Dietary Fibre: Importance for Gut & Probiotic Health

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Dietary Fibre: Importance for Gut & Probiotic Health

Facts

  • Over 50% adults have digestive or gut issues
  • Gas, bloating and constipation are most common
  • Fibre is part of plant-based foods that the body cannot break down (eg. grains, fruits, vegetables, nuts, and beans)
  • Fibre has beneficial effects on:
    • gut health, digestion and bowel movements
    • cholesterol and blood sugar levels and regulation of body weight
    • may prevent and control chronic diseases like cardiovascular disease, diabetes, obesity or cancer
  • Dietary fibres exist as soluble, insoluble and prebiotic
  • 80% Australian adults don’t meet the recommended daily fibre requirements, 30g/day

What is fibre and how it works

More than 50% of Australian adults experience digestive or gut issues such as gas, bloating and constipation.

1 in 7 experience distressing symptoms that can have profound effects on quality of life. 

Dietary fibre is well known for having beneficial metabolic effects including reducing cholesterol levels, improving control of blood sugar, and assisting in regulation of body weight (assist in body weight loss and maintenance).

Dietary fibres provide beneficial effects for prevention and control of chronic diseases including cardiovascular disease, diabetes, obesity and cancer

 

In recent years there is growing scientific evidence supporting an important role for dietary fibres in maintaining good gut health. 

There are different types of dietary fibre. These include soluble, insoluble and prebiotic fibres. These fibres serve different functions in the bowel and eating them in combination may promote different health benefits.

 

Soluble fibre

Soluble fibre slows gut transit time and helps us to feel fuller for longer. Soluble fibre dissolves in water and forms a thick gel that slows movement of food through the gut. The gelatinous substance formed by soluble fibre also acts like a sponge during digestion, attracting fluid and softening stools to make it easier for waste to move through the bowel. This may be important for maintaining regular bowel movements and reduce risk of bowel cancer.

The benefits of soluble fibre include:

  • Stabilisation of blood sugar levels in people with diabetes.
  • Lower bad cholesterol namely LDL which may reduce risk of cardiovascular disease, leading cause of death in Australia.

Soluble fibers include inulin or beta-glucan.

Foods high in soluble fibre include oats, legumes, lentils, nuts and seeds.

 

Insoluble fibre

Insoluble fibre is found in plant-based foods, namely the structural parts of plant cell walls.

Insoluble fibre does not dissolve in water. Instead it adds physical bulk to your stools and helps to speed up the removal of waste from your gut. These two important functions of insoluble fibre help to prevent constipation.

Insoluble fibers include cellulose, hemicellulose and lignin.

Foods high in insoluble fibre include wheat bran, rice bran, fruit and vegetable skins, nuts, seeds, legumes and wholegrains.

 

Prebiotic fibre

Not all fibre is prebiotic.  To be classified as prebiotic, the fibre must transit through the stomach and small intestine undigested. It must also promote the growth of good bacteria or "probiotics" in the large intestine.  Many prebiotics are a form of soluble fibre.

Prebiotic fibre includes inulin, fructans (fructo-oligosaccharides, FOS) and galacto-oligosaccharides (GOS). These are non-digestible carbohydrates. However, non-carbohydrate prebiotics have recently been discovered and these include cocoa flavanols.

 

Recommendations on fibre intake? 

It is recommended that Australian adults consume 30g of dietary fibre per day for good gut function and optimal health and wellbeing.

However, average intakes sit well below recommendations. Over 80% of Australian adults do not consume the recommended daily intakes.

Skipping breakfast is associated with lower daily fibre intake.

 

 

Australian recommendations:  children (14-18g/day), adolescents (20-28g/day) and adults (25-30g/day). Refer to pg42 of guide for recommendations during pregnancy and lactation.

 

 

 

What about those with digestive issues including IBS?

Irritable Bowel Syndrome (IBS) is characterised by chronic repetitive symptoms of abdominal pain and discomfort, bloating, wind, distension and altered bowel movements that can range from diarrhoea to constipation.

15% of adults suffer from IBS.

The suitability of fibre supplements for people with IBS depends on fibre type - for example fibre’s solubility in water, water holding ability and fermentability - or the potential to contribute to gas production in the large intestine. 

FODMAPs (Fermentable, Oligosaccharides, Disaccharides, Monosaccharides and Polyols) are a group of carbohydrates or sugars that can trigger IBS due to not being properly digested in the gut.

A low FODMAP diet is recommended for people with gut sensitivities especially in the context of IBS. Monash University has the largest FODMAP food database available, helping millions of people manage IBS.

 

Reading food labels 

Qualifying criteria for nutrition content claims about dietary fibre include:

  • Source  2g/serve
  • Good source  4g/serve
  • Very high or Excellent source  >7g/ serve

One serve (22g) of Plant Science’s Gut-Feeling provides an excellent source of dietary fibre at 8.4g per serve; equivalent to one third of recommended daily intake.

 

Take home message

  • Fibre important in your diet as it improves digestion, blood lipids and regulation of blood sugar, relieves constipation, assist with mineral absorption and satiety and supports immune system.
  • This prevents against chronic disease
  • Increase consumption of foods high in fibre:
    • Wholegrain breakfast cereals, wholewheat pasta, wholegrain bread and oats, barley and rye
    • Fruit such as berries, pears, melon and oranges
    • Vegetables broccoli, carrots, sweetcorn, potatoes with skin
    • Peas, beans and pulses
    • Nuts and seeds
  • Choose less refined and processed foods
  • Read food labels
  • Increase intake of water, consume at least 2 litres per day
  • If you have IBS chose low FODMAP foods

 

References

https://www.nature.com/articles/nrgastro.2017.75

https://confluence.csiro.au/download/attachments/1275461754/Gut%20health%20%26%20Weight%20Loss%20Report.pdf?version=1&modificationDate=1593990933390&api=v2

https://www.monashfodmap.com/

https://pubmed.ncbi.nlm.nih.gov/23609775/

https://pubmed.ncbi.nlm.nih.gov/31126110/

https://pubmed.ncbi.nlm.nih.gov/30336163/

https://pubmed.ncbi.nlm.nih.gov/29495569/

https://www.gutmicrobiotaforhealth.com/the-different-ways-that-prebiotics-and-fiber-affect-the-gut-microbiota/