Le vieillissement de la population est le résultat de l’amélioration de la prise en charge des individus, en particulier des sujets âgés, conduisant à l’apparition d’une nouvelle catégorie démographique, le quatrième âge avec les plus de 75 ans. Cette population polypathologique présente de nombreuses spécificités, avec entre autres, une intolérance au glucose, un état de dénutrition et une altération des fonctions cardiovasculaires, les maladies cardiovasculaires restant la première cause de mortalité dans cette tranche d’âge. Comme évoqué dès les années 50 par Harman, le stress oxydant pourrait jouer un rôle important dans l’ensemble de ces comorbidités. Le resvératrol, un polyphénol anti-oxydant connu pour ses biens-faits cardiovasculaires pourrait ainsi être une molécule d’intérêt dans ce contexte. Nos objectifs dans ce travail ont donc été d’évaluer les effets d’un traitement chronique par le resvératrol accompagné ou non d’une prise en charge nutritionnelle chez la souris très âgée. Ces effets du resvératrol ont été étudiés aussi bien sur le plan métabolique que sur le phénotype cardiovasculaire. Nos résultats montrent qu’un régime riche en protéines et pauvre en glucides a des effets variables en fonction de l’âge. Sans effet sur la souris jeune, il devient délétère chez la souris adulte et très âgée avec une majoration de l’altération de l’homéostasie glucidique associée à une détérioration du bilan lipidique. Ces dysrégulations métaboliques ont pour conséquence une dégradation accrue des fonctions artérielles et cardiaques. Chez la souris très âgée, un traitement par le resvératrol amplifie les dommages liés à ce régime en accentuant les altérations métaboliques et cardiovasculaires, soulignant, et ce pour la première fois, de potentiels effets délétères du resvératrol dans le cadre du vieillissement. En revanche, chez la souris âgée dénutrie en l’absence de prise en charge nutritionnelle, le resvératrol présente des effets bénéfiques avec une amélioration de l’insulino-sensibilité et des fonctions artérielles, associée à une modification d’expression de TXNIP, protéine à l’interface de la régulation de l’homéostasie du glucose et de la balance oxydative, faisant d’elle une piste à explorer tant pour expliquer certains mécanismes impliqués dans le vieillissement que dans les effets du resvératrol. / The aging of the population is the result of the improvement of the care of individuals, especially the elderly, leading to the emergence of a new demographic category, the « fourth age » with people more than 75 years old. This polypathological population has many specificities, with among other things, glucose intolerance, a state of malnutrition and impaired cardiovascular function. Cardiovascular disease remains the leading cause of death in this age group. As mentioned in the 50s by Harman, oxidative stress may play an important role in all of these diseases. Resveratrol, an antioxidant polyphenol known for its properties on cardiovascular events could thus be a molecule of interest in this context. Our objectives in this study were therefore to assess the effects of chronic treatment with resveratrol with or without a nutritional care in the very old mice. These metabolic and cardiovascular effects of resveratrol have been studied. Our results show that a high protein and low carbohydrate diet has different effects depending on age. Despite no effect have been observed on young mice, this diet becomes deleterious in adult and very old mice with an increase of impaired glucose homeostasis associated with a deterioration of the lipid profile. These metabolic dysregulations result in a further deterioration of arterial and cardiac function. In the very old mice, treatment with resveratrol boosts the damage related to this plan by increasing the metabolic and cardiovascular alterations, highlighting, for the first time, potential deleterious effects of resveratrol in aging. However, in elderly malnourished mice in the absence of nutritional care, resveratrol has beneficial effects with improved insulin sensitivity and arterial functions associated with altered expression of TXNIP, protein regulating glucose homeostasis and oxidative balance, making it worth exploring as to explain some of the mechanisms involved in aging and in the effects of resveratrol.

