Is it possible to give up sugar completely?

It’s January, a month that’s traditionally marked by cold weather, large credit-card bills and, of course, an awful lot of highly questionable health stuff. Juicing, detox, supplements… it’s all good fun. Until someone gets hurt.

"Refined" sugar is almost entirely made up of a molecule called sucrose.

“Refined” sugar is almost entirely made up of a molecule called sucrose.

One substance that regularly gets a bashing is sugar, particularly so-called “refined” sugar. We’re told it’s toxic (it’s not), it’s more addictive than cocaine (it isn’t) and we should definitely all be trying to give it up.

Now, before I go any further with this, a word about healthy eating. I’m not a dietician. I don’t even claim to be a nutritionist (although I could, if I wanted). However, I think I’m on fairly safe ground if I say that we should all be striving for a healthy, balanced diet. That is, a diet containing a broad range of foods, plenty of fruits and vegetables, healthy amounts of protein and some good fats.

A lot of people have diets that fall short of this ideal. Cutting back on foods which contain a lot of added sugar (cakes, chocolate, fizzy drinks, etc) and eating more vegetables and fruits is a good, and sensible, course of action.

The problem is that bit of common-sense advice doesn’t sell books or make an interesting TV show. It’s all a bit boring and, worse, it’s freely available. Compelling entertainment needs to be more exciting, more dramatic, more… extreme.

Which brings us to ITV’s Sugar Free Farm.

Page 81 of the current issue of Radio Times tells us that the celebrities face a "completely sugar-free regime".

Page 81 of the current issue of Radio Times tells us that the celebrities face a “completely sugar-free regime”.

This is actually the second series of this show, which first aired last year. According to the 7-13th January 2017 issue of the Radio Times:

“Seven celebrities who admit to terrible diets succumb to a few weeks of hard farm labour and a completely sugar-free regime (so no white carbs or fruit, let alone chocolate).”

Hm. Now, I’ve written about sugar more than once before, but to save clicking back and forth, here’s another quick summary:

Sugar is not one thing. The chemistry of sugars is quite complicated, but a human being trying to understand the food they eat probably needs to be aware of three main types, namely: glucose, fructose and sucrose.



Glucose is the sugar that all your cells need. Not having enough glucose in your bloodstream is called hypoglycaemia, and the result is seizure, coma and ultimately death. This isn’t a risk for healthy people without pre-existing conditions (like diabetes, for example) because evolution has put some clever safety-nets in place. First, our bodies are extremely efficient at carrying out the necessary chemistry to turn the molecules we eat into the molecules we need. Should that fail, our bodies are very good at storing nutrients to use in times when our diet doesn’t supply them. If you don’t eat glucose, your body will break down other foods to produce it, then it’ll start on your glycogen stores, move on to fat stores, and eventually start breaking down protein (i.e. the stuff in your muscles). This means that unless you stop eating completely for a fairly long period of time, you’ll survive.

Still, I think it’s important to emphasise the point: glucose is essential for life. The suggestion that this substance is “toxic” and thus should be completely eliminated from our diets is really, when you think about it, a bit odd.

Sucrose ("refined sugar") is a unit of glucose joined to a unit of fructose

Sucrose (“refined sugar”) is a unit of glucose joined to a unit of fructose

Ah but, I hear some people saying, no one is saying that glucose is toxic! They’re talking about refined sugar!

Fine. So what’s “refined” sugar? In simple terms, it’s pure sucrose. And sucrose is just a molecule made from a unit of glucose stuck to a unit of fructose. As I said, our bodies are really good at breaking up the molecules we eat into the molecules we need: our cells can’t use sucrose for energy, so all that happens is that it more or less instantly gets broken up into glucose and fructose.

Refined sugar is, basically, half glucose and half fructose, and it’s no more dangerous or “toxic” than either of those substances. And while I’m here, “natural” sugar options are little different: honey, for example, contains similar ratios of fructose and glucose.



Allrighty then, what’s fructose? Fructose is another simple sugar, and it’s the one that plants produce. For that reason it’s sometimes called “fruit sugar”.

