Chemical du jour: how bad is BPA, really?

BPA is an additive in many plastics

When I was writing my summary of 2017 I said that there would, very probably, be some sort of food health scare at the start of 2018. It’s the natural order of things: first we eat and drink the calorie requirement of a small blue whale over Christmas and New Year, and then, lo, we must be made to suffer the guilt in January. By Easter, of course, it’s all forgotten and we can cheerfully stuff ourselves with chocolate eggs.

Last year it was crispy potatoes, and the year before that it was something ridiculous about sugar in ketchup causing cancer (it’s the same sugar that’s in everything, why ketchup? Why?). This year, though, it seems that the nasty chemical of the day is not something that’s in our food so much as around it.

Because this year the villain of the piece appears to be BPA, otherwise known as Bisphenol A or, to give it its IUPAC name, 4,4′-(propane-2,2-diyl)diphenol.

BPA is an additive in plastics. At the end of last year an excellent documentary aired on the BBC called Blue Planet II, all about our planet’s oceans. It featured amazing, jaw-dropping footage of wildlife. It also featured some extremely shocking images of plastic waste, and the harm it causes.

Plastic waste is a serious problem

Plastic waste, particularly plastic waste which is improperly disposed of and consequently ends up in the wrong place, is indisputably something that needs to be addressed. But this highlighting of the plastic waste problem had an unintended consequence: where was the story going to go? Everyone is writing about how plastic is bad, went (I imagine) editorial meetings in offices around the country – find me a story showing that plastic is even WORSE than we thought!

Really, it was inevitable that a ‘not only is plastic bad for the environment, but it’s bad for you, too!’ theme was going to emerge. It started, sort of, with a headline in The Sun newspaper: “Shopping receipts could ‘increase your cancer risk’ – as 93% contain dangerous chemicals also linked to infertility. Shopping receipts are, of course, not made of plastic – but the article’s sub-heading stated that “BPA is used to make plastics”, so the implication was clear enough.

Then the rather confusing: “Plastic chemical linked to male infertility in majority of teenagers, study suggests” appeared in The Telegraph (more on this in a bit), and the whole thing exploded. Search for BPA in Google News now and there is everything from “5 Ways to Reduce Your Exposure to Toxic BPA” to “gender-bending chemicals found in plastic and linked to breast and prostate cancer are found in 86% of teenagers”.

Yikes. It’s all quite scary. It’s true that right now you can’t really avoid plastic. Look around you and it’s likely that you’ll immediately see lots of plastic objects, and that’s before you even try to consider all the everyday things which have plastic coatings that aren’t immediately obvious. If you have young children, you’re probably drowning in plastic toys, cups, plates and bottles. We’re pretty much touching plastic continually throughout our day. How concerned should we be?

As the Hitchiker’s Guide to the Galaxy says, Don’t Panic. Plastic (like planet Earth in the Guide) can probably be summed up as mostly harmless, at least from a BPA point of view if not an environmental one.

BPA is a rather pleasingly symmetrical molecule with two phenol groups. (A big model of this would make a wonderfully ironic pair of sunglasses, wouldn’t it?) It was first synthesized by the Russian chemist Alexander Dianin in the late 19th century. It’s made by reacting acetone – which is where the “A” in the name comes from – with two phenol molecules. It’s actually a very simple reaction, although the product does need to be carefully purified, since large amounts of phenol are used to ensure a good yield.

It’s been used commercially since the fifties, and millions of tonnes of BPA are now produced worldwide each year. BPA is used to make plastics which are clear and tough – two characteristics which are often valued, especially for things like waterproof coatings, bottles and food containers.

The concern is that BPA is an endocrine disruptor, meaning that it interferes with hormone systems. In particular, it’s a known xenoestrogen, in other words it mimics the female hormone estrogen. Animal studies have suggested possible links to certain cancers, infertility, neurological problems and other diseases. A lot of the work is fairly small-scale and, as I’ve mentioned, focused on animal studies (rather than looking directly at effects in humans). Where humans have been studied it’s usually been populations that are exposed to especially high BPA levels (epoxy resin painters, for example). Still, it builds up into quite a damning picture.

