Publication Q&A: Diet Quality and Exposure to Endocrine-Disrupting Chemicals among US Adults
What are the significant findings in this paper?
Healthy diets such as the Mediterranean diet, the Dietary Guidelines for Americans (DGA), and the Dietary Approaches to Stop Hypertension (DASH) can reduce the risk of certain cancers, diabetes, and heart disease. By emphasizing fruits, vegetables, whole grains, and healthy protein sources, these diets supply many nutrients that promote health. However, diets are more complex than their nutrient profiles. Foods can also contain harmful chemicals from the surrounding environment. Chemicals in soil, water, and food packaging materials can contaminate foods. Some chemicals are also approved to be added to foods in small amounts for preservation, flavoring, and other purposes.
Endocrine-disrupting chemicals (EDCs) are one important class of chemicals found in food. EDCs interfere with hormone activity and can increase the risks of many diseases. We examined whether three healthy diets (DGA, DASH, and Mediterranean) or fast-food consumption were associated with EDC exposures in the National Health and Nutrition Examination Survey (NHANES), a survey of the general population.
None of these dietary patterns appeared to increase or decrease exposure to most EDCs. However, adults who closely followed the Mediterranean diet or the DGA had higher exposure to nitrate and perchlorate. These chemicals are found as both approved additives and unintentional contaminants of foods. They appeared to disrupt the production of thyroid hormones in adults who closely followed these diets, especially women.
Overall, this study showed that recommended healthy diets do not protect against exposure to many EDCs and that some healthy diets may increase exposure to chemicals that impair thyroid function.
What does this research tell us that we didn’t know before?
Decades of research have shown the health benefits of diets like the Mediterranean diet, the DGA, and DASH. However, few studies have examined whether these diets reduce exposure to EDCs. We found that exposure to many EDCs including phthalates, bisphenols, and polycyclic aromatic hydrocarbons was widespread, and was not reduced with a healthy diet. We also showed that in some cases, these diets could increase exposure to harmful EDCs.
What are the broad implications of this research?
This study confirms that we are exposed to many EDCs in our daily lives, including through diet. Currently, we do not have a comprehensive set of dietary guidelines to minimize EDC exposure. Even by following recommended healthy diets, individuals may not be able to control their exposure. This suggests that other approaches are needed to reduce the levels of EDCs in our diets, such as changes in food production practices.
What are the next steps and long-term goals for this research?
We are conducting a systematic review to gather and organize data on the levels of many chemical contaminants in foods. This will help us to learn more about the key dietary sources of these harmful chemicals. It will also be useful for developing recommendations for changes in our food production systems to reduce EDC contamination and improve public health.
Seattle Children’s contributing authors:
Melissa Melough, PhD
Sheela Sathyanarayana, MD, MPH