We all have seen the picture of a banana with dark spots passing by on social media platforms, accompanied by the words “Ripe Banana With Dark Patches Combats Cancer And Abnormal Cells”. Or “Eat Bananas. Cure Cancer”. And these pictures get shared like crazy…
When I saw this claim passing by on Facebook, it grabbed my attention as a biologist and I wanted to learn more. So first of all I went over to google and copy/paste the sentence there to see what popped up. I opened some of the hits, mainly blog posts, to give them a closer look and try to find some scientific resources.
To my astonishment I only found these vague words “According to Japanese Scientific Research, full ripe banana with dark patches on yellow skin produces a substance called TNF (Tumor Necrosis Factor) which has the ability to combat abnormal cells”. But no mentioning where to find this mysterious Japanese study.
So I went over to PubMed, a database with all important scientific publications, to do my research. And again no word to be found. Which I thought was odd, as such a discovery would be groundbreaking news.
So I dug deeper and finally found the document I was looking for. It was published in a low impact journal (lower than impact factor 1, which are not indexed by PubMed) in 2009. Click here if you want to read it too.
Can Bananas With Dark Patches Cure Or Prevent Cancer In Humans?
The answers is NO. The meme relies on a misinterpretation of an unimportant scientific paper and the experiments have never been repeated.
So what’s the article talking about? Well these Japanese researchers found that pure banana extract from overripe bananas injected in the blood stream of mice can have a stimulatory effect on white blood cells, which may induce the production of certain cytokines, like TNF (Tumor Necrosis Factor).
White blood cells are the protectors of our body that deal with foreign matter such as bacteria and viruses, or other threats to the body, like banana extract being injected into the bloodstream.
We might think TNF is a protein that kills cancer cells due to its name, but TNF is far more complex than that. It is part of our inflammatory response and immune system, hence its association with not only cancer but many autoimmune and inflammatory disorders such as asthma, IBS, arthritis, psoriasis and many more.
It’s actually no wonder these mice produced TNF, next to other protective proteins, as a reaction to get rid of the compounds foreign to their body. So although there may be a chance that certain compounds in bananas may induce the production of TNF, bananas do not contain or produce TNF. Plants don’t have an immune response and therefore it would make no sense for them to make such a complex protein like TNF.
These Japanese researchers weren’t actually trying to prove or say that overripe bananas could cure or prevent cancer, they were simply looking for differences in biological responses when banana extract was injected into the bloodstream of mice, and raised TNF levels was one of these differences.
And even if ripe bananas would produce TNF, there is no possible way they could end up as a whole protein in our blood stream to help fight or cure cancer. Our digestive tract breaks down complex proteins into smaller compounds to be able to pass through the intestinal wall and end up in the bloodstream. And another thing, it would be impossible to eat that much bananas to get the amounts of TNF needed to have any effect.
Take Home Message
Although internet and social media platforms are a great and easy way to spread information, unfortunately there are a lot of misconceptions out there… and eating bananas to cure cancer is unfortunately one of these.
Eating more bananas will definitely not cure or prevent cancer, but they are packed with lots of healthy nutrients, TNF not being one of them, that help nourish your body.
So if you like to eat bananas, go ahead. But there is absolutely no need to let them become mushy, full of dark spots to prevent or cure cancer… except if you like eating them in that way. I prefer my bananas yellow and ripe… but definitely not with dark sugars spots. Too mushy and odd tasting for me.