Do Ripe Bananas Cure Cancer? Or is it just Another Internet Hoax?


We've all seen that picture, showing a bunch of bananas at various levels of ripeness, and the accompanying article that goes as far as to boldly state that bananas with brown spots on them can cure cancer! 

Out of curiosity, how many of you believed it?  How many of you thought:  "hmmm... that's a bold claim?"  And how many of you just reposted it, taking it (and many other Internet memes) at face value.  I mean, if it's on the Internet, it has to be true, right?

I have seen dozens of  photos of these (and other) bananas posted and reposted, with a few words that some Japanese scientists claim that ripe bananas have high levels of “tumor necrosis factor,“ so therefore, the call to action was that you should eat more ripe bananas to boost your immune system, thereby preventing or curing cancer.  Social media is famous for such claims attached to little pictures with a few words and broad conclusions, but yet not a source in sight.

Well, there is a "slight" problem with the claim that ripe bananas prevent cancer.  The problem is that ripe bananas do NOT prevent cancer.  Moreover, that cockamamie hypothesis is based on faulty science.  So let's first examine that often cited Japanese study.  Here are the most important high level issues with that study (for a more critical analysis, click here):

  1. This "Japanese scientist study" was bad study! 
    • The study is in a mouse model and many animal model experiments just don’t transfer to human clinical research.  
    • The article is published in a low impact journal, with an impact factor of less than 1.0. This indicates a very low quality journal and it’s not even indexed in PubMed, which further indicates its low value. 
    • No one has repeated this experiment, and certainly no one has shown this effect in humans.  
    • There is not a single double-blind clinical trial to show that bananas induce a TNF-alpha response in humans.  
  2. The authors do not make one single claim that there is tumor necrosis factor (TNF) in a banana (i.e., there is no TNF in bananas!)
  3. Even if bananas had TNF, your digestive tract would destroy the TNF, breaking it into constituent molecules.
  4. But even if it could pass through the digestive tract and enter the bloodstream, you couldn’t consume enough bananas to raise your blood level of TNF to actually have a biological effect.
  5. And even you could raise your blood level of TNF, it’s name is a misnomer, since TNF doesn’t cause tumors to necrose. TNF, in fact, causes the inflammatory response, and numerous autoimmune disorders.
  6. And if you downed that much TNF, you’d die. So sure, the cancer is dead., but so are you.

So the bottom line is this. Stop relying on Internet memes for nutrition information. Unless it's coming from a reliable source, chances are it's bunk.  Do your own research, check with an expert, but stop believing (and reposting) everything that appears on your wall.

Also, if you want to eat a banana, go ahead.  It really is very good for you (see below). However, a banana is not going to prevent cancer.  It's not going to cure cancer.  It's not going to make you live longer.  It’s just going to provide nutrition.