Gut healthy foods for living a long and healthy life

It may be time to rewrite the saying “you’re only as old as you feel”, as it increasingly appears that aging is actually linked to your gut health. 

Gut health has been the hot research trend for some time and there is no sign of that abating, with scientists continuing to unravel the many and wide-ranging implications of a healthy gut – and it’s no wonder, with the human body containing more than 100 trillion microbes. 

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In the past year, we’ve increasingly seen research linking a balanced gut microbiota with healthy aging.

As well as wrinkles, we know ageing is accompanied by major physiological changes and this includes the gut microbial composition. With age comes an increasing risk of an imbalance in gut microbiota due to factors such as an inadequate diet, taking multiple medications, reduced physical activity, and potentially, underlying disease.

A recent Australian review, led by the University of Tasmania, concluded that gut microbial diversity declined with age and its function in metabolism and regulation of the immune system were also reduced¹. The review found the decline in gut health provided the chance for harmful bacteria to invade and inflame the gut, giving rise to various diseases.

This is supported by broader gut research that links an imbalance of the gut microbiota with diseases that accelerate the aging process: obesity, non-alcoholic fatty liver disease, anxiety, depression, aging of the brain and gut-related conditions such as irritable bowel syndrome and inflammatory bowel disease^2,3,4,5,6.

While there is a lot of research on gut health, more is needed to determine how to maintain a healthy gut as we age. What we do know is that diet plays a significant role in building and maintaining gut health throughout life^7,8,9. A gut-friendly diet can make a significant difference to the gut microbiota in just a matter of days and a poor diet can have a negative impact just as quickly.

So consistently maintaining a gut-friendly diet is key and this may be particularly important as we get older.

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A large cross-sectional microbiota study conducted in humans found that “ridiculously healthy” Chinese people in their 90s had similar gut microbiota to healthy 30 year olds¹⁰. It also determined that maintaining gut diversity was a biomarker for healthy aging, just like lower serum cholesterol was a biomarker for heart health. 

So what are the key elements of a gut-healthy diet?

Dietary fibre and prebiotic foods

• Eating enough dietary fibre has many health benefits, including improving gut health^11,12. It promotes the growth of gut-friendly Bifidobacteria and Lactobacillus, increases short chain fatty acid (SCFA) production and decreases intestinal pH, reducing the colonisation of pathogenic bacteria. 
  • But less than 20 per cent of Australian adults are getting enough fibre to reduce the risk of chronic disease^13,14(based on the Suggested Dietary Target for men of 38g/day, and women 28g/day¹⁵).
  • Research indicates the easiest way to boost fibre intake is to regularly eat high-fibre breakfast cereals¹⁶. The Australian Bureau of Statistics’ Australian Health Survey data showed breakfast cereal eaters had higher daily intakes of fibre(19% higher for adults)¹⁷. Perhaps that’s not surprising when there are currently more than 370 Australian breakfast cereals providing a source of fibre, and many classified as ‘good’ or ‘excellent’ sources of fibre¹⁸.

• Prebiotics are mostly soluble fibres and resistant starches that act as fuel for the good bacteria in the large intestine (or colon). One way of increasing the number of good bacteria (specifically Bifidobacteria and Lactobacilli) in the gut is by regularly eating foods high in prebiotics.
  • Some foods that are naturally high in prebiotics include cereal grains (such as barley, rye, wheat and oats), vegetables (like asparagus, onions and cabbage), legumes (including chick peas and lentils), fruit (such as apples and pears), and nuts.
  • Digging even deeper, emerging evidence indicates that B-glucans – which are found in foods like barley and oats, and are a vital component of prebiotics foods – support the growth of the good bacteria, Bifidobacteria and Lactobacilli¹⁹.

• Resistant starch is another component in food that stimulates the gut microbiota to produce SCFAs, which are the main source of energy for the cells lining the large intestine, so play an important role in gut health. 
  • Resistant starch is found in firm (green) bananas, legumes (such as lentils), vegetables (including peas and corn), cooked and cooled potatoes, pasta and rice, and certain wholegrain products, such as uncooked oats, wheat and barley.

Probiotic foods

• Prebiotics and probiotics are often termed the ‘dynamic duo’. Probiotics are live ‘good’ bacteria or yeasts found naturally in the gut and in some foods. They work to reduce the number of harmful bacteria that survive in the gut.
  • Probiotics are found in foods like yoghurt with live cultures, kefir, and other fermented foods, like kombucha, kimchi, miso, tempeh, sauerkraut, and sourdough bread. Eating a variety of these foods, and on a regular basis, can help cultivate a variety of good gut bugs. 
  • Regularly consuming probiotic foods is another way older Australians can increase the diversity of the gut microbiota.

Need ideas for a gut healthy start to the day? Try these 7 types of food:

1. High fibre wheat flakes topped with chopped apple and milk
2. Overnight oats soaked in milk, containing grated vegetables – try sweet veggies like carrot or zucchini
3. Fruit and nut muesli with probiotic yoghurt
4. Whole grain bix/brits with sliced pears and milk
5. Bran cereal with sultanas and probiotic milk
6. Barley clusters with milk and a dollop of yoghurt
7. High-fibre cereal containing added prebiotics, with milk.

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Want more information?

Our nutrition fact sheets, created by accredited dietitians, provide the latest nutrition and lifestyle information to help you understand which foods are the best to eat. Click here to see the gut health nutrition fact sheets.