Report of the Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN) on the available evidence in relation to the potential obesogenic activity of certain chemical compounds that may be present in foods

*This record is given in both English and Spanish According to the World Health Organization (WHO), obesity and overweight have reached epidemic proportions globally. In Spain, the prevalence of obesity is high, especially in childhood, with an upward trend in the last two decades. While improving dietary habits and increasing physical activity has been the main focus on reducing obesity, its rapid increase in countries with different dietary habits and physical activity patterns suggests the possible existence of environmental factors, such as exposure to chemicals with obesogenic activity. Obesogens have been defined functionally as chemical compounds that promote obesity by increasing the number of adipose cells and/or the accumulation of fat in existing adipocytes. Among the most studied obesogens are substances used in the plastic industry such as bisphenols and phthalates, organotin compounds, flame retardants, perfluorinated compounds, polychlorinated biphenyls and dioxins, pesticides and metals, among others. Because the term obesogens includes a large number of compounds, exposure to them can occur by different routes such as inhalation, dermal exposure or ingestion, the latter being the main route of exposure. The mechanisms of action of obesogens are diverse, and they can act by activating or antagonizing the action of nuclear hormone receptors that directly regulate the expression of genes involved in the differentiation of adipocytes, body weight and metabolism, such as oestrogen, androgen and thyroid hormone receptors, and the peroxisome proliferator activated receptor-γ, among others. They can also act in the regulation of different immune-neuroendocrine metabolic pathways, which can lead to pathophysiological consequences in adipogenesis, lipogenesis, lipolysis, immunity, in the influence on the central regulations of appetite and energy expenditure, and changes in the intestinal microbiota, among other processes. It is important to highlight that the most critical periods of exposure to obesogens are preconception, pregnancy and childhood given their importance for metabolism, and may result in permanent changes in adolescence and in adulthood. In this context, the Scientific Committee of the Spanish Agency of Food Safety and Nutrition (AESAN) has carried out a review of the evidence that exists on food exposure to obesogens and its possible effect on health. Scientific literature shows in in vivo and in vitro studies the obesogenic effect of some chemical compounds present in food, and epidemiological studies reinforce this hypothesis. The Scientific Committee recommends that a greater number of studies be carried out to assess the effect of exposure to these compounds, standardizing biomarkers of exposure and effect in order to predict and evaluate their obesogenic capacity and the possible transmission of the effect to other generations through epigenetic mechanisms. Once all the necessary evidence is available, there must be coordination and communication between scientists, clinicians and national and international regulatory bodies, in order to develop a global and efficient strategy in the implementation of risk management measures to reduce exposure to these substances as much as possible.