Mango: The New Diabetes and Cancer Buster

Duagu sent me an email about a month ago asking me to verify the claim of whether mango is a diabetes buster. Well duagu, I can't really verify claims, but what I can do is to offer my two cents worth as a trained food science professional.

According to the journal article published in the British Journal of Nutrition, researchers from both OK State U and NCSU suggested that the inclusion of freeze-dried (FD) mangoes in the diet of experimental mices were able to show improvements in terms of glucose tolerance and overall lipid profile.

Now duagu, if this really is the case, that would be wonderful, mainly based one reason. Mangoes are so abundant in the tropical region of the world like Malaysia, if mangoes are really diabetes busters, this would be a huge deal for mango farmers (although I don't think most Malaysians really care about the additional health benefits, because regardless of whether it is good or bad, we do love our kerabu mangga).

However I am presenting my skepticism based on a few reasons:

1. I can never reiterate any much more than this is an animal study, and most people have no idea about the vast amount of experimental biological studies that failed to transpose comparable results (if not the same) from mice models to human beings. So in order for us to fully conclude that mangoes indeed help counter diabetes in human, a similar study will have to be done with humans. With this mice study, we can only at most say that mangoes are potentially effective in regulating glucose levels. 

2. Surprisingly with the high levels of naturally occurring sugars in mangoes, mice fed with a diet supplemented with FD mangoes were still able to show the improvement in glucose tolerance. I am saying that this is fabricated, it's just that it's a bit too good to be true, but then this paper is published in the BJN which is highly reputed. To me, it is just like trying to achieve a goal with something that is not conventional and indirect. It's like you are trying to follow a sugar-free diet and just because lard is sugar-free, all you eat is just lard. But then again, they are still unclear of how this actually is happening biochemically in the mice, so until more studies are done, I rest my case.

TNF in bananas?

I received a question about bananas from Mom last week (exciting!), but have only had time to respond to it today (Sorry mom, been very busy analyzing all ye poop samples!). Anyway, mom's question goes,

Hi Ben,

Is it true that a full ripe banana with dark patches on d skin produces TNF ( tumor necrosis factor) which has the ability to combat abnormal cells. Therefore the riper the banana the better the anti cancer quality. Pls enlighten us. Tq

Very interesting question, mom.

I actually did some research online and found this Japanese journal article, and what I can say is that I am actually quite skeptical. There are a few reasons for my skepticism.

1. This is actually a mice model. You all outside of the scientific community have no idea how mice model results failed to transpose to humans.

2. The banana extract is given intravenously to mice. Anybody with some biology in high school will understand that taking things orally and intravenously can be totally different. If the Japanese scientists found that there are increase in immune cells in the mice, I would argue that anything that is injected intravenously would somehow induce the immune response against this xenobiotic, hence the proliferation of immune cells.

From a food scientist point of view, again I am skeptical that the black part of the bananas are producing TNF. Why?

1. We understand the blackening of bananas as one of the two mechanisms: a. The diminishing of carotenoids, hence exposing black pigments or b. The aggregation of compounds, creating a mass of black pigments, hence covering up the indigenous yellow pigments. I am more inclined towards the latter. We also know that banana emits ethylene constantly (Yes, banana is an ethylene producing machine, so if you want to ripen whatever fruit, just put it in a bag with bananas, and yes if you put it one day longer, everything will rot, haha!). So the black pigments are actually signs of cell death. Just like when you put your bananas in the refrigerator. Bananas are so chill-labile, that once exposed to even refrigeration temperature (4 deg Celsius), oxygen transfer across the cell membrane becomes impaired, so your banana dies and becomes black.

2. Even if bananas produces TNF, how likely is it to survive your stomach acid and digestive proteases in your gastrointestinal tract, and still is able to be absorbed into your bloodstream intact as TNF? We all know that TNF is a protein complex, and most protein complex diminishes into smaller units to aid transfer into the bloodstream.

All in all, I just think that this needs more research. We can either do an oral challenge in mice model again, or simply do a human study (It's not like you're feeding them arsenic, you're feeding them banana extract, duh!)

So, if you think you should eat black bananas versus yellow bananas, you are wise. It's not because it produces TNF, it's because it's sweeter and tastier (because most starch have broken down to simple sugars by now).


I hope I answered your question, mom.