GUT HEALTH – COULD IT BE THE SECRET TO 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 how well your gut feels.

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

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 disease2,3,4,5,6.

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 life7,8,9. 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.

A large cross-sectional microbiota studyconducted 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 health11,12. 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 disease13,14(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 evidenceindicates 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:

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

November 2018

Leigh suit cereal variety IMG_0882 Leigh Reeve is an Advanced Accredited Practising Dietitian and Director of the Australian Breakfast Cereal Manufacturers Forum (ABCMF). Leigh has over 30 years experience as a dietitian and is passionate about sharing practical, evidence-based nutrition information and delicious food ideas.


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2. White LS, Van den Bogaerde J, Kamm M. The gut microbiota: cause and cure of gut diseases.Med J Aust 2018; 209 (7): 312-317. https://www.mja.com.au/journal/2018/209/7/gut-microbiota-cause-and-cure-gut-diseases

3. Sidhu M, van der Poorten, D. The gut microbiome. Aust Family Phys, 2017; 46(4): 206-11. https://www.racgp.org.au/afp/2017/april/the-gut-microbiome/

4. Bull MJ, Plummer NT. Part 1: The human gut microbiome in health and disease. Integr Med (Encinitas), 2014; 13(6):17-22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4566439/

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6. Holleran G, Lopetuso LR, Ianiro G et al. Gut microbiota and inflammatory bowel disease: so far so gut! Minerva Gastroenterol Dietol. 2017; 63(4):373-384. https://www.ncbi.nlm.nih.gov/pubmed/28293937

7. Graf D, Di Cagno R, Fak F, et al. Contribution of diet to the composition of the human gut microbiota. Microb Ecol Health Dis. 2015; 26:261-64. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4318938/

8. De Angelis M, Garruti G, Minervino F, Bonfrate L, Portincasa P, Gobbetti M. The food-gut human axis: The effects of diet on gut microbiota and metabolome. Curr Med Chem. 2017; 24:1. https://www.ncbi.nlm.nih.gov/pubmed/28462705

9. Singh RK, Chang H-W, Yan D, et al. Influence of diet on the gut microbiome and implications for human health. Journal of Translational Medicine. 2017; 15:73. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5385025/

10. Bian G, Gloor GB, Gong A, et al. The Gut Microbiota of Healthy Aged Chinese Is Similar to That of the Healthy Young. mSphere. 2017; 2(5). https://msphere.asm.org/content/msph/2/5/e00327-17.full.pdf

11. Lin D, Peters BA, Friedlander C, Freiman HJ et al. Association of dietary fibre intake and gut microbiota in adults. Br J Nutrition. 2018; 120(9): 1014-1022. https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/association-of-dietary-fibre-intake-and-gut-microbiota-in-adults/B3CC9A3F0DCA89528FDC9CFF26089E74

12. Valdes AM, Walter J, Segal E, Spector TD. Role of the gut microbiota in nutrition and health. BMJ. 2018; 361. https://www.bmj.com/content/361/bmj.k2179

13. Australian Bureau of Statistics. Australian Health Survey: Nutrition First Results – Foods and Nutrients, 2011-12. Canberra: ABS; 2014. (Also available from: http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/4364.0.55.007main+features12011-12, accessed 13 November 2018).

14. Australian Institute of Health and Welfare.Nutrition across the life stages. Cat. no. PHE 227. Canberra: AIHW; 2018.Also available from: https://www.aihw.gov.au/getmedia/fc5ad42e-08f5-4f9a-9ca4-723cacaa510d/aihw-phe-227.pdf.aspx?inline=true, accessed 13 November 2018).

15. National Health and Medical Research Council, Australian Government Department of Health and Ageing, and New Zealand Ministry of Health. Nutrient Reference Values for Australia and New Zealand. Canberra: NHMRC; 2006. (Also available from: https://www.nrv.gov.au/chronic-disease/micronutrients-dietary-fibre, accessed 13 November 2018).

16. Fayet-Moore F, Cassettari T, Tuck K, McConnell A, Petocz P. Dietary Fibre Intake in Australia. Paper II: Comparative Examination of Food Sources of Fibre among High and Low Fibre Consumers. Nutrients 2018; 10(9): 1223. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6163727/

17. Nutrition Research Australia, Breakfast and Breakfast Cereal Consumption Among Australians. A secondary analysis of the 2011-12 National Nutrition and Physical Activity Survey, Sydney, February 2016 http://www.cereal4brekkie.org.au/new-data-bowls-sugar-spin/

18. Grains & Legumes Nutrition Council. Breakfast Cereal Audit 2018. (Also available from: https://www.glnc.org.au/wp-content/uploads/2018/10/Breakfast-Cereal-Factsheet-2018_WEB-1.pdf, accessed 13 November 2018).

19. Jayachandran M, Chen J, Chung S, Xu B. A critical review on the impacts of β-glucans on gut microbiota and human health. The Journal of Nutritional Biochemistry 2018. 61: 101-110. https://www.sciencedirect.com/science/article/pii/S0955286317310070?via%3Dihub

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