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Fermented Foods, Prebiotics and Probiotics

Author: kim

You probably already eat fermented foods in your diet. Chocolate, coffee, vanilla, some teas, pickles, vinegar, cheese and yoghurt are all fermented foods. Then there’s alcohol, sauerkraut, kombucha, sourdough and kefir, again all fermented! This article looks at some of our most popular fermented foods and their nutritional benefits.  We've also sourced you a recipe for Kimchi so you can make your own ferments at home!

Fermentation simply means ‘to boil', not from cooking, but from the bubbles that form when fermentation is taking place, it occurs in yeasts and bacteria. The health benefits of eating fermented foods include enhancing nutrients, protection from ‘bad’ bacteria, building your immunity and aiding digestive and pre-digestive processes.

Fermenting sauerkraut
Fermenting sauerkraut

The main reasons for fermenting are

  • To produce alcohol (converting carbohydrates including sugars into ethanol)
  • To convert it from a form in which it will not keep (e.g. turning milk into cheese)
  • To convert the food from something indigestible in its’ original state to something edible and digestible (e.g. wheat into bread)
  • To remove any toxic potential (e.g. soya beans into tempeh, soya in raw form is toxic to humans)
  • To improve the flavour or taste of the raw food

Fermenting has been around for centuries, it helps to preserve foods and can reduce cooking times and fuel requirements. In addition, it can eliminate anti-nutrients and biologically enrich the foods with amino acids and vitamins.

Riazhenka (fermented milk) and Kefir
Riazhenka (fermented milk) and Kefir

Fermented range at Real Foods

Some of the products are already fermented – these are only available in the fridge section. We don't sell chilled items online yet (we are working on it), but if you live in Edinburgh pop into one of our stores and have a look at the range.

This is a fermented milk called Riazhenka. It is created by baking the milk prior to fermenting. Historically the milk was baked in a clay pot for a day until a crust formed. "Prolonged exposure to heat causes the Maillard reaction between the milk's amino acids and sugars, resulting in the formation of melanoidin compounds that give it a creamy colour and caramel flavour."(Wiki - Ryazhenka - sourced 06.03.15). The ones we stock are from Bio-tiful Dairy - the dairy is situated on the beautiful Riverford Organic Farm in Devon that repeatedly wins awards as the best organic farm in the UK. They deliberately leave the natural balance of nutrients in the milk and do not add anything to it, except for the wonderful ancient live cultures that further enrich the minerals-packed organic milk with beneficial microorganisms, vitamins and amino-acids. It has a sweet taste and is very popular with our customers instore.

Kefir range
Kefir range

You can find our kefir range here. These are only in our chilled department and not available online - to see the product available simply tick the top of the search to 'show all product' this will show you the Real Foods full chilled range. This is the Kefir starter culture (freeze dried kefir in skimmed milk) and there are also ready-made mixes, including one with added chia seeds. Kefir is made from lactic acid bacteria and yeasts, meaning that several varieties of probiotics can be found in Kefir.

This is our kombucha range. It’s made with bacteria and yeast with water and green tea. The taste can be anywhere between a sparkling apple cider to a champagne, depending on which type of tea is used. It's not at all what you would imagine fermented tea to taste, it can be quite sour, depending on how long the bacteria has grown for - the bacteria eats the sugar, so the longer it's fermented, the less sweet it will be. As the Kombucha culture digests the sugar it produces a range of organic acids including gluconic acid, lactic acid, glucuronic acid, acetic acid, butyric acid, malic acid and usnic acid. It also provides vitamins (particularly B vitamins and vitamin C) as well as amino acids, enzymes. The probiotic micro-organisms themselves provide health benefits in digestion.

Sauerkraut range
Sauerkraut range

Sauerkraut, kimchi and dill pickles are all made in a similar way. They are all fermented by lactic acid bacteria to prolong the shelf life and have a distinct sour flavour. This converts the sugars in the vegetables to lactic acid which gives the flavour and exceptional shelf-life (quite apart from the health benefits - fermentation is an excellent way to store food for longer without pasteurisation.)

This is our sauerkraut range. Basic sauerkraut is made from cabbage, salt and water, although there are variations with additional beets or infusions of juniper berries. Or if you’d like to try making your own, our wild fermentation section is below.

Dill pickles are made from cucumber and can be found here in the webshop.

You can find Kimchi here in our webshop. Kimchi (an incredibly popular Korean side-dish) is made from cabbage, spring onions, and daikon radishes then mixed with a seasoned paste of red pepper powder (kochukaru), ginger, garlic and kelp powder. Or try making your own with our recipe below.

