evaluer les apports alimentaires d’adolescents obeses ou post-obeses et ; 2) d’etudier les effets d’une education dietetique sur la precision de cette methode. Les apports alimentaires de 26 adolescents obeses ont ete determines par les 2 methodes pendant des periodes de 7 jours a 3 reprises : avant le debut et a la fin de la prise en charge en institution et 4 mois plus tard. Pour l’ensemble des 3 periodes les quantites moyennes d’aliments consommes et les apports moyens d’energie, de glucides, de proteines et de lipides, evalues par les 2 methodes, ne sont pas significativement differents, mais les limites d’agrement entre les 2 methodes sont larges. Les adolescents obeses ou post-obeses sous-estiment la consommation des aliments qu’ils aiment (pâtes, pommes de terre frites…), mais surestiment souvent leur consommation de legumes, de lait et de fromages secs. La methode iconographique SU.VI.MAX constitue une methode fiable pour evaluer les apports alimentaires de groupes d’adolescents obeses ou post-obeses dans des etudes epidemiologiques, mais elle ne convient pas pour un individu. L’education dietetique a permis de reduire de moitie la difference moyenne des apports energetiques entre les 2 methodes, ainsi que la variabilite interindividuelle des differences.

Higher calcium urinary loss induced by a calcium sulphate-rich mineral water intake than by milk in young women â reply by Brandolini et al.

It is well known that the intestinal availability of Ca from Ca-rich mineral waters is equivalent to that of milk Ca. However, the effect of associated anions on Ca urinary loss needs to be addressed. The aim of the current study was to compare, under ordinary conditions of consumption, milk and a SO4-rich mineral water as the Ca provider in a large number of subjects consuming the same quantity of Ca from the two sources in a crossover study lasting for an extended period. Thirty-seven healthy women completed a 12-week protocol, divided into four periods of 3 weeks (W). In the first (W1-3) and third (W6-9) periods, dietary Ca intake was restricted to 600 mg/d. In the second (W4-6) and final (W10-12) periods, either 400 ml/d medium-fat milk or 1 litre of a Ca- and SO4-rich mineral water, each providing about 480 mg Ca/d, was added to the diet in a random manner. Dietary evaluation, blood and urinary measures were performed during the last week (W6 and W12) of each Ca supplementation period. The urinary excretion of Ca was higher (0.5 mmol/d more) with water than with milk (P<0.001). An examination of all the dietary factors known to influence calciuria suggested that the acidogenic action of SO4 was responsible for this increased calciuria. Thus, despite an equal Ca intake and assuming an unchanged intestinal absorption, these results suggest that Ca balance is better with milk consumption than with CaSO4-rich water.