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.

Follow The Chronicle Flask on Facebook for regular updates.

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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Are artificial preservatives really that bad?

Are preservatives really such a bad thing?

But are preservatives really such a bad thing?

As something of a skeptic, I am fond of myth- and hoax-busting type things.  I find them reassuring.  If I had to accept that absolutely everyone swallowed stories about poisonous bottled water, free Disneyland tickets, and the Pope coming out as gay without a second thought, I really would lose all faith in humanity.  But occasionally, just occasionally, a bizarre story pops up that actually turns out to be true.

And so it was a few days ago, when the Hoax Slayer feed on Facebook threw up a story about the luminous, foil-packed beverage Capri-Sun.  It would appear that mould (or, indeed mold – never mind fungi growing in children’s drinks, the story generated far more upset over American versus British spelling) has actually been found growing in Capri-Sun containers, in some cases in some really rather spectacular shapes and sizes.  This was no hoax.  It wasn’t even, unlike the story of the giant snake hanging around a mechanical digger, a twisted misrepresentation of the facts.  No, mould really has been found growing in more than one Capri-Sun container.

In a statement, Kraft, who make Capri-Sun, said:

Among the many, many millions of pouches we sell each year, it does happen from time to time because the product is preservative free. A statement is included on all cartons telling consumers to discard any leaking or damaged packages. If mold does occur, we completely agree that it can be unsightly and gross, but it is not harmful and is more of a quality issue rather than a safety issue.

This got me thinking, and funnily enough my thoughts were less “never, ever buy Capri-Sun” but rather “why is ‘preservative free’ such a good thing”?

salt-sugar-fatHumans have been preserving food for a very long time.  In fact, arguably since we first learned that holding bits of dead mammoth over that new-fangled fiery stuff makes it taste nicer and a bit less chewy.  The earliest preservatives are, of course, those oh-so-healthy staples of salt, sugar and fat.  And they’re still in use today.

Salt, otherwise known as sodium chloride, found in rocks and seawater.  We all like our salty foods, but how often do you stop and wonder why that delicious slice of ham is traditionally so salty?  It’s not just for flavour.  Salt is an excellent preservative, and humans have been using it for that reason for at least eight thousand years.  It’s a drying agent, drawing moisture from cells by osmosis, and since bacteria and fungi need moisture to grow salting food keeps them at bay.  Adding salt to food allowed people to travel over long distances and reduced the problem of seasonal availability.  As such it was an important commodity, even being used as a form of currency.  These days of course it’s far less valuable, until Britain suffers a dusting of snow that is.

Salt may help to keep our food fresh, but it’s not great when it comes to keeping us healthy.  In recent years too much salt has been increasingly associated with certain health problems.  Salt appears to raise blood pressure, and raised blood pressure puts you at increased risk of heart disease and stroke.  There is some controversy over exactly how causal this link is, but most health professionals agree that we could do with eating a bit less NaCl.

Next on the list, sugar.  Again, it’s been used since ancient times.  Preserves aren’t called preserves for nothing.  Jam (for our American cousins, jelly) wasn’t invented purely because it was delicious on toast.  No, jam, marmalade and the like are a handy way of making the summer fruit glut last all through the year.  Sugar works in a similar, although sweeter, way to salt: drawing water from cells by osmosis and producing an environment that’s hostile to bacteria.  Of course, as we all know, too much sugar isn’t great for our waistlines and it’s really bad for our teeth.  And tooth decay is far more than a cosmetic problem: in extreme cases infection can spread from the tooth to the surrounding tissues and lead to potentially fatal (really) complications such as cavernous sinus thrombosis and Ludwig’s angina.

What about fat?  Traditionally used as a layer on top of foods such as shrimp, chicken liver and pâté, it produces an air- and water-tight seal that makes a very effective barrier to bacteria.  Very high-fat foods, such as butter and cream, aren’t bacteria-friendly because, again, they have a low water content and bacteria need water to grown and reproduce.  Such foods also have fewer sugars, in particular lactose, that provide bacteria with their lunch.  This is why the use-by date on the cream is longer than the one on the milk, and why you can safely store the butter out of the fridge (you can, honestly).  Funnily enough, fat is probably the most controversial ‘additive’ from a health point of view.  Increasingly various groups are questioning the conventional wisdom that a high intake of saturated fat leads to cardiovascular disease, and of course there are essential fatty acids that are, well, essential.  We definitely need fat, at least certain kinds of fat, in our diet.  But there’s no doubt it’s high in calories, and it’s clear that being overweight is bad your health, so moderation is key.

