What is fibre?
What is fibre and why is it important? Registered nutritionist, Jo Lewin, explains how upping your intake has a positive impact on your health. Plus, find recipes and tips for eating more fibre.
You may know that fibre is crucial for good digestion and gut health, but did you know there are different types of fibre and our bodies break these down differently? Below you'll find everything you need to know about fibre including how much you should eat a day, the side effects of not eating enough and ways to get more fibre in your diet.
What is fibre?
Fibre is the blanket term given to the non-digestible, mainly carbohydrate material, found in plants. It is the part of the plant which our digestive enzymes can’t break down, so it passes through our digestive system relatively unchanged. That said, some of this fibre can be worked on by the many beneficial bacteria that live in our gut.
Why is fibre important?
Including enough fibre in your diet is essential for a number of reasons, and not just for a healthy bowel function. Adequate fibre may help:
- Lower your risk of heart disease, stroke and diabetes
- Help manage your blood sugar levels
- Support digestive efficiency
- Strengthen your immune defences
- And by adding fibre you may provide a much-welcome boost to achieving your weight loss goals
Are there different types of fibre?
There’s a huge number of different types of fibre in our food and, in an attempt to simplify them, they are commonly divided into two main groups, soluble and insoluble:
- Soluble – this type of fibre partially dissolves in water and takes on a gel-like appearance. It can be helpful for managing blood sugar, cholesterol levels and for promoting fullness because it slows down stomach emptying. Foods which supply soluble fibres include oats and barley, apples and pears.
- Insoluble – insoluble fibre comes mainly from plant cell walls (cellulose) and does not blend or dissolve in water, it is resistant to digestion by our digestive enzymes, which means it passes through our gut relatively unchanged. It’s the bulk or roughage you often hear talked about because it helps speed the passage of waste material through your digestive system and stops you from getting constipated. Sources include wholewheat flour, wheat bran, popcorn, dried fruit, beans and pulses.
In reality different plant foods have varying proportions of both of these types of fibre. Some experts believe a more meaningful way of categorising fibre might be to class them as fermentable by the microbes that live in your gut or non-fermentable.
How much fibre should I eat?
Health experts recommend we have at least 30g a day, depending on our age and gender. Sadly, very few of us achieve these levels.
What are the health implications of not eating enough fibre?
Inadequate amounts of fibre have been associated with conditions such as diverticulosis, bowel cancer and haemorrhoids. In addition to this many of our modern lifestyle diseases such as obesity, diabetes and poor cholesterol management are associated with a highly refined diet of processed foods, low in fibre.
This is because adequate amounts of dietary fibre may help with weight management by slowing down digestion (keeping us fuller for longer) and helping the release of glucose and insulin. Soluble fibres have been shown to help normalise serum cholesterol levels by binding directly to cholesterol, decreasing the chance of reabsorption and promoting excretion. Fibre also feeds our gut microbes, this beneficial community of microbes that reside in our intestines, support our health and maintain bowel regularity.
How would I know if I am constipated?
If you have to strain to have a bowel movement, have hard stools, infrequent or incomplete bowel movements or experience any discomfort then you may be suffering from constipation. This condition affects women twice as often as men and is more common in people over 65. Although age is commonly listed as a cause of constipation, it is attributed more to lifestyle. Eating low fibre, packaged or prepared foods, taking certain medications or food supplements combined with a lack of mobility may contribute to the condition.
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If you are a woman in your reproductive years you may notice that your bowel habits change at various points in your menstrual cycle. Pregnancy is also a common but temporary cause or it may be caused by an under-active thyroid.
It is normal to have one to three soft bowel movements each day. Optimal bowel transit time is 12 to 24 hours. Slow bowel transit time raises the risk of colon disease and contributes to other health problems.
Bowel movements should be painless. If you experience pain or blood during a bowel movement, see your GP.
How do I know if a packaged food is high in fibre?
Get used to reading labels and look for foods that contain 6g fibre or more per 100g (or at least 3g per 100kcal) – these are considered to be high-fibre foods, while those containing at least 3g of fibre or more per 100g (or at least 1.5g per 100kcal) are considered to be a ‘source’ of fibre.
How can I get more fibre in my diet?
Making some easy and sustainable changes to your daily diet may help you achieve a greater fibre intake. You can do this by:
- Eating at least five portions of fruit and vegetables each day
- Making wholegrains the rule and processed grains the exception
- Starting the day with a high-fibre breakfast cereal (bran, oats or wholegrain) topped with dried or fresh fruit. Most cereals give an average of 3g fibre per serving.
- Choosing wholemeal, wholegrain, granary or multi-seeded bread
- Adding legumes such as kidney beans, lentils and chickpeas to stews and casseroles.
Is extra fibre safe for everyone?
If you wish to increase the amount of fibre in your diet, do so slowly. A quick change from a low-fibre to high-fibre diet may cause uncomfortable gas, cramps and bloating. In conjunction with increasing your fibre intake, be sure to keep fluid levels up to help make stools easier to pass.
If you have been diagnosed with a condition such as diverticulitis or colitis, refer to your GP or healthcare professional for the correct dietary advice specific to your condition.
High-fibre recipes to try
Browse all our high-fibre recipes or try our top picks.
Soaking or stewing dried fruit provides a great source of soluble fibre and makes a wholesome pudding:
10-minute winter fruit compote.
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Kerry Torrens BSc. (Hons) PgCert MBANT is a Registered Nutritionist with a post graduate diploma in Personalised Nutrition & Nutritional Therapy. She is a member of the British Association for Nutrition and Lifestyle Medicine (BANT) and a member of the Guild of Food Writers. Over the last two decades she has been a contributing author to a number of nutritional and cookery publications including BBC Good Food.
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