What is the Gut Microbiome?
Our gut microbiome is made up of trillions of microorganisms, mainly bacteria, that live in our intestinal tract.
The highest concentrations are found in the large intestine, with many diverse types of bacteria present, due to the favourable conditions such as slower transit time, pH and the nutrients available. The diversity and numbers of bacteria can be influenced by genetics, stress, illness and medications, and lifestyle factors such as diet, physical activity levels and sleep patterns.
Dietary fibre that we are unable to digest (known as prebiotics) are fermented by the gut bacteria resulting in the production of short chain fatty acids (SCFAs), otherwise known as metabolites. Of the three major SCFAs (acetate, propionate and butyrate), butyrate in particular in anti-inflammatory, reduces oxidative stress and improves immunity by maintaining the health of the mucus lining of the intestines. Gut bacteria synthesise Vitamin K and the B vitamins, folate, B12 and biotin. SCFA production also improves absorption of magnesium, calcium and iron into the bloodstream.
What are prebiotics?
Prebiotics are essentially food for our gut bacteria. They include cellulose, hemicellulose, pectins and gums and some oligosaccharides (fructo- and galacto-, including inulin, lactulose and resistant starch). The best way to feed our gut bacteria is to eat high fibre foods in our diet, including vegetables, fruit, legumes, breads and cereals, nuts and seeds. A general diet high in prebiotics (fibre) includes foods such as:
- Jerusalem artichokes
- Garlic
- Onion
- Asparagus
- Chickpeas
- Lentils
- Stone fruits such as nectarines and peaches
- Dried fruit
- Rye bread
- Pasta
- Oats
- Cashews and pistachio nuts
What are probiotics?
The most widely accepted definition of probiotics in the scientific community is :
“Live microorganisms which, when administered in adequate amounts confer a health benefit on the host”.
In other words, a probiotic must contain live bacteria in the right amounts to achieve a benefit to our health. The key here is that recent research has identified that different strains of probiotics are linked to specific health benefits, such as having a protective function against pathogenic bacteria and diseases. A balance between pathogenic and beneficial bacteria is required to maintain health.
Probiotics can be taken in the form of supplements or in fermented foods in the diet, to improve health and prevent or treat illness. However, fermented foods cannot technically be classified as probiotics unless the strains contained in them have been studied and shown to benefit health. However, fermented foods are a good choice in the diet to help maintain the gut microbiome and improve health. Fermented foods that contain beneficial bacteria include:
- yoghurt containing live cultures
- kefir
- kimchi
- sauerkraut
- kombucha
Many of the probiotic supplements on the market contain strains of Lactobacillus and/or Bfidobacterium, however, it is important to remember that different strains of probiotics are suitable to treat different health conditions. It is always wise to speak to a health professional to be sure that you are using the correct strain at the correct dose to treat specific conditions, always scientifically supported by current research.
References:
1 Collado MC et al. 2009. The Impact of Probiotic on Gut Health. Current Drug Metabolism. 10, 68-78
2 Dieterich W et al. 2018. Microbiota in the Gastrointestinal Tract. Medical Sciences. 6(4):116
3 Food and Mood Centre. What is the Gut Microbiome? Available at www.foodandmoodcentre.com.au
4 Hills RD et al. 2019. Gut Microbiome : Profound Implications for Diet and Disease. Nutrients. 11(7):1-40
