How does bisphenol A harm humans?
The most frequently reported toxicological effects noted from
exposure to Bisphenol-A include adverse effects on liver cells,
potential for carcinogenicity, and also endocrine effects during
pregnancy and throughout lifelong exposure to this substance. Of
particular concern to the general public health is the widespread
nature of exposure (over 90% of general population testing positive
for bisphenol-A in urine samples) and the long-term nature of
toxicity. The subclinical effects seen throughout life make it
difficult to design adequately robust trials over a sufficient
number of years to identify effects specifically related to
exposure. Like cancer trials, such "longitudinal" studies may
require decades of follow-up to determine confidence in any
clinical significance. The current most significant documentation
concerns the ability of bisphenol-A to act as an estrogen-like
substance within the body. This effect was originally identified as
long ago as over 70 years, but has gained more attention with the
increased emphasis by the FDA on chronic long-term exposure of
minute quantities of chemicals in the population. As a hormonal
"shadow" of estrogen, effects have been implicated such as reduced
sexual dimorphism, or a greater tendency towards androgony
(possessing both traits of male/female) between the genders. It has
also been implicated in the documented increase in female sexual
maturation, based on age of onset of menstruation coming one year
earlier in females and on the appearance of earlier and more
exagerrated features of sexual maturity among girls. It has also
been implicated in the increased rates of miscarriage among women.
Again, these effects occur due to the exposure of the body to
estrogen-like chemicals at an age before the ovaries would normally
produce natural estrogen.