And that was after one week of avoiding foods that may have come into contact with the notorious hormone-disrupting chemical!
A recent study from the University of Exeter has found traces of bisphenol A (BPA) in 86 percent of teenagers. This is concerning, since BPA is a known hormone-disrupting chemical that imitates female sex hormones and has been linked to breast and prostate cancers, as well as low sperm counts and sperm disfigurements in men.
Despite its bad reputation, BPA continues to be used in many plastic containers, water bottles, food cans, dental floss, and heat-resistant papers, which means that humans come into contact with it frequently.
This particular study set out to see if it was possible to reduce one's BPA level by altering dietary choices. It was designed to be a 'real-world setting', unlike prior studies that have focused on families and related individuals, who likely share sources of BPA, and participated in strict dietary interventions that are not realistically sustainable. From the discussion:
"Our intervention is a ‘real-world’ diet, designed to a set of guidelines (such as reduction in the usage of tinned foods or foods with high levels of processing), rather than the strict, prescribed diets that have been used in other studies, which suggested that it was possible for participants to reduce their urinary BPA excretion by approximately 60% in a period of just 3 days. In our self-designed, self-administered study this was unachievable."
Participants included 94 students between the ages of 17 and 19 from schools in southwestern England. They followed a BPA-reduction diet for seven days. This included switching to stainless steel and glass food containers, not microwaving food in plastic, washing their hands after handling receipts, avoiding canned foods and takeout in plastic, and using a coffee filter or percolator instead of plastic coffee makers that may contain polycarbonate-based water tanks and phthalate-based tubing. The students gave urine samples before and after the interventions.
"Participants were unable to achieve a reduction in their urinary BPA over the 7-day trial period, despite good compliance to supplied guidelines."
This alarming discovery goes to show that BPA is so ubiquitous in our environment that, even when we take measures to minimize exposure, it's impossible to avoid entirely. Where it's coming from, however, is unclear. The study authors write that exposure can happen through dust ingestion and skin absorption, and that BPA can leach into food from polycarbonate or epoxy resins after manufacture. The migration rate increases with higher temperatures, and with time and use (which is why you should never reuse a disposable plastic water bottle or microwave food in plastic).
The majority of study participants (66 percent) said it would be difficult to maintain the BPA-reduction diet over the long term, due to inconsistent labelling, sourcing challenges, and having to alter food preferences. Comments included:
"Almost everything is packaged in plastic." "The biggest problem was that a lot of packaging doesn't state what type of plastic it is or whether it contains BPA." "You can't get it all from supermarkets." "[I] had to go to more individual food shops"."
The researchers are calling for more consistent labelling on packaging to make it easier for people to avoid BPA. As Professor Lorna Harries, one of the study authors, told the University of Exeter:
"In an ideal world, we would have a choice over what we put into our bodies. At the present time, since it is difficult to identify which foods and packaging contain BPA, it is not possible to make that choice."