|
 “The results were actually exactly what we were expecting to find,”
said lead author Dr. Jorge E. Chavarro of the Harvard School of
Public Health-Nutrition in Boston.
BPA is known to mimic estrogen in the body, and therefore it’s
believed to disrupt conception and implantation of a fertilized egg
in the womb, the researchers write in the Journal of Clinical
Endocrinology and Metabolism.
Experiments in rodents suggest that soy, which also interacts with
estrogen receptors, could offset or mitigate those effects of BPA,
they add.
“We wanted to follow-up on the results of two experimental models in
rodents where two independent groups had found that some adverse
reproductive effects of BPA could be prevented by placing the mice
on a soy based diet,” Chavarro told Reuters Health by email. “We
wanted to see whether a similar interaction occurred in humans.”
The researchers studied 239 women who underwent in vitro
fertilization cycles between 2007 and 2012. The women completed
dietary questionnaires and provided urine samples before egg
retrieval for each fertility cycle.
The questionnaire included assessment of the women’s intake of 15
soy-based foods, including tofu, soy burgers, miso soup, soy protein
and soy bars. Consumption of these items ranged from never or less
than once per month to twice daily.
Almost three quarters of the women said they consumed at least some
soy foods.
Most women underwent one IVF cycle, 18 percent underwent two cycles
and 11 percent underwent three cycles.
As urinary BPA levels increased, the women who did not eat soy foods
had lower rates of implantation, clinical pregnancy and live birth.
But for women who did eat soy, increasing BPA levels were not tied
to fertility outcomes.
“We still need to evaluate whether the same is also true for couples
trying to get pregnant without medical help or whether risks extend
to the health of children,” Chavarro said.
[to top of second column] |
In one of the previous mice studies, BPA was able to switch on and
off certain genes and soy prevented BPA from doing so, Chavarro
said.
“We cannot be certain whether this is the same mechanism operating
in our case or whether other mechanisms yet to be identified could
also be at play,” he said.
BPA is safe in the current levels occurring in foods, according to
the U.S. Food and Drug Administration.
“Based on nationally representative surveys we know that more than
90 percent of Americans are exposed at varying levels,” but exposure
to BPA can be minimized by switching from consuming canned foods to
their fresh or frozen counterparts, replacing hard polycarbonate
plastic food containers with glass or metal containers, and not
handling thermal receipts such as those used in supermarkets, ATMs
and gas stations, Chavarro said.
It is important to confirm these findings, since this is the first
time that an interaction between BPA and diet has been reported in
humans, he said.
But soy on its own, regardless of whether or not it interacts with
diet, appears to be beneficial to women who are trying to become
pregnant, he said.
SOURCE: http://bit.ly/1T1Cobk Journal of Clinical Endocrinology and
Metabolism, online January 27, 2016.
[© 2016 Thomson Reuters. All rights
reserved.] Copyright 2016 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
 |
