What Are Prebiotics, Probiotics, Synbiotics and Postbiotics? Benefits & Sources.
Let’s get straight into the definition, differences and benefits of the 4 biotics: prebiotics, probiotics, synbiotics and postbiotics.
You’re going to be a biotic boffin by the end of this post.
Prebiotics
What are prebiotics?
Prebiotics are non-digestible dietary substances, often fibre, that act as a fuel for gut microbiota (beneficial bacteria, yeast and archaea). Think of prebiotics like fertiliser helping the flowers grow.
What are the benefits of prebiotics?
When gut microbes ferment the prebiotics they produce beneficial metabolites including anti-inflammatory short chain fatty acids (SCFAs) acetate, butyrate and propionate, lactate and gases. Benefits of prebiotics include:
- Improved metabolic health e.g. weight management, improved blood glucose control, reduced inflammation
- Improved bone health by increasing the absorption of minerals such as calcium
- Improved satiety
- Better skin health – reducing redness and improving water retention
- Alleviating constipation
- Supporting immunity
- Supporting urogenital health, including the health of the vaginal microbiome
Examples of prebiotics
Types of prebiotics include inulin, fructooligosaccharides (FOS), galactooligosaccharides (GOS), xylooligosaccharides (XOS), raffinose, resistance starch, polyphenols cellulose and glucomannan.
Prebiotics are found in plant based foods such as:
- Fruit – apples, berries, pomegrante, red grapes, green bananas and plantain
- Onion, shallots, spring onion and leek
- Garlic
- Jerusalem artichokes
- Cooked, cooled and reheated potato and pasta
- Wholegrains – oats, wheat, rye, barley, millet
- Pulses and legumes – lentils, peas, chickpeas
- Nuts – especially pistachios, cashews, almonds
- Dandelion greens
- Cocoa/ cacoa – dark chocolate 70%+ cocoa content
Synthetic prebiotics that may be added to food, supplements or certain medications include: lactitol (made via hydrogenation of lactose (a sugar in milk)), lactulose in UHT milk, acacia gum and partically hydrolised guar gum (PHGG) – all of which may help alleviate constipation.
Not sure if you’re getting enough prebiotics and fibre?
Track your intake. Mix it up. Challenge yourself to eat the rainbow 🌈
Probiotics
What are probiotics?
The World health organisation (WHO) defines probiotics as “live micro-organisms that, when administered in adequate amounts, confer a health benefit to the host”.
Essentially this means that a probiotic:
- Must contain micro-organisms, such as bacteria or yeasts, that are alive when they reach their target site, e.g. the gastrointestinal tract or vagina.
- Should state its dose, i.e. the number of live (viable) micro-organisms per serving. This is often displayed as colony forming units (CFUs), or may be counted as AFUs (Active Fluorescent Units).
- Must have been shown to benefit human health in research – usually randomized control trials (RCTs)
Technically, fermented foods are not probiotics because the number of microbes in the food can vary greatly, the specificstrains cannot be identified and the microbes have not been tested in trials for specific health benefits. Instead, the International Scientific Association for Probiotics and Prebiotics terms them sources of “live dietary microbes”. Or just fermented foods to you and I.
What are the benefits of probiotics?
Areas with strong of emerging eveidence for the benefits of probiotics include:
Digestive health
– reducing antibiotic associated digestive issues
– reducing IBS symptoms such as constipation, diarhhoea, gas and abdominal pain
– reducing the risk of traveler’s diarrhea
Respiratory health
– reducing upper respiratory tract infections
Oral health
– reducing dental caries
Metabloic health
– improving metablic health
– reducing non-alchoholic fatty liver disease (NAFLD)
Urogenital health
– reducing bacterial vaginosis and thrush
Skin health
– improving rosacea
– reducing psoriasis severity
– preventing the development of eczema
Mental health
– reducing anxiety
– reducing mild to moderate depression
However, the benefits of probiotics are strain specific and dose specific.
Example of probiotics
When looking at a probiotic supplement you should see the micro-organism’s genus, species and strain. The genus and species will be written in italics. The strain is usually a bunch of letters and/or numbers. Common genera (the plural of genus) of probiotics include Bifidobactererium, Lactobacilli, Bacillus and Saccharomyces.
