- Bisphenol A is used in the production
of epoxy resins and polycarbonate plastics. These plastics are
used in many food and drink packaging applications, whilst the
resins are commonly used as lacquers to coat metal products such
as food cans, bottle tops and water supply pipes (ENDS, 1995).
- Some polymers used in dental treatment
Hormone disrupting effects
- Bisphenol A was first shown to be oestrogenic
in 1938, using ovariectomized rats (Dodds and Lawson, 1938)
- More recently, it was found to be oestrogenic
in the MCF-7 human breast cancer cell culture assay in 1993 (Krishnan
et al., 1993). The hormonal effects could be measured at concentrations
as low as 2-5 ppb (2-5 µg/l).
- Bisphenol a can also act as an antiandrogen,
blocking the action of dihydrotestosterone in a yeast screen
containing a human androgen receptor (Sohoni and Sumpter, 1998).
In this screen bisphenol a was approximately as potent as flutamide,
a well known anti-androgenic chemical.
- Liquor containing bisphenol-A obtained
from tinned vegetables has been found to be oestrogenic to human
breast cancer cells (see below).
- Bisphenol a produces identical effects
to those produced by oestradiol on rat uterus and vagina; the
vagina was particularly sensitive to the chemical (Steinmetz,
- Exposure of developing male mice in the
womb has been shown to enlarge their prostate glands (Nagel et
al, 1997). This research has however be disputed by two controversial
chemical-industry backed studies, see the low
dose page for more details.
- It has been claimed that bisphenol acts
in the same way as female hormones in the area of the developing
rat brain which regulates fertility and sexual behaviour (Anon,
- Administration of bisphenol a to male
rats just after birth led to slight changes in the structure
of the efferent ducts, though these changes seemed to only be
transient (Fisher et al., 1999).
- New research shows that female mice exposed
in the womb to low doses of bisphenol a (2.4 micro-g per kg per
day to the mother) had a significantly reduced delay between
vaginal opening and first vaginal oestrus (Howdeshell et al.,
1999). This research also used information on litter position
in the womb, which showed that those females positioned between
female litter mates were most affected by bisphenol a, those
between males were least affected. Research is suggesting that
girls are reaching puberty earlier, see human
health page for details.
- The liquid in some cans of tinned vegetables
have been found to contain both bisphenol A, and the related
chemical dimethyl bisphenol-A. The highest levels of bisphenol
A were found in cans of peas, with an average of 23 µg
per can. Other liquors containing bisphenol A were from cans
of artichokes, beans, mixed vegetables, corn and mushrooms. There
was no detectable bisphenol A in cans of palm hearts, asparagus,
peppers and tomatoes (Brotons et al., 1995).
- All liquors which contained bisphenol
A were oestrogenic to a human breast cancer cell assay. Those
liquors without detectable bisphenol A were not oestrogenic.
The liquor from the most contaminated vegetables, the peas, produced
58% of the oestrogenic response generated by oestradiol (Brotons
et al., 1995).
- The vegetables themselves were not tested
for oestrogenicity or Bisphenol A content , though since they
probably contain more fat than their liquor, they are likely
to contain at least as much Bisphenol A as the liquor.
- This research also included an examination
of cans of other, more fatty, products, including condensed milk,
pork and beans and concentrated milk-based infant formula. Unfortunately,
the products themselves were not analysed. Instead, the cans
were emptied, cleaned, then filled with distilled water and autoclaved
at 125 °C for 30 minutes, then the water was analysed. Some
of these water samples, including those from condensed milk cans,
were found to contain bisphenol A and were oestrogenic. All canned
foods are autoclaved after canning; the fact that bisphenol A
is leached into water during autoclaving in these experiments
suggests that any product packed in similar cans will contain
bisphenol A. It is also likely that substantially more bisphenol
A will leach into fatty products.
- NB: Which canned products do or do not
contain bisphenol A cannot be determined from this study, since
it will depend on the particular brand of product tested. The
cans were purchased in Spain and the USA, but came from a variety
- US Food and Drug administration research
has found that bisphenol a leaches from infant formula cans into
infant formulae (Biles et al, 1997). The levels of bisphenol
found in the formula varied between 0.1 ppb and 13.2 ppb, from
one to six times lower than the Brotons study, above.
- EC rules limit migration of bisphenol
A into food to 3 mg/kg, compared with a maximum liquor concentration
in this research of 80 µg/kg (ENDS, 1995). The EC limit
does not allow for oestrogenic toxicity.
