To help support the balance of bacteria in our gut there are certain foods that should feature regularly in your diet. The two food groups you should include are prebiotics and probiotics.
In this article we look at why beneficial bacteria are important, what prebiotic and probiotic foods are and provide some examples of good pre and probiotic foods to try an include in your diet.
We also explore the lesser known postbiotics and what you can do to support postbiotic production.
What are Probiotics?
Probiotics are live microorganisms that, when consumed in adequate amounts, confer a health benefit on the host. They are often referred to as “good” or “beneficial” bacteria because they help keep the gut healthy. Probiotics work by enhancing the composition of the gut microbiome, which is the community of microorganisms living in the digestive tract. These beneficial bacteria compete with harmful bacteria for nutrients and attachment sites in the gut, produce substances that inhibit harmful microorganisms, and stimulate the immune system.
Probiotics are found in fermented foods, where bacteria naturally ferment the sugars present in the food, creating lactic acid or other substances that contribute to the food’s preservation, flavour, and health benefits. They can also be taken as dietary supplements. Different strains of probiotics offer various health benefits, but the most common genera found in probiotic foods are Lactobacillus and Bifidobacterium. Each of these groups includes many different species and strains that can have unique effects on the body.
Probiotic food list
- Yogurt: Made from fermented milk, often containing Lactobacillus and Bifidobacterium strains. Opt for natural, unsweetened yogurts to avoid added sugars.
- Kefir: A fermented milk drink similar to yogurt but with a thinner consistency. It contains a wider range of bacteria and yeasts.
- Sauerkraut: Fermented cabbage rich in Lactobacillus bacteria. Ensure it is unpasteurised, as pasteurisation kills the beneficial bacteria.
- Kimchi: A spicy Korean side dish made from fermented vegetables, primarily cabbage, along with a variety of seasonings. It contains Lactobacillus kimchii among other beneficial microbes.
- Miso: A Japanese seasoning produced by fermenting soybeans with salt and a fungus called Aspergillus oryzae. Miso soup is a popular way to consume it.
- Tempeh: An Indonesian product made from fermented soybeans. It’s a good source of protein and probiotics.
- Pickles (Gherkins): Cucumbers that have been pickled in a solution of salt and water. They ferment over time, and lactic acid bacteria develop, making them sour.
- Natto: Another fermented soybean product popular in Japan. It contains Bacillus subtilis.
- Kombucha: A fermented tea drink that has become popular worldwide for its probiotic content. It’s made by fermenting tea with a symbiotic colony of bacteria and yeast (SCOBY).
What are Prebiotics?
Prebiotics are types of dietary fibre that feed the friendly bacteria in your gut. These substances come from types of carbs (mostly fibre) that humans can’t digest. The beneficial bacteria in your gut eat this fibre. Prebiotics act as food for probiotics, the beneficial bacteria found in your gut, helping to promote their growth and activity. By doing so, prebiotics play a crucial role in maintaining a healthy gut microbiome and supporting overall health.
Prebiotics are found naturally in many foods, and unlike probiotics, they are not destroyed by heat or stomach acid. This resilience ensures that they reach the colon where they can provide the most benefit. Consuming a diet rich in prebiotics can help improve digestion, enhance calcium absorption, and lead to better overall gut health, which is linked to a lower risk of disease and improved immune function.
Prebiotic Food List
- Chicory Root: Rich in inulin, chicory root is one of the best sources of prebiotics. It can be added to foods or consumed as chicory coffee.
- Jerusalem Artichoke: Also known as the sunroot, sunchoke, or earth apple, it’s high in inulin.
- Garlic: Acts as a prebiotic by promoting the growth of beneficial Bifidobacteria in the gut. It also helps prevent disease-promoting bacteria from growing.
- Onions: Contain inulin and FOS (fructooligosaccharides) that help boost digestive health, improve the body’s ability to absorb calcium, and have antibiotic properties.
- Leeks: Related to onions and garlic, leeks are another good source of inulin and FOS.
- Asparagus: Contains inulin, making it a great prebiotic food that supports the growth of beneficial bacteria in the gut.
