Common chemicals in food may disrupt satiety signals that can cause overeating and obesity.
Chemicals used to preserve food may be causing an uptick in obesity, according to a new study published by Nature Communications. Significant evidence from animals suggests that a link exists between preservatives and obesity, but the effect in humans has not been established.
In the new study, the authors created a new platform and protocol for determining how endocrine disruptors may affect humans.
The authors explored the effect of 3 common chemicals: butylhydroxytoluene (BHT) is an antioxidant used to protect nutrients and prevent fats from becoming rancid; perfluorooctanoic acid (PFOA) is a polymer found in cookware, carpets, and other products; and tributyltin (TBT) is a compound in paints that can contaminate water and affect seafood.
The researchers used hormone-producing tissues from human stem cells to explore how exposure to these chemicals interfere with satiety signals from the digestive signal to the brain. This may cause individuals to eat more than they should and gain weight.
"We discovered that each of these chemicals damaged hormones that communicate between the gut and the brain," said researcher Dhruv Sareen, PhD. "When we tested the three together, the combined stress was more robust."
The authors reported that BHT produced the most negative effects of the 3 chemicals, according to the study.
Although other studies have shown that the chemicals can disrupt hormone systems in animals, this is the first to use stem cells and tissues to determine how it may interrupt gut-to-brain signaling and promote obesity in humans.
"This is a landmark study that substantially improves our understanding of how endocrine disruptors may damage human hormonal systems and contribute to the obesity epidemic in the US," said researcher Clive Svendsen, PhD.
Currently, more than one-third of American adults are obese. The new testing system used in the study provides a safe, cost-effective method to determine how chemicals can affect human health, according to the authors.
In the study, the authors collected blood samples and converted the cells into pluripotent stem cells by introducing reprogramming genes. Using the stem cells, the authors grew human epithelium tissue, which lines the gut and the neuronal tissue in the brain that regulates appetite and metabolism, according to the study.
The investigators then exposed the tissue to BHT, PFOA, TBT, and a combination of the chemicals to determine how they affected the cells.
The authors discovered that the chemicals disrupted the networks that prepare signaling hormones to maintain their structure and be transported outside of the cell, according to the study. This disruption was observed to make the hormones ineffective.
The chemicals were also observed to damage mitochondria, which create energy and drive metabolism.
Since the damage occurred in young cells, the authors hypothesize that the chemicals could impact pregnant women and fetuses; however, the effects of endocrine disruptors have not been proven to occur in humans.
More than 800 chemicals are used in everyday products, including food. Although the chemicals are registered with the National Toxicology Program of the Department of Health and Human Services, the authors report that the effects of the chemicals on human health are unknown.
Currently, many common chemicals have not been evaluated in terms of human health for various reasons, including costs.
"By testing these chemicals on actual human tissues in the lab, we potentially could make these evaluations easier to conduct and more cost-effective," Dr Sareen concluded.