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A recent study finds drinking from BPA-lined containers can immediately raise ones blood pressure. Did you notice the word 'immediately'?
Most of us know – or should know by now – that bisphenol-A mimics estrogen and can thus interrupt our cells' reception of hormones. This is called hormone disruption.
But most of us probably figure that drinking from a BPA-lined container won't do much immediate harm, right? Such a notion is shared by many, but unfortunately, it is wrong. Drinking from a BPA-lined container can cause immediate cardiovascular harm.
The ramifications of such a presumption, if true, is disastrous. Today, bisphenol-A and its supposedly-safer version, bisphenol-S, are found in many plastic food and beverage containers along with the linings of many canned food and beverage containers.
In the case of most cans, BPA is contained in the epoxy lining that theoretically protects the food from metal ions (see below) leaching into the food. These can be toxic as they can build up in cells and throw off our body's ionic balance.
But in one of nature's whack-a-mole type ironies, the supposed technological solution to one toxin has simply exposed us to yet another unnatural toxin.
Immediate blood pressure difference from BPA-lined cans
A new study has found that drinking just two drinks from a BPA-lined can significantly raise our levels of BPA. And jack up our blood pressure as a result.
Researchers from the College of Medicine and the Institute of Environmental Medicine at South Korea's Seoul National University studied 60 adults over the age of 60 years old. Their average age was 73 years old and they were mostly women. The subjects attended a testing site three times and during each visit were given soy milk to drink in different containers.
Separated by a few hours, they were each given two soy milks in one type or a combination of two containers. Some were given the two soy milk drinks in two glass containers. Others were given the soy milk in one BPA-lined can and one glass container. And still others were given the soy milk drinks in two BPA-lined cans. Before and two hours after each soy milk drink, the researchers measured urinary BPA concentrations, blood pressures and heart rate variability.
Those who drank out of the BPA-lined cans had urinary BPA levels about 16 times higher than those who drank from the glass containers. This revealed the immediate release of toxins from these containers.
More disconcertingly, two hours after consumption, those who drank both soy milks from a BPA-lined can had significantly higher systolic blood pressure: By an average of 4.5 mm/Hg as compared with those who drank both soy milks from a glass container.
The researchers concluded:
"The present study demonstrated that consuming canned beverage and consequent increase of BPA exposure increase blood pressure acutely."
Keeping the can away from the food or beverage
One might ask why epoxy linings are needed for cans. Today, most cans are made from a blend of metals, which often include aluminum and/or tin-plated steel. In general, there are two primary types - the tin-plated steel can - used for many foods - and the aluminum can used for most beverages.
While the metals used are considered non-corrosive - this is relative to other types of metals. The metals in these cans can corrode and leach to one degree or another, especially in the presence of acids within foods and extreme environmental conditions.
Early cans were made with lead. It didn't take long for people to start suffering from lead poisoning.
Luckily lead-containing cans are no longer produced in modern societies. The primarily aluminum cans of today's beverage containers release some aluminum into a drink's contents, especially when the drink is more acidic (lemonade, for example).
To be fair, studies have shown that the kind of aluminum levels released in normal circumstances are pretty low in comparison to most dietary levels of aluminum consumption. Yet reducing ones intake of foods or drinks from aluminum cans is still advisable.
As far as today's tin-steel cans, the tin content can certainly leach into the food and this can provide some toxicity. For this reason, linings to steel-tin cans are also critical. Assuming they are BPA-free.
In the case of plastic containers - especially polycarbonate - the BPA is a component of the plastic. This means the entire plastic container contains BPA - which can leach BPA directly into foods and beverages. This is worsened by heat or sunlight, which means not leaving plastic containers of food in the sun or in the microwave.
Personally, I am saddened by the abandonment of glass containers by many - even supposedly healthier - food and beverage producers over the past few years. While plastic containers might add a few cents per unit to their bottom line, they are also adding toxicity to their products in the form of BPA.
We can encourage change by choosing glass containers when that option exists.
Bae S, Hong YC. Exposure to bisphenol A from drinking canned beverages increases blood pressure: randomized crossover trial. Hypertension. 2015 Feb;65(2):313-9. doi: 10.1161/HYPERTENSIONAHA.114.04261.
Seruga M, Grgić J, Mandić M. Aluminium content of soft drinks from aluminium cans. Z Lebensm Unters Forsch. 1994 Apr;198(4):313-6.