According to a recent study
presented at the 2016 European Congress of Endocrinology in
Munich, Germany, early exposure to two chemicals often found in food packaging
and fungicides may cause damage to children's teeth that can never be reversed,
a new study finds.
Lead study author Dr. Katia Jedeon, of the French National Institute of Health
and Medical Research (INSERM), and colleagues found exposure to the chemicals
bisphenol A (BPA) and vinclozolin may interfere with hormones responsible for
the growth of dental enamel.
BPA and vinclozolin have been
identified as endocrine disruptors (EDs) in numerous studies. This means they
can interfere with hormone functioning in mammals, increasing the risk of
reproductive problems, cancer, births defects, and various other conditions.
BPA is used in the production of
certain plastics and resins, many of which are used for food and drink
packaging (especially bottles containing beverages and the resins that coat the
inside of food cans) while vinclozolin is a fungicide used to protect
vineyards, orchards, and golf courses.
These researchers noted that
previous animal studies have indicated that EDs may be related to a condition
called molar incisor hypomineralization (MIH),
which is estimated to affect up to 18 percent of children aged 6-9 years.
MIH is a developmental condition in
which enamel defects occur in the first permanent teeth, most commonly the
molars and incisors. Such a defect is irreversible; once tooth enamel is
damaged, it cannot grow back. Children
with MIH can experience heightened tooth sensitivity, particularly to cold
foods and drinks, and they are at greater risk for dental caries. Their teeth
may be creamy, yellow, or brown in appearance, and they may chip away easily.
For their study, Dr. Jedeon and
colleagues conducted two experiments to gain a better understanding of how
exposure to EDs might be associated with MIH. They first exposed rats to daily doses of
either BPA alone or a combination of BPA and vinclozolin from birth for 30
days. Doses were equivalent to the average daily dose a human would be exposed
to. At the end of the 30 days, the
researchers collected cells from the surface of the rats' teeth.
On analyzing the cells, they found
that exposure to BPA and vinclozolin altered the expression of two genes - KLK4
and SLC5A8 - that regulate tooth enamel mineralization.
Next, the researchers cultured
ameloblast cells of rats, which are cells that deposit enamel during tooth
development. They found that these cells contain sex hormones - including estrogen
and testosterone - that increase the expression of genes that
produce tooth enamel. Interestingly,
they found that testosterone increases the expression of the KLK4 and SLC5A8
genes.
Because
both BPA and vinclozolin are known to inhibit the effect of male sex hormones,
the authors say their findings indicate that the chemicals may lead to MIH by
blocking hormones needed for development of tooth enamel. The study’s lead author, Dr. Katia Jedeon,
stated, "Tooth enamel starts at the third trimester of pregnancy and ends
at the age of 5, so minimizing exposure to endocrine disruptors at this stage
in life as a precautionary measure would be one way of reducing the risk of
enamel weakening."
How can you avoid BPA?
- Use BPA-free products. Manufacturers are creating more and more BPA-free products. Look for products labeled as BPA-free. If a product isn't labeled, keep in mind that some, but not all, plastics marked with recycle codes 3 or 7 may be made with BPA.
- Cut back on cans. Reduce your use of canned foods since most cans are lined with BPA-containing resin.
- Avoid heat. The National Institute of Environmental Health Sciences, part of the National Institutes of Health, advises against microwaving polycarbonate plastics or putting them in the dishwasher, because the plastic may break down over time and allow BPA to leach into foods.
- Use alternatives. Use glass, porcelain or stainless steel containers for hot foods and liquids instead of plastic containers.
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