Hábitos nutricionales, estilo de vida y exposición a disruptores endocrinos como factores influyentes en el sobrepeso y la obesidad en adolescentes y adultos jóvenes

Resum

Excess weight (overweight and obesity) is one of the most important public health problems in the world. In general, people who suffer from obesity are at risk of suffering from other diseases such as hypertension, diabetes, metabolic syndrome, hyperlipidemia, depression, cardiovascular pathologies, some types of cancer and it is also associated with increased mortality. Although improving eating habits and a healthy lifestyle is key to reversing this problem, there are other environmental factors that seem to be involved in its development, such as endocrine disruptors. The human being is exposed to endocrine disruptors that enter the body through the digestive, respiratory and dermal routes. Avoiding exposure to these hormonally active chemical pollutants is a complicated since there are a multitude of chemical compounds in our daily lives. These chemical substances are used as raw material for the manufacture of other compounds and preparations, which can be plastic containers for food use, pesticides or form part of cosmetics, which makes it difficult to identify the sources of exposure. Exposure in humans usually occurs at low concentrations of mixtures of substances that can interact with each other and with endogenous hormones producing antagonistic, additive and/or synergistic effects. The association between exposure to chemical compounds and body weight has been evaluated in different epidemiological studies. Understanding the health consequences of exposure to dietary endocrine disruptors in vulnerable populations such as children and adolescents is very important to improve current understanding of dietary contributions to exposure to these chemicals and to develop appropriate exposure mitigation programs. That is why several studies have been carried out in this Doctoral dissertation firstly at evaluating the relationship between dietary exposure to certain endocrine disruptors, such as Bisphenol A and its analogs and Parabens, with the aim of establishing a relationship with overweight. and obesity in a vulnerable population such as children and adolescents. Second, the possible hormonal effect of this exposure is established. The obesogen hypothesis proposes that endocrine disruptors can modify susceptibility to obesity, which explains in part the epidemic growth of cases of overweight and obesity. These compounds could trigger weight gain through disruption of adipogenesis and lipid metabolism by binding to nuclear transcription factors, including peroxisome proliferator-activated receptors and steroid hormone receptors. Other mechanisms of action have also been proposed, such as the induction of epigenetic modifications, the deterioration of chromatin structure and the alteration of the intestinal microbiota. And finally, in this Doctoral dissertation, the study hypothesis is raised on the frequency of the expression of certain polymorphisms of a single nucleotide related to adipogenic processes and their relationship with exposure to these chemical substances (bisphenols and parabens). Although obesity has a high heritability, there are more than 900 single nucleotide polymorphisms that have been identified in obesity. There are genetic variants of genes associated with fat mass and obesity that are highly expressed in the brain, negatively interfering with the leptin-mediated response to food and energy balance, metabolism and adipogenesis, which is why these genes are associated with an increased risk of overweight and obesity in children and adults.