No, ketchup does not cause cancer

ketchup and coke

Do these things really cause breast cancer? (Spoiler: no)

Less than two days into the new year, and I’d already found what might well be one of the silliest health headlines of the year. What is it I hear you ask? Well, it was in a national newspaper on New Years Day, and it was this:

Sugar found in ketchup and Coke linked to breast cancer

This, to borrow a favourite line from an online greetings card company, had me rolling my eyes so hard I could practically see my brain. Why? Because even without reading any further, I knew immediately that it was the equivalent of saying, “too much of thing found in most stuff might cause cancer!”

But let’s not be one of the 70% of users that only read the headline, let’s dig a little further. The newspaper article, which in fairness isn’t too bad – it’s just a bit of a silly headline, alludes to work carried out the University of Texas’ MD Anderson Cancer Centre. If you click on the link I’ve added back there, you’ll see that MD Anderson’s headline was:

“Sugar in Western diets increases risk for breast cancer tumors and metastasis”

Note, they just say ‘sugar’, not sugar in two apparently randomly-selected foodstuffs. The researchers divided mice into four groups, fed some a diet high in sucrose (more commonly called table sugar – in other words, the stuff in the sugar bowl) and compared them to others fed a low-sugar, ‘starch-controlled’ diet. They found that the high-sugar diet lead to increased tumour growth, particularly in mammary glands.

I’ve covered forms of sugar before but still, here’s a quick reminder before we go any further: this is a molecule of sucrose:

Saccharose2

Sucrose

Sucrose is made of two ‘bits’ joined together: one unit of fructose and one unit of glucose.

157px-Alpha-D-Glucopyranose

Glucose

These two molecules are what chemists call isomers. They contain the same number and type of atoms, just joined up differently. They’re both sugars in and of themselves. Glucose is used directly by cells in your body for energy. Fructose, on the other hand, is trickier. It has a lower glycemic index than glucose, in other words, it doesn’t raise your blood sugar as rapidly as glucose, but this doesn’t mean it’s healthier. It’s metabolised almost exclusively in the liver and, long story short, invariably ends up being converted into, and stored as, fat.

179px-Beta-D-Fructofuranose

Fructose

Fruit is high in fructose, and fructose tastes very sweet to us (sweeter than either glucose or sucrose). This is nature’s way of telling us, and other animals that might eat the fruit, that it’s high in nutrients. From the plant’s point of view, it’s an incentive to eat the fruit and, ahem, spread the seeds around.

Humans have, of course messed around with this perfectly sensible survival mechanism by stuffing all kinds of easily-available and not particularly nutrient-rich foods with fructose, and herein lies the problem. Co-author of the paper that started all this, Lorenzo Cohen, Ph.D., professor of Palliative, Rehabilitation, and Integrative Medicine, said “we determined that it was specifically fructose, in table sugar and high-fructose corn syrup […] which was responsible for facilitating lung metastasis and 12-HETE production in breast tumors.” Notice that he mentions fructose in table sugar; this is because, once you eat sucrose, it breaks down into units of glucose and fructose.

The article goes on to suggest that sugar-sweetened beverages are a significant problem, so was the newspaper wrong to pick on Coke? It’s a popular drink after all, and a standard can of Coca-Cola contains approximately 35 grams of sugar (which might come from either sucrose or high fructose corn syrup mainly depending on where you buy it). The guidance for adults is no more than 30 grams of sugar per day, so a single can of regular Coca-Cola would take you over that limit, and it’s very easy to drink two or even three cans without giving it a second thought.

sugar

Soft drinks and fruit juice both contain a lot of sugar

However, the same goes for pretty much any non-diet soft drink.  Pepsi, for example, has a similar amount. Lemonade can be even more sugary, with some drinks hitting 40 grams per 330 ml can. Ginger beer might well be the worst; there are 53 grams per 330 ml in Old Jamaica Ginger beer for example. Fruit juice is no better, with many juices containing 35 g of sugar per 330 ml, although at least fruit juice might contain some other nutrients such as vitamin C.

So really, I’d say it’s a bit unfair to single out Coke in a headline like this.

What about the ketchup (note they didn’t pick a specific brand here, just generic ‘ketchup’)?

Well, ketchup IS high in sugar. It contains about 24 grams of sugar per 100 grams. But hang on, 100 grams of ketchup is quite a lot. A more realistic serving size of a tablespoon is only about 15 grams, which works out at about 3.5 grams of sugar. Still quite a lot, but probably a drop in the ocean compared to all the sugar in cake, bread, drinks, fruit juice, breakfast cereals and the tubs of Roses and Quality Street you scoffed over Christmas. Unless you make a habit of drinking ketchup by the bottle (apparently some people do) this is frankly a ridiculous foodstuff to pick on.

I imagine that someone did a quick search for ‘foods that contain fructose’ and picked Coke because, well, everyone knows that Coke’s bad, right? So that sounds credible. And ketchup because we all sort of suspect it’s probably not that healthy, but it hasn’t been the subject of a health scare recently so that makes it stand out. Great clickbait, bad science.

mouse

Mice are not people

Plus, let’s be absolutely clear, the study was in mice. Mice are not people. While a study that shows an effect in mice is an interesting start, and may well be good reason to conduct more studies, quite possibly in humans, it’s not proof that this mechanism exists in humans. Humans have, after all, evolved to eat a very different diet to mice. There might well be a link, but this doesn’t prove it, and even if a link does exist we certainly can’t say anything about the significance or size of it from this research.

I’m not a dietician, but I’m going to go out on a (fairly sturdy) limb here and say that cutting back on sugar will not do you any harm and is likely to be a jolly good thing. Let’s also be clear that sugar in fruit juice, agave, honey etc is still sugar and is no healthier than table sugar. Eating too much of the sweet stuff is almost definitely bad for your waistline and, as we all learned as children, bad for your teeth too – something which is often overlooked but really shouldn’t be, poor dental health having been linked to other serious health problems including diabetes and heart disease.

ketchup on bread

Maybe cut back on the fried ketchup sandwiches

But, and here’s my big problem with the newspaper’s headline, none of this means that Coke and ketchup directly cause breast cancer which is how, I fear, some people will interpret it. Cut out sugary fizzy drinks by all means, and perhaps ditch the ketchup sandwiches (especially fried ones), but please don’t worry that the occasional dollop of red sauce is going to kill you. I’m pretty certain it won’t.

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A small edit was made on 6th January to clarify that pure fructose isn’t used as an ingredient in Coke, but rather high fructose corn syrup.

 

 

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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.