I usually reserve this site for posting about happy, nerdy topics, but I also like to post the best scientific innovations on here as well, as a big part of being a nerd is being scientifically knowledgeable. The problem is there is a lot of misinformation out there regarding science, namely regarding the science of health. Scientifically proven health facts are the most attacked facts on the planet, with evolution as a close second. In this day of anti-vaccination movements and germ theory denialists, I think it’s important to weed through the misinformation out there. So, here we go.
I’m assuming many of you have seen this image floating around lately, attached with a claim about cancer-fighting agents in bananas:
Was not aware of this: According to a Japanese scientific study, fully ripened bananas with dark patches produce a substance called TNF(Tumor Necrosis Factor) which has the ability to combat abnormal cells. Apparently, the more dark patches a banana has, the higher its immunity enhancement quality will be. So, extremely ripe bananas actually possess an anti-cancer quality. I always thought they were too ripe and too sweet. Will have to let bananas ripen more from now on…
I hate to be the curmudgeon here, but this is actually not true. Here are the facts about the claims made:
1. TNF is not produced in flora. Tumor Necrosis Factor is actually an animal proteinaceous hormone, which essentially means it’s a protein produced by animals – not plants.
2. More importantly, proteins do not survive the gut, therefore it would be useless anyway. If proteins survived the kinds of acids we produce in our digestive system, diabetics would not have to stick needles in their arms for a dose of insulin – there would be an oral insulin by now.
3. TNF has actually been linked to autoimmune disorders ranging from arthritis to asthma. TNF inhibitors are prescribed by doctors to many patients suffering from an extremely broad range of autoimmune disorders.
I don’t necessarily like to be the bringer of bad news for those who hoped this were true, but I feel better in knowing I can help people stray away from false hope and continue proven cancer treatments.
Keep in mind, this isn’t meant to nullify the health benefits of eating any kinds of fruits or vegetables. It’s very important to eat both as often as you can. However, bruised bananas are not going to cure cancer.
Here are some links for further study if you’re interested:
TNF Inhibition:
http://adsabs.harvard.edu/abs/1985Natur.316..552B
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2187983/?tool=pmcentrez
http://www.nature.com/nature/journal/v316/n6028/abs/316552a0.html
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2188124/?tool=pmcentrez
Nerd Monkey 
Hi
I find it difficult to believe some of the statements above:
1- I haven’t found a published article (from your list of references) stating that TNF cannot be produced in a banana.
2- Proteins can survive the gut’s chemical environment. Otherwise, what is going to happen to the proteins that we consume?
3- Pharmaceutical compounding has come a long way that most of the active ingredients can be made resistant to different chemical environments in different parts of the digestive system. The active ingredient can be masked in such a way that it can be released in a particular part of the digestive system (stomach, intestine, etc).
It will be awesome if you can provide more info that you might have found on these topics. Have a nice day!
You can read the studies cited more carefully on how TNF alpha is produced, or you can read the following: http://www.skepticalraptor.com/skepticalraptorblog.php/checking-pseudoscience-real-science-news/ This in particular – http://www.skepticalraptor.com/blog/wp-content/uploads/2012/10/Banana-Paper.pdf – is important, as it’s the original paper that the false meme is in reference to. Notice the claim made by the meme itself seems to be mysteriously missing in the paper. I do, however, always appreciate skeptical people who take the time to research and check up on citations and sources. We need more of that today more than any other time.