BPA has been banned from baby bottles in many countries, including the USA and Europe

Of course, we don’t normally eat plastic, but BPA can leach from the plastic into the food or drink that’s in the plastic, and much more so if the plastic is heated. Because of these concerns, BPA has been banned from baby bottles (which tend to be heated, both for sterilisation and to warm the milk) in several countries, including the whole of Europe, for some years now. “BPA free” labels are a fairly common sight on baby products these days. BPA might also get onto our skin from, for example, those thermal paper receipts The Sun article mentioned, and then into our mouths when we eat. Our bodies break down and excrete the chemical fairly quickly, in as little as 6 hours, but because it’s so common in our environment most of us are continually meeting new sources of it.

How much are we getting, though? This is a critical question, because as I’m forever saying, the dose makes the poison. Arsenic is a deadly poison at high levels, but most of us – were we to undergo some sort of very sensitive test – would probably find we have traces of it in our systems, because it’s a naturally-occuring mineral. It’s nothing to worry about, unless for some reason the levels become too high.

When it comes to BPA, different countries have different guidelines. The European Food Safety Authority recommended in January 2015 that the TDI (tolerable daily intake) should be reduced from 50 to 4 µg/kg body weight/day (there are plans for a new assessment in 2018, so it might change again). For a 75 kg adult, that translates to about 0.0003 g per day. A USA Federal Drug and Administration document from 2014 suggests a NOAEL (no-observed-adverse-effect-level) of 5 mg/kg bw/day, which translates to 0.375 g per day for the same 75 kg adult. NOAEL values are usually much higher than TDIs, so these two figures aren’t as incompatible as they might appear. Tolerable daily intake values tend to have a lot of additional “just in case” tossed into them – being rather more guidance than science.

The European Food Standards Authority published a detailed review of the evidence in 2015 (click for a summary)

So, how much BPA are we exposed to? I’m going to stick to Europe, because that’s where I’m based (for now…), and trying to look at all the different countries is horribly complicated. Besides, EFSA produced a really helpful executive summary of their findings in 2015, which makes it much easier to find the pertinent information.

The key points are these: most of our exposure comes from food. Infants, children and adolescents have the highest dietary exposures to BPA, probably because they eat and drink more per kilogram of body weight. The estimated average was 0.375 µg/kg bw per day.  For adult women the estimated average was 0.132 µg/kg bw per day, and for men it was 0.126 µg/kg bw per day.

When it came to thermal paper and other non-dietary exposure (mostly from dust, toys and cosmetics), the numbers were smaller, but the panel admitted there was a fair bit of uncertainty here. The total exposure from all sources was somewhere in the region of 1 µg/kg bw per day for all the age groups, with adolescents and young children edging more toward values of 1.5 µg/kg bw per day (this will be important in a minute).

Note that all of these numbers are significantly less than the, conservative, tolerable daily intake value of 4 µg/kg bw per day recommended by EFSA.

Here’s the important bit: the panel concluded that there is “no health concern for BPA at the estimated levels of exposure” as far as diet goes. They also said that this applied “to prenatally exposed children” (in other words, one less thing for pregnant women to worry about).

When it came to total exposure, i.e. diet and exposure from other sources such as thermal paper they concluded that “the health concern for BPA is low at the estimated levels of exposure”.

The factsheet that was published alongside the full document summarises the results as follows: “BPA poses no health risk to consumers because current exposure to the chemical is too low to cause harm.”

Like I said: Don’t Panic.

What about those frankly quite terrifying headlines? Well, firstly The Sun article was based on some work conducted on a grand total of 208 receipts collected in Southeast Michigan in the USA from only 39 unique business locations. That’s a pretty small sample and not, I’d suggest, perhaps terribly relevant to the readership of a British newspaper. Worse, the actual levels of BPA weren’t measured in the large majority of samples – they only tested to see if it was there, not how much was there. There was nothing conclusive at all to suggest that the levels in the receipts might be enough to “increase your cancer risk”. All in all, it was pretty meaningless. We already knew there was BPA in thermal receipt paper – no one was hiding that information (it’s literally in the second paragraph of the Wikipedia page on BPA).