Our cells can’t use fructose for energy, either. But, same thing again: if you eat it your body will still use it. In this case, your liver does the heavy lifting; changing fructose into glucose and other substances, some of which are fats. On the one hand, this is a slower process so you don’t get the blood sugar spike with fructose that you get with glucose. On the other, some of the fructose you eat inevitably ends up being converted into fat.

As I mentioned, fructose is the sugar in plants. It’s found in almost all plant-based foods. For example, the USDA food composition database tells us that 100 g of carrots contains about 0.6 g of fructose. Perhaps surprisingly, broccoli contains slightly more: about 0.7 g per 100 g. Iceberg lettuce contains even more, at 1 g per 100 g, whereas green peas contain a mere 0.4 g.

Even a really small glass of fruit juice contains about 150 g.

Even a small serving of fruit juice usually contains at least 150 g.

None of this comes close to fruit. Apples contain about 6 g of fructose per 100 g, grapes 4 g and bananas 5 g. Dried fruit, as you’d expect, has considerably higher amounts by weight – because the water’s gone. Juices have similar amounts of fructose per unit of weight but, of course, you tend to drink a lot more than 100 g of juice at a time.

Now we understand why “Sugar Free Farm” has banned fruit. But this is why I have a problem with the title: you CAN’T eat an entirely “sugar-free” diet, unless all you eat is meat, fish, eggs and dairy products like cream and butter (but not milk, which contains lots of another sugar: lactose). This would be a far from healthy diet, seriously lacking in fibre as well as a host of vitamins and minerals (even “phase 1” or the “induction” period of the controversial Atkins diet isn’t quite this extreme).

The show hasn’t aired yet, and I admit I didn’t watch it last year, so I don’t know if that’s what they’re doing. But I seriously doubt it – it would be unethical and irresponsible. Plus, the words “white carbs” in the listings blurb make me suspicious. Why specify “white”? Are whole grains included? And what about pulses? Whole grain foods might be relatively low in fructose and glucose before you put them in your mouth, but as soon as saliva hits them the starch they contain is broken down into…. glucose. By the time you swallow that chewed-up food, it contains sugar.

In summary, Sugar Free Farm is almost certainly not sugar free. What they appear to have set up is a place where sugars are restricted and foods with added sugar are banned, and then mixed that with lots of outdoor activities (the celebrities are also expected to work on the farm).

Most people would lose weight following such a regime, because it’s likely that calories in are going to be lower than calories out. It’s a simple calorie deficit.

give-up-sugarWhat bothers me is that the show might go on to conclude that we should all “give up” sugar to lose weight – and some people might misinterpret that and end up embarking on an unbalanced, unhealthy and ultimately unsustainable diet – when in fact the results are simply due to calorie deficit.

There’s no need to try to give up sugar. Cut down, yes, but you can eat some sweet foods and still manage a calorie deficit. In fact you probably should: fruit in particular has lots of nutrients, including fibre. Besides, such a diet will probably be a lot more sustainable in the long term.

Unfortunately, “Eat Fewer Calories And Do Some Exercise Farm” doesn’t have quite the same ring, does it?

EDIT, 11th Jan 2017

Well, the first episode aired last night. No, the diet is not “zero sugar”. It’s very low in sugar, yes, but there are sugars. They used milk (contains lactose), ate wholemeal bread, brown rice and oats (all of which are broken down into glucose) and ate a variety of vegetables which, as I mentioned above, all contain small amounts of sugar. In fact, on their very first morning they eat a strange granola mixture made with sweet potato. The USDA food database tells me that sweet potato contains about 0.4 g of fructose, 0.5 g of glucose, 3.3 g of maltose AND 1.4 g of sucrose per 100 g. Yep. Sucrose. The stuff in “refined” sugar.

There was much talk of “detox” and “detoxing” from sugar. Sigh. That’s not a thing. Most worryingly of all, poor Peter Davison (he was “my” Doctor, you know) was carted off in an ambulance on the second day, suffering with dizzy spells. Everyone immediately started talking about how dreadful it was that “sugar” had caused this. There was only one, in passing, comment shown suggesting that perhaps the 65-year-old might have something else wrong with him. In fact, it turned out that he had labyrinthitis, an inner-ear condition. It’s usually viral. It’s not caused by “sugar withdrawal”. I’m sure they’ll make that clear in the next episode, right?

