Estrogen exposure could significantly increase the risk of developing breast cancer later in life for girls who experience early puberty. Several results from studies have consistently shown that early onset of puberty increases the risk of breast cancer due to longer exposure to the hormone. Puberty is a period in a girl’s life considered highly sensitive to stimulation by estrogen. The Jersey Girl Study based at The Cancer Institute of New Jersey (CINJ), which aims to analyze factors that affect puberty in girls, has shown that estrogen-like substances produced by fungi might act as a hormone disrupter.

In the urine samples donated by 163 girls participating in the study, a multidisciplinary team of researchers led by CINJ epidemiologist Elisa Bandera, M.D., Ph.D., discovered detectable levels of these fungal compounds, known as mycoestrogens. The findings indicate that height growth and the onset of breast development may be delayed due to the presence of mycoestrogens.

Mycoestrogens are produced by fungi and are present in grains and foods, such as eggs, meat and dairy products through contamination or deliberate introduction of the synthetic mycoestrogen zeranol into livestock for the purpose of improved meat production. The most important mycoestrogen is Zeranol – a non-steroid agent approved by the U.S. Food and Drug Administration to promote animal growth in beef production. In the European Union and other countries the use of Zeranol for these purposes is banned.

The researchers measured zearalenone mycoestrogens and zeranol in the participants urine samples and discovered:

  • The substances were detected in 78% of urine samples.
  • High levels of zearalenone mycoestrogens were detected in 55% of the samples.
  • While low levels of zeranol were detected in over 20% of samples.

The team also analyzed food sources for these mycoestrogens and discovered that popcorn and beef intakes were strong predictors of detectable levels in urine. When the association with development and growth was analyzed they discovered that girls whose urine contained the fungal hormones tended to be shorter and less likely to have started developing breasts.

Dr. Bandera, who is the lead author of the study and an associate professor of epidemiology at UMDNJ-Robert Wood Johnson Medical School., explained:

“Because zearalenone mycoestrogens are widely distributed in the food supply, it is critical that we have a better understanding of their levels, their food sources and their effects on the development of young girls, which ultimately has important implications for their future breast cancer risk. To our knowledge this is the first study evaluating mycoestrogens in healthy girls. More studies are need in this very important research area. This is just the beginning.”

CINJ is a Center of Excellence of UMDNJ-Robert Wood Johnson Medical School. Findings from the investigation are scheduled to be published in the Nov. 15 print edition of the journal Science of the Total Environment (doi:10.1016/j.scitotenv.2011.09.029).

As well as investigators from CINJ, the Jersey Girl Study team includes experts in environmental health at the Environmental and Occupational Health Sciences Institute (EOHSI – jointly administered by UMDNJ-Robert Wood Johnson Medical School and Rutgers, The State University of New Jersey), pediatric endocrinology at UMDNJ-Robert Wood Johnson Medical School, and biostatistics at CINJ and UMDNJ-School of Public Health.

Further information about the Jersey Girl Study can be found here.

Written by Grace Rattue