The Telegraph article, and the many others it appeared to spawn, also weren’t based on especially rigorous work and, worse, totally misrepresented the findings in any case. Firstly, let’s consider that headline: “Plastic chemical linked to male infertility in majority of teenagers, study suggests”. What does that mean? Are they suggesting that teenagers are displaying infertility? No, of course not. They didn’t want to put “BPA” in the headline because that, apparently, would be too confusing for their readers. So instead they’ve replaced “BPA” with “plastic chemical linked to male infertility”, which is so much more straightforward, isn’t it?

And they don’t mean it’s linked to infertility in the majority of teenagers, they mean it’s linked to infertility and it’s in the majority of teenager’s bodies. I do appreciate that journalists rarely write headlines – this isn’t a criticism of the poor writer who turned in perfectly good copy – but that is confusing and misleading headline-writing of the highest order. Ugh.

Plus, as I commented back there, that wasn’t even the conclusion of the study, which was actually an experiment carried out by students under the supervision of a local university. The key finding was not that, horror, teenagers have BPA in their bodies. The researchers assumed that almost all of the teenagers would have BPA in their bodies – as the EFSA report showed, most people do. No, the conclusion was actually that the teenagers – 94 of them – had been unable to significantly reduce their levels of BPA by changing their diet and lifestyle. Although the paper admits the conditions weren’t well-controlled. Basically, they asked a group of 17-19 year-olds to avoid plastic, and worked on the basis that their account of doing so was accurate.

And how much did the teenagers have in their samples? The average was 1.22 ng/ml, in urine samples (ng = nanogram). Now, even if we assume that these levels apply to all human tissue (which they almost certainly don’t) and that therefore the students had roughly 1.22 ng per gram of body weight, that only translates to, very approximately, 1.22 micrograms (µg) per kilogram of body weight.

Wait a second… what did EFSA say again…. ah yes, they estimated total exposures of 1.449 µg/kg bw per day for adolescents.

Sooooo basically a very similar value, then? And the EFSA, after looking at multiple studies in painstaking detail, concluded that “BPA poses no health risk to consumers”.

Is this grounds for multiple hysterical, fear-mongering headlines? I really don’t think it is.

It is interesting that the teenagers were unable to reduce their BPA levels. Because it’s broken down and excreted quite quickly by the body, you might expect that reducing exposure would have a bigger effect – but really all we can say here is that this needs to be repeated with far more tightly-controlled conditions. Who knows what the students did, and didn’t, actually handle and eat. Perhaps their school environment contains high levels of BPA in dust for some reason (new buildings or equipment, maybe?), and so it was virtually impossible to avoid. Who knows.

In summary, despite the scary headlines there really is no need to worry too much about BPA from plastics or receipts. It may be worth avoiding heating plastic, since we know that increases the amound of BPA that makes its way into food – although it’s important to stress that there’s no evidence that microwaving plastic containers causes levels to be above safe limits. Still, if you wanted to be cautious you could choose to put food into a ceramic or glass bowl, covered with a plate rather than clingfilm. It’ll save you money on your clingfilm bills anyway, and it means less plastic waste, which is no bad thing.

Roll on Easter…


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Something about sugar (free)

Blenheim Flower Show

The Blenheim Flower Show

Last month I went to the Blenheim Flower Show. I hadn’t been before, and I wasn’t quite sure what to expect. In my head I was imagining rows and rows of flowers with a sort of maze-like path through them. I have no idea why, possibly I’ve been doing too much Wizard of Oz (this is not a euphemism).

Perhaps not surprisingly it wasn’t like that at all. In fact the flowers were confined to a couple of easily-avoidable tents, leaving me to wander around stalls selling everything from jewellery to space-saving furniture, chat to the jolly interesting chaps giving a bee-keeping demonstration and scrounge free samples from the food tent.