Speaking of which, the celebrities are on Sugar Free Farm for 15 days. A safe rate of weight loss is generally considered to be 0.5-1 kg (or 1-2 lb) a week. So they should lose about 2 kg, or 4 lb, on the outside. A snippet was shown at the end of the program in which Alison Hammond said she was “pleased” she’d lost 8 lbs. Whether that was after two weeks or a shorter period of time wasn’t clear, but either way, it’s a lot. It suggests that her diet is/was too low in calories, particularly considering all the extra physical activity.  Perhaps some of her so-called “sugar withdrawal” symptoms were actually simply due to the fact that she wasn’t consuming enough to keep up with her energy needs?

That aside, the diet they followed did seem to be fairly balanced, with plenty of vegetables and adequate healthy fats and protein. They had all been eating huge quantities of sugary foods beforehand, and cutting down is no bad thing. I’m just skeptical about exactly how much of the bad, and indeed the good, can be pinned on sugar.

Still, it made good telly I suppose.

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The Chronicles of the Chronicle Flask: 2016

2016 is limping to its painful conclusion, still tossing out last-minute nasty surprises like upturned thumb tacks in the last few metres of a marathon. But the year hasn’t been ALL bad. Some fun, and certainly interesting, things happened too. No, really, they did, honestly.

So with that in mind, let’s have a look back at 2016 for the Chronicle Flask….

January kicked off with a particularly egregious news headline in a well-known broadsheet newspaper: Sugar found in ketchup and Coke linked to breast cancer. Turns out that the sugar in question was fructose. Yes, the sugar that’s in practically everything, and certainly everything that’s come from a plant. So why did the newspaper in question choose ketchup and Coke for their headline instead of, oh, say, fruit juice or honey? Surely not just in an effort to sell a few more newspapers after the overindulgent New Year celebrations. Surely.

octarineThere was something more lighthearted to follow when IUPAC  verified the discoveries of elements 113, 115, 117 and 118. This kicked off lots of speculation about the elements’ eventual names, and the Chronicle Flask suggested that one of them should be named Octarine in honour of the late Sir Terry Pratchett. Amazingly, this suggestion really caught everyone’s imagination. It was picked up in the national press, and the associated petition got over 51 thousand signatures!

In February I wrote a post about the science of statues, following the news that a statue to commemorate Sir Terry Pratchett and his work had been approved by Salisbury City Council. Did you know that there was science in statues? Well there is, lots. Fun fact: the God of metalworking was called Hephaestus, and the Greeks placed dwarf-like statues of him near their Hearths – could this be where the fantasy trope of dwarves as blacksmiths originates?

MCl and MI are common preservatives in cosmetic products

MCl and MI are common preservatives in cosmetic products

My skeptical side returned with a vengeance in March after I read some online reviews criticising a particular shampoo for containing a substance known as methylchloroisothiazolinone. So should you be scared of your shampoo? In short, no. Not unless you have a known allergy or particularly sensitive skin. Otherwise, feel free to the pick your shampoo based on the nicest bottle, the best smell, or the forlorn hope that it will actually thicken/straighten/brighten your hair as promised, even though they never, ever, ever do.

Nature Chemistry published Another Four Bricks in the Wall in April – a piece all about the potential names of new elements, partly written by yours truly. The month also brought a sinus infection. I made the most of this opportunity by writing about the cold cure that’s 5000 years old. See how I suffer for my lovely readers? You’re welcome.

In May I weighed in on all the nonsense out there about glyphosate (and, consequently, learned how to spell and pronounce glyphosate – turns out I’d been getting it wrong for ages). Is it dangerous? Nope, not really. The evidence suggests it’s pretty harmless and certainly a lot safer than most of its alternatives.

may-facebook-postSomething else happened in May: the Chronicle Flask’s Facebook page received this message in which one of my followers told me that my post on apricot kernels had deterred his mother from consuming them. This sort of thing makes it all worthwhile.

In June the names of the new elements were announced. Sadly, but not really very surprisingly, octarine was not among them. But element 118 was named oganesson and given the symbol Og. Now, officially, this was in recognition of the work of Professor Yuri Oganessian, but I for one couldn’t help but see a different reference. Mere coincidence? Surely not.