Les diètes faibles en glucides (Low-Carbohydrate Diet [LCD]; moins de 30 % de l'énergie provenant des glucides) gagnent en popularité chez les personnes atteintes de diabète de type 1 (DbT1). Cependant, l’impact de ces diètes sur le contrôle glycémique et le risque cardiovasculaire (CV) est controversé. Objectif : Évaluer les associations entre le score LCD, le contrôle glycémique et des facteurs de risque CV chez les adultes atteints de DbT1 par le biais d’un registre de DbT1 au Québec (Canada). Méthodologie : Il s’agit d’une étude transversale des données du registre BETTER, utilisant les rappels alimentaires de 24 heures afin de calculer les scores LCD et incluant les données suivantes : mesures anthropométriques auto-rapportées ou mesurées (ex. tour de taille), questionnaires sur les antécédents d’épisodes d’hypoglycémies modérées (nombre d’épisodes dans le dernier mois) et sévères (présence d’au moins un épisode dans la dernière année), perception altérée des symptômes de l’hypoglycémie (score Clarke ≥4) et données biochimiques (HbA1c, cholestérol LDL et cholestérol non-HDL). Un score de 0 à 10 points a été attribué pour chaque macronutriment pour un total de 30 points. Pour les glucides, les participants avec l’apport le plus faible ont reçu 10 points, et l’attribution des points a été inversée pour les lipides et protéines, les participants ayant les apports les plus élevés recevant 10 points. Les participants ont été divisés en quartiles (Q) en fonction de leur score LCD. Résultats : 285 adultes (âgés de 48,2 ± 15,0 ans ; durée du DbT1 de 25,9 ± 16,2 ans) ont été inclus. Dans l’ensemble, les participants ont rapporté des apports faibles en glucides et en fibres et un apport élevé en lipides comparativement aux recommandations. L'apport moyen en glucides contribuait à 31,2 ± 6,9 % (Q1) à 56,5 ± 6,8 % de l'apport énergétique total (Q4). Par rapport au Q4, plus de personnes au Q1 ont signalé une HbA1c ≤ 7 % (Q1 : 53,4 % vs Q4 : 29,4 %; p = 0,011). Les participants au Q3 ont rapporté moins souvent d’avoir un antécédent d’hypoglycémie sévère que le Q1 (Q1 : 60,0 % vs Q3 : 31,0 %; p = 0,004). Il n’y avait aucune différence entre les quartiles pour la fréquence d’évènements d’hypoglycémies modérées, l’altération de la perception des symptômes de l’hypoglycémie et le profil lipidique : cholestérol LDL et cholestérol non-HDL. Conclusions : Les participants avec un faible apport en glucides sont plus nombreux à atteindre la cible d’HbA1c et moins nombreux à présenter des antécédents d’hypoglycémie sévère comparativement à ceux ayant un apport plus élevé en glucides. Cependant, la LCD n’est pas associée à une fréquence de l’hypoglycémie modérée, à une altération de la perception des symptômes de l’hypoglycémie, ni aux facteurs de risque CV. / Low-carbohydrate-diets (LCD; less than 30% of energy from carbohydrates) are gaining popularity in individuals with type 1 diabetes (T1D). However, the impact of such diet on glycemic control and cardiovascular (CV) risk factors is debated. Objective: To evaluate associations between LCD score, glycemic control and CV risk factors in adults with T1D using a registry in Québec (Canada). Research Design and Methods: This is a cross-sectional study using data from the BETTER registry, using 24-hour dietary recalls to calculate LCD scores and including the following data: self-reported or measured anthropometric data (e.g. waist circumference), questionnaires on history of moderate (number of episodes in the last month) and severe (experienced at least one episode in the last year) hypoglycemic episodes, impaired awareness of hypoglycemia (Clarke score ≥4) and biochemical data (HbA1c, LDL-cholesterol and non-HDL-cholesterol). A score of 0 to 10 points was given for each macronutrient for a total of 30 points. For carbohydrates, participants with the lowest intake received 10 points, and the point allocation was reversed for fat and protein, meaning participants with the highest intakes received 10 points. Participants were divided into quartiles (Q) based on LCD score. Results: 285 adults (aged 48.2 ± 15.0 years; T1D duration of 25.9 ± 16.2 years) were included. Overall, participants reported low carbohydrate and fiber intakes and high fat intake compared to recommendations. Mean carbohydrate intake ranged from 31.2 ± 6.9 % (Q1) to 56.5 ± 6.8 % of total energy (Q4). Compared to Q4, more people in Q1 reported HbA1c ≤7 % (Q1: 53.4 % vs Q4: 29.4 %; P = 0.011). Participants in Q3 reported less often having a history of severe hypoglycemia than Q1 (Q1: 60.0 % vs Q3: 31.0 %; P = 0.004). There were no differences between quartiles for frequency of moderate hypoglycemia events, impaired awareness of hypoglycemia and lipid profile: LDL-cholesterol and non-HDL-cholesterol. Conclusions: Participants with low carbohydrate intake are more likely to reach HbA1c target and less likely to have a history of severe hypoglycemia compared to those with a higher carbohydrate intake. However, LCD is not associated with moderate hypoglycemia frequency, impaired hypoglycemia awareness or CV risk factors.

We eat foods not nutrients. What is more, we eat them in combinations. Consequently, capturing our complex food habits is likely an advantage in nutrition research. The overall aim of this doctoral thesis was therefore to investigate dietary patterns in the Swedish population –nutrient intakes, nutritional biomarkers and health aspects. Prostate cancer is the most common cancer among men in the developed world. However, the impact of dietary factors on disease risk is largely unknown. In Study I we investigated the association between a Mediterranean- and a Low-carbohydrate-high-protein dietary pattern and prostate cancer risk, in a cohort of elderly Swedish men. The latter (but not the former) was associated, inversely, with prostate cancer risk when taking validity in food records into account. Diet is one of our main exposure routes to environmental contaminants. Hence, such exposure could act as a mediating factor in the relation between diet and health. In Study II we investigated the association between; a Mediterranean- and a Low-carbohydrate-high-protein dietary pattern, as well as the official dietary recommendations, and circulating levels of environmental contaminants, in an elderly Swedish population. The first two patterns were positively related to levels of both persistent organic pollutants and heavy metals, whilst the dietary recommendations were inversely associated to dioxin and lead. Finally, although dietary patterns are likely to influence health, little is known about current dietary patterns in Sweden. In Study III we used a data-reduction method to identify dietary patterns in a nationwide sample of the Swedish population. Two major patterns were derived; a Healthy pattern of foods generally considered healthy (e.g. vegetables, fruits, fish and vegetable-oils) and a Swedish traditional pattern (with e.g. meats, potatoes, sauces, non-Keyhole milk-products, sweet-bakery products and margarine). Derived patterns were associated to population characteristics and the Healthy dietary pattern was inversely associated to anthropometric variables in Study IV. Dietary characteristics of the patterns were well reflected in correlations to nutrient intake and (to a lesser extent) in nutritional biomarkers. In conclusion dietary patterns for overall health should be considered, as well as other lifestyle-factors, when interpreting results in nutrition epidemiology and establishing dietary recommendations.

