What Is Fibre And Why Is It Important?

Fibre occurs in plants, and is a plant based source of carbohydrate. It is not present in animal sources of food, so when you eat meat, eggs, fish, or other similar animal sources, there is no fibre present.

It can be helpful to have a clear picture in your head of where it comes from so think 'plants, fruits and vegetables'. We derive fibre from foods such as fruits, vegetables, beans, peas, lentils and whole grains (it is mainly found in leaves, skin, stems and seeds). 

It's different from other sources of carbohydrate as we do not fully digest it. When you consume a food containing fibre some of it gets digested (the non-fibre carbohydrate) but in the case of the actual fibre it passes through our digestive system and out the other side. he difference with fibre as a source of carbohydrate is that it has a very complex structure and cannot be broken down properly and digested by the body.  

We don't fully digest fibre, but it does play an important role in our body.

Fibre is NOT an essential nutrient, not consuming it won't cause you to deteriorate and fall in to ill health, BUT, it has been shown to have very important health benefits so getting enough fibre in your habitual diet can help you thrive.

A quick recap - fibre comes from plants, we don't digest it and it passes straight through our digestive system, it's not essential to life BUT we know it provides several health benefits. 

The Benefits.

Daily adequate fibre intake is linked to the following health benefits:

  • Helps maintain bowel health and is linked to lower levels of colon cancer and other digestive related diseases.
  • Helps control blood sugar levels.
  • Helps lower cholesterol and in turn promotes heart health.
  • Weight management - it adds low energy density to the diet and keeps you feeling fuller for longer.
  • Associated benefits from the other numerous nutrients present in plant based foods.

There are direct and indirect benefits of consuming enough fibre every day. We know about certain mechanisms in body such as lowering cholesterol and regulating blood sugar, but there are many indirect benefits. A diet with adequate fibre means more a person's overall diet has plenty of nutrient dense food in it.

When it comes to managing weight, fibre gives a feeling of fullness. Eating a meal containing fibre based foods will help you feel satisfied by that meal, making someone less likely to over consume food throughout the day which can help in maintaining or losing weight if it is needed. 

Sources Of Fibre.

Remember, for sources of fibre think 'plants, fruits and vegetables'. You can see below there is a mixture of fruits, vegetables, beans and whole grains, and they are all high fibre foods.

What about fruit juices and smoothies?

It's important to remember that fibre comes from leaves, skin, stems and seeds, and that if you consume juices that the process of juicing removes the fibre. Smoothies generally keep the fibre content. Below is a great visual representation of fibre versus fibre removed, you can see the smoothie on the left which has it's fibre, while on the right the fibre has been removed and separated with only juice/liquid left.

That's not to say juices aren't healthy, you are still getting plenty of nutrient value - just remember you lose the fibre and it's related benefits.

The Two Types Of Fibre.

There are two types of fibre - soluble and insolube. When something is soluble it means it can be dissolved or form a gel like substance in water, while something that is insoluble doesn't mix or dissolve in water. 

Soluble sources of fibre act absorb water and like a gel-like substance passing slowly through the digestive system. This slows down digestion and can help with feeling fuller for longer. It is also linked to lowering the cholesterol type that we would like to keep low (LDL), and it also helps regulate blood sugar levels by attenuating our absorption of sugar.

Insoluble sources do the opposite in terms of digestion and the transit time of food through our digestive system. It passes more quickly. The bulk of fibre adds to stool size and helps keep us going to the toilet as regularly as we should and without any problems. Insoluble fibre is associated with a reduced risk of diabetes but the exact mechanism isn't clear.

There is no set guideline for intake for each of the types of fibre and a good mix of both is recommended. Food labelling doesn't distinguish between fibre types so your best bet is to be aware of which foods contain which type. Myfitnesspal actually does quite a good job of tracking fibre which is another reason why a period of tracking food is so important. Once you get in to a routine of eating a certain amount of plant based food you end up knowing by knowledge and intuition. Tracking isn't forever, but it will help you learn very useful nutritional skills like this.

You'll soon see once you're eating nutrient dense food from plant sources you'll hit your target regularly. This is another reason why the meal template of 'protein + plants' is so important for managing weight and health. Plant based food is nutrient dense AND is a good source of fibre.

Remember, we don't eat single nutrients, we eat food. When aiming to consume adequate fibre it's you're looking to find meals and recipes you enjoy which contain the foods highlighted as high in fibre. There are many available in the recipe folder.

Fibre And Gut Health.

Your gastrointestinal tract (mostly the colon) is full of trillions of microbes (tiny bacteria and other such microorganisms) which is collectively known as the gut microbiome. The content of the microbiome can vary greatly from person to person and we don't know enough about it yet to distinguish what is the 'ideal' microbiome.

If our GI tract is full of microbes it should make sense that our diet can effect the composition of our microbiome because the food we eat passes through. More and more research is uncovering just how important the link is between a thriving gut microbiome and good health. We've got lots of bacteria inside us and if we eat well it provides far reaching health benefits. How do we do this?

We can directly affect our microbiome through two parts of our diet - probiotics and prebiotics.

Probiotics are found in fermented foods like kefir, kimchi, yogurt and sauerkraut. Prebiotics are found in certain plant based foods such as fruits, vegetables, whole grains and legumes (high fibre foods).

Probiotics provide health benefits themselves directly, however, prebiotics are basically like food for the good bacteria inside us. Our bacteria use the prebiotics to form short chain fatty acids which are linked to many positive health benefits such as helping to regulate inflammation, optimal immune system function and improved absorption of certain other nutrients. A diet high in fibre helps promote good health through our gut microbiome interacting with prebiotics. The bacteria inside us use fibre to produce other things that add to health.

We are learning more and more as time passes but the importance of plants, fibre and the gut microbiome seems incredibly important for health.

Recommended Daily Intake.

The current guidelines from the European Food Safety Authority (2010) recommend a daily intake of 25 grams of fibre for adequate and normal bowel function but also state that evidence does show there are health benefits linked to higher intakes and this should be considered when the next guidelines are released.

The Irish Nutrition and Dietetic Institute (INDI) currently recommends between 24-35 grams per day. Government guidelines in the U.K (2015)  recommend 30 grams per day and some other countries recommend closer to 40 grams.

The recommend intake generally falls between 25 and 40 grams per day. It is worth noting that studies from many Westernised countries show that intake usually falls below 20 grams daily with most people missing out on the potential health benefits. This points toward a low intake of fruit, vegetables and other nutrient dense food as well. It should make sense that if people aren't consuming enough fibre their plant based food intake is probably on the low end and high calorie, poor quality food intake might be higher. This may have implications for obesity levels.

If you're wondering 'can you eat too much fibre?' the answer is yes, of course. It's the same with everything. With fibre it's highly improbably and impractical that you would do this however. Because of the low energy density of fibre based food it's a LOT of food to eat, plus consuming amounts upward of 40-50 grams will make you need the toilet a little too much so that's how eating too much manifests itself.

Consuming adequate fibre provides many direct and indirect health benefits. I hope this short piece has explained the how, the why, and what foods you should be looking to eat to reach the recommended guidelines.

 How does your intake look?