July brought another return to skepticism. This time, baby wipes, and in particular a brand that promise to be “chemical-free”. They’re not chemical-free. Nothing is chemical-free. This is a ridiculous label which shouldn’t be allowed (and yet, inexplicably, is still in use). It’s all made worse by the fact that Water Wipes contain a ‘natural preservative’ called grapefruit seed extract which, experiments have shown, only actually acts as a preservative when it’s contaminated with synthetic substances. Yep. Turns out some of Water Wipes claims are as stinky as the stuff they’re designed to clean up.

Maria Lenk Aquatic Enter, Tuesday, Aug. 9, 2016. (AP Photo/Matt Dunham)

Maria Lenk Aquatic Enter, Tuesday, Aug. 9, 2016. (AP Photo/Matt Dunham)

August brought the Olympics, and speculation was rife about what, exactly, was causing the swimming pools to turn such strange shades of green. Of course, the Chronicle Flask knew the correct solution…

August also saw MMS and CD reared their ugly heads on social media again. CD (chlorine dioxide) is, lest we forget, a type of bleach solution which certain individuals believe autistic children should be made to drink to ‘cure’ them. Worse, they believe such children should be forced to undergo daily enemas using CD solutions. I wrote a summary page on MMS (master mineral solution) and CD, as straight-up science companion to the commentary piece I wrote in 2015.

mugsSeptember took us back to pesticides, but this time with a more lighthearted feel. Did you know that 99.99% of all the pesticides you consume are naturally-occurring? Well, you do if you regularly read this blog. The Chronicle Flask, along with MugWow, also produced a lovely mug. It’s still for sale here, if you need a late Christmas present… (and if you use the code flask15 you’ll even get a discount!)

In October, fed up with endless arguments about the definition of the word ‘chemical’ I decided to settle the matter once and for all. Kind of. And following that theme I also wrote 8 Things Everyone Gets Wong About ‘Scary’ Chemicals for WhatCulture Science.

Just in case that wasn’t enough, I also wrote a chapter of a book on the missing science of superheroes in October. Hopefully we should see it in print in 2017.

Sparklers are most dangerous once they've gone out.

Sparklers are most dangerous once they’ve gone out.

I decided to mark Fireworks Night in November by writing about glow sticks and sparklers. Which is riskier? The question may not be as straightforward as you’d imagine. This was followed by another WhatCulture Science piece, featuring some genuinely frightening substances: 10 Chemicals You Really Should Be Scared Of.

And that brings us to December, and this little summary. I hope you’ve enjoyed the blog this year – do tell your friends about it! Remember to follow @ChronicleFlask on Twitter and like on Facebook – both get updated more or less daily.

Here’s wishing all my lovely readers a very Happy New Year – enjoy a drop of bubbly ethanol solution and be careful with the Armstrong’s mixture…. 

See you on the other side!


10 Chemicals You Really SHOULD Be Scared Of

Some chemicals really ARE scary...

Some chemicals really ARE scary…

People are increasingly worried about chemicals these days (even if they don’t quite know what the word means), but most of that fear is unfounded. The ingredients in cosmetics and foods are actually pretty harmless on the whole, certainly in the quantities you usually meet them.

This is because we’ve had decades of extensive testing and health and safety regulations – the truly nasty stuff simply isn’t allowed anymore. Even, sometimes, in fairly-obviously dangerous things like rat poison.

But the nasty stuff exists. Oh yes it does. You might be unlikely to come across it, but it’s still out there. Locked away. (Or not.)

So, come with me as I take you on a tour of 10 chemicals you really SHOULD be scared of…

Click to continue reading this article at WhatCulture Science

Glow sticks or sparklers: which is riskier?

by Unknown artist,print,(circa 1605)

Remember, remember the 5th of November… (Image by Unknown artist, circa 1605)

It’s fireworks night in the UK – the day when we celebrate a small group of terrorists nearly managing to blow up the Houses of Parliament in 1605 by, er, setting fire to stuff. No, it makes perfect sense, honestly, because…. look, it’s fun, all right?

Anyway, logical or not, Brits light fireworks on this day to mark the occasion. Fireworks, of course, are dangerous things, and there’s been more than one petition to ban their sale to members of the general public because of safety concerns. It hasn’t happened yet, but public firework displays, rather than private ones at home, are more and more popular.