Examples of strain specific benefits of probiotics:
- Lactobacillus rhamnosus LGG at 20 billion CFUs – reduces antibiotic associated diarrhoea, bloating and taste disturbances
- Lactiplantibacillus plantarum 299v at 10 billion CFUs – improves iron absorption and may enhance treatment of iron deficiency
- Bifidobacterium lactis BB-12 at 1 to 10 billion CFUs – may reduce functional constipation
- Lactobacillus rhamnosus LGG with Bifidobacterium lactis BB-12 at 20 billion CFUs – reduces the severity and duration of upper respiratory tract infections
- Bacillus coagulans Unique IS-2 at 2 billion CFUs – may reduce IBS symptom severity
- Saccharomyces boulardii* at 10 to 20 billion CFUs – reduces the risk of experiencing traveller’s diarrhoea
*Previously thought to be a species, Saccharomyces boulardii is now considered to be a strain of the Saccharomyces cerevisiae species.
Saccharomyces = the genus
cerevisiae = the species
boulardii = the strain
Synbiotics
What are synbiotics?
Synbiotics are products that contain both probiotics (live micro-organisms) and prebiotics (fuel for the micro-organisms).
There are two subtypes of synbiotics:
1. Synergistic synbiotics
This is when the prebiotic is chosen specifically to feed the probiotic that comes with it. Essentially, the micro-organism is matched with it’s preferred fuel source so the probiotic has a better chance of surviving and doing its job.
2. Complementary synbiotics
This is when a probiotic and a prebiotic are included together, but the prebiotic is designed to provide fuel for existing gut micro-organisms, not just the added probiotic. Most commercially available synbiotics are complementary synbiotics.
What are the benefits of synbiotics?
The main benefit of a synbiotic is that pairing probiotics with prebiotics helps support the growth of beneficial gut micro-organisms and supports their production of health promoting metabolites, such as short-chain fatty acids (SCFAs).
Examples of synbiotics
An example of a synbiotic would be a supplement that contains Lactobacillus rhamnosus LGG and fructooligosaccharide fibre (FOS).
Common prebiotics added to a probiotics are:
- Inulin
- FOS
- Rice fibre
- Acacia fibre
- Polyphenolic prebiotics e.g. cranberry or pomegranate extract
Postbiotics
What are postbiotics?
Postbiotics are the beneficial metabolites and chemicals produced as byproducts of microbial fermentation of prebiotic fuel sources.
What are the benefits of postbiotics?
Postbiotics are more stable than probiotics because they don’t contain live bacteria. Research suggests they may be a useful adjunct therapy in helping to combat antibiotic-resistant bacteria, such as Klebsiella pneumoniae. Key benefits of postbiotics include:
- Modulating existing gut bacteria
- Protecting against pathogens
- Improving eradication of pathogens such as Helicobacter pylori (H. pylori) and bacterial urinary tract infections
- Enhancing gut barrier health
- Supporting appropriate immune responses
Examples of postbiotics
Postbiotics can include:
- Inactive micro-organisms – probiotics are gently heated making them inactive. During this process they produce compounds and become postbiotics. This process is called tyndallization.
- Short chain fatty acids – the SCFA butryrate support the health of the intestinal barrier and reduces brain inflammation
- Bacteriocins – antimicrobial peptides
- Lactic acid – reduces pH which helps inhibit pathogens
To get the benefits of postbiotics from food ensure you eat:
- A colourful variety of prebiotic foods to feed the beneficial microbes so they can produce postbiotics. This means eating a variety of plant based foods every week.
- A daily serving of fermented foods which contain beneficial microbes and therefore their health promoting postbiotics. Yogurt with live cultures, kefir, miso, sauerkraut, kimchi, natto, aged cheeses and kombucha are all sources of fermented foods.
A simple summary:
- Prebiotic = fuel for benefical micro-organisms
- Probiotic = live benefical micro-organisms
- Synbiotic = live benefical micro-organisms + their fuel – a.k.a probiotic + prebiotic
- Postbiotic = beneficial metabolites of micro-organisms
References
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