Welcome to Bad Science on the Internet! Here, we highlight some of the crazy and sometime dangerous stuff people post online,  and then give you the facts.  

The bad science: There is a viral post making the rounds on Facebook claiming that mixing tomatoes and cucumbers together is “not beneficial to your health”. Several people have asked me about this – thanks, Maureen H!

What do they claim? I’m going to quote the entirety of their argument, because it’s funnier this way:

“Tomatoes and cucumbers have different digestion time and mixing them can cause health complications. The bad food combination can trigger digestive problems such as stomach ache, gas, nausea and bloating. Cucumbers also contain a substance that destroys vitamin C in tomatoes. So it is more beneficial to our health to eat cucumbers without any additions.”

This is actually all over the internet! I found another site that claims this combination could kill you!  They make no mention of how this could kill you, but they do say that you should never eat a watermelon with another kind of melon, because “these fruits were meant to be eaten alone, not in combination with any other fruit”.  As if the watermelon plant’s feelings might be hurt if you mixed the flesh of it’s fruit that that of another species.  That’s melon racism, and it’s not cool.

Are they trying to sell you something? Just misinformation. It seems like they just want you to eat your cucumbers alone – who does that?

Is any of this true? Hahahahaha!  HAHAHA! Oh, you were seriously asking?  Ok then, no.

Actually, there are a couple of shreds of truth here, but they are grossly misstated. First, it is true that eating food with vastly different digestion times can upset the stomach of some people (you already know who you are if you have a sensitive stomach).  This happens because your stomach doesn’t have the time to properly digest the more difficult foods before they make their way into the small intestines, and this can lead to fermentation in the gut and… gas. However, cucumbers and tomatoes aren’t that different in terms of their makeup – yes, tomatoes have more fiber, and are more slowly digested, but cucumbers have some fiber too.  The worst possible combination for this effect would be a very high fiber food (beans, broccoli, brussels sprouts, lentils, etc) eaten with foods high in simple sugars and fat – something deep-fried perhaps.  Now you know why eating that chimichanga upset your tummy. The fact is that any complex meal containing both types of food will have the same effect.  There is nothing particularly bad about tomatoes plus cucumbers.

The second shred of truth is that cucumbers totally do have an enzyme that destroys vitamin C.  However, they are not the only fruit or vegetable with this enzyme – it’s also found in cabbage, cauliflower, apples and bananas.  Also, since this is an enzyme, the risk to your vitamin C only occurs if you mix chopped up tomatoes with chopped up cucumbers (or others) in your salad.  Once you eat these fruits together, the enzyme (like all enzymes, a protein) will be digested down to amino acids and can no longer hurt your precious vitamin C.  You could also just add vinegar to the salad, since it inhibits the enzyme.  Most recipes for cucumber/tomato salad I have seen have vinegar, so you’re good there.

While we’re on the subject, are you really so desperate for vitamin C that you’ll never eat another Greek salad again?  Drink some orange juice – there is way more vitamin C in there than a tomato anyway.   Unless you have an extremely restricted diet, you probably get plenty of vitamin C.  Or just take a supplement – then you’re fine either way.

Is any of this Dangerous? No.  If it hurts your little tummy-wummy, then don’t eat it.  If not, no worries.

What’s the bottom line? This is an utterly ridiculous internet rumor. You know you’ve eaten a salad with tomatoes and cucumber in it before and you’ve been just fine.  Cucumber/tomato salads are very common.  People EAT THESE FOODS TOGETHER ALL THE TIME!  How does it make sense that we’ve been poisoning ourselves since the domestication of tomatoes and cucumbers and it took the internet to finally save us?  This just doesn’t pass the smell test.

Carl Sagan* famously said that extraordinary claims require extraordinary evidence.  It is most certainly an extraordinary claim to say that two of the most common vegetables in the western diet, when combined are toxic, even though people literally eat them together all of the time and are doing it right now.  There is no extraordinary evidence here.  In fact, there is no evidence at all.

Now, who’s up for a salad?

* We at UYBFS are big fans of Carl Sagan.

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