Which brings me to this snippet from a letter a friend of mine recently received.


In case you can’t read it, it says:

“NO SPARKLERS PLEASE – with so many children runni[ng] around, we believe it is too dangerous fro children to be [words missing] lighted sparklers around.
Last year we had a few incidents of children drinking the [words missing] glowsticks – please advise against this.”

Now there are some words missing here, but it’s fairly clear that sparklers are prohibited at this event, and it seems to be suggesting that children have managed to get into, and swallow, the contents of glowsticks. But they, by contrast, haven’t been banned. Indeed, parents are merely being asked to “advise” against it.


Does this seem like an appropriate response? Well, let’s see…

1024px-sparklers_moving_slow_shutter_speedWhat are these things? Let’s begin with sparklers. They’re hand-held fireworks, usually made of a stiff metal wire, about 20 cm long, the end of which is dipped in a thick mixture of metallic particles, fuel and an oxidising agent. The metal particles are most commonly magnesium and/or iron. The fuel usually involves charcoal, and the oxidiser is likely to be potassium nitrate. Sometimes metal salts are also added to produce pretty colours.

Sparklers are designed to burn hot and fast. The chemical-dipped end can reach temperatures between 1000-1600 oC, but the bit you hold doesn’t have time to heat up before the firework goes out (although gloves are still recommended). The sparks, likewise, are extremely hot but burn out in seconds. This makes sparklers relatively safe, if they’re held well way from the face and body, and if the hot end isn’t touched.

If. Every year there are injuries. Sparkler injuries aren’t recorded separately from other firework injuries in the UK, but the data we do have suggest we might be looking at a few thousand A&E admissions each year, and probably a lot more minor injuries which are treated at home.

Sparklers are most dangerous once they've gone out.

Sparklers are most dangerous after they’ve gone out.

The biggest danger comes from people, usually children, picking up ‘spent’ sparklers. The burny end takes a long time to cool down, but once the sparkles are finished and it’s stopped glowing it’s impossible to judge how hot it is just by looking.

The burns caused by picking up hot sparklers are undoubtedly very, very nasty, but they’re also relatively easy to avoid. Supply buckets of cold water, and drill everyone to put their spent sparklers into the buckets as soon as they go out. Hazard minimised. Well, assuming everyone follows instructions of course, which isn’t always a given. Other risks are people getting poked with hot sparkers – which can be avoided by insisting sparkler-users stand in a line, facing the same way, with plenty of space in front of them – and people lighting several sparklers at once and getting a flare. Again, fairly easily avoided in a public setting, where you can threaten and nag everyone about safety and keep an eye on what they’re doing.

Although I do understand the instinct to simply ban the potentially-dangerous thing, and thus remove the risk, the idea does worry me a little bit. I was born in the 70s and I grew up with fire. I remember the coal truck delivering coal to us and our neighbours. I was taught how to light a match at an early age, and cautioned not to play with them (and then I did, obviously, because in those days it was usual for kids to spend hours and hours entirely unsupervised – but fortunately I emerged unscathed). Pretty much everyone kept a supply of candles in a drawer, in case the lights went out. And bonfires were a semi-regular event – this being long before garden waste collections.

These days things are very different. It’s not unusual to meet a child who, by age 11, has never lit a match. If their home oven and hob are electric, they may never have seen a flame outside of yearly birthday cake candles. But so what? You may be thinking. Aren’t fewer burns and house fires a good thing?

Of course they are, but people who’ve never dealt with fire tend to panic when faced with it. If the only flame you’ve ever met is a birthday cake candle, your instinct might well be to blow when faced with something bigger. This can be disastrous – it can make the fire worse, and it can spread hot embers to other nearby flammable items.

I’m personally of the opinion that children ought to be taught to handle fire safely, how to safely extinguish a small fire, when to call in the experts, and not to disintegrate into hysterics the presence of anything warmer than a cup of tea. Sparklers, I think, can be part of that. Particularly if they’re used in a well-supervised setting, with plenty of safety measures and guidance on-hand. (As opposed to, say, picking them up for the first time at university with some drunk mates, setting fire to half a dozen at once and immediately dropping them.)