Cultured rice (kome koji) is rice that has been inoculated with Aspergillus oryzae, the fungus that is the basis for many kinds of fermented foods such as miso, natto (fermented soybeans) and soy sauce. You can find the full range of Japanese foods here. Or try Tempeh a fermented soya bean product originally from Indonesia.

Amazake is made from water, steamed rice and cultured rice. This mixture is allowed to ferment until the starches in the rice are saccharified and converted into glucose as well as oligosaccharides, which is said to be the ideal food for intestinal flora and helps combat constipation. The amino acids and B-vitamins in the rice are also converted into an easily digestible form.

In Japan Amazake (translated as “sweet sake”), is taken as a sweet, slightly fermented rice drink. It is diluted with hot water, sieved and drunk as a comforting winter warmer. However Amazake is very versatile and can also be used to add texture and protein to your favourite fruit smoothie, natural sweetness to pancakes and muffins or even as a batter to make dairy free French Toast. We have rice, millet and oat versions available here.

Realfoods Organic Asparagus Green UK 500g
Realfoods Organic Asparagus Green UK 500g

Health Benefits of fermenting

The bacteria that live in our gut are essential for health. That is how nutrients are absorbed, assimilated and digested. They also play a role in our immune systems, are linked to our mental health and there is a TRILLION of them living in each gut! They weigh around 4 pounds per person. They are also known as gut flora.

In addition, there are 300-1000 species of bacteria living in the gut. These micro-organisms perform a huge array of useful functions, such as training the immune system, preventing the growth of harmful, pathogenic bacteria, fermenting unused energy substrates, regulating the development of the gut, producing vitamins for the host, such as biotin and vitamin K, and producing hormones to direct the host to store fats.(Wiki Gut Flora- retrieved 02.02.17)

Highly stressful lives, processed foods and refined sugars all help feed the ‘bad’ bacteria. An imbalance of too much ‘bad’ and not enough ‘good’ can result in problems like constipation, diarrhoea and bloating. Fermented products help to increase the ‘good’ bacteria and help keep your gut healthy along with prebiotic foods.

Prebiotics are non-digestible parts of food that promote the growth of beneficial microorganisms in the intestines. Onions, asparagus, chicory, leeks and artichokes are all good sources. These fibre-rich foods feed the good bacteria in the gut.

For example, Inulin is a prebiotic. It is a starchy substance (or storage carbohydrate) found in a wide variety of fruits, vegetables, and herbs, including wheat, onions, bananas, garlic, leeks, artichokes, and asparagus. It is used by plants as an energy reserve so is usually found in roots or rhizomes.

Inulin is not digested or absorbed in the stomach. It goes to the bowels where bacteria are able to use it to grow. It supports the growth of a special kind of bacteria that are associated with improving bowel function and general health. Inulin decreases the body's ability to make certain kinds of fats.(Wiki Inulin- retrieved 02.02.17)

For more information on how to maintain good gut health have a look at this article on our site.

The main ways of fermenting are

First of all, there’s wild fermentation. This means using the organisms already present in the food.

Secondly, there’s using a starter culture to introduce the organisms to start the process. Starter culture fermentation includes kefir, sourdough and kombucha, the cultures are sometimes referred to as ‘the mother’.

Fermenting cucumbers
Fermenting cucumbers

Starting fermenting? Wild fermentation

You will need:

  • Glass jars. Save all of your re-sealable jars, you will need a variety of sizes, so the more the merrier really!
  • Sea salt (or Himalayan, rock or crystal salts) – just not table salt if you can avoid it.
  • For large fermentations - A large container with a wide-mouth and a lid or plate that fits inside the opening of the container. Glass or ceramic is preferable but food-grade plastic will work. You’re looking for a container that can hold 4-8 litres.
  • Tea towels or clean offcuts of cloth and rubber bands to cover the ferments.

Ingredients – Seasonal, local and organic are the watchwords here. Seasonal is cheaper and more abundant (using up excess is a good reason to ferment foods in the first place). Local means the foods are at their freshest and ripest (more nutrients) and may help the yeasts and bacteria ferment as they’re used to the local conditions already! Organic food contains more nutrients (see this page for more information on organic nutrition) and fewer pesticides than non-organic foods. Pesticides can stop the growth of the essential bacteria.

Most people start with something simple like sauerkraut or kimchi.

How to wild ferment

Put the vegetables you wish to ferment in a jar with some salt and water. Salt and water combined make brine. Turnips, swedes, carrots, beetroots and cabbage are all relatively simple to ferment.