So, salt, sugar and fat are all natural preservatives which are all associated with genuine health concerns.  What about artificial preservatives?  Well there are quite a few, and it would take a while to list them all (I’m not going to).  Some of them are definitely controversial.  Nitrates and nitrites, for example, form nitrosamines when foods are cooked, and these have been linked to an increased cancer risk.  But on the other hand, nitrates and nitrites prevent the growth of botulinum toxin, and if you ingest that, we’re not talking about a small increased risk, we’re talking about dead.  Plus, unlike fat, sugar and salt, their addition to foods is strictly regulated, so you’re unlikely to consume dangerously high quantities unless you’re practically living off processed meat.  In which case… well we’re back to salt and saturated fat again.

Sulfites, such as potassium and sodium sulfite, are common food additives which are known to be problematic for certain individuals, particularly if they have asthma or aspirin sensitivity.  But then, some people are allergic to peanuts and they haven’t been banned, yet.  There’s no evidence that sulfites are dangerous to everyone.

Sodium benzoate is another preservative that’s been linked with health problems, in particular hyperactivity in children.  But, and it’s quite a big but, only in combination with certain artificial colours.  And the effects observed weren’t consistent.  The Food Standards Agency concluded that, if real, the observed increases in hyperactive behaviour were more likely to be linked to the colours rather than the preservative.  Professor Jim Stevenson, author of the report, commented that “parents should not think that simply taking these additives out of food will prevent hyperactive disorders”.

dscf28802And this brings us back to soft drinks, because sodium benzoate is, or at least was, a fairly common ingredient in flavoured beverages.  Although, not Capri-Sun, as we’ve already established.

But Capri-Sun does contain sugar.  Admittedly, it’s main purpose isn’t preservative – there’s not quite enough for that – but still it’s an ingredient, and a significant one.  A quick glance at the nutritional information reveals that Capri-Sun contains 10.5 g of sugar per 100 g.  That’s 21 g in one of the foil packs, or roughly 5 teaspoons.  Some of this comes from the fruit juices the drink is made of, but not all.  Sugar is clearly listed as an added ingredient.  NHS guidelines suggest we shouldn’t be eating more than about 50 g (for women) or 70 g (for men) of sugar a day, so that one, really quite small, packet of Capri-Sun contains about half of a woman’s recommended daily sugar intake.

Make no mistake, sugar is bad.  It’s really bad.  Quite apart from dental decay and obesity, excessive sugar exposure has been firmly linked to type 2 diabetes.  And, guess what, eating less sugar cuts the risk of developing this potentially life-threatening illness.  Want to look after your family’s health?  You could do a lot worse than cutting back on sugar.

Let’s briefly consider some other favourite sticky beverages.  The Coca Cola Company is in the process of phasing sodium benzoate out of its products — including Coke, Sprite, Fanta, and Oasis — as soon as a “satisfactory alternative” is developed, and a quick look at some cans in my fridge (oh the shame) suggests they’ve already done it, in this country anyway.  Sugar, not so much (diet alternatives aside, obviously).  Sprite contains 6.6 g of sugar per 100 g (less than Capri-Sun, hmmm) and Coke contains 10.6 g per 100 g.

Now, I find this very interesting.  We have a small risk from sodium benzoate, when it’s combined with other additives, maybe.  And suddenly food companies are desperate to get it out of their products, and to prominently label everything as “free from artificial preservatives”.  It’s a real sales point.  Sugar, on the other hand, is definitively bad.  No argument.  Over-consumption of sugar is definitely associated with a number of negative health outcomes.  But we don’t seem to see quite so much enthusiasm for lowering the sugar content of foods or drinks, unless they’re being marketed as diet options.

Why so keen to get rid of one but not the other?  Sugar is cheap and tasty, and consumers like sweetness.  Artificial preservatives, on the other hand, cost money, don’t add anything to the taste (until the product goes off, that is) and make products last longer.  Preservative-free products have shorter use-by dates, and so people throw more away with the result that… they end up buying more.

A cynical person might wonder who really benefits from these “free from artificial preservatives” policies…. especially when the result is freaky lumps of mould in your sugary orange drink.