And it was in the food tent that I came across the Raw Chocolate Pie stall. Sounds good doesn’t it? They’ve combined some very appealing words there. Anyway, the ladies on the stall were very nice and gave me some pieces to taste, and it was indeed scrummy, and sweet. I mention this because in huge letters across the top of the stall were the words “sugar free”. Hm, I thought. They had already told me that the ‘pies’ (actually more like chocolatey lumps) were made with raw cacao beans. Now, I’m a fan of dark chocolate and I’ve tasted 90% cocoa chocolate. It’s bitter. Bitter with a capital bit. It also has a sort of powdery texture due to the low fat content, and this had neither quality.

“So,” I said conversationally, “what’s it sweetened with?”

“Agave nectar,” came the reply.

thefoodofthegodsAt this point I’d heard of agave nectar but I wasn’t really sure what it actually was, so I simply nodded and bought a bar of nut pie. I intended to bring it home and investigate it properly, but it was hot and it got a bit melty, so I was forced to eat it at lunchtime. I took a picture of the wrapper though.

See how it says “sugar free” right there at the top? They are big on this claim. It says sugar free all over the Living Food raw chocolate pie website too.

What would you imagine that means?

It’s a pertinent question. Sugar is one of those words, like ‘salt‘ and ‘alcohol‘, which has a subtly different meaning in chemistry than it does in everyday speech. For chemists these are groups of compounds, but if you read “add pinch of salt” in a recipe book you don’t wonder whether to add sodium chloride or the copper sulfate from your child’s chemistry set. Likewise, if a bottle of wine claims to be 14% alcohol you don’t ponder whether it’s safe to drink or whether you should save it for paint stripper. (Unless, that is, it’s very cheap wine indeed.)

No, in everyday speech we know that salt means sodium chloride, alcohol means ethanol and sugar means, er… sugar means…

Sucrose

Sucrose

This is where it gets a bit sticky. Because there’s more than one sugar that we eat on a regular basis. The white, or sometimes brown, stuff that people bake with and plop into their hot beverages is mainly sucrose. It’s also called ‘table sugar’, or sometimes ‘cane sugar’ or ‘beet sugar’, because those are the plants from which it’s extracted.

Raw chocolate pies haven’t been made with cane/beet sugar, so they might be able to truthfully claim to be sucrose-free. But sugar-free? We-ell…

180px-Glucose_chain_structure

Glucose

The other two sugars that we’re probably most familiar with are glucose, which is the fuel our cells use for energy during respiration, and fructose, which is found in plants and which, like glucose, can be absorbed directly into the bloodstream.

200px-Skeletal_Structure_of_D-Fructose

Fructose

So fructose is found in plants. In fact, fructose is often found in plants chemically bonded to glucose. To make…. sucrose.

So in short:
glucose + fructose = sucrose

And they’re all sugars, and we eat them all on a fairly regular basis. Our bodies break up sucrose into units of glucose and fructose during digestion, and it’s fair to say that none of them are particularly healthy if consumed in large quantities. They’re calorific, bad for your teeth, nutrient-free (other than as an energy source), and regularly eating large quantities of sugar (of any kind) puts you at a greater risk of type II diabetes.

So what’s in agave nectar? Well it comes from a plant, the agave plant, so if you’ve been paying attention that should give you a clue. Yep, it’s packed full of fructose. Which is a sugar. In fact, there are a lot of health concerns around fructose. You may have heard of high fructose corn syrup, or HFCS. This stuff is controversial, with claims that it contributes to obesity, cardiovascular disease, diabetes and non-alcoholic fatty liver disease. Other groups claim these links are unproven, and it’s no worse than any other type of sugar. These groups are mainly people that make and sell high fructose corn syrup, so draw your own conclusions.

Back to agave nectar or, more accurately, syrup. It actually has considerably more fructose than high fructose corn syrup. So bearing all that in mind, is it a healthy alternative? Er, almost certainly not.

Is it correct to call something that’s sweetened with agave ‘sugar free’?

