Dietary fibre, often referred to as fibre and sometimes ‘roughage’, is an important and essential component of a healthy diet. It belongs to the carbohydrate family and describes the edible component of plants. Unlike other foods, which can be broken down by our digestive enzymes, fibre is broken down by the bacteria in our large intestine. It’s important to include fibre in our diet not only for general health and wellbeing, but also for our gut health and the prevention of digestive-related disease. Many of us have heard of fibre, maybe from our GP, magazines, food packaging etc. and although many of us know its importance, many of us are not eating enough or know why it’s important. So, what actually is dietary fibre and why do we need it?
The term ‘fibre’ covers a few different types, including soluble fibre, insoluble fibre and resistant starch. Together, the different types of fibre aid regular bowel movements, support the gut microbiota and may help to reduce cholesterol levels.
· Soluble fibre is found in fruits, vegetables, pulses and oats and is absorbed by the body to reduce the amount of cholesterol in the blood.
· Insoluble fibre sources include nuts and wholegrains and are insoluble. They absorb water, making stools softer and much easier to pass – very important for preventing constipation!
· There is also another type of fibre called resistant starch, which is often incorporated commercially into foods and is valued due to the low glycaemic index of its sources which include bananas, potatoes, some grains and legumes.
The important thing is not focus on eating each type of fibre, but to eat a varied and colourful diet. Thankfully, the different types of fibre are often found together and so by eating a wide range of foods, it should be relatively easy to incorporate all three into your diet.
Low glycaemic index
The glycaemic index (GI) is a measurement of how carbohydrates affect your blood glucose levels. The term ‘low glycaemic index’ is used to describe foods which are broken-down slowly by the body. This allows a gradual release of glucose into the bloodstream without increasing blood glucose levels too quickly.
Typically, low GI foods include pulses, beans, wholegrains and some fruits and vegetables and high GI foods include white alternatives, sugary foods and drinks and potatoes. Having a low GI does not mean that foods are healthy though, and it is definitely not balanced to eat only low GI foods. Avoiding high GI foods is recommended for those managing diabetes and remember that a flexible, varied and balanced diet is best for your health!
Why is fibre important?
The combined roles of fibre are important for preventing disease and are associated with a decreased risk of cardiovascular disease, bowel cancer and type 2 diabetes.
· Reduced risk of heart disease and stroke (cardiovascular disease) - the beta glucan in soluble fibre helps to reduce cholesterol levels
· Reduced risk of bowel cancer (also known as colorectal cancer) – fibre helps the beneficial bacteria of our gut microbiota which may have positive effects on bowel health, it may also reduce risk by softening stool and moving waste along the bowel quickly, preventing waste from ‘sitting’ in the bowels for long periods of time
· Reduced risk of type 2 diabetes – some high fibre foods release glucose slowly and gradually into the blood after a meal, preventative for the development of type 2 diabetes
Not only can we reap the benefits of reduced risk of disease in the long-term, but we can take advantage of the digestive benefits fibre brings to our everyday life!
One of the key functions of fibre is regular and healthy bowel movements. By getting enough fibre in your diet, you are preventing the passing of hard, stubborn stools as insoluble fibre functions to prevent constipation. This type of fibre allows our waste to become bulky and soft, making it pass through our bowels much quicker and much easier to pass. Soluble fibre and resistant starch also support our gut microbiota by providing a food source to the beneficial bacteria that live there. These friendly bacteria have a huge role in digesting and absorbing nutrients from foods, so we must protect and nourish our microbiota. A healthy gut microbiota contains trillions of bacteria with a lower diversity associated with obesity. Eating enough fibre can also aid weight loss. By slowing the movement of food from the stomach to the small intestine, fibre helps us to feel fuller for longer, reducing the likelihood of overeating or snacking throughout the day. This slowed rate of digestion also protects us from absorbing glucose too fast and increasing our blood glucose levels.
What foods contain fibre and how can I include fibre in my diet?
Thankfully, fibre-rich foods are often great micronutrient sources and so come in a variety of colours, textures and flavours! This makes it much easier for us to include them in our meals and contributes to getting more fruit and vegetables in our diet. Fibre can be mostly found in fruits, vegetables, cereals, nuts and grains; key carbohydrates which should be making up a large proportion of our diets on a daily basis.
Guidelines recommend adults to consume 30g of fibre a day, but on average we consume a lot less than this, between 12-18g. We need to make conscious efforts to include more fibre in our diet in order to reap the many benefits.
Tips for getting more fibre in your diet:
· Eat a high fibre, wholegrain breakfast cereal or porridge with added fresh fruit and nuts
· Leave the skin on fruits and vegetables before cooking or eating
· Eat more wholemeal, wholegrain and whole-wheat carbohydrates such as brown bread and pasta
· Include vegetables in as many meals as possible (fresh or frozen)
· Snack on fresh fruit (with skins)
Even when we know we should consume 30g of fibre a day, it can be hard to know what this looks like! Here are some high fibre meal and snack ideas and their fibre content to give you an idea:
• 2 Weetabix biscuits, milk, sliced banana and a handful of blackberries – around 7.4g
• Baked potato (with skin) and half a tin of baked beans – about 12g of fibre
• An apple/banana – 1.2/1.4g
• Handful of unsalted almonds – up to 3g
Food preparation, cooking and storage has an impact on the fibre content of foods, so make sure to become savvy when reading food labels to know what you’re really eating!
Finally, when increasing your fibre intake, it’s important to remember two things:
1. Increase your fibre intake gradually to avoid bloating, constipation or excess gas production and
2. To drink plenty of fluids! Insoluble fibre can only absorb water that is there and will remain hard and difficult to pass without it.
Written by Beth Mullholland