- Bananas: Slightly underripe bananas are high in resistant starch, a type of prebiotic fibre. Even ripe bananas contain small amounts of inulin.
- Barley: A whole grain rich in beta-glucan, barley is a good source of prebiotic fibre that supports gut health.
- Oats: Contain large amounts of beta-glucan fibre, as well as some resistant starch.
- Apples: Rich in pectin, a prebiotic fibre that feeds beneficial gut bacteria and may help reduce harmful bacteria and enhance mineral absorption.
- Flaxseeds: These seeds are not only rich in omega-3 fatty acids but also high in prebiotic fibres that support healthy gut bacteria.
- Wheat Bran: The outer layer of the wheat kernel is high in AXOS (arabinoxylan oligosaccharides), a type of fibre with strong prebiotic benefits.
- Seaweed: A marine plant that is high in fibre, seaweed acts as a prebiotic and can help feed the beneficial bacteria in the gut.
Including a variety of these prebiotic-rich foods in your diet can help ensure the growth and maintenance of a healthy gut microbiome. This, in turn, supports overall health, including improved digestion, enhanced immune function, and reduced risk of certain diseases. It’s important to introduce prebiotics gradually to your diet to avoid gastrointestinal discomfort and to drink plenty of water to aid in the digestion and absorption of these fibres.
The above prebiotic list is not exclusive, practically all fruits and veggies have prebiotic benefits and the importance of eating as many different colourful fruits and veggies is important, not to mention their phytonutrient benefits.
What are Postbiotics?
Postbiotics are a relatively new area of interest within the field of gut health, referring to the byproducts produced by probiotic bacteria as they digest prebiotics in the gut. These substances include metabolic products such as short-chain fatty acids (SCFAs), functional proteins, peptides, cell wall fragments, teichoic acid, and polysaccharides, among others. Unlike probiotics, which are live organisms, and prebiotics, which are the food for these organisms, postbiotics are the beneficial compounds that result from the fermentation process in the gut.
The Role of Postbiotics
Postbiotics play several crucial roles in health and wellbeing, including:
- Supporting the Immune System: Some postbiotics have antimicrobial properties, which can help control the growth of harmful bacteria.
- Maintaining Gut Barrier Integrity: They can strengthen the gut barrier, reducing the risk of harmful substances leaking into the bloodstream (a condition known as leaky gut).
- Modulating Inflammation: Certain postbiotics can help reduce inflammation in the gut and throughout the body.
- Supporting Metabolic Health: They may influence metabolic processes, potentially helping to regulate blood sugar levels and support overall metabolic health.
Examples of Postbiotics
- Short-Chain Fatty Acids (SCFAs): These include acetate, propionate, and butyrate, which are produced when probiotic bacteria ferment dietary fibers in the colon. SCFAs are the most studied postbiotics and have been shown to have numerous health benefits, including nourishing colon cells, supporting the immune system, and regulating metabolism.
- Bacterial Cell Components: Components like cell walls, peptidoglycan, and teichoic acids can have immunomodulatory effects, helping to stimulate the immune system in a beneficial way.
- Functional Proteins and Peptides: These include bacteriocins, which are antimicrobial peptides produced by bacteria that can inhibit the growth of harmful bacteria.
- Exopolysaccharides (EPS): These are complex sugar molecules produced by certain bacteria that can have anti-inflammatory and immunomodulatory effects.
- Lipoteichoic Acid: Found in the cell walls of lactic acid bacteria, this substance can help modulate immune responses and support gut barrier function.
Sources of Postbiotics
Unlike prebiotics and probiotics, which are obtained directly from consuming certain foods or supplements, postbiotics are not typically consumed in isolated form. Instead, they are produced within the body as a result of probiotic activity. However, some fermented foods and certain dietary supplements are being developed to contain specific postbiotics, aiming to deliver these beneficial compounds directly.
Research into postbiotics is still evolving, and more studies are needed to fully understand their health benefits and how best to utilize them. However, the existing evidence suggests that they play a significant and beneficial role in human health, particularly in relation to gut health and the immune system.