Now. Onto glowsticks. They’re pretty neat, aren’t they? We’ve already established that I’m quite old, and I remember these appearing in shops for the first time, sometime in the very early 90s, and being utterly mesmerised by that eerie, cold light.


Diphenyl oxalate (trademark name Cyalume)

They work thanks to two chemicals. Usually, these are hydrogen peroxide (H2O2 – also used to bleach hair, as a general disinfectant, and as the subject of a well-known punny joke involving two scientists in a bar) and another solution containing a phenyl oxalate ester and a fluorescent dye.

These two solutions are separated, with the hydrogen peroxide in a thin-walled, sealed glass vial which is floating in the mixture of ester and dye solution. The whole thing is then sealed in a tough, plastic coating. When you bend the glowstick the glass breaks, the chemicals mix, and a series of chemical reactions happen which ultimately produce light.

How Light Sticks work (from - click image for more)

How Light Sticks work (from – click image for more)

Which is all very well. Certainly nice and safe, you’d think. Glowsticks don’t get hot. The chemicals are all sealed in a tube. What could go wrong?

I thought that too, once. Until I gave some glowsticks to some teenagers and they, being teenagers, immediately ripped them apart. You see, it’s actually not that difficult to break the outer plastic coating, particularly on those thin glow sticks that are often used to make bracelets and necklaces. Scissors will do it easily, and teeth will also work, with a bit of determination.

How dangerous is that? Well… it’s almost impossible to get into a glowstick without activating it (the glass vial will break), so it’s less the reactants we need to worry about, more the products.

And those are? Firstly, carbon dioxide, which is no big deal. We breathe that in and out all the time. Then there’s some activated fluorescent dye. Now, these vary by colour and by manufacturer, but as a general rule they’re not something anyone should be drinking. Some fluorescent dyes are known to cause adverse reactions such as nausea and vomiting, and if someone turns out to be allergic to the dye the consequences could be serious. This is fairly unlikely, but still.

Another product of the chemical reactions is phenol, which is potentially very nasty stuff, and definitely not something anyone should be getting on their skin if they can avoid it, let alone drinking.

Inside every activated glowstick are fragments of broken glass.

Inside every activated glowstick are fragments of broken glass.

And then, of course, let’s not forget the broken glass. Inside every activated glowstick are fragments of broken glass – it’s how they’re designed to work. If you break the plastic coating, that glass is exposed. If someone drinks the solution inside a glow stick they could, potentially, swallow that glass. Do I need to spell out the fact that this would be a Bad Thing™?

The thing with hazards is that, sometimes, something that’s obviously risky actually ends up being pretty safe. Because people take care over it. They put safety precautions in place. They write risk assessments. They think.

Whereas something that everyone assumes is safe can actually be more dangerous, precisely because no one thinks about it. How many people know that glowsticks contain broken glass, for instance? Probably not the writer of that letter back there, else they might have used stronger language than “please advise against this.”

So glowsticks or sparklers? Personally, I’d have both. Light on a dark night, after all, is endlessly fascinating. But I’d make sure the sparkler users had buckets of water, cordons and someone to supervise. And glowstick users also ought to be supervised (at least by their parents), warned in the strongest terms not to attempt to break the plastic, and all efforts should be made to ensure that the pretty glowy things don’t fall into the hands of a child still young enough to immediately stuff everything into his or her mouth.

The most important thing about managing risks is not to eliminate every potentially hazardous thing, but rather to understand and plan for the dangers.

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What IS a chemical?


You at the back there! Get your nose out of that dictionary and pay attention!

What do we mean when we use the word “chemical”? It seems like a simple enough question, but is it, really? I write about chemicals all the time – in fact my last WhatCulture article was about just that – and I’ve mentioned lots of different definitions before. But I’ll be honest, some of them have bothered me.

I don’t often like the definitions you find in dictionaries. Lexicography and chemistry don’t seem to be common bedfellows, and dictionary compilers haven’t, generally speaking, spent their formative years being incessantly nagged by weary chemistry teachers about their choice of vocabulary.

For example, in the Cambridge Dictionary we find:
any basic substance that is used in or produced by a reaction involving changes to atoms or molecules.”

