One sentence: LMAO.
I was pretty scared when I discovered dark patches on the bananas I bought last week (like the picture above). Fully preconceived that te bunch was already rotten, I almost threw it into the dustbin, until a sudden flash of inspiration stopped me, and forced me to seek for the truth in the Internet. And there’s a picture, as shown above, that I got from Google. Realizing that too many opinions on Internet can be, under false premises, contradicted into facts, I decided to analyze further by browsing for some references. The first source, originating from myth-busting website Hoax or Fact (but probably looks insensitive to sophisticated fabricated stories), precisely from May 2012, explained it like this:
It is a fact that nutrient content of fruits change slightly as they ripen. As a banana ripens and turns yellow, its levels of antioxidants increases. These antioxidants in ripe bananas protect your body against cancer and heart diseases. But while overripe bananas certainly have nutritional value, they also lose some benefits. In full ripe bananas with dark spots on skin, the starch content changes to simple sugars that are easier to digest and may raise your blood glucose levels quickly, but it could be harmful for people with diabetes. Also, the micronutrients like vitamins and minerals decrease as the bananas ripen.
Tumor Necrosis Factor(TNF-α) is a cytokine, substances secreted by certain cells of the immune system that have an effect on other cells. This is indeed helpful in fighting abnormal turmor cells in body. Research done on ripening bananas has proved that the levels of TNF-α induction increased markedly with dark spots on skin before the entire banana peel turned brown. The research concluded that the activity of banana was comparable to that of Lentinan, a chemical immunostimulant that is intravenously administered as an anti-cancer agent. So, ripe banana can act as an anti-cancer agent by stimulating the production of white blood cells in the human cell line.
Both green and yellow bananas are high fiber foods rich in potassium, vitamin B6, fiber, and vitamin C. They have high calorific value because of their high sugar levels. A medium sized banana provides about 105 calories. Also, bananas are very good for our Gastro-Intestinal tract and aid in digestion. Therefore, eating one or two bananas is indeed good for health. Once bananas ripen fully, store them in the refrigerator to minimize further vitamin loss. Fresh bananas with brown patches on the skin are ripe enough to eat immediately. Make sure to avoid over-ripe bananas whose skin has turned brown or split open.
Still unsure about the authenticity of this explanation, I solicited another piece of information, this time counter-attacking the statement above, by a self-proclaiming ‘Internet pseudoscience hunter’ titled Skeptical Raptor, managed by, also, a self-claiming long-time, reliable expert (the author mentions (s)he has had the expertise worth a century’s quarter, but the explanation sounds convincing, though), originating from May 2013. And here it goes:
The “Japanese scientists” made no claim that there’s TNF in a banana, but the junk medicine pushers continue to make the claim, facts be damned. The problem is that anyone with a basic comprehension of biochemistry would understand that tumor necrosis factor (TNF) is a fairly complex protein, with a highly specific role in the human immune system (something notably lacking in a plant), so the chances that a banana would have some substance that exactly mimics or copies TNF is so tiny as to be close to impossible. A banana has no need for TNF, since it lacks an immune system of a vertebrate, so evolving a complex protein like TNF would be crazy; in fact, if it did, we’d have to rewrite our understanding of evolution. Let’s make this clear–we don’t have to rewrite evolution, because there is no TNF in bananas.
Even if we could assume that a banana makes TNF, the digestive tract would break down the complex proteins and substances, such as TNF, into its constituent components, such as amino acids, simple sugars, and fats, before being absorbed into the bloodstream. The TNF probably wouldn’t survive intact within the digestive tract. The true scientific skeptic would, even if they thought that maybe a banana evolved a TNF molecule by some strange mechanism, know that it could not enter the body.
Since TNF has a very specific action on the immune response, and not directly on cancer cells, how do we eat sufficient bananas (even if it did have TNF and it could be absorbed into the bloodstream) to increase the level locally to actually cause the appropriate immune response? And which one of the 200 or so cancers would it effect? It is clear that the name, tumor necrosis factor, leads one to believe that a drop of it on a cancer immediately kills the cancer. I would have to write a 20 page paper just to describe how TNF is regulated and disregulated within the immune system both locally and generally in response to a wide variety of immune challenges, including cancers. It is incredibly complex, and the name is simply one given without consideration to future alternative medicine pushers who jump on it as the the “cure” to all cancers. It isn’t.
Which leads us to how TNF causes many of the clinical problems associated with autoimmune disorders such as rheumatoid arthritis, ankylosing spondylitis, inflammatory bowel disease, psoriasis, hidradenitis suppurativa and refractory asthma. So, if a banana had TNF, if it could pass into the bloodstream from the digestive system, and if it could reach high enough levels to actually do something, it probably wouldn’t have any effect on any of the cancers, but it could have serious side effects. However, I wouldn’t worry about it, since there are so many “if’s” that it’s just not possible.
And this “boost the immune system” myth? The immune system is an incredibly complex system, with an almost infinite number of interactions between various proteins, compounds, organs, factors, and cells. As long as you’re healthy, so is your immune system, there is nothing you can do to make it stronger, better, or “boostier.” Well, vaccinations help, but they rely upon an appropriate immune response. So even if you won the Nobel Prize by finding some miracle compound that “boosts the immune system,” it would work on one tiny part of that system, and it would have a zero net effect.
Well, to cease perplexing yourself, you can actually find out that most of the search results regarding this ‘magic banana’ are of negative receptions. Or just consult your doctor to avert hypochondria from ruining your mindset.