A fungal toxin that inhibits animal reproduction and fetal growth could potentially interfere with human sex hormones during pregnancy, as indicated by research conducted at Rutgers Health.

Zearalenone (ZEN) is a contaminant found in cereal grains, meats, and processed foods globally. Due to its structural similarity to the hormone 17β-estradiol (E2), it has the ability to bind with estrogen receptors. In certain animals, high doses of ZEN can lead to a decrease in the number and size of offspring. Interestingly, despite this negative effect, these compounds are known to enhance growth in livestock post-birth. In fact, a synthetic form of ZEN is frequently given to cattle in the United States to promote growth.

The research, which was published in the International Journal of Hygiene and Environmental Health, establishes a link between ZEN exposure and hormone levels in pregnant women (1^✔

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Associations between mycoestrogen exposure and sex steroid hormone concentrations in maternal serum and cord blood in the UPSIDE pregnancy cohort

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“The big picture takeaway is that sex steroid hormones like estrogens and androgens are important for all kinds of development, so in theory, this very common dietary compound could be disrupting many aspects of development by disrupting these hormones,” said Carolyn Kinkade, a doctoral degree candidate in the Rutgers School of Graduate Studies Exposure Science program of and first author of the study. “These fungal toxins could impact things ranging from neurodevelopment to asthma to growth patterns to metabolism. It’s important to replicate these results, so we’re currently further looking into these issues using data from other cohorts that have tracked pregnancies and early childhood.”

Mycotoxins are metabolites of fungi which grow on crops. These naturally occurring toxins contaminate food. Zearalenone (ZEN) is a common mycotoxin in the food chain and has been linked to adverse effects on female reproduction.

The research team examined urine and blood samples collected in every trimester of pregnancy, as well as placenta samples obtained postpartum, from 297 individuals participating in a study cohort in Rochester, New York. In addition, cord blood samples were provided by 118 cohort participants.

ZEN was detected in over 93 percent of urine samples and over 57 percent of placental samples.

The research findings indicated a correlation between exposure of Zen and estrogen as well as androgen levels, with variations noted based on the sex of the fetus. For pregnancies carrying male fetuses, increased ZEN levels were linked to decreased estrone and free testosterone, whereas for pregnancies with female fetuses, higher levels of 17β-estradiol were observed. When analyzing cord hormones, which provide a more accurate reflection of the fetus' surroundings, ZEN exposure showed a negative correlation with the weak androgen androstenedione in both male and female fetuses. Furthermore, placental ZEN levels were positively correlated with free testosterone in the cord blood of male offspring.

ZEN and other estrogen-like fungal compounds are known as mycoestrogens. These fungi can be found contaminating cereal crops, with a particular focus on corn and wheat. Scientists anticipate a rise in crop contamination due to the increasing temperatures and humidity levels brought on by climate change.

The rise in these levels would coincide with the growing prevalence of other substances that interfere with hormones during pregnancy, such as plastics and pesticides. An investigation conducted in 2022, which analyzed urine samples from 177 women for 103 various compounds derived from plastics, pesticides, and other pollutants, discovered over 30 chemicals present in the majority of the participants in the study.

“We’re making rapid progress in our understanding of how various environmental factors affect fetal development, but much work remains to be done,” said Emily Barrett, senior author of the latest study, a coauthor of the 2022 study and the George G. Rhoads Endowed Legacy Professor at the Rutgers School of Public Health. “Many questions remain about how to minimize the potential danger of environmental contaminants and maximize the chances of healthy pregnancy and fetal development.”

The researchers suggested future work will explore the potential effects of ZEN on pregnancy, focusing on gestational weight gain and fetal growth, as well as the long-term consequences for the fetus, such as postnatal growth and neurodevelopmental outcomes. It is crucial to examine the possible influences of mycoestrogens and strategies to mitigate exposure for the betterment of public health.

Reference:

1. Associations between mycoestrogen exposure and sex steroid hormone concentrations in maternal serum and cord blood in the UPSIDE pregnancy cohort - (https://www.sciencedirect.com/science/article/pii/S1438463924000865?via%3Dihub)