Make sure the vegetables are covered in brine and put on the lid tightly. Release the pressure once a day for the first week. The longer you leave it fermenting, the stronger the flavour will become. Yes, it is common to ferment foods throughout the winter in many cultures for a truly strong flavour, but perhaps start with 3-4 days! Taste it, see if it is to your taste, if not ferment a few more days. When it is to your taste, simply pop it in the fridge and use it whenever suits.

When you’ve mastered the small jars and have your preferred recipes, then move on to fermenting several cabbages or large amounts of food in the large container.


Recipe for Kimchi


  • 1 turnip or radish - finely sliced or in matchsticks if you can!
  • 1 large cabbage - finely sliced, shredded or grated
  • 2-3 shallots or spring onions
  • 1 apple sliced (or a teaspoon of sugar)
  • 2-3 carrots - julienned, matchsticks or simply chopped
  • 2 crushed cloves of garlic
  • 1 chilli - chopped finely
  • 2 teaspoons of mineral or rock salt

How to ferment your own Kimchi

Sprinkle the salt onto the cabbage and massage it in (the salt is used to add flavour, preserve and eliminate moulds, it also helps release the vegetables natural juices). Pop in a bowl cover with water (you might need a plate on top to weigh it down) and leave for at least 10 minutes.

Mix together the rest of the ingredients. Rinse the cabbage and mix together.

Squash it all down into a large jar; make sure the vegetables are covered in their natural juice. If there’s not enough released, add salted water (brine) or celery juice. Make sure the vegetables are covered and there is a little room at the top of the jar (it’s going to ferment, that means bubbles and they need some space!) Leave at least an inch of room.

Screw the lid on tightly and let the Kimchi ferment. The longer you leave it… the stronger and more intense the flavour will be. It’s a good idea to leave it on a plate as the brine may overflow slightly.

The best idea is to taste it daily until you have the taste you like. Simply press down on the vegetables with a clean spoon to keep them submerged under the brine before you close the lid again. This also helps the gases release. Once you have the flavour you like, transfer to the fridge and enjoy the fruits (and vegetables) of your labours! For most folk, it’s about a week, but many people like fresh kimchi when it has barely fermented. As long as the vegetables are submerged there’s no danger of mould.

Kimchi traditionally has seafood or an umami flavour to it, so do try adding kelp powder or chopped seaweed. There are also spinach, radish and courgette kimchi recipes, so experiment until you find the one you like.

What are gut flora?

Gut flora (the bacteria that lives in your gut - also known as intestinal microflora or gut microbiota) outnumber human cells by 3 to 1 although it may be as much as 10 to 1. These single-celled microbiomes number as much as one trillion in EACH human body. In addition, there are between 300 and 1000 species of the bacteria living in the gut - most estimates suggest around 500 on average. The microorganisms perform a huge array of useful functions, such as training the immune system, preventing the growth of harmful, pathogenic bacteria, fermenting unused energy substrates, regulating the development of the gut, producing vitamins for the host, such as biotin and vitamin K, and producing hormones to direct the host to store fats.(Wiki Gut Flora - retrieved 20.03.15)

It looks like some of the bacteria are actually genetically inherited. A study looking at identical twins versus non-identical twins "When the group compared the levels of similarity in gut bacteria generally, they found no difference between identical and non-identical twins, suggesting that genes don't influence the microbiome. But when they looked at the heritability of different groups of bacteria separately, they found that some bacteria were more similar in identical than in non-identical twins. In other words, some components of the microbiome are heritable."(New Scientist Composition of gut bacteria - retrieved 20.05.15) Some of the heritable bacteria are ones that have been linked to diseases.

Anatomy of Colon
Anatomy of Colon

What steps can you take to improve the bacteria in your gut?

1. Stop taking unnecessary antibiotics. It's well known and widely studied that taking antibiotics wipes out much of your gut flora - around 60% suggest most studies. The advice is simple; only take antibiotics if you absolutely have to. If there is no other option but to take them, make sure you replace the gut flora with a good probiotic after the course of treatment. S. Boulardii is not killed during a course of antibiotics so it's worth taking a probiotic that contains it for gut health whilst on a course. Try this one from Optibac.

2. External exposure to bacteria. It is widely accepted that the only way to defend yourself against a vast array of bad bacteria, is to have a host of good bacteria fighting on your behalf. This means getting down and dirty! Exposure to earth, plants, and even fresh air will help to generate the bacteria needed to fight off pathogens. Something as simple as opening a window and ensuring you have a good supply of fresh air in a well-ventilated room will help. "Bacterial communities in indoor environments contained many taxa that are absent or rare outdoors, including taxa closely related to potential human pathogens." (NCBI Architectural design influences the diversity and structure of the built environment microbiome -retrieved 15.03.15). Starting a garden or even a small window box will expose you to useful bacteria found in soil. Try our Plant N Grow range to start you off (edible flowers? yum!) or sprouting seeds.

