Bisphenol A (BPA) is a chemical building block used in polycarbonate plastic and epoxy resins production. Polycarbonate plastic is lightweight, tough, has optical clarity and high heat resistance.
Due to these characteristics, polycarbonate is being used for a variety of common products including digital media (like CDs and DVDs), electrical and electronic equipment, automobiles, sports safety equipment, reusable food and drink containers and many other products. All these products contain BPA, the chemical in question.
What should worry us the most is that BPA is also being used in making shatterproof baby bottles, sippy cups, hard plastic flatware and utensils but its traces can also be found in drinking water, dental sealants, dermal exposure, and through inhalation of household dusts.
Scientists have long debated about how terrible may be the BPA’s long-term health effects?
Close to 700 animal studies have showed an implication of the BPA chemical in a variety of health problems. BPA has been found to mimic human estrogen, linked to hormone imbalances, breast and prostate cancers, early puberty in women and reproductive system problems. In laboratory rats, exposure to BPA has been linked to breast enlargement in males, decreased sperm counts and reduced fertility, hyperactivity, obesity, diabetes as well as changes in brain structure, particularly for exposures during key points of fetal or early neonatal development.
However, many have debated the validity of studies on BPA because of the animal and not human involvement since human and rodents’ organs and endocrine systems differ.
Evidence of harmful effects in animals exposed to BPA have been valuable but did not manage to provide sufficient statistical power to correlate low-dose effects in humans.
One of those against the BPA’s health involvement is The Food and Drug Administration (FDA), the agency responsible for determining the safety of what Americans put in their bodies.
They have looked at the dangers of Bisphenol A and concluded that "adequate margin of safety exists for BPA at current levels of exposure from food contact uses.”
Based on two multigenerational rodent studies sponsored by the American Plastics Council, FDA has estimated that BPA exposure from use in food contact materials in infants and adults is 2.42 µg/kg bw/day and 0.185 µg/kg bw/day respectively and determined that the appropriate no observed adverse effect level (NOAEL) is 5 mg/kg bw/day (5000 µg/kg bw/day). The FDA reports there is no reason to ban or restrict the use of BPA in food or drink containers because human exposure levels to the chemical from these sources are too low to have any adverse effects.
The 5 mg/kg bw/day standard was set by the EPA and is questioned by many groups as being way too high. Many are trying to involve politics into the story, saying that the FDA is basing its conclusions on two studies, both funded by an industry trade group, in spite of over 100 published studies by government scientists and university laboratories that had raised health concerns about a chemical compound which worldwide production has now reached approximately 7 billion pounds per year.
The FDA is arguing that the studies with rats and mice it relied on for its assessment are more thorough than some of the human research that has raised doubts.
A monthly journal Environmental Health Perspectives published by the National Institutes of Health issued a lab experiment involving human fat tissue, which found that BPA can interfere with a hormone involved in protecting against diabetes, heart disease and obesity.
Toxicology experts, from the government's National Toxicology Program, who have no regulatory authority, recently completed their own report in which they found no strong evidence of health hazards from BPA but expressed "some concern" about possible effects on the brain in fetuses, infants and children.
Health Canada, Canada's national public health department is the first regulatory body in the world who has called BPA "a potentially harmful chemical".
In the first large-scale study in humans, exposure to bisphenol A was linked to cardiovascular disease, type 2 diabetes and liver-enzyme abnormalities in adults.
Dr. David Melzer of the Peninsula Medical School in Exeter, Britain, and his colleagues took advantage of results from the 2003-2004 U.S. National Health and Nutrition Examination Survey, which for the first time measured concentrations of BPA in urine from a representative sample of 1,455 adults ages 18 to 74.
The researchers found that the quarter of the population with the highest BPA levels, which were still at levels the FDA considered safe, were more than twice as likely to suffer from diabetes and cardiovascular disease as those in the quarter with the lowest levels. The total number of people with these conditions was small: 79 had heart disease and 136 had diabetes. Higher BPA levels also were associated with clinically abnormal concentrations of three liver enzymes. Researchers did not find a link to any other health problems, including cancer or respiratory disease.
