Fibre refers to the bits and pieces of plant foods that cannot be broken down by your digestion. Because of this, fibre moves through your gastrointestinal (GI) tract, bulking and softening your stools.
For those who don’t know, stools are poos and poos need fibre to get out of your body in a safe and smooth manner. Basically, getting enough fibre from your diet will help you to pass a soft stool, regularly and easily. However, lack of fibre, to say the least, will just make everything “harder”.
Current analysis of the most recent Australian National Nutrition and Physical Activity Survey showed that only 42 per cent of children and 28 per cent of adults meet the adequate intake for dietary fibre daily. Adequate intake for children is 14-28g (range depends on age) and for adults, 25g for women and 30g for men. These are the minimum amounts of dietary fibre required daily to achieve regular bowel motions. Any less and you’re likely setting yourself up for an irregularly hard time.
It’s important to note that straining on the toilet is not good for your GI system. You probably need more fibre and more water, but talk with your dietitian or GP first.
To make matters worse, the same national survey found that less than one in five adults meet the suggested dietary target (SDT) for fibre. The SDT is the amount of dietary fibre recommended to significantly reduce your risk of chronic disease, including type 2 diabetes, colorectal cancer and cardiovascular disease. The SDT for fibre is higher, being 28g per day for women and 38g for men.
Get to know the three faces of fibre
It is important to understand that fibre comes in many different forms. These are classified based on their GI solubility, bacterial fermentation capacity, products of fermentation and physiological properties. Put simply, they are categorised by how they function in and on your GI tract. The most common fibre categories include soluble fibre, insoluble fibre and resistant starch. All three are essential.
Soluble fibre, found in rolled oats for example, attracts water in your GI tract. This results in a nice soft gel forming, which in turn slows digestion and softens your stools. It also slows carbohydrate breakdown, which helps with better blood glucose control (lowers glycemic index). Soluble fibre is favourable for diabetics and those seeking weight loss. Furthermore, because of its stool-softening effects, soluble fibre makes passing a motion a lot easier. Plus, some soluble fibres are prebiotics and prebiotics are gold for your gut. More on that later.
Insoluble fibre, found in foods such as wheat bran and brown rice, does not dissolve in water, therefore passes through your GI tract unchanged. It adds significant bulk to your stools, making them heavier and causing them to flow through your GI tract more efficiently. This is really important, because slow-moving stools (constipation) can putrefy and release toxins. Therefore, insoluble fibre helps you go to the toilet more regularly.
Resistant starch is a special type of carbohydrate that “resists” digestion in your small intestine and gets rapidly fermented by the microbes living in your large intestine. Because of its fermentation capacity, it is classified as a prebiotic. You might even call it a super prebiotic.
Interestingly, resistant starch levels in certain foods vary according to different cooking methods, cooking and cooling processes and degrees of ripeness. For example, unripe bananas are rich in resistant starch, yet ripe bananas contain little. Cold potato salad is full of resistant starch, yet freshly cooked hot potato contains nada. This is because when you cook potatoes then cool them, their starch becomes retrograded into a non-digestible (resistant) form. The same process happens with pasta.
So, The Wiggles almost got it right. Eat cold spaghetti, mashed banana, but trade your hot potato for cold potato salad. Bam. Prebiotics coming at you.
Prebiotics are defined as selectively fermented ingredients that result in specific changes in the composition and/or activity of your gut microbes, thus conferring health benefits. In a nutshell, prebiotics feed your good gut microbes, and in turn ferment them, resulting in the release of certain gases and beneficial compounds called short-chain fatty acids (SCFAs).
To highlight just a few of their benefits, SCFAs fuel the cells lining your gut, fuel the growth and activity of other good gut microbes, reduce your gut’s pH level which increases the absorption of essential minerals, enhance your gut barrier integrity and immune system, as well as help to regulate the movement of food and waste through your GI tract.
Obviously, prebiotics are integral for good gut health. You can find them in plant foods such as garlic, onion, leeks, cashews, green bananas, wheat, rye, barley, figs, asparagus, beetroot, artichokes and legumes.
No fibre, no fun
Not consuming enough dietary fibre in general can contribute to numerous disorders, including constipation, haemorrhoids, diverticular disease, irritable bowel syndrome, diabetes, cardiovascular disease, overweight and obesity and colon cancer.
And if you don’t eat enough prebiotics this can compromise your gut microbes, which in turn has been linked to bloating, abdominal discomfort, diarrhoea, constipation, reduced immunity, overeating, sugar cravings, nutritional inadequacies and even impacts on mood, including anxiety, depression and nervousness.
Eat these six foods daily to get the right mix of fibres
All plant foods contain fibre, so aim to eat a variety of fruits, nuts, seeds, vegetables, wholegrains and legumes every day. And yes, it really is that simple. For some more defined actions, see below:
- Include some wholegrains at each main meal, for example rolled oats, quinoa, brown rice, barley, sprouted bread or buckwheat.
- Include at least two cups of coloured vegetables with lunch and dinner.
- Snack on a piece a fruit between meals and/or add some into your breakfast muesli, porridge or smoothie. Also vary your fruits often.
- Eat a handful of nuts each day.
- Aim to include a few teaspoons of seeds daily. Try adding chia seeds, flaxseeds or LSA to your smoothies, muesli or yoghurt, or pumpkin or sesame seeds to your salads.
- Replace your spreads with hummus, tahini, nut butters or avocado.
- Include ½-1 cup of legumes (chickpeas, lentils) at least three to four times per week. You can add these to salads, curries, stir-fries, burritos, soups and so on.
- Drink lots of water when you’re upping your fibre. Aim for at least two litres per day.
- And if you don’t normally eat much fibre, increase your fibre intake slowly over a number of days to weeks.
Aim to eat a variety of plant foods daily, making sure they contain the three different fibre types:
- Soluble fibre: oats, barley, sweet potato, flaxseeds and the flesh of fruits and vegetables (passionfruit, avocado)
- Insoluble fibre: wheat bran, brown rice, wholegrains, brazil nuts, flaxseeds, root vegetables, cabbage, broccoli, peas, green beans and the skins of fruit and vegetables
- Resistant starch: barley, sorghum, millet, legumes, unripe bananas, cooked and cooled potato, pasta and rice