Facts
- The gut is home to trillions of bacteria, some good others not so good
- An imbalance between good and bad bacteria can contribute to poor gut and overall health and wellbeing including immune system and mood
- A healthy gut protects against chronic diseases including cardiovascular disease, diabetes, obesity and cancer
- 50% adults have digestive or gut issues including gas, bloating and constipation
- Increasing intake of dietary fibre, prebiotics and probiotics can improve your gut health
- Probiotics are good gut bacteria
- Prebiotics provide food for probiotics
- Dietary fibre includes some prebiotics and is important for digestion, bowel movements, regulation of blood sugar, hormones, appetite mood and weight
Dietary fibre
Dietary fibre provides beneficial effects for both the prevention and control of chronic diseases including cardiovascular disease, diabetes, obesity and cancer.
Dietary fibres are also important for maintaining good gut health.
Scientific interventional studies show that dietary fibre (and increase intake of whole grain foods especially those high in prebiotics) increases gut microbial diversity. This means that there is a greater variety of microbes or bugs in your gut. This is a good thing as this is protective against disease. Having higher amounts of good bacteria or “probiotics” in your gut is also protective.
In contrast, low fibre intake common in Western society contributes to reduced gut diversity and development of chronic disease.
There are 3 different types of dietary fibre: soluble, insoluble and prebiotic fibres. These fibres serve different functions in the bowel and eating them in combination may promote different health benefits.
Eating a variety of plant foods such as wholegrains, fruit, vegetables and legumes is the best way to achieve fibre diversity.
80% Australian adults don’t meet the recommended daily fibre requirements of 25 to 30g/day. Children require less ranging from 14 to 28g per day depending on age and sex.
Foods high in fibre include hempseeds, oats, legumes, fruit and vegetable skins, nuts, seeds and wholegrains. Whole hempseeds contain high amounts of both soluble and insoluble fibre.
Prebiotics
Science defines prebiotics as “a substrate that is selectively utilized by host microorganisms conferring a health benefit”, with the benefits including defence against pathogens, immunity, bowel function, mineral absorption, metabolism and satiety.
In plain English, this means that when you ("the host" for the microorganisms) include prebiotics in your diet, you're making sure that everything from your immune system to your gut is in tip-top shape.
Probiotics
Probiotics from pro and biota, meaning "for life". Science defines probiotics as “live microorganisms which when administered in adequate amounts confer a health benefit on the host”. This means gut bacteria or microbes that have a positive effect on health. This may include improved digestion, immunity and reduced inflammation/ disease risk.
Use of probiotics to improve gut health is becoming increasingly popular.
Probiotics are taken as a dietary supplement or naturally in foods like yoghurt, kombucha, kefir and sauerkraut, which are fermented with beneficial bacteria.
Current research does not strongly support the use of probiotics to improve gut health. However, some studies have shown some benefit.
Some reason why? Probiotics must be kept alive to be active. They can be killed by heat, stomach acid, or just die over time. Probiotic use i. after antibiotics may disturb rather than aid recovery of gut microbiota ii. to treat diarrhoea and vomiting also appears to be ineffective at reducing clinical symptoms and recovery time.
Take home message
- Dietary fibre exists in 3 forms, each having differential and beneficial effects of gut and overall health.
- Prebiotic fibres provide food for good gut bacteria (microbes) also known as probiotics
- Scientific evidence to support use of probiotics is not consistent
- Consumption of a variety of foods especially those high in fibre and prebiotics can ensure gut microbial diversity which is beneficial for protecting against chronic disease.
References
https://pubmed.ncbi.nlm.nih.gov/23609775/
https://pubmed.ncbi.nlm.nih.gov/31126110/
https://www.bmj.com/content/361/bmj.k2179
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7146107/
https://pubmed.ncbi.nlm.nih.gov/19335713/
https://www.nhmrc.gov.au/sites/default/files/images/nutrient-refererence-dietary-intakes.pdf
https://www.nature.com/articles/nrgastro.2017.75
https://www.nature.com/articles/nrgastro.2014.66
https://www.thelancet.com/pdfs/journals/langas/PIIS2468-1253(18)30415-1.pdf
https://www.cell.com/cell/fulltext/S0092-8674(18)31108-5
https://www.nejm.org/doi/10.1056/NEJMoa1802598