3. Over-use of antibacterial soaps and cleaning products. Obviously, you need to kill as many bacteria as possible in a clinical hospital environment, but that's because people are seriously ill. You do not need to kill all of the bacteria on a daily basis for a healthy life. Try some gentle baby wipes if you want cleanliness on the go, or look at this range of soaps and natural cleaning products. Hot water and a good scrub will be just as effective at ridding you and your house of dirt without wiping out all of the bacteria. Natural solutions for cleaning can also be found here.

4. Internal exposure to bacteria - eat plants! Your gut microbes thrive on a diversity of fermentable substrates (aka dietary fibre). However not all fibre is the same – you need diversity and you need to be eating more of the whole plant – not just the tasty leaves! For example, the trunk of broccoli has a different substrate for your microbes to feed on than the tips. So trying eating all of the plant as the parts that are harder to digest will help extend your metabolic activity. Aim for as diverse a range of plants as possible. Here are our fresh fruit and vegetable selection. Try some of the specialist items and other fresh veg and trial a few new vegetables!

Naturally probiotic foods

Probiotics are thought to directly kill or inhibit the growth of harmful bacteria, stopping them producing toxic substances that can make you ill.

Some foods are naturally probiotic. Sauerkraut, kimchi, kefir, yoghurt, miso and tempeh are amongst them. Most of these are only available in-store as they are kept in the fridge. The health benefits of eating fermented foods include enhancing nutrients, protection from ‘bad’ bacteria, building your immunity and aiding digestive and pre-digestive processes. You can find starter cultures here.

Linwoods Flaxseed has added vitamin D and probiotics to encourage a healthy system. Try sprinkling over a bowl of non-dairy milk porridge to give yourself an excellent start to the day.

Real Foods Organic Wormwood Herb Tea
Real Foods Organic Wormwood Herb Tea

Helpful foods for health


Maintaining hydration can be key to having a healthy digestive system.

Plant juices can be very helpful to support health. Try Salus Plant Juices which use traditional natural remedies with as little processing a possible. Stinging Nettle juice is reportedly excellent for helping the metabolism.

Alternatively, try this range of herbal and fruit teas.

Natural nutrients

Psyllium Seed – An excellent source of soluble dietary fibre.

Chlorella - Its nutritive value, high plant protein and chlorophyll content make it one of the world's superfoods. Have a look at our superfoods shop, green superfoods can be particularly helpful.

Wormwood - In ancient Egypt, wormwood was highly prized as anti-parasitic. It promotes the secretion of bile and other digestive juices.

Aloe Vera - Nature's enzymatic aid to digestion.

Cayenne - Aids circulation and useful in inflammations, stomach and bowel disorders.

Senna - If constipation is a problem this helps cleanse the colon.

Garlic - Rejuvenates and stimulates the lymphatic system to throw off waste materials.

Rosehips - A digestive stimulant. Excellent antioxidant value from high vitamin C levels.

A Vogel Molkosan Prebiotic Supplement Gluten Free 275g
A Vogel Molkosan Prebiotic Supplement Gluten Free 275g

Probiotic and prebiotic supplements

We would recommend taking a good probiotic if suffering from digestive issues or some skin complaints (particularly eczema). OptiBac's range includes specific cultures for recovering from antibiotic impacts, travel and daily wellbeing.

BioCare provide a wide spectrum digestive support including lactobacillus acidophilus. Or they have a Micro FloraGuard supplement that includes natural remedies like garlic and cloves along with lactobacillus acidophilus and bifidobacteria.

Higher Nature have a powder suitable for people who don't like capsules, simply add to drinks.

Molkosan's prebiotic drink is excellent for activating the pancreas and other digestive functions. Again simply add to water or drinks.

Or try MagniFoods pre and probiotic natural supplement containing beetroot and burdock.

Acidophilus supplements can be found here in our webshop.

Reducing stress

Stress has been linked to your gut health. Frankly, I find being told to 'reduce stress’ simply makes me more stressed! However, these tips should help focus you on how to reduce it.

Gentle exercise. Any exercise is good, but try to find something you enjoy! It may be yoga or Pilates with a good instructor, but dancing to your favourite music, learning a new skill (perhaps you've always wanted to try archery or quite fancy a ballet class!). Whatever your interests, trying a class or getting together with friends to inspire each other, helps you to maintain the exercise.

