Over my last couple of years as a dietitian, I have seen some clients with severe constipation. I’m talking situations that are so bad that I literally spent a significant chunk of my time thinking about how to help these clients because I hated the thought of somebody having to live like that.
And throughout the process of spending a crazy amount of time digging through the research on the topic, I quickly came to realise two things:
- The commonly given advice is not actually that effective. And some of it might make things worse.
- There are very few things that significantly help. And what I mean by that, is that the 3 things I am going to mention in this article, literally do help constipation in terms of improved frequency/evacuation. Whereas most other things prescribed to help actually show no difference when they are researched.
Obviously, medical options are an exception to this and do not fit into the two points above, since medical options can be quite effective. But as a dietitian, I am going to just talk about nutritional recommendations.
Challenges Associated with Standard Recommendations
The 3 most common recommendations for constipation are “fibre, fluid and exercise.”
This sounds like solid advice, but when you dig deeper there are some flaws.
Increasing fibre intake is the most common advice that I hear. And in theory, this can make sense.
And in a lot of cases it can help. But this is also actually one of the things that can make the issue worse.
Firstly, the research indicates that those who consistently experience constipation, on average, consume a similar amount of fibre as those who do not experience constipation.
We also have evidence that stopping or reducing fibre intake can help improve symptoms. If increasing fibre intake helps, then why would this happen?
Of course there is a bit of a basis for the claim that increasing fibre intake can improve constipation. The claim did not come out of nowhere. A meta-analysis on the topic concluded that increasing fibre intake can improve stool frequency. But there is a catch, it does not improve other symptoms like stool consistency, gas, bloating or painful defecation.
Taking it a step further though, increasing soluble fibre intake actually does seem to help. And the research on insoluble fibre is far more inconsistent.
One reason why it can potentially be detrimental advice though, is because if somebody quickly increases their fibre intake (particularly if the emphasis is on insoluble fibre) it is quite likely to make symptoms worse.
A slower increase in fibre intake is far less likely to be detrimental though.
The theory as to why increasing fluid intake works makes sense.
The logic is that increasing water content inside the gut can help soften stools and make it easier to have bowel movements.
And I would wager this actually does help for people who are consistently dehydrated.
But my issue with this advice is that when you look at the research that has been done on constipation, there is no sign that the advice actually helps people at all.
Since I’m a results driven person and my goal is to help people, obviously I am looking for recommendations that actually move the needle in terms of improving symptoms noticeably.
It is a great idea to focus on being hydrated. But it is unlikely to help constipation outside of specific cases.
Exercise actually is incredibly effective for helping constipation symptoms. It is one of those things that moves the needle in terms of improving results.
The reason I’m putting exercises in the challenges section though, is because almost all of my clients exercise regularly. So the fact that I am still getting new clients with severe constipation tells me that exercise obviously is not magical for solving all cases.
It also means exercise is not a tool I can use with my clients, since they are already exercising at a high level (and in a way that they are not interested in changing if it is counterproductive to their other goals).
Taking this a step further though and reading between the lines: gentle/moderate exercise seems to be really helpful.
The clients I see with severe constipation are typically people who are resistance training at a high intensity and have also typically been through a body building competition prep and have been exceptionally lean in the last 6 months or so. So this can be an exception.
What Actually Works Consistently?
My experience with these clients with severe symptoms has made me narrow things down to 3 key recommendations that actually work.
1) Kiwi Fruit
As a general rule, I’m not overly specific with fruit recommendations and I prefer focusing on variety. This is because we have clear research highlighting that >30 different plant foods per week is going to likely be beneficial for overall gut-health.
Constipation is an exception to this rule on specificity. I still encourage variety, since that is important. But I am quite specific in that I recommend 2x kiwi fruits per day.
This recommendation clearly helps to improve frequency of bowel movements, as well as improving other symptoms of constipation.
It is low-FODMAP (which will be discussed later) which is a bonus as well.
