Endocrine Disrupting Chemicals

The endocrine system is a vital network of glands and organs responsible for producing hormones that regulate essential biological processes, including growth, fertility, and reproduction. Endocrine Disrupting Chemicals (EDCs) are substances that can interfere with this system, and potentially cause health issues.

What Are EDCs?

EDCs are natural or synthetic chemicals that can mimic, block, or interfere with the body’s hormones. These chemicals can be found in various sources and can enter the body through breathing, eating, drinking, or skin absorption. Some EDCs act as “hormone mimics,” while others block natural hormones or alter the body’s ability to produce, release, or eliminate hormones. Continuous exposure to EDCs disrupts the delicate balance of the endocrine system.

The Impact of EDCs on Health

EDCs are linked to a range of health problems. They are known to cause cancers, infertility, reproductive health issues, diabetes, obesity, and thyroid disorders. Recent decades have seen a rise in reproductive health disorders and a decline in fertility rates, which may be connected to increased exposure to EDCs.

EDCs and Metabolism

EDCs can disrupt lipid and glucose metabolism in organs like the liver, pancreas, and gut. This disruption can lead to metabolic diseases such as obesity, non-alcoholic fatty liver disease, and type 2 diabetes. EDCs can act directly by interacting with hormone receptors or indirectly by altering the epigenome. Early-life exposure to EDCs can reprogram metabolic processes, potentially leading to lifelong and even transgenerational health effects.

EDCs and Liver Disease

Exposure to EDCs is particularly concerning regarding metabolic-associated fatty liver disease (MASLD). EDCs may reprogram liver metabolism during early life, promoting MASLD. They can exacerbate the effects of a high-fat diet, genetic predispositions, and lifestyle factors, acting as a “second hit” that advances liver damage. Some evidence suggests EDCs might also serve as the “first hit,” compromising the liver’s ability to handle over-nutrition and leading to more severe conditions like steatohepatitis and cirrhosis.

EDCs and Reproduction

Foetal exposure to EDCs can disrupt sexual development with potentially life-long consequences for reproductive function and sexual health. Hormone signalling is crucial for developing male and female sexual characteristics. When this process is disrupted, it can lead to health issues, such as congenital conditions, genital malformations, infertility, and cancers. 

The Hypothalamic-Pituitary Axis and EDCs

The hypothalamic-pituitary axis, where the central nervous system and endocrine system converge, is particularly vulnerable to EDCs. This axis regulates critical hormones like thyroid-stimulating hormone (TSH), growth hormone, and oxytocin, which coordinate growth, lactation, and stress response. Disruption in this system can have profound effects on bodily functions and overall health.

Sources of EDCs

EDCs are pervasive and can be found in:

• Pesticides
• Clothing, furniture, paints, and electronics
• Food and beverages
• Food contact materials
• Plastics and plasticizers
• Personal care products
• Household cleaning products
• Children’s toys
• Industrial chemicals

Regulatory and Research Efforts

The growing concern over EDCs has prompted significant research and regulatory efforts. Projects like HYPIEND specifically analyse EDC impacts on the hypothalamic-pituitary axis. Reports, such as “Endocrine Disrupting Chemicals: Threats to Human Health” by the Endocrine Society in collaboration with IPEN, highlight the severe implications of EDC exposure. However, despite these efforts, the mechanisms of EDC action are still not fully understood, and the lack of detailed mechanistic data and predictive models poses challenges for risk assessment and regulation.

The European Commission’s Strategy on Endocrine Disruptors was adapted in 2018 and has not been updated since. Various ongoing initiatives address the relationship between chemicals and health, for example:

• the 8th Environment Action Programme,
• the Zero Pollution Action Plan,
• the EU’s chemicals strategy for sustainability towards a toxic-free environment,
• the Regulation on the registration, evaluation, authorisation and restriction of chemicals (REACH),
• the Regulation on the Classification, Labelling and Packaging of Substances and Mixtures (CLP),
• the Cosmetic Products Regulation,
• and the OECDs Revised Guidance Document 150 on Standardised Test Guidelines for Evaluating Chemicals for Endocrine Disruption. 

EDCs represent a significant challenge to public health due to their ability to disrupt the endocrine system and contribute to a variety of health problems. Understanding and mitigating the effects of EDCs require continued research and comprehensive regulatory approaches to ensure the safety and well-being of current and future generations.

How ENKORE contributes

ENKORE brings together five different EU research projects that study different health impacts of EDCs. The cluster aims to explore and leverage connections between these projects from research questions and data analysis to interoperability. It also works on translating the science into policy by compiling findings and evidence and tracking the policymaking process. For this, the cluster has established three working groups.