Bananas fight cancer?

[Zorro]

I've seen this on Facebook:

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. The more darker patches it has the higher will be its immunity enhancement quality; Hence, the riper the banana the better the anti-cancer quality.

The only sites I can find anything on this are full of woo. Anyone have anything more scientific?

[Tootsie Plunkette]

I used this article in response to a friend who posted about this a while back.

[jimmy101_again]

Tumor Necrosis Factor is an animal proteinaceous (a protein) hormone. Plants don't produce animal hormones (protein or small molecule).

And, like Tootsie's link says (and this is quite general for proteins in food, including growth hormone in meat products) proteins are not biological active when eaten since they don't survive in the gut. If proteins did survive then there would be orally active insulins (insulin is a small protein).

There are a few plant products that up or down regulate synthesis of TNF in humans and other mammals.

[Nick Theodorakis]

The blog that Tootsie linked to provide a link to the original paper that might have provoked the confusion. It seems that the researchers (for reasons that still remain unclear to me, and I have occasionally studied TNF in the past) looked at the ability of phytochemicals in bananas to prime mouse peritoneal macrophage activation (in vivo and in vitro, or at least ex vivo), and one of the measurements was TNF production by activated macrophages. It said nothing about bananas actually having TNF.

Of course, even it was true that injecting banana extract into your stomach cavity could induce systemic TNF production, Nothing Good will come from that. TNF is one of the most potent pro-inflammatory cytokines and its production can cause a host of acute (fever, shock) and chronic (IBD, RA, etc.) pathological states. It might accidentally kill a few tumor (and non-tumor) cells along the way, stimulate some others, and have no effect on still others.

Nick

[Zorro]

So...in layman's terms, for those of us who don't speak Science? It's inconclusive?

[Nick Theodorakis]

No, it's irrelevant.

Nick

[Nick Theodorakis]

It's irrelevant because (1) bananas don't make TNF. (2) It seems that extracts of bananas might possibly prime your own macrophages to make TNF if you inject it into your stomach. (3) TNF doesn't work the way the OP (FB post) thinks it works anyway.

Nick

[DawnStorm]

Well, if there is any truth to the OP I'm screwed. I'm extremely allergic to bananas.