It used to be called "roughage", and people tried to get rid of
it. Now we all know we need fibre in our diet, but why?
In this section, you will find out what dietary fibre is, why we
need it, what it does for us and where we find it in our foods.
Why do we need dietary fibre?
Dietary fibre refers to the carbohydrate that does not get
digested by enzymes in our small intestine, and so its sugar units
are not absorbed into the bloodstream. Dietary fibre is
therefore known as 'non-glycaemic'.
However, fibre has important effects on other nutrients within
the small intestine and through effects on the large intestine,
where few other nutrients arrive intact. It has a range of
valuable health effects:
- Smooths out digestion and absorption of glucose and fats in the
small intestine. It reduces the Glycaemic Index of a
- Provides fuel for the healthful or "good" bacteria in our large
intestine which in turn benefit us by making vitamin B12, and by releasing
volatile fatty acids from the dietary fibre which are important for
the health of our colon.
- Speeds up transit though the intestines to remove waste and
toxins from our body
- Regulates bowel action, so reducing cancer risks
Did you know? Dietary fibre has been sold
for years as a 'bulking agent' as people thought it must reduce
appetite and help weight loss. But research shows that it
doesn't actually reduce appetite or assist weight loss directly.
So, what is
dietary fibre? Find out more by clicking that
Where do we find dietary fibre in our food?
Generally, dietary fibre is present in all plant foods - fruits,
vegetables and grains - but not in animal foods. This is
mainly because of the different in cell structures - plants cells
have cell walls, animal cells don't.
Insoluble fibre can be found in foods such as wheat, corn,
wholemeal bread, brown rice, bran, whole grain cereals, nuts and
seeds, vegetables and peels of fruits.
Soluble fibre is particularly rich in legumes - lentils and peas
and beans (including peanuts) and bean products like 'soya protein'
- and in oats, barley, fruits, vegetables and potatoes
Is there a down-side? Can you
have too much dietary fibre?
Well, yes you can…
First, some advice for you if you want to add more fibre to your
diet… Increase fibre-rich foods gradually, because a sudden
large addition of fibre into your diet can cause stomach cramps and
wind. Your intestine will adapt in time.
And, too much dietary fibre can interfere with the absorption of
minerals such as iron, zinc and calcium from foods. This is not
often a problem because high-fibre foods usually contain plenty of
these minerals, and vegetarians on very high fibre diets tend to be
healthy, but it can cause problems when the overall diet quality is
poor. If you are taking fibre supplements, be careful and
only use them occasionally.
It's important to always make sure that you keep yourself well
hydrated in relation to your fibre consumption, because fibre can
dehydrate you a little and become sluggish in your
So we can see that dietary fibre has lots of plus-features, but
it can have a few minuses too. Our health depends on eating a
balanced diet- and it can sometimes be a bit tricky to work out all
the pluses and minuses of all the nutrients.
See also What is dietary fibre?