Hm. Firstly, “basic” has a specific meaning in chemistry. Obviously the definition doesn’t mean to imply that acids aren’t chemicals, but it sort of accidentally does. Then there’s the implication that a chemical reaction has to be involved. So inert substances aren’t chemicals? Admittedly, “used in” doesn’t necessarily imply reacts – it could be some sort of inert solvent, say – but, again, it’s bothersome. Finally, “atoms or molecules”. Ionic substances not chemicals either, then?

Yes, it’s picky, but chemists are picky. Be glad that we are. A misplaced word, or even letter, on a label could have serious consequences. Trust me, you do not want to mix up the methanol with the ethanol if you’re planning cocktails. Similarly, fluorine is a whole other kettle of piranhas compared to fluoride ions. This stuff, excuse the pun, matters.

Dictionary definitions have their problems.

Dictionary definitions have their problems.

Let’s look at some more definitions (of the word as a noun):

The Free Dictionary tells us that a chemical is:
“A substance with a distinct molecular composition that is produced by or used in a chemical process.”

Merriam Webster says:
“of, relating to, used in, or produced by chemistry or the phenomena of chemistry <chemical reactions>”

And goes with the simple:
“a substance produced by or used in a chemical process.”

That idea that a chemical reaction must be involved somehow seems to be pervasive. It’s understandable, since that’s the way the word is mostly used, but it’s not really right. Helium, after all, is still very much a chemical, despite being stubbornly unreactive.

Possibly the best of the bunch is found in the Oxford Living Dictionary:
“A distinct compound or substance, especially one which has been artificially prepared or purified.”

Not bad. Well done Oxford. No mention of chemical reactions here – it’s just a substance. We do most often think of chemicals as things which have been “prepared” somehow. Which is fair enough, although it can lead to trouble. In particular, ridiculous references to “chemical-free” which actually mean “this alternative stuff is naturally-occurring.” (Except of course it often isn’t: see this article about baby wipes.) The implication, of course, is that thing in question is safe(r), but there are lots and lots of very nasty chemicals in nature: natural does not mean safe.

You keep using that word. I do not think it means what you think it means.

Sometimes people will go the other way and say “everything is chemicals.” We know what this means, but it has its problems, too. Light isn’t a chemical. Sound isn’t a chemical. All right, those are forms of energy. What about neutrinos, then? Or a single proton? Or a single atom? Or, going the other way, some complicated bit of living (or once living) material? In one debate about this someone suggested to me that a “chemical was anything you could put in a jar,” at which point I pedantically said, “I keep coffee in a jar. Is that a chemical?” Obviously there are chemicals in coffee, it works from the “everything is chemicals” perspective, but it’s a single substance that’s not a chemical.

Language is annoying. This is why chemists like symbols and numbers so much.

Anyway, what have we learned? Firstly, something doesn’t necessarily have to be part of a chemical reaction to be a chemical. Secondly, we need to include the idea that it’s something with a defined composition (rather than a complex, variable mixture, like coffee), thirdly that chemical implies matter – light, sound etc don’t count, and fourthly that it also implies a certain quantity of stuff (we probably wouldn’t think of a single atom as a chemical, but collect a bunch together into a sample of gas and we probably would).

So with all that in mind, I think I shall go with:

So what IS a chemical?

A chemical is…

(Drum roll please….)

Any substance made of atoms, molecules and/or ions which has a fixed composition.

I’m not entirely convinced this is perfect, but I think it more or less works.

If you have a better idea, please do comment and let me know!

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8 Things Everyone Gets Wrong About ‘Scary’ Chemicals

scaryChemicals. The word sounds a little bit scary, doesn’t it? For some it probably conjures up memories of school, and that time little Joey heated something up to “see what would happen” and you all had to evacuate the building. Which was actually good fun – what’s not to love about an unplanned fire drill during lesson time?

But for others the word has more worrying associations. What about all those lists of additives in foods, for starters? You know, the stuff that makes it all processed and bad for us. Don’t we need to get rid of all of that? And shouldn’t we be buying organic food, so we can avoid ….

….Read the rest of this article at WhatCulture Science.

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I love my naturally-occurring pesticide


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99.99%, by weight, of all the pesticides we consume are naturally-occurring.

