Bacteria could explain the crucial link between the food we eat and how we feel.

Two-thirds of Australians aren’t meeting their daily recommended intake of fibre despite a growing awareness of gut health.

Today is World Digestive Health Day, aiming to raise awareness of the importance of having a healthy gut, which can contribute to a range of improved outcomes.

According to the CSIRO, a growing body of research has linked gut health to conditions like cancer, auto-immune disease and obesity.

A new study commissioned by cereal maker Kellogg’s, released today, found four-in-five Aussies know a high-fibre diet can improve gut health, but two-in-three don’t eat enough each day.

When probed about their low intake, 45 per cent of respondents said they couldn’t resist takeaway, chips and lollies, while 31 per cent blamed the high cost of products marketed as high in fibre.

Large amounts of saturated fats can promote bad bacteria and cause gut stress.

Nutritionist Jacqueline Alwill said the gut health trend had exploded in popularity, with a boom in the sale of probiotics, kombucha and fermented foods.

“Although we aren’t able to see inside our bodies, the science tells us that we can help our gut by eating fibre-rich foods daily,” Ms Alwill said.

“This can be from whole grains such as cereal, vegetables, fruits, nuts, seeds and legumes — essentially, fibre is found in plant-based foods.”

The gastrointestinal tract is home to trillions of microorganisms and up to 1000 different bacterial species. Collectively known as the “microbiota”, they are vital to the proper function of the body.

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Health experts are increasingly focusing on gut health, with research showing a proper diet can improve good bacteria and support the immune system, reduce inflammation and regulate the body’s other systems, including the brain.

A study by the University of Florence examined the gut health of children in Europe and in Africa, as well as their diets.

The kids in Europe ate more processed foods compared to the plant-rich diets of children in Africa, resulting in the latter cohort having more types of good bacteria.

Probiotic foods and supplements are marketed as a way to improve gut health, but they’re often not enough on their own.

“You can eat as many probiotic foods as you like, but without the food that feeds the good bugs, you won’t be realising the full potential of those probiotic foods,” Kellogg’s senior nutrition manager Dr Gina Levy said.

“Fibre feeds the good bacteria living in your gut, and when they’re well fed, they grow and thrive. More good bacteria helps to outnumber the less favourable species of bacteria, and this supports your gut health.”