There are a lot of mechanisms as to why it can help, but the main thing I care about is that it improves bowel movement frequency by an average of 45%, while also reducing symptoms like gas and bloating more than any other common lifestyle option.
Dosage: 2x kiwi fruits per day
Adding up to 2 tablespoons per day of linseed/flaxseed (I believe they are the same thing, just different names, but I could be wrong) over the course of 3 months has been shown to significantly reduce symptoms of constipation.
It improves bowel movement frequency and reduces bloating and abdominal pain.
The effects are pretty gradual though, so this one takes a bit of time to have a noticeable impact.
Dosage: Up 2 tablespoons per day (for people on restricted calories, I sometimes reduce it to 1 tablespoon per day)
3) Psyllium Husk
Psyllium husk is a form of soluble fibre that has commonly been recommended as treatment for constipation.
In fact, as a treatment for irritable bowel syndrome in general (both IBS-D and IBS-C), psyllium husk has been shown to be beneficial.
For constipation, the magnitude of improvement is pretty significant. On average, 10g of psyllium husk per day appears to increase bowel movement frequency by 64%. It also improves some of symptoms, such as making it easier to defecate.
Dosage: 10g per day. An alternative is to have 1x serve of Metamucil per day, since Metamucil is based on psyllium husk and just packaged in what could be considered a more convenient/consumable product for some.
Bonus #1: Magnesium Citrate
Magnesium supplementation is not a long-term solution, but it can have a laxative effect. This is due to the osmotic activity of unabsorbed magnesium salts in the intestines and how this draws in water and stimulates bowels.
This a tool I only really use in severe cases, for those who need slightly more immediate results than the tools mentioned above will provide. And obviously, this is not recommended if there are any specific medical reasons you should not supplement magnesium.
Dosage: 400mg per day of magnesium citrate for 3-6 weeks.
Bonus #2: FODMAPs
The low-FODMAP diet is another tool that is interesting and can potentially be beneficial for constipation. That being said, while the success rate for IBS-D is particularly high, it is often far less effective for constipation.
Theoretically the low-FODMAP diet can help by reducing the intake of foods linked with gas production. This gas production clearly contributes to the symptoms of bloating and gas. Beyond that, it potentially compacts the faecal matter more, making it harder to undertake bowel movements.
From that perspective, a low-FODMAP diet clearly helps with some symptoms. But it is not guaranteed to actually help bowel movement frequency.
The low-FODMAP diet is not really a first-line treatment measure for constipation, but I still keep it in mind. It is also the reason why I do not typically look at prune juice or pear juice as go-to recommendations right off the bat either, even though they both can be useful in the management of constipation.
If you are thinking about undertaking a low-FODMAP diet, please read our article on it, since there are some key points in there about why you do not want to stay low-FODMAP forever.
Although the 3 common recommendations are fibre, fluid and exercise, there are often cases of constipation where those 3 recommendations do not get the job done.
These 3 recommendations regarding kiwi fruit, linseed/flaxseed and psyllium husk consistently lead to dramatic improvements in symptoms.
If you are somebody with a severe case of constipation, they would be great additions to your diet. If you are somebody with a less severe case, they are also worth considering and they can also be used as tools to help with the prevention of constipation in the future.
Aidan is a Brisbane based dietitian who prides himself on staying up-to-date with evidence-based approaches to dietetic intervention. Dating back to well before starting uni he has been fascinated by all things nutrition, particularly the effects of different dietary approaches on body composition and sports performance. Due to this passion, he has built up an extensive knowledge base and experience in multiple areas of nutrition and is able to help clients with a variety of conditions. One of Aidan’s main strengths is his ability to adapt plans based on the client’s desires. By having such a thorough understanding of optimal nutrition for different situations he is able to develop detailed meal plans and guidance for clients that can contribute to improving the clients overall quality of life and performance. He offers services both in-person and online.