More tales of asking for evidence: is there any point to anti-bac pens?

Anti-bac pen

A pen you can lend without fear of passing on bugs?

My last post concerned Asking for Evidence about chia seeds and ended with a thrilling cliffhanger: what happened when I started asking questions about anti-bac pens? I’ll bet you’ve been biting your nails (you shouldn’t, bad habit) just dying to hear about it. Well the wait is finally over…

First of all, in case you’ve never heard of an ‘anti-bac’ pen, allow me to enlighten you. These are pens made of a special plastic that has been treated to be antibacterial. That pen you lent your mate only to suspect they might have been sticking it in their mouth, and possibly even more disturbing bodily orifices? Fear no more, if it’s an anti-bac pen no germs will adhere to its plastic barrel, and you can continue to chew it yourself with impunity.

Well that’s the theory anyway. A quick look at the website throws up a number of interesting claims. In particular, “The active agent is moulded into the pen and is effective 100% of the time for the entire lifetime of the pen.” and “kills 99.9% of harmful bacteria and viruses” (hey biologists, can you kill a virus?)

The anti-bac website also mentions BS EN 20645, and after a bit of studious googling (I believe I’m correctly following official guidance in using that verb) I discovered this standard relates to the antibacterial activity of textiles, specifically “woven, knitted and other flat textiles”. At the risk of stating the obvious, these pens aren’t knitted. Although apparently the standard can be applied to other materials, providing it’s “adapted accordingly”.

So, how was the test adapted? Are the results published somewhere? Does it really last for the ‘entire lifetime’ the pen (and what is that?) Exactly how much bacterial and viral genocide actually occurs on contact with this shiny white plastic?

I emailed the company to ask them about these questions. What did they say?

Wait for it…

Nothing, nil, nada. No answer. I even used the ‘sales’ address, as companies often actually check that one.

Huh. Well obviously this would be a very short piece if I’d stopped there. So I went in search of another expert, and quickly managed to dig up the contact details of Professor Ian Jones at the University of Reading.

A molecule of triclosan; bacteria beware!

Unlike Anti-bac Ltd he was very quick to reply to my emails, and told me that these pens work in a similar way to anti-bacterial chopping boards. They incorporate a disinfectant into the plastic, usually triclosan. Triclosan is an antibacterial and antifungal agent. It’s actually quite a small molecule, falling into a group called polychloro phenoxy phenol. Sounds good doesn’t it? For the non-chemists out there, things with benzene rings (those hexagon thingies) and phenols (hexagon thingies with OH attached) are often not especially good for one’s health.

Screen Shot 2013-08-19 at 20.04.33And so we find the fire diamond for triclosan… now if you’re a regular reader you’ll be an expert with these by now. If not, just a quick reminder, the higher the number the nastier it is. That 2 in the blue section means that continued exposure could cause possible residual injury. Other substances with a 2 include the old-fashioned anaesthetic ether, and anti-freeze ingredient ethylene glycol. Of course, this is referring to significant quantities of the free chemical, not minute amounts embedded in plastic. And the Environmental Protection Agency concluded that exposure to triclosan – which turns up in lots of things, including anti-bacterial soaps – doesn’t present significant risks to human health. It might not even be triclosan in the anti-bac pens (the company didn’t get back to me, so we don’t know). Still… it raises an interesting point, given how paranoid many people are about chemical exposure. Which is riskier? Bacterial exposure or chemical exposure? Especially taking into account the findings from the University of Michigan School of Public Health that washing with plain soap is actually more effective than using those with antibacterial agents such as triclosan.

Anyway, back to the anti-bac pen claims. Professor Jones went on to say that these pens “have their place, especially in situations which are very sensitive to contamination issues like hospital wards and surgeries. The downside is a false feeling of safety when in fact everything else you touch has not been sanitised in the same way and the fact that their use detracts a little from the real challenge which is to get people to adopt routine hygiene measures such that their hands are not likely to be sources of infection in the first place.”

I asked him more about the ‘lifetime of the pen’ issue, and he explained that the disinfectant is built into the plastic, so organisms are indeed killed when they come into contact with it. As the grip wears down fresh plastic is revealed, so theoretically the anti-bacterial properties never wear out. The problem is that that, of course, pens are picked up by sticky, greasy, sweaty fingers all the time and stuffed into icky pockets and less-than-pristine pencil cases. Once the plastic gets covered in a layer of grime, the whole thing will stop working.

He finished by telling me that “these materials never completely kill organisms, they reduce numbers between 100 and 1000 times. However that can still leave a significant number of organisms alive.

So in summary, chances are the active ingredient won’t really be effective for the lifetime of the pen under normal handling conditions. It might be true that active ingredient kills 99.9% of bacteria, but that could still leave quite a lot on the pen. Worth spending your money on? Maybe in places such as hospital wards, where the people handling them already (we hope) have scrupulously clean hands, but in your child’s grubby pencil case? Probably not.

Want more? The third part of my Ask For Evidence work was recently published on the Sense About Science website, you can read it here.

Tales of asking for evidence: are chia seeds all they’re cracked up to be?

I’ve mentioned it before, but this summer I got involved with Sense About Science’s Ask for Evidence Campaign. This is a brilliant campaign in which Sense About Science (for some reason they never abbreviate their name to initials) encourages people to ask organisations about dubious ‘scientific’ claims. Ever wondered what on earth Boswelox actually is and whether it can really counteract ‘skin microcontractions’? Ask the company for evidence. See what they say. (In that particular case the UK Advertising Watchdog has already weighed in, but you get the idea.)