The causes of the increased risks are unclear, but certain previous studies may give hints. Spanish researchers found that BPA in mice causes pancreatic cells to increase their production of insulin, leading to the well-known metabolic syndrome that is a precursor of both diabetes and heart disease.
Environmental Working Group says it's crucial to protect fetuses and infants from BPA as they are the most vulnerable to hormonal influences and more than 12 times as much BPA per pound of body weight as adults.
The author, Dr Melzer, a professor of epidemiology and public health, says that the study indicates that the effects of BPA in humans need to be examined more closely. “Until these results are repeated in another study and the effects clarified, it cannot be said with certainty that BPA causes disease in humans.”
Frederick vom Saal, a professor of biology at University of Missouri, Columbia, who has been studied the effects of BPA on molecular levels, strongly believes that BPA is "one of the largest food contact items in existence" and sees the latest results as no surprise.
On the other hand, Polycarbonate/BPA Global Group of the American Chemistry Council (an industry trade group) representatives, report several limitations of the research one of them being lack of causality. Measuring who has disease and high BPA levels at a single point in time cannot tell which comes first, which is a major limitation of the study.
The council believes that the onset and development of these diseases occurred over time periods well before the bisphenol A exposure measurements were made. Due to this as well as other inherent limitations, this study doesn’t show cause and effect relationship between bisphenol A and the health effects.
The council agrees with the study authors that further analysis are needed.
What can we do?
This scientific debate could drag on for years. While we wait for scientists and other organizations to argue over the health effects of the plastic additive BPA, why not take some safety precautions and limit our exposure to food and beverage containers that contain the chemical until we get proper information and proof?
Safe alternatives and safety actions
Instead of hard plastic drinking bottles, it is advisable to use refillable glass or stainless steel ones. Although glass can easily break, it may help the kids drink from a glass sooner with their own hands. Lined aluminum bottles would be best for juices while stainless steel for water. For baby bottles, choose glass or look for companies that make hard plastic bottles Bisphenol A free.
- Avoid using plastic enamelware but try getting baked ones or silveplates.
- Instead of buying soft drinks in cans, choose glass bottles.
- Instead of eating canned food, concentrate on fresh or frozen fruits and vegetables and start cooking instead of just heating. A devastating fact is that at the moment, 17% of the American diet comes out of cans.
- Get rid of the clear plastic baby bottles as the researches are pointing out to the effect of the estrogen-like BPA on children as being the most significant.
- Get rid of older tin cans that sit around a long time, often lined in plastic BPA
- Avoid using polycarbonate bottles for hot drinks, get then replaced with the new BPA free
- Polycarbonates in non-food related products like CDs and DVDs shouldn’t be posing a threat as loon as you keep them out of babies' mouths.
- It is essential you don’t put plastic dishware or containers in the microwave and dishwasher as well as wash them with harsh detergents. High heat and abrasive cleansers damage the plastic, making it more likely to leach. Warm the bottle or cup by placing it in a pan of hot water.
- When buying plastic bottles, avoid those labeled 7 (at the bottom of the containers), as they contain BPA. Use only containers coded 1, 2, 4, or 5.
- By breastfeeding your baby, you will be avoiding BPAs in both bottles and formula can liners. If you do bottle-feed your baby, make sure you use glass baby bottles or those made from BPA-free plastic instead of polycarbonate bottles. When using plastic, look for bottles labeled "BPA free" or buy bottles made of polypropylene, which are usually opaque or colored rather than clear. Getting rid of polycarbonate baby bottles and sippy cups that turn cloudy or are scratched or cracked is a must as worn bottles leach BPA more easily.
- Use powdered instead of liquid formula. While both liquid and powdered formula cans contain BPA, powdered is a safer choice as babies getting reconstituted powdered formula probably receive eight to 20 times less BPA than those fed liquid formula from a metal can. If buying liquid formula, select a concentrated version instead of ready-to-use formula as diluting the product with water will reduce the amount of BPA your baby gets
Large retailers like Wal-Mart and Target are not waiting for the FDA to put forth an opinion on Bisphenol-A either. They’re planning to remove products made with BPA from their shelves since the alternatives to BPA plastics have been long present on the market.