- In 2001 the UK Food Standards Agency published
a study on the leaching of bisphenol a from food cans.
Many transparent 'plastic' bottles are
made from polycarbonate, usually a polymer of bisphenol a. Several
studies have been done on leaching of bisphenol a from these
bottles. The US campaign group the National Environmental Trust
has done their own research on this issues and also have background
information on their
Some (but not all) dental resins contain
bisphenol A. Olea et al. (1996) found that a sealant containing
bisphenol A diglycidylether methacrylate (bis-GMA) was oestrogenic
to MCF7 breast cancer cells. Samples of the saliva from 11 patients
taken 1 hour after dental treatment contained bisphenol a and
bis-GMA. There is some dispute about the deatils of this research
(Ashby, 1997; Imai, 1999;Olea, 1999).
Bisphenol -A is not used in all can lacquers,
but the Metal Packaging Manufacturers Association considers that
the industry might have problems switching to new formulations
(ENDS, 1995). The general secrecy surrounding the chemicals used
in can linings makes it very hard for any external observer to
evaluate what alternatives are available.
For more information
WWF published a detailed report on the
hormone disrupting effects of bisphenol A in May 2000; it is
available free on the web: "Bisphenol
A - A known endocrine disrupter".
This page was last
updated in June 2000
to the hormone disrupting chemicals home page
Anon, 1998. Sex on the brain, New Scientist
Ashby, J. 1997. Bisphenol-a dental sealants:
The inappropriateness of continued reference to a single female
patient. Environmental Health Perspectives 105(4).
Biles, J. E., McNeal, T. P. and Begley,
T. H. 1997. Determination of bisphenol a migrating from epoxy
can coatings to infant formula liquid concentrates. Journal
of Agriculture and Food Chemistry 45, p4697-4700.
Brotons, J. A., Olea-Serrano, M. F., Villalobos,
M., Pedraza, V. and Olea, N. 1995. Xenoestrogens released from
lacquer coatings in food cans. Environ. Health Persp. 103: 608-612.
Dodds, E. C. and Lawson, W. 1938. Molecular
structure in relation to oestrogenic activity. Compounds without
a phenanthrene nucleus. Proc. Royal Soc. Lon. B. 125: 222-232.
ENDS 1995. Public exposed to oestrogen risks
from food cans. ENDS Report 246: p3.
Fisher, J. S., Turner, K. J., Brown, D.
and Sharpe, R. M. 1999. Effect of neonatal exposure to estrogenic
compounds on development of the excurrent ducts of the rat testis
through puberty to adulthood. Environmental Health Perspectives
Howdeshell, K. L., Hotchkiss, A. K., Thayer,
K. A., Vandenbergh, J. G. and vom Saal, F. S. 1999. Exposure to
bisphenol A advances puberty. Nature 401, p763-764.
Imai, Y. 1999. Comments on "Estrogenicity
of resin-based composites and sealants used in dentistry".
Environmental Health Perspectives 107, pA290.
Krishnan, A. V., Starhis, P., Permuth, S.
F., Tokes, L. and Feldman, D. 1993. Bisphenol-A: an estrogenic
substance is released from polycarbonate flasks during autoclaving.
Endocrin. 132: 2279-2286.
Nagel, S. C., vom Saal, F. S., Thayer, C.
A., Dhar, M. G., Boechler, M. and Welshons, W. V. 1997. Relative
binding affinity-serum modified access (RBA-SMA) assay predicts
the relative in vivo bioactivity of the xenoestrogens bisphenol
a and octylphenol. Environmental Health Perspectives 105,
Olea, N. 1999. Comments on "Estrogenicity
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Olea, N., Pulgar, R., Pérez, P.,
Olea-Serrano, F., Rivas, A., Novillo-Fertrell, A., Pedraza, V.,
Soto, A.M., Sonnenshein, C. 1996. Estrogenicity of resin-based
composites and sealants used in dentistry. Environ. Health Persp.
Sohoni, P. and Sumpter, J. P. 1998. Several
environmental oestrogens are also anti-androgens. Journal of
Endocrinology 158, p327-339.
Steinmetz, R., Mitchner, N. A., Grant, A.,
Allen, D. L., Bigsby, R. M. and Ben-Jonathan, N. 1998. The xenoestrogen
bisphenol a induces growth, differentiation, and c-fos gene expression
in the female reproductive tract. Endocrin. 139: 2741-2747.