Do Bananas Help Constipation? – Explained

Why Bananas Can Put an End to The Vein-popping Bathroom Visits

1. Pectin to Save the Day

The USDA lists a medium sized banana as having 3.1g of fiber. That is a fair amount considering that the daily recommended amount for most adults is around 25 to 30 g.

Some of this fiber is what is called pectin, which is a soluble fiber found in many other fruits as well, such as strawberries for example. According to the World's Healthiest Foods about 1/3 of the fiber in bananas is this soluble pectin fiber.

Why does this matter?

Well… Because soluble fiber can help stop diarrhea as well as constipation (which is why pectin-containing fruits are also good for treating diarrhea). It can do so by helping bring water into the intestines as well as absorb water, overall keeping a healthy balance of large and soft stool, rather than the hard/compact stool that you will experience when you are constipated.

A 2014 study published in a Chinese journal found pectin to accelerate bowel movements and alleviates symptoms of constipation. In this study 80 patients with constipation were given a 4-week supplementation of pectin, at 24 g per day.

*Of course in the study these people were given very high amounts of pectin. You would have to eat a considerable amount of bananas to reach that amount.

2. Insoluble Fiber

It's true that a small percentage of the fiber in bananas is soluble, but this isn't a big deal because insoluble fiber is great for treating constipation as well.

Insoluble fiber, as you can probably imagine, is not soluble. It does not absorb water but is still great as a constipation treatment, helping bring more water into the colon.

As a general role of thumb, soluble fiber is good for treating both constipation and diarrhea, but you only want to up your intake of insoluble fiber when you have constipation.

3. Fructose May Help

Bananas are considered as moderately high in fructose, which is a sugar. They can be very sweet so it might be surprising that they are only "moderately" high in this.

Why is this good potentially?

Because fructose is difficult for our human bodies to digest, which is why "fructose intolerance" is common. This difficulty with digestion is something that often leads to faster and more lose stools.

HOWEVER, fructose intolerance may be a good thing according to an article in Global Pediatric Health. It depends on the person, but for someone with constipation it may be a good solution to help soften and loosen their stools. But for others it can be too much and cause diarrhea.

Under-ripe Bananas - Good or Bad

Much of the controversy as to whether bananas are a cause or cure for constipation is focused around bananas that are not fully ripe, a.k.a. green bananas.

Some sources say that they cause constipation while others disagree.

The fact of the matter is that green bananas contain a lot more starch than yellow, fully ripened bananas. This is because because the starch has not yet went through the process of being converted into sugar, which makes ripe yellow bananas so much more sweet than green bananas.

The problem here is that much of this starch is "resistant starch", meaning that it is resistant to digestion. Before a banana is fully ripened it is said that around 70 to 80% of its weight is starch, most of which is resistant.

This starch is difficult for our bodies to digest and because of this it makes its way through the small intestine into the large intestine, where acts as a food for good bacteria living there.

What Studies Say About It:

A 2019 study published in the Jornal de Pediatria that took 80 children with functional constipation and tested the effectiveness of eating green bananas as well as taking laxatives. The results were that at a "statistically significant" reduction in constipation was observed.

There was also an earlier study performed in 2014 that is published in Journal of Medicinal Food that tested the resistant starch that is found in bananas' effectiveness against constipation in mice. It was found to increase the digestion speed through the small intestine and quicken bowel movements overall.

While there are claims that green bananas may cause constipation, there doesn't seem to be any good proof of this. 

That said, they have also been shown to help relieve diarrhea, by firming up loose stools, which may be surprising. This may make it seem more acceptable that they could harden it up "too much", but it seems that they are best for supporting an overall balance in digestion.

Don't Eat Too Much

It is well known that you don't want to eat too much of anything, including bananas. It doesn't really matter how healthy a food is, if you eat too much of it, it can become unhealthy.

There have been reports of eating too many bananas leading to constipation and/or diarrhea… Just digestion problems in general.

How much is too much?

Well, this depends on how big of a person you are, but generally speaking adults can eat quite a bit. 

Potassium is a mineral that bananas are well known for having quite a bit of and could be considered the "limiting factor" for how much one should consume, and since the average banana has around 450 mg of potassium and the recommended daily dose is around 3500 mg, you can consume somewhere in the range of 6 to 7 bananas in one day before even reaching that recommended amount. 

Of course this is just a very general number. Many people will be able to eat more without a problem while some may have problems and may want to be less.

Cause or Cure?

So do bananas help constipation or not? There seems to be some conflicting information given here.

The answer is that they can potentially be a cause and a cure. Results will vary greatly depending on the person and many variables, such as what their diet looks like, intolerances they might have, and so on.

As with any food or supplement, you have to find what works for you. If you are constipated and have not tried eating bananas, it very well could be worth the attempt.