April health news -- Dangerous drinking bottles?

Bisphenol A, a chemical used in some plastics, has been at the center of controversy since late last year, with scientists and environmental groups accusing the compound of leaching out of containers and jeopardizing our health.

BPA has been used for decades to make polycarbonate plastics, a hard material used in the linings of some food cans and in some clear, reusable bottles such as baby bottles and water bottles.

But recent studies suggest that the chemical, known as an "endocrine disrupter" for mimicking estrogen and interfering with the hormone system, has been linked to a host of health problems, from reproductive issues and cancer to diabetes.

The suspected dangers of BPA
In the anti-BPA camp, the following information reveals suspected threats of BPA:
In February, a study commissioned by Environmental Defence, a Canadian activist group, tested baby bottles made by Gerber, Playtex and Avent. The findings showed no notable leaching at room temperature, but "significant" levels when heated -- 5 to 8 parts per billion. (Canada's designated limit of BPA exposure is 25 parts per billion per day).

A 2008 study from scientists at the University of Cincinnati and published in the journal Toxicology Letters found that when hard plastic bottles were filled with boiling water, BPA was released 55 times faster than when filled with room temperature water. 

A 2007 article by Frederick Vom Saal, a biologist at the University of Missouri, and 37 other leading experts on BPA published in the journal Reproductive Toxicology stated that exposure to the chemical led to changes in prostate, testes, mammary gland, brain structure and behaviour in lab animals.

The article also suggests BPA may be linked to human health hazards including:
-breast and prostate cancer
-Type 2 diabetes
-early onset of puberty in girls
-obesity and;
-neurological behaviour problems.
The assessment was sponsored by the U.S. National Institute of Environmental Health Sciences.

Belief of BPA threat varies, according to whom you ask
"Along with the health ailments, they're saying that the current concentrations in the population are above the concentrations that are being found in the studies to cause health effects," Aaron Freeman, policy director of Environmental Defence says about the NIEHS evaluation. "The other thing they said is, because of the way this chemical interacts with the body, what we're seeing in animal studies we can expect to see in the human population."

However, Dr. Joe Schwarz, director of McGill University's Office for Science & Society, says it's almost impossible to determine just how the chemical will affect humans. "You could eat Bisphenol A by the spoonful and you wouldn't notice anything now. It's a question of what may happen over the long term, and that's very, very difficult to evaluate. The only way you could ever have an answer to this is to take two groups of humans, expose one group to known amounts of BPA and follow them for decades. It's not doable. There are a lot of experts making guesses on this."

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Favourable findings for BPA
Meanwhile, the flip side of the BPA debate offers the following considerations:
In 2007, a 12-member panel of experts convened by The Center for the Evaluation of Risks to Human Reproduction, part of the National Toxicology Program in the U.S., reviewed over 700 published studies and concluded that they had "some concern" that PBA exposure could cause neural and behavioural effects for fetuses, infants and children. They had "minimal concern" that exposure affects the prostate or accelerates puberty, and "negligible concern" for adults and their reproductive health. 

Studies by The American Council on Science and Health found that BPA causes no adverse health conditions in humans and in February rejected calls for a baby bottle ban.

After sampling urine output from more than 2,500 people from ages 6 to 85, The Centers for Disease Control in the U.S. found that BPA does not accumulate in the body.

The European Food Safety Authority (EFSA) declared the Tolerable Daily Intake (TDI) of BPA for humans, based on observable toxic effects in animals, to be 50 micrograms per kilogram of body weight per day. Drawing its conclusions from completed leaching experiments, EFSA found that exposure was less than 30 per cent of the TDI.

After sampling urine output from more than 2,000 people from ages 6 to 85, The Centers for Disease Control in the U.S. found BPA exposure levels to be 1,000 times less than EFSA's TDI.

While your body can excrete BPA every 24 hours or so, Freeman notes that you can ingest these chemicals every day. "We're being exposed to this chemical on a chronic basis," he explains, but points to hopeful evidence on the other side of the world: "When Japan got rid of BPA in food containers, they measured before and after, and what they found was that the levels of BPA in the population went down by 50 per cent."

BPA investigations continue
The U.S. National Toxicology Program is reviewing the effects of BPA exposure on human health, Ontario Premier Dalton McGuinty is looking into whether restrictions need to be placed on the chemical's use, and Health Canada is examining 200 chemicals "of interest to Canadians," including BPA. The report is expected in May 2008. In the meantime, outdoor retailer Mountain Equipment Co-op and Lulumemon Athletica have pulled their BPA water bottles from store shelves.

But Schwarz says the controversy is unwarranted. "It's unrealistic to point fingers at one specific compound. We are exposed to thousands and thousands and thousands of compounds every day in the food we eat, the water we drink, the cosmetics we use, the air we breathe," he says. "We worry about BPA but we allow the sale of cigarettes. It's ludicrous. When you have something that is killing people by the millions every year without a doubt, it's a known carcinogen and it's legally sold, and then you worry about trace amounts of a possible carcinogen."

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Pregnant woman, babies and infants
Schwarz believes there is some legitimacy surrounding BPA concerns when it comes to pregnant women, babies and infants because of their small body weight. "If there is some sort of hormonal effect, that's when it's going to happen, during the most significant developmental stage. But for adults, I don't see any evidence that causes this concern."

As for lining canned foods, Schwarz says BPA resins are ideal. "When push comes to shove, manufacturers can come up with alternatives, and they will, not because they believe they need to do it because of safety but because that's what the marketplace demands."

How to reduce your BPA exposure
While the debate continues and health organizations continue to test and review evidence, consumers will have to make their own decisions on whether they'll continue to use BPA items or not.

If you want to reduce your exposure:
-Check your plastic containers for the recycling symbol with a # 7 on it. That indicates it's a BPA product. Be aware, though, that although all BPA products should have a #7, not all #7 products are BPA.
-Use glass, plasticized glass, stainless steel or non-BPA plastic baby bottles.
-Switch to stainless steel, lined aluminum or non-BPA plastic water bottles and storage containers.
-Avoid placing plastic in the microwave or in the dishwasher.
-Limit consumption of canned foods; buy fresh or dried instead.
-Use wax paper to wrap foods, rather than plastic.
The final call is yours to make

"The main pathways for BPA are food and beverage containers. Consumers should not have to do the constant calculus when they walk up and down the store aisles," says Freeman. "But until the government takes action, avoid them. There are safe alternatives."

"BPA is the toxin du jour," says Schwarz. "Nobody knows what are the long-term consequences of thousands of chemicals that we are exposed to because it cannot be known. What we do know is that the average life expectancy gets longer every year. So we can't be doing everything wrong."

What's your take on BPA? Will you stop using these plastics in your household? Click the microphone icon on this page to share your thoughts.

In addition to bisphenol A, protect yourself from 4 cancer-causing substances.

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