Fibre, a Carbohydrate

We have long thought of carbohydrates as simply a source of energy.  This has been the main focus of diet programmes and nutrition education for years.  But, fibre is a type of carbohydrate that has no energy value.  This is because it is not broken down into sugar molecules during our digestive process.  Despite this, the fibre content of packaged foods is included in the total carbohydrate figures on nutritional labels – to see the energy-giving carbohydrate content you need to subtract the fibre contribution that should also be stated.  No carbohydrate – no fibre.

Fibre can be separated into two main types – soluble and insoluble.  Insoluble is what you may have heard termed as “roughage”.  It helps attract water into the stool making the stool softer, adds bulk and helps to ‘keep things moving’.  It also supports insulin sensitivity.  Great sources of insoluble fibre include:

• Whole grains: wheat bran, brown rice, quinoa
• Vegetables: legumes, leafy greens, rhubarb
• Nuts and seeds
• Seeds
• Fruit with edible skins: grapes, apples, kiwi, berries.

Soluble fibre dissolves water forming a kind of gel which slows down our digestion and helps us feel full for longer.  It’s ability to soak up water also helps to attract fluid to the stool making it softer and easier to pass.  It is believed to help regulate blood sugar in people with diabetes, and may have a role in lowering LDL (“bad”) cholesterol levels in the blood.  Sources of soluble fibre include:

• Grains: oats and barley
• Chia seeds
• Vegetables: carrots, leafy greens, sweet potatoes
• Pulses: peas, beans, lentils
• Fruit: Apples, pears, citrus fruit.

Besides helping us get rid of waste, fibre has other roles inside our gut too – it feeds our microbiome.  The microbiome is the term for the ecosystem of bacteria, viruses and fungi that live on and in our bodies, including our gut (the gut microbiome).  As horrible as that may sound, the microbiome is important for our general health including our immune system, mental health and heart, it can even influence our weight.  For best health we need a variety of bacteria and for those bacteria to be balanced.   We can support this by making sure we get plenty of prebiotic foods in our diet.  Prebiotic foods contain fibre that feeds the bacteria in our guts.  They include:

• Fruit: Apples, unripe/green bananas
• Alliums: Garlic, leeks and onions
• Grains: wheat bran, oats and barley
• Asparagus
• Chicory root
• Dandelion greens (use cooked or raw)
• Jerusalem artichokes
• Cocoa – watch the sugar content in cocoa products such as chocolate and chocolate drinks!
• Flaxseeds/linseeds
• Seaweed
• Cooked and cooled rice, white potatoes and pasta.

The greater the variety of foods we eat, the more we support our microbiome; and the more we support our microbiome, the more it supports us.  Within that variety of foods it is worth trying to avoid ultra-processed foods and food and drinks high in free sugar and/or sweeteners.  Also try to reduce your alcohol consumption if you regularly drink more than the recommended daily limits.

The bacteria also need to be in the right place.  Most of our gut bacteria resides in the large intestine, particularly in the first part called the cecum.  There is very little bacteria in the small intestine and so if any bacteria develop there or spread from the large intestine it can cause problems with our digestion and may result in small intestine bacterial overgrowth (SIBO).

Medically constipation may be diagnosed if you go longer than three days without passing a stool, however going to the toilet 1-3 times per day is generally considered normal.  If you are experiencing constipation or find that your stools tend to be quite hard, it may be that you are not getting enough fluids, or that you are not getting enough fibre.  In fact, according to the British Dietetic Association the average adult consumes around only 60% of the recommended fibre intake of 30g – it is certainly something to consider!

Remember that soluble fibre may slow your digestion down potentially making constipation worse – if you have this problem try gradually increasing your insoluble fibre and fluids.

Of course if you have health concerns, including unexpected changes in your toilet habits or stools, seek medical advice.

There is a caveat…. Don’t suddenly start adding large amounts of fibre-rich foods to your plate a couple of times every day if you don’t normally eat them.  Doing so will have unpleasant side effects!  It is best to gradually increase your fibre intake over a few weeks with a variety of fibre sources employed to ensure you get a greater variety of nutrients, food-based fluids, and types of fibre without over-loading yourself.

Even drinking a large amount of veg-rich smoothie (such as carrot and celery, or a green smoothie) may cause some tummy discomfort if you aren’t used to it.  Drink a small amount per day to start with.  Remember: 150ml of fruit/veg juice or smoothie counts as a portion of fruit/veg per day.  If you drink two 150ml glasses of it, it will still only count as one portion (even if they are different ingredients).  This is because the sugars are in effect released from the food which affects teeth, digestion and blood sugar.  The British Heart Foundation has some great information about sugar on their website, including free sugars: https://www.bhf.org.uk/informationsupport/heart-matters-magazine/nutrition/sugar-salt-and-fat/free-sugars  (the animation on this link doesn’t load on my screen but the page information is worth reading).