I admit it, I postponed writing this banana constipation article for a while.
I have a long list of constipation articles to write ahead of me. Over the years, I have taken copious notes every time I saw constipated people in my naturopathic clinic, and my head is full of ideas.
I thought banana constipation could wait, there were more important topics to cover.
Yet the subject pops up on a regular basis, and I believe there is much confusion on the internet, including conflicting views (many).
So let's put that discussion to rest. This article will be short (I am giving you a break on this one!). So if you’re wondering about that Chiquita, stay with me for another few minutes...
Without a doubt, unripe fruits can cause constipation. They contain tannins and tannins are astringent. When tannins get in contact with the sensitive mucosa of your gastrointestinal tract, they have a tissue shrinking effect. Think of the mouth puckering effect of an unripe fruit, applied to your bowel this time.
Or think of what leather makers do to tan a hide – they apply tannins. So an unripe fruit tans your gut mucosa, and thus diminishes the secretions released into your stools. This leads to a drier gut, and therefore to constipation.
Lots of bananas are sold and eaten unripe. Even if the color is yellow, it doesn’t mean the banana is ripe. If it is still firm to the touch, or if there are small touches of green on the skin, it is still unripe.
A banana that has ripened in the supermarket or your home should give way when pressed with your fingers, and the skin should be yellow turning to brown spots in some areas. The tannins will then be at a minimum.
Note that sometimes even if brown spots are present, there will still be a touch of green in some areas (see picture at the top, green area on the stem – that banana is not fully ripe).
In the previous section we saw how tannins of the unripe banana can cause banana constipation. But what about a banana that has been left to ripen nicely?
Bananas are always imported in our western industrialized world. And they are always picked unripe. That is the nature of the fruit export business. They are then forced through an artificial ripening process at the destination.
An unripe banana contains lots of starches(1). When the banana ripens on the tree, these starches are nicely transformed into sugars. The sugars are easily digestible. The starches are not.
It is clear that "different banana cultivars vary in the amount of starch remaining in ripe fruits"(2). When the bananas have not ripened on the trees, there is unfortunately quite a bit of starch left.
One study goes into the reasons of the “poor digestibility of banana starch granules in the human small intestine”(3), showing that “84% of the starch ingested reached the terminal ileum".
In other words: banana starches are not easily digestible.
Why give your gut so much trouble and risk banana constipation when a slew of other fruits are available around you, hopefully grown locally and picked ripe (or containing less starch)?
If you really love bananas, can you eat one a day? Or even two, left to ripen as much as possible?
Maybe. It may not cause any banana constipation trouble. The tannins will be mostly gone. But some starches will remain, and you may or may not be very sensitive to them. It’s hard to tell.
But if you are chronically constipated and looking for the source of the issue, I recommend removing bananas from your diet. It is not the most digestible fruit.
There are so many other good sources of fibers and vitamins, other fruits grown locally and picked ripe.
Why take the risk?
(1) Menezes EW, Tadini CC, Tribess TB, Zuleta A, Binaghi J, Pak N, Vera G, Dan MC, Bertolini AC, Cordenunsi BR, Lajolo FM. "Chemical composition and nutritional value of unripe banana flour (Musa acuminata, var. Nanicão)". Plant Foods Hum Nutr. 2011 Sep;66(3):231-7.
(2) Shiga TM, Soares CA, Nascimento JR, Purgatto E, Lajolo FM, Cordenunsi BR. "Ripening-associated changes in the amounts of starch and non-starch polysaccharides and their contributions to fruit softening in three banana cultivars". J Sci Food Agric. 2011 Jun;91(8):1511-6. doi: 10.1002/jsfa.4342. Epub 2011 Mar 28.
(3) Faisant N, Gallant DJ, Bouchet B, Champ M. "Banana starch breakdown in the human small intestine studied by electron microscopy". Eur J Clin Nutr. 1995 Feb;49(2):98-104.