We all have heard that drinking more water is better for our health, but the plastic bottles we drink from may contain dangerous toxins! Some scientific research showed that plastics can emit toxin chemicals that are hazardous to the body.

Harvard School of Public Health researchers report that the plastic bottles in which bottled water is typically sold are made up of toxin polycarbonate which leaches chemical bisphenol A (BPA) leaches. It increases the physiological concentration of this toxic chemical within the body.

"We found that drinking cold liquids from polycarbonate bottles for just one week increased urinary BPA levels by more than two-thirds. If you heat those bottles, as is the case with baby bottles, we would expect the levels to be considerably higher. This would be of concern since infants may be particularly susceptible to BPA's endocrine-disrupting potential," said one of the researchers Karin B Michels of Harvard School of Public Health.

Virtually everything that requires shatterproof, lightweight, clear material that can endure high heat: Reusable food and drink containers, plastic food wrap, eyeglass lenses, medical

devices, dental fillings and sealants, helmets, computers, appliances, power tools, CDs, DVDs and carbonless paper used for receipts.

BPA is an endocrine disruptor meaning that it disrupts hormone function (BPA acts as a potent estrogen). Studies show laboratory animals exposed to low levels of BPA have increased rates of reproductive problems, decreased sperm count, early puberty, obesity, diabetes, memory and

prostate cancers, and neurological problems.

Last year, in the Journal of the American Medical Association, researchers from the US and the UK reported the relationship between urine concentrations of BPA and increased cardiovascular disease, type II diabetes and liver enzyme abnormalities in humans.

Now, Harvard School of Public Health researchers focused on drinking cold beverage from polycarbonate bottles, measured urinary BPA concentration and demonstrated an increase in BPA level. Incidentally, boiling water is known to increase BPA leaching rate up to 55-fold.

BPA is pervasive and can be detected in virtually everybody in the United States. Canada has declared BPA a "toxic chemical" and banned its use in polycarbonate baby bottles in 2008. A few plastic bottle manufacturers have voluntarily removed BPA from their products.

Epidemiological research data warrant the regulatory agencies to pay attention to the growing body of evidence, curb the health hazards posed by BPA and limit human and environmental exposures.

Muhammad Arif is a microbiologist at the Broad Institute of MIT and Harvard University In Cambridge, Massachusetts. E-mail arif@broad mil edu