The power of probiotics

Compelling evidence backs the use of probiotics – beneficial live bacteria – to support health and wellbeing. Should general practitioners be advising patients to add them to their diets?

Learn more about probiotics in the HealthCert Professional Diploma program in Medical Nutrition Management – online nutrition training for GPs.

Each person has their own unique microbiome, which houses nearly 100 trillion bacteria and outnumbers human cells 10 to 1 (1). The microbiome refers to the complex community of microorganisms that are found mainly in the gut, but also skin and elsewhere (2). Gut microbes contribute to effective digestion and absorption of nutrients from food, promotes the development of a strong immune system, and contributes to metabolic functions essential to the prevention of disease and dysfunction (3, 4). Imbalances in the gut microbiome can increase inflammation and lead to the development of metabolic disorders, liver disease, certain mood disorders, and autoimmune conditions (5), and are therefore an important consideration in medical nutrition therapy.

What are probiotics?

Probiotics refer to ''good'' bacteria and yeasts that restore and support the good bacteria in the digestive system (6). Probiotics can help repopulate the beneficial bacteria in the gut, for example after taking a course of antibiotics, and common species include the genera Lactobacillus and Bifidobacterium. Research has shown that probiotic supplements can support digestive health and immune function, including reducing antibiotic associated diarrhoea (7); reducing bloating and inflammatory gastrointestinal conditions such as Crohn's disease and irritable bowel syndrome (8); and improving digestion of lactose (9). Other benefits include reducing the risk of eczema and colic in infants (10).

Are fermented foods a good source of probiotics?

Although fermented foods are made with live cultures, they cannot automatically be deemed a ''probiotic'' unless the strains contained have been studied and shown to confer a health benefit.

Fermented foods high in ''good'' bacteria include:

• yoghurt with live cultures – look for one billion probiotics per serve 1 x 10⁹ CFU
• kefir (fermented milk or water-based drink)
• fresh kimchi (Korean fermented vegetables)
• fresh sauerkraut (fermented cabbage).

Eating a variety of these foods can help cultivate a variety of good bacteria. Look for words such as ''live'', ''active'', ''raw'' or ''unpasteurised'' on packaging to ensure the manufacturing process has not killed the probiotic strains.

In summary

A healthy gut plays a vital role in our overall health. Research has linked a healthy gut to lower rates of obesity, reduced risk of diabetes, improved mood and a strong immune system. The more diverse our gut bacteria are, the better for our bodies!

Learn more about probiotics with the online HealthCert Professional Diploma program in Medical Nutrition Management.

– Lynette Law, Accredited Practising Dietitian

References

1. Sender R, Fuchs S, Milo R. Revised Estimates for the Number of Human and Bacteria Cells in the Body. PLoS Biol. 2016;14(8):e1002533.
2. Bull MJ, Plummer NT. Part 1: The Human Gut Microbiome in Health and Disease. Integr Med (Encinitas). 2014;13(6):17-22.
3. Evans JM, Morris LS, Marchesi JR. The gut microbiome: the role of a virtual organ in the endocrinology of the host. J Endocrinol. 2013;218(3):R37-47.
4. Durack J, Lynch SV. The gut microbiome: Relationships with disease and opportunities for therapy. J Exp Med. 2019;216(1):20-40.
5. Sidhu M, van der Poorten D. The gut microbiome. Australian Family Physician. 2017;46:206-11.
6. Slavin J. Fiber and prebiotics: mechanisms and health benefits. Nutrients. 2013;5(4):1417-35.
7. Goodman C, Keating G, Georgousopoulou E, Hespe C, Levett K. Probiotics for the prevention of antibiotic-associated diarrhoea: a systematic review and meta-analysis. BMJ Open. 2021;11(8):e043054.
8. Tsai Y-L, Lin T-L, Chang C-J, Wu T-R, Lai W-F, Lu C-C, et al. Probiotics, prebiotics and amelioration of diseases. Journal of Biomedical Science. 2019;26(1):3.
9. Leis R, de Castro MJ, de Lamas C, Picáns R, Couce ML. Effects of Prebiotic and Probiotic Supplementation on Lactase Deficiency and Lactose Intolerance: A Systematic Review of Controlled Trials. Nutrients. 2020;12(5).
10. Sestito S, D'Auria E, Baldassarre ME, Salvatore S, Tallarico V, Stefanelli E, et al. The Role of Prebiotics and Probiotics in Prevention of Allergic Diseases in Infants. Frontiers in Pediatrics. 2020;8.