Dr Michelle Dickinson: nanotechnologist on what will help you poop

We’ve all been told the same advice for decades: 'Eat more fibre if you’re constipated.' From breakfast cereals to bran muffins, fibre has long been the go-to remedy for getting things 'moving.' 

But new research published in two major international journals, the Journal of Human Nutrition & Dietetics and Neurogastroenterology & Motility has just turned that advice on its head. 

It turns out that while a high-fibre diet is good for your overall health, the science doesn’t actually support it as an effective treatment for constipation. 

The researchers looked at more than 75 clinical trials and rather than just counting grams of fibre, they focus on measurable outcomes like how often someone passes stools, whether straining occurs, and overall quality of life. 

They identified a few key foods and supplements that have solid evidence behind them: 

Kiwifruit – This one topped the list! Studies show it helps improve stool frequency and consistency.

Rye bread – Rich in unique fibres and bioactive compounds that appear to support gut movement.

Mineral-rich water – Particularly waters high in magnesium, which can naturally draw water into the bowel.

Psyllium fibre, magnesium oxide, and certain probiotics – These supplements also showed evidence of helping reduce constipation symptoms. 

In contrast, general 'high-fibre diets' and popular senna-based laxatives were found to lack convincing scientific support for long-term effectiveness. 

Constipation isn’t just uncomfortable, it can seriously affect quality of life. It’s also incredibly common, especially among adults and older populations. 

Until now, most medical advice has been frustratingly simple: 'Eat more fibre and drink more water.' But the new research suggests that this one-size-fits-all approach is outdated. 

Fibre is still vital for heart health, gut bacteria, and blood sugar control. But when it comes to constipation specifically, it may not be the magic bullet we’ve all been led to believe. 

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Episode Transcript

Speaker 1 (00:06):
You're listening to the Sunday Session podcast with Francesca Rudgin
from News Talks EDB.

Speaker 2 (00:13):
Joining me now for science Study of the Week is
doctor Michelle Dikinson.

Speaker 3 (00:18):
Good morning, Good morning.

Speaker 2 (00:21):
Fiber. We're going to talk about fiber. Now, when we
talk about fiber, it's quite trendy at the moment when
we're talking about wellness and we think of it being
news for various you know, having various benefits to us,
especially keeping us regular. But new research has implied that
fiber might not be the answer for constipation.

Speaker 3 (00:39):
Yes, sorry Sunday Morning, I know, but we're going to
talk about if you're a little backed up down there
and what the new researcher said. So lots of people say,
have a high fiber diet, eat more fiber if you're
going to if you're struggling to go to the toilet,
because that's going to push everything through. And it's sort
of an old livestyle. So there's lovely new set of studies.
They're published in the Journal of Human Nutrition and Dietics

(01:01):
and also Neurogastrionology and Motim, both published the same fire
have actually just said, sure, fiber is great for you
for other reasons, but if you are constipated, we have
found due to this big study. They looked at seventy
five big studies, put all the evidence together and said,
it's not about your high fiber breakfast cereal, it's not

(01:24):
about your brand muffins. But it's about these four things
that we have found that actually will help you get
things moving. So they are not about how do you
know how many grams are fiber you're supposed to eat
a day, by the way, No, most people don't, right,
So when when people say a high fiber diet, most
people don't even know what fiber is. So twenty five

(01:47):
to thirty grams a day should be your normal amount
of fiber anyway, So when they're saying high fiber dietes,
you're going over thirty grams a day. But ignore all that.
If you need to go to the bathroom, what you
need to do. And luckily, because we live in New Zealand,
it's something that we have all seasoned round is that
Kiwi fruit. So they said the humble key we fe
is actually the best thing you could have to help

(02:10):
improve store frequency and consistency, as it says in the paper,
and you will need to eat three kiwifruit per day
for up to four weeks to get things really regular.
But this is what I found really interested, So you
know me, I read all the details in the paper
and it said please eat it without the skin, and

(02:30):
I was like, who eats kiwi fruit with the skin?
But lots of people do, do they? I don't, Yeah, anyway,
So it said the skin will give you more fiber
and help you move more regularly, if you need that.
But they said eating kiwi fruit skin gives you other
side effects, and they listed a whole bunch of other
tummy upset side effects and itchy mouth and all sorts

(02:52):
of weird things. So if you are in if you
already eat kiwi fruit skin and it doesn't bother you,
carry on doing it, it's great. But for the rest
of us, I thought it was weird that people did that.
Take the skin off and you'll be fine. To three
kiwi fruit a day four weeks is what you need.
But the other things on the list are quite nice.
One of them is rye bread, and so rye bed

(03:14):
has actually these nice bioactive compounds that appear to help
support the movement inside our gut. One is magnesium rich water,
so it's usually sold as mineral rich water, and actually
in the magnesium in the water can draw water into
the bowel to help you get things more liquid down there.

(03:35):
And the final one is called a sillium fiber and
a couple of probiotics and they also help. So basically,
the advisors high fiber diets are amazing for you for
other reasons hot health, gut bacteria, blood shook control. But
if you are constipated, ignore high fiber diets and ignore

(03:55):
senna based laxatives which also apparently didn't have any scientific
evidence behind them, and just go to your local grosser
and make sure you've got enough for three Kiwi frou.

Speaker 2 (04:07):
Look, I love that, I love the kere, we throw
the key we frow. I also learned recently is really
good for our absorption because of its high content and
envitement c So there we go. It caters to a
whole lot of different different needs that we have. Michelle Dickinson,
thank you so much. We'll talk next week.

Speaker 1 (04:23):
For more from the Sunday session with Francesca Rudkin. Listen
live to News Talks it'd be from nine am Sunday,
or follow the podcast on iHeartRadio,