The topic of the diploma thesis is the influence of a low-carbohydrate diet on the treatment of type 1 diabetes mellitus. It is an autoimmune disease for which it is necessary for patients to administer insulin. The selection of suitable sports activities, good health and mental condition and, above all, the adjustment of eating habits also contribute to the successful compensation of diabetes. This work demonstrates a low-carbohydrate diet as one of the possibilities diabetics can eat. The work is divided into two parts, theoretical and practical. The theoretical part briefly describes the disease and presents the recommended and a low- carbohydrate diet. The following section also addresses physical activity. It describes the issues of sports for people with diabetes who are on a regular diet, as well as on low-carbohydrate diet. The practical part shows the results of glucose sensors (Free Style Libre, Dexcom G6 and Medtronic), which continuously measure blood sugar levels. In the practical part, eight respondents with type 1 diabetes, who switched the recommended diet for a low-carbohydrate diet, were surveyed in the form of a questionnaire. The purpose of the questionnaire was to assess the effects of switching to a low- carbohydrate diet on: the compensation of diabetes; the frequency of...

Weight gain due to poor diet and lack of exercise is responsible for over 300,000 deaths each year (U.S. Department of Health and Human Services, 2010). Obese adults have an increased risk for serious health conditions including high blood pressure and cholesterol, type 2 diabetes, coronary heart disease, stroke, gallbladder disease, osteoarthritis, sleep apnea, respiratory problems, and certain cancers (National Cancer Institute, 2012). Participation in exercise can help control weight, strengthen muscles and bones, and reduce the incidence of cardiac events, stroke, hypertension, type 2 diabetes, colon and breast cancers, osteoporotic fractures, gallbladder disease, obesity, depression, anxiety, and delay mortality (ACSM, 2009). The purpose of this study was to determine the effectiveness of exercise participation during weight loss on a high protein-low carbohydrate diet plan during a 12-week span in females aged 15 to 25 years. Specifically, this research study was a comparison of markers of health such as weight, fat mass, percent body fat, and fat-free mass in females who consistently exercised during the diet (Exercisers) from those who did not participate in consistent exercise (Non- Exercisers). The population in this study was selected due to the transition from high school to college being a critical period because it is associated with many identity choices and lifestyle changes that can lead to weight gain (Anderson, Shapiro, & Lundgren, 2003). The data indicate participation in regular exercise, while consuming a high protein-low carbohydrate diet plan, increases the loss of body weight, fat mass, and percent body fat when compared to participating in the diet plan alone. There was no significant difference in fat-free mass reduction between the groups. One implication for practice is recommending moderate to vigorous exercise for a minimum of 30 minutes at a time, totaling a minimum of 150 minutes per week, for females trying to achieve weight loss. Based from the results of this research study, in order to achieve a greater amount of body weight, fat mass, and percent body fat reduction one should consider incorporating exercise participation and high protein-low carbohydrate dieting into their weight loss plan.

This study explores the possible efficacy of a low carbohydrate and high fat nutritional intervention (LCHF) as a treatment possibility aiming to improve the ability of self-control and regulation in the context of carbohydrate-addiction. The study first outlines why increased simple carbohydrate consumption has been implicated as a risk-factor in numerous chronic conditions, and then explores the possibility that a reduction of such consumption could lower general medical expenditure in the healthcare sector of already overburdened institutions, especially in developing countries like South Africa. Since the neurobiological evidence for food addiction is compelling, this study investigates the impact of a low carbohydrate and high fat eating (LCHF) regimen by measuring the change in the severity of addictive behaviour in relation to a reduced carbohydrate consumption. Results indicate that a LCHF nutritional intervention lessened addictive behaviour after just 30 days, resulting in a statistically significant decrease in addiction symptoms from day 1 to day 30. The weight and BMI values of the participants recorded at the end of the study showed a reduction from those obtained during the pre- treatment stage, and the self-perceived ‘feeling in control’ also improved in all participants after the intervention. The introduction of a LCHF nutritional intervention presents a relatively cost-effective treatment and preventative measure to combat carbohydrate over-consumption and its numerous health complications, and it is therefore hoped that the positive findings of this study will foster further research, using larger samples, into this type of nutritional intervention against addictive eating behaviour. / Psychology / M.A. (Psychology)