Alimentation de type occidental

L'alimentation de type occidental est une alimentation qui se distingue de celle prévalente durant la majorité des deux millions d'années d'évolution humaine par des sources de protéines principalement animales, une consommation plus faible de glucides mais dont la moitié est constituée de sucres, un triplement de la consommation de lipides - principalement d'origine animale -, une consommation de fibres de trois à cinq fois plus faible et provenant en majorité de fruits et légumes plutôt que d'aliments de base riches en amidon et enfin une consommation de sel de dix à quinze fois plus élevée. L'alimentation de type occidental a été introduite en partie par la révolution néolithique ans avant notre ère, et surtout par la révolution industrielle au début du . Évolution de l'alimentation La révolution néolithique a introduit les aliments de base de l'alimentation occidentale, parmi lesquels les viandes d'animaux domestiqués (plus grasses), le sucre, l'alco

Computational Approaches for Studying Dietary Behaviors with Digital Traces

Kristina Gligoric

Human nutrition and dietary habits shape our health, daily life, societies, the environment, and life on earth in general. However, it remains challenging to understand and attempt to change dietary behaviors using traditional methods due to measurement and causal identification challenges.In this thesis, we contribute computational and causal approaches leveraging large-scale passively sensed digital traces to shed new light on our dietary behaviors and derive novel scientific insights. We study dietary behaviors in two types of contexts: campus-wide and worldwide. Based on digital traces capturing behaviors of tens of thousands of people on campus and millions of internet users, we develop observational study designs that enable the isolation of causal effects of implicit behavioral interventions, including forming social ties, being exposed to the food choice of others, and stay-at-home interventions. The thesis is organized into three parts.The first part presents studies based on situated on-campus food purchase logs. In the first study, we show how, when a person acquires a new eating partner on campus, the healthiness of their food choice shifts significantly in the direction of their new eating partner's dietary patterns. In the second study, we identify purchasing mimicry, i.e., copying the food choices of others in the purchasing queue, as a specific behavioral mechanism for how similarities in dietary behaviors between individuals occur on campus. The second part of the thesis leverages online information-seeking traces (Google search query logs). Studying worldwide dietary behaviors, we identify and describe global shifts in dietary interests during the first wave of the COVID-19 pandemic, larger and longer-lasting than the typical changes during the end-of-year holidays in Western countries.In the third part, we critically investigate the limits to how much computational approaches can reveal about dietary behaviors in the general population. We contribute a framework for reasoning about biases of digital traces and present a case study of food consumption in Switzerland. The bias estimates derived in the case study imply that researchers should aim to establish evidence of validity before relying on social media and tracking apps---two frequently used digital traces---as proxies for true food consumption in the general population.The novel scientific findings and methodological advances presented here contribute to the existing knowledge about human dietary behaviors and inform the design of future food systems, policies, and behavioral interventions.

EPFL2022

An Increased Arginase Activity Is Associated with Corpus Cavernosum Impairment Induced by Hypercholesterolemia

Younouss Faye, Fabiana Pereira Da Costa Fraga, Nikolaos Stergiopulos, Mikaël Nils Sturny

IntroductionHypercholesterolemia is a prevalent risk factor for the development of erectile dysfunction (ED), mostly due to an increase in oxidative stress and impaired nitric oxide (NO) bioavailability within the penis. Arginase is an enzyme that shares the common substrate L-arginine with NO synthase. Augmented arginase activity reduces NO production and is associated with ED development. However, the contribution of arginase hyperactivity in hypercholesterolemia-induced ED is unknown. AimIn the present study, we investigated the activity and role of arginase in the corpus cavernosum of hypercholesterolemic mice. MethodsApolipoprotein E (ApoE) gene-deleted mice fed with a Western-type diet for 11 weeks were treated with the selective arginase inhibitor, N--Hydroxy-L-norarginine (NOHA), or vehicle (saline 0.9%) during the last 9 weeks. Arginase activity and expression were measured in penis protein extraction. Reactive oxygen species (ROS) content within the corpus cavernosum was measured by dihydroethidium staining. Functional in vitro studies were performed using cavernosal strips mounted in an isometric organ bath to evaluate NO production. Main Outcome MeasureArginase activity and its role in modulating NO and ROS production within the corpus cavernosum of hypercholesterolemic mice is the main outcome measure. ResultsTotal arginase activity and arginase type II protein expression were increased in hypercholesterolemic mice compared with wild-type mice. The long-term treatment with NOHA normalized this alteration. Moreover, pharmacological arginase inhibition by NOHA attenuated the augmented ROS production within the corpus cavernosum of ApoE(-/-) mice, which increased the NO-dependent response in cavernosal strips. ConclusionThese evidences indicate that arginase hyperactivity is associated with ED induced by hypercholesterolemia, suggesting that this enzyme is a potential target for treating ED. Fraga-Silva RA, Costa-Fraga FP, Faye Y, Sturny M, Santos RAS, da Silva RF, and Stergiopulos N. An increased arginase activity is associated with corpus cavernosum impairment induced by hypercholesterolemia. J Sex Med 2014;11:1173-1181.

Wiley-Blackwell2014