Understanding dietary fibre

August 27, 2020

Welcome to the first of our 4 part blog series on dietary fibre.

What is so good about dietary fibre?

We all know that fibre is good for you. It is great for bowel health and regular poos. Fibre improves blood glucose control for those with diabetes and keeps you feeling fuller for longer tereby assisting with weight management.

Other potential health benefits (of which there are many) include reducing the risk of heart disease. Fibre does this by helping to improve cholesterol levels and high blood pressure, reducing inflammation and boosting immune function.

Fibre has all of these health benefits, yet many of us are not getting enough. We need around 25-30 g fibre a day. You may need a fibre supplement as a top up to meet your daily fibre needs.

High fibre foods

What actually is fibre?

The term “fibre” describes a group of carbohydrates that are not digested in the gut. Fibre is mostly found in plant-based foods. Not all fibres are the same. They all have different properties and these influence how the fibre behaves in the gut. These properties include:

  • the chemical structure of the fibre
  • the biochemical chain length
  • the fibre’s ability to dissolve (solubility)
  • the fibre’s ability to thicken fluids (viscosity)
  • how much the fibre ferments (fermentability)

We will describe each of these properties over the coming weeks in our series of dietary fibre blogs. This week, we will begin with fermentability.

What does “Fermentability of fibre” mean?

The fermentability of fibre is measured by how much gas the fibre produces. In this case: gas = good.

Fibre is fermented by bacteria in our gut, producing gas.

Fermentability describes the rate and extent to which a fibre is broken down by our gut bacteria in the large bowel.

What are the health benefits of the fibre fermentation?

Fermentable fibres provide the gut bacteria with energy and nutrients to grow. The specific bacteria that are able to ferment fibre are beneficial. In short, we want to keep this beneficial bacteria healthy (and at a good level) to help the gut environment stay nice and balanced.

The breakdown of particular fibres (prebiotics) by the gut bacteria produces beneficial by-products called short chain fatty acids (SCFAs) such as acetate, butyrate and propionate. SCFAs help to:

  • fuel the cells of our colon and produce a healthy mucous layer in this part of our intestine
  • reduce gut inflammation and sensitivity
  • strengthen the immune system in our gut (offering protection against intestinal infections)
  • reduce the risk of colon cancer

Up next…. “Not all dietary fibres are created equal“.

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