That’s a pretty amazing statement, isn’t it? It comes from a paper about dietary pesticides that was published in 1990, and referred to the American diet, but it’s almost certainly still not far from the truth – pesticide use, despite what some of the crazier corners of the internet will tell you – hasn’t increased significantly in the last 26 years. The authors of the paper concluded that “the comparative hazards of synthetic pesticide residues are insignificant” and it’s a valid point. Many of these natural pesticides – chemicals which plants use to defend themselves – have never been fully tested, and some of them are actually well-known toxins.

Plants have been on this planet for a very long time, 700 million years give or take, which means they’ve had an awful lot of time to evolve defences. Some of these are physical, like thorns or spines, but chemistry plays a key role.

For example, one of the most common toxins is solanine. It turns up in potatoes which, as any good gardener will tell you, are part of the nightshade family. Yep, like deadly nightshade. But don’t panic, it’s mostly in the parts of the plant we don’t eat, namely the leaves and stems, with only very small amounts found in the skin and virtually none in the flesh.



Unless, that is, your potatoes are exposed to light. Then the tubers start producing lots of extra solanine (and another alkaloid called chaconine), as a defence to stop the uncovered tuber from being eaten. At the same time, they produce extra chlorophyll, which causes them to turn green. The chlorophyll is harmless, but the solanine most definitely is not. It causes vomiting and diarrhoea, and can even be fatal – although this is really only a risk for people who are undernourished. Still, if your potatoes have turned green its safest to throw them out, since cooking doesn’t break the toxins down. Even if they’re not green, if they have a bitter taste it’s safest to get rid of them if you don’t want to risk an extended visit to the porcelain throne.

But solanine is just the tip of the lettuce. Capsaicin (the stuff in chillies) also evolved as a defence mechanism to repel and kill insects, and there’s evidence that it may be carcinogenic under some circumstances. 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) is another chemical which is found in corn, wheat, rye and other grasses and which has been shown to cause carcinogenic changes in human cell lines. Then there are all the various substances in herbs and spices, such as tetradecanoic acid in nutmegpulegone in peppermint, carvacrol in oregano and eugenol in cloves, nutmeg and basil.

But not to panic. None of these chemicals are dangerous in the quantities that we usually consume them. And neither, while we’re here, are the really teeny, tiny amounts of synthetic pesticides that we might be exposed to. So just relax and eat your greens. Well, not if they’re potatoes. You know what I mean.

Anyway, there’s one substance I haven’t mentioned yet, and it’s a biggie – it’s something most of us consume on a regular basis. In fact, it might be the source of over a gram of naturally-occurring pesticide a day, and few of us even give it a thought.

What is it? Coffee. Yes, your daily dose of americano is a veritable cocktail of chemicals. As the dietary pesticides paper points out, “13 g of roasted coffee per person per day contains about 765 mg of chlorogenic acid, neochlorogenic acid, caffeic acid, and caffeine.” A single espresso shot uses about 8 grams of ground coffee, so a mere two shots will take you up to best part of a gram of chemically-goodness, and who restrains themselves to two shots a day?

But there’s good news. Some of these substances could actually be beneficial. Chlorogenic acid appears to moderately lower blood pressureNeochlorogenic acid might actually help to prevent certain cancers, as might caffeic acid (although results are mixed in this case).


The world’s most widely-consumed psychoactive drug.

And then, of course, there’s caffeine itself – the world’s most widely consumed psychoactive drug. It has umpteen (technical term) effects not the body, both positive and negative, the most famous being its ability to keep us alert and awake. It’s performance-enhancing and its use was at one point restricted for Olympic athletes, until 2004 when officials decided to remove those restrictions – presumably because they were proving impossible to enforce.

But caffeine didn’t evolve for the convenience of humans, although we have, of course, played our part in farming and selectively-breeding plants. No, it originally evolved to paralyse and kill predator insects. Basically, to stop the plant being eaten which, from the plant’s point of view, is quite important. Interestingly, there’s evidence that it evolved separately in coffee, tea and cacao, suggesting it really is a pretty advantageous thing for a plant to make. But in case you’re wondering, it’s broken down by UV light, which explains why it’s not used as an insecticide spray on other plants.

So, if you’re worrying about pesticides with a cup of coffee in your hand, you can stop. You’re probably consuming more pesticide, daily, than you will get from carrots in your lifetime. Drink up!


Do you love your naturally-occurring pesticide?

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