I had a little poke around the Food Standards website. It was something of a slog, but as far as I can work out, the word ‘sugar’ in an ingredients list specifically refers to sucrose. So, you don’t have to list ‘sugar’ in the ingredients list if sucrose isn’t specifically used as an ingredient. But what about the term ‘sugar-free’?

I struggled to find a clear definition of this term on the FSA website, which was a bit annoying (see update below). The best source I can come up with is The Sugar Association, which I’m fairly sure is an American site and so the information quoted wouldn’t apply to a British producer. Still, it’s the best I’ve got, and I’d put money on the rules being similar if not quite identical. This is what they say:

‘“Sugar Free”: Less than 0.5 g sugars per reference amount and per labeled serving (or for meals and main dishes, less than 0.5 g per labeled serving). No ingredient that is a sugar or generally understood to contain sugars except as noted below(*)’ (sic)

The “as noted below” refers to sugar alcohols. These are things like xylitol, mannitol and sorbitol. They often turn up in things like chewing gum. Fructose, at the risk of stating the obvious, is not a sugar alcohol.

There was no percentage composition on the raw chocolate pie wrapper, but just from the taste I’m pretty certain it had more than 0.5 g of sugars (i.e. fructose) per serving. Nothing is that sweet without sugars, unless it also contains artificial sweeteners (which aren’t listed as an ingredient).

I did find this on the Food Standards website:

“To sell food and drink products, the label must be: […] not misleading”

Sugar-free Coke?

Sugar-free Coke?

Is calling something sweetened with a high-fructose syrup (because that’s what agave ‘nectar’ is) misleading? I’m afraid to say that, although I did very much enjoy my nut pie snack, I think it is. By the logic that seems to be being applied here, Coca Cola could use high fructose corn syrup as an sweetener and label their red non-diet bottles and cans as sugar-free, which would be patently ridiculous.

It’s a shame really, because Living Food have a nice product. They just need to get their labelling sorted out.

—-

Update 4th August 2014
After I wrote this I continued my quest to find a proper definition of “sugar-free”. I tried the Food Standards Agency, who sent me to Defra, who ignored me. So I went back to the FSA, who eventually sent me this link. It’s a very interesting document, clarifying and giving examples of how EU Regulation No. 1924/2006, which is all about nutrition and health claims on food, should be applied. On page 70 it says:

‘”The Regulation does […] define any product with no more than 0.5g of sugar per 100ml or per 100g as “sugar free”’

And so conversely, anything with more than 0.5 g of sugar per 100 g as NOT sugar-free. (The official definitions of sugar-free, low-sugar and no added sugar can all be found in the Annex, on page 14, of EU Regulation No. 1924/2006). What still wasn’t entirely clear was exactly what’s meant by ‘sugar’. But now I had somewhere to start. Rooting through EU Regulation No. 1924/2006 I found that it referred to Directive 90/496/EEC for definitions. And there, finally, I got my answer, in Article 1, page 4:

“‘sugars’ means all monosaccharides and disaccharides present in food, but excludes polyols”

Voilà! Fructose is a monosaccharide, and therefore if your product has more than 0.5 g of fructose per 100 g, then it cannot accurately be labelled sugar-free.

I can’t prove this is the case for the Raw Chocolate Pies, since I my testing involves tasting two samples. But if it looks like a duck, and quacks like a duck, it’s probably a very sugary duck.

The question of ‘no added sugar’ may be somewhat irrelevant, since they’re not making this claim, but I think it’s illuminating. If agave syrup has been added then “no added sugar” can’t even be used, since (from regulation (EC) No. 1924/2006):

“A claim stating that sugars have not been added to a food, and any claim likely to have the same meaning for the consumer, may only be made where the product does not contain any added mono- or disaccharides or any other food used for its sweetening properties.”

So that’s the end of the journey, really. You can only call something sugar-free if there’s no sugar in it, and that includes fructose (‘fruit sugar’), glucose and sucrose (‘table’ sugar). Foods sweetened with agave, which contains fructose, aren’t sugar-free, unless they have only the tiniest amount – less than 0.5 g per 100 g – added.