Posted at 7:00 a.m.
In the urine of eight out of ten Canadians
Water bottles, stretch wrap, receipts, reusable or disposable food containers, inner linings of cans and tins… Bisphenol A (BPA) is everywhere in our environment. It makes the plastic hard, transparent and heat resistant. However, it can migrate into food by simple contact and end up in the body, or even penetrate through the skin. Statistics Canada estimated in 2017 that it was found in the urine of 81.5% of the Canadian population. Those with the highest levels of BPA were young people and children.
Should we be worried about it? “Scientists have been studying BPA for decades, but it is still used today almost as if there had never been any studies on it,” says Valérie Langlois, professor at the Institut national de scientific research (INRS). In February 2022, she published an editorial in Environmental Research : it is based on no less than 14 literature reviews and paints a portrait of the current state of knowledge on endocrine disruptors, including BPA.
A molecule that pretends to be a hormone
To better understand the risks associated with BPA, we must go back to its chemical structure. “Like all endocrine disruptors, it looks like a molecule produced in our body, which carries messages between organs,” explains Vincent Prévot, research director at the National Institute of Health and Medical Research, France.
PHOTO PROVIDED BY VINCENT PRÉVOT
Vincent Prévot, research director at the National Institute of Health and Medical Research
BPA resembles estrogen. When it passes through the body, it can give bad information to the brain: it will for example believe that it must stop a stage of the child’s development and move on to the next one, and perhaps not at all at the right time.
Vincent Prévot, research director at the National Institute of Health and Medical Research
According to Health Canada, “most Canadians are exposed to very low levels of BPA that do not pose a health risk.” Do you need a high concentration to see an effect on the body? On the contrary, says Vincent Prévot. A Belgian study published in endocrinology in 2016 showed that even very low doses of BPA could have consequences on the reproductive system of baby rats. “In our body, hormones are secreted in very low concentrations. So when there is a large excess of this pollutant, the organism will say to itself that the signal is so strong that it makes no sense, and it will not take it into account. On the other hand, extremely low doses will have a very large effect – which is not good news”, explains the researcher.
PHOTO PROVIDED BY VINCENT PRÉVOT
In the brain, GnRH neurons (in green) participate in particular in the onset of puberty. Their proper functioning is ensured by other cells, called astrocytes (in red). According to the research work of Vincent Prévot, exposure to bisphenol A in young rats prevents communication between these two types of cells, which leads to dysfunction of the reproductive function (delayed puberty, absence of cycle in the female).
The effects of this endocrine disruptor on the body are multiple. “We know that very low concentrations of BPA in the placenta increase the risk of breast cancer in babies, that its concentration in the urine is correlated with the increased risk of cardiovascular disease”, lists Valérie Langlois.
In search of cause and effect
To change BPA regulations, it must be demonstrated how it affects the human body. This is where things get tricky. “It mimics our hormones, but there are receptors for them all over our body, so the effects can be multiple. It’s difficult to pull a thread to find a very specific mechanism,” explains Vincent Prévot. Added to this is a cocktail of contaminants to which we are exposed throughout our lives, supports Valérie Langlois. “It’s difficult to isolate one, to have certain proof that such a product has such an effect. It’s a project of several lives,” she sighs.
In a study published in November 2021 in Nature Neuroscience, Vincent Prévot and his team have achieved a tour de force. “BPA has been shown to affect neural connections that control reproductive function,” explains the researcher. “This is one of the first times that we clearly see how this endocrine disruptor puts a grain of sand in the cogs of development. A good hope to tip the scales in favor of stricter regulations.
Possible solutions?
Valérie Langlois is convinced that the solution is in the hands of the population. “It’s very political. The more the population will be aware, ask questions, want action, and the more it will happen, ”she argues. However, regulations on BPA like those adopted by Europe are insufficient, warns Vincent Prévot. “Industries are replacing it with other bisphenols, which have not yet been studied, but it is extremely likely that they have the same kind of effect,” he laments.
“We have to stop banishing one molecule at a time; it is rather necessary to ban the activity of this one”, proposes Valérie Langlois.
PHOTO PROVIDED BY VALÉRIE LANGLOIS
Valérie Langlois, professor at the National Institute for Scientific Research (INRS)
The molecules that we put in consumer goods must not interfere with the endocrine system beyond a certain threshold, for example, so that the industry can ensure upstream that the molecules that she uses are not harmful. It may seem simple, but it rarely happens like that.
Valérie Langlois, professor at the National Institute for Scientific Research (INRS)
In the meantime, it is possible to try to limit your exposure to BPA, by favoring baby bottles or glass containers, specifies Vincent Prévot. “The problem is that in our modern society, plastic is fantastic,” grimaces the researcher. “He literally invaded us. If we ban plastic, it will have enormous consequences on everyday life. These are very complex problems, we should develop transversal programs to take all these aspects into account and see how we could change things without destroying everything. »
The BPA ban in a few dates
- 2008: in baby bottles in Canada
- 2010: in baby bottles in France
- 2015: in food containers in France
- 2020: in receipts in Europe