Walking has been linked to reducing stress. A simple 20-minute stroll will help you reduce stress. What's particularly good is walking outside, in the fresh air (remember those good bacteria are everywhere!). Studies have shown that exposure to countryside scenes (even a picture of them) helps to improve your mental and emotional health and has a knock-on effect on your physical wellbeing. If you're lucky enough to live near water try walking along the canal or river and feel the benefits accrue.

Getting a good night's sleep - easier said than done for many people, but going to bed early and waking up naturally have a plethora of benefits for your health. Trying natural remedies like lavender, warm baths an hour before sleep and removing exposure to screens all help. Clipper's Sleep Easy tea has had good feedback on being helpful along with chamomile and peppermint teas.

Breathe! Meditation and breathing techniques can help reduce stress. There's no excuse not to, nobody is so busy they don't have a minute to practise calm breathing! Let's face it, you're breathing 24 hours a day, you may as well get the best benefits possible. This guide is from Guy's and St Thomas' NHS Hospital and has a 15-20 minute technique for relaxing - try it with a friend and see if it works for you.

Reducing caffeine, sugar and processed foods can all help reduce stressors on the body.

Symptoms of 'bad' gut health

The problem with many of the symptoms of an unhealthy gut is that they often fall into 'medically unexplained symptoms'. Many people suffer from persistent physical complaints, such as dizziness or pain, that don't appear to have an obvious medical cause. This DOES NOT mean that they are not real, with up to a fifth of visits to the GP in the UK being classed as medically unexplained. For example, fatigue, pain, headaches, heart palpitations, shortness of breath and dizziness and feeling sick are all often 'medically unexplained'. It is always worth seeing your GP. Sometimes there is simply no explanation and doctors can't diagnose a cause. This isn't unusual in medicine and doesn't mean that nothing can be done to help you. Read more on the NHS website for the information you should take to your GP to try and find underlying causes.

Certainly they'll tell you to reduce stress, eat a healthy diet and take gentle exercise, however, there may be an underlying cause of the symptoms and you need to get the tests done to rule out any illnesses.

Rude Health Organic Almond Milk with Rice Drink dairy free, 1l
Rude Health Organic Almond Milk with Rice Drink dairy free, 1l

A low FODMAP diet

This diet has been linked to reducing IBS and other gut issues. FODMAP stands for Fermentable, Oligo-, Di-, Mono-saccharides and Polyols. The idea is to follow a low FODMAP diet for 8 weeks, then review and re-introduce some foods slowly. It is supported by the NHS so it is worth consulting your GP for further support.

FODMAPs are osmotic (means they pull water into the intestinal tract), may not be digested or absorbed well and could be fermented upon by bacteria in the intestinal tract when eaten in excess. A low FODMAP diet may help reduce symptoms, which will limit foods high in fructose, lactose, fructans, galactans and polyols.

  • Fructose (fruits, honey, high fructose corn syrup (HFCS), etc)
  • Lactose (dairy)
  • Fructans (wheat, garlic, onion, inulin etc)
  • Galactans (legumes such as beans, lentils, soybeans, etc)
  • Polyols (sweeteners containing isomalt, mannitol, sorbitol, xylitol, stone fruits such as avocado, apricots, cherries, nectarines, peaches, plums, etc)

Try eating alternatives to dairy and soy - try almond, rice or coconut drinks.

Limit gluten-containing cereals. Try naturally gluten-free alternatives like brown rice flour, quinoa, buckwheat, sorghum, corn and oat flour. Oats have also been linked with providing excellent levels of fibre (essential for gut health) and promoting good cholesterol. All of our flours that don't contain gluten can be found here on the site. Please be aware - some are batch tested to 20ppm, these are suitable for coeliacs and people with strong sensitivity and are marked Gluten Free. Flours marked No Gluten Containing Ingredients, are not batch tested - while they don't contain gluten they could have been exposed in packing or production.

The idea is to follow a low FODMAP diet and drink plenty of water, then once the trial is over, gradually re-introduce foods and watch for symptoms of gastro-intestinal distress. We wouldn't recommend excluding groups of foods forever! For example, perhaps you're following a low-gluten diet with some impact on the reduction of distress. However, it may be that wheat is actually the culprit, not gluten, by re-introducing foods gradually and noting your body's response you can find what your triggers are.

It is worth remembering that EVERYBODY is DIFFERENT. By all means try out a diet or foodstuff a friend has recommended but it's always worth recording a food diary and seeing if you can isolate culprits for yourself - food reacts differently with different people (not to mention different gut flora), so unless you've actually got an identical twin, seeing how other people manage may not help!

A review of other diets is available in this article.