Are chia seeds all they’re cracked up to be?

I picked up on a few different claims, the first of which had to do with chia seeds. They are the latest health food craze (well, you know, one of latest – this is an area that moves fast, another health food craze could have gone from magical weight-loss aid to dangerous cancer risk in the time it’s taken me to type this), and come with all manner of interesting claims from stabilising blood sugar levels to having “8 times more Omega 3 than salmon“. The trail led back to AZChia, a company set up by Dr Wayne Coates of the University of Arizona. Although, in Dr Coates defence, many of the more hyperbolic media claims don’t appear to have actually started with him, and his work seems to be rigorous.

There are lots of claims out there in the press, but they most seem to boil down to omega-3 fatty acids. Now, there’s a whole other essay to be written on that topic, but essentially (wait for it) these are essential (boom) fatty acids. That means we need them to maintain good health and although there’s some controversy over exactly what they do and don’t affect, there’s no question they’re vital for a healthy metabolism. However they can’t be made in the body (not from scratch, anyway) so we have to eat them. This is potentially tricky for vegetarians because the main source of omega-3 fatty acids is fish oils. But they do turn up in certain plant foodstuffs, and one such foodstuff is chia seeds. In fact, chia seeds biggest claim is that they are the “richest natural plant source of omega-3 fatty acids“.

But before we go any further with this it’s important to realise that there’s more than one type of omega-3 fatty acid. There is a group of molecules that fall into this category, and some of them are tricker to obtain from certain food sources than others. In particular, there’s something called ALA (α-Linolenic acid), another called EPA (eicosapentaenoic acid) and finally DHA (docosahexaenoic acid – these names just get better and better don’t they?).

The main source of these last two, DHA and EPA, is cold-water oceanic fish, like cod and salmon. Both EPA and DHA are converted into prostaglandins which regulate cell activity. DHA is a structural component of such minor essentials as your brain, retina and skin. Make no mistake, you need these molecules.

ALA is slightly different. ALA is available from plants such as, guess what, chia. And also kiwifruit seeds (bizarrely, these have nearly as much as chia seeds), perilla and flax, otherwise known as linseed. Humans cannot make ALA; we have to eat it. However our bodies can make DHA and EPA from ALA.  So, eat your ALA-packed plants and, in theory, you get the complete set.

But it’s not quite that simple (it never is, is it?)  Yes we can synthesise DHA and EPA from ALA, but only poorly. For adults, it might be less than 1% for DHA, and probably less than 5% for EPA (the numbers are slightly higher, although not much, for babies).

Back to that claim that chia seeds have 8 times more omega-3 than salmon (not, I should stress, a claim actually made by Dr Coates). It is true? Well, 100 g of salmon contains roughly 0.4 g of ALA, whereas 100 g of chia seeds contains more like 18 g. So that’s actually a lot more than 8 times. On the other hand, chia seeds contain no DHA or EPA (fish sources, remember) whereas salmon will give you about 1.4 g and 0.4 g respectively. Chia seeds may contain more omega-3 in total than salmon, but it’s not the good stuff. There’s none of the DHA that’s so important for healthy brain, skin and eyes. You might be able to convert a little bit from the ALA that is there, probably enough to get by (particularly if you’re a vegetarian or a vegan and willing to eat a lot of seeds), but oily fish really is the best source.

What about the claim that chia seeds are the richest plant source of omega-3 fatty acids? I pressed Dr Coates for evidence of this, since it’s a statement he makes on his website, and his response was as follows:

“No one paper is going to say that. You are wanting something that does not exist to my knowledge. You would need to compare hundreds of analyses and papers, determine good analyses from bad, etc. Different harvest cycles, growing locations, varieties, all affect the numbers so impossible to really do it. The statement is based on years of work and knowledge.”

So tricky to prove, but probably true. Possibly.

There is a little more to this story. Chia seeds are often promoted as a whole food, packed full of many nutrients over and above omega-3s. A ‘super-food‘, if you will. They do indeed contain a whole range of nutrients. But Dr Loren Cordain, author of the book The Paleo Dietcontends that chia seeds also contain high levels of phytate.  Phytate is the salt of phytic acid, and is a substance that binds minerals such as calcium, iron, zinc, magnesium and copper, making them unavailable for absorption by the body. As a result, chia seeds are actually quite a poor source of these minerals. And, as with all plants, it’s a similar situation with vitamin B6 – it’s something we absorb far more effectively from animal sources. In short, just because something’s in a plant, doesn’t mean we can make use of it.


If you’re not a vegetarian, stick to your oily fish.

So, in summary, should you be sprinkling chia on your breakfast cereal? Well, it probably won’t do any harm. If you’re a strict vegetarian or vegan they may be worth considering, although they’re probably not worth paying a lot of money for. If you’re a meat eater, you’re almost certainly better off sticking with oily fish – it’s a much better source of the really essential fatty acids.


I also investigated some other claims for Ask for Evidence, one of which was the statement made by Health Journalist Hazel Courteney on national radio that “the average person absorbs into their bloodstream alone about 14 kg of toxins annually through their skin.” There is more to follow on this particular story, and it should appear on the Ask for Evidence page shortly.

There was also something on anti-bac pens which I’ll discuss next time. Watch this space!