Fermented Foods – What You Need To Know

Fermented foods have fizzed onto the healthy food scene over the last few years, but we Nutritional Therapists have had them in our tool kits for quite some time already.

Hippocrates once said, “All Disease Begins in The Gut.” There is no denying that optimising one’s gut health is now deemed to be important and it is one of the aspects I question most when working with patients. So, let me tell you a little more about why fermented foods are so often part of the dietary recommendations in my Health Plans.

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What is Fermentation?
The fermentation of foods certainly isn’t new. It is a process that has been known about for thousands of years and was useful for preserving foods. Fermenting food in simple terms, means that the sugars and carbohydrates in a food have been broken down by beneficial (or “good”) bacteria. In scientific terms, it involves a process called lacto-fermentation. During this process, natural bacteria (also called lactobacilli) feed on starches and sugars, converting them to lactic acid. This preserves the food and creates prebiotics and probiotics, along with other nutrients including b-vitamins (crucial for the nervous system, mental function & digestion), omega-3 fatty acids (essential for brain health, fighting inflammation & cellular functioning) and beneficial enzymes (needed for digestion & metabolism).

What are Fermented Foods?
Common fermented foods include: sourdough, kombucha, live yoghurt, kefir, blue cheese, apple cider vinegar, sauerkraut, kimchi, miso, tempeh, pickles and natto.

Why Fermented Foods?
There are many benefits of fermented foods. Firstly, fermented foods are live and active. They are teeming with beneficial bacteria and yeast. They contain a variety of live cultures (probiotics) along with prebiotics (the food the probiotics feast on to help them grow). Benefits include:

  • Improving the digestion and absorption of vital nutrients
  • Reducing constipation and bloating
  • Improving the colonisation of intestinal, respiratory and urogenital tracts
  • Lowering cholesterol and improving blood lipid profiles
  • Improving mood, mental function and emotional stability
  • Increasing energy and reducing stress
  • Increasing acidity, inhibiting pathogenic bacteria and yeasts like Candida.
  • Helping our bodies to detoxify & acts as a natural chelator of toxins, pesticides & harmful chemicals

Apart from being great for the gut, they act on our immune system. The mucosa (gut lining) is a natural immunity barrier which helps ensure a strong immune system. When more probiotic-rich foods are eaten, the good bacteria are supported and flourish. When more prebiotics are added to your diet, the good bacteria have the perfect nutrition to get the upper hand. If things are out of balance, the disease-causing microbes can grow and may cause inflammation.

Does Everyone Benefit From Fermented Foods?
Most people thrive and benefit from eating fermented foods on a regular basis. However those with histamine intolerance, may find that too many of these foods flare up their histamine symptoms like headaches, itching and sneezing. Those with Small Intestine Bacterial Overgrowth (SIBO) may also find that they cannot tolerate fermented foods at the beginning stages of their treatment, leading to bloating and associated anxiety and fatigue. This is because the gut is overloaded with bacteria already. Usually once the bacterial overgrowth is rebalanced, these foods can be added in slowly and are very beneficial in the longer term, especially after SIBO antibiotic treatment.

Unfortunately, not all fermented foods are created equal. Some fermented foods have been pasteurised so that they can be stored on the shelf at room temperature for longer; and this process kills off any live beneficial bacteria. Always aim to buy live unpasteurised fermented foods where possible.

The best way to get your fermented food intake is by making it yourself. Fermented foods require minimal hands on time as it’s about mixing in the cultures and leaving them to do their job. My favourite fermented foods are sauerkraut, kefir, kimchi and kombucha.

Look after your gut and it will look after you!


About Emma Louise

Emma Louise Winter is a NatureDoc specialist in Fertility, Hormones & Female Health. Find out more about her here. To book an appointment with her, please call NatureDoc reception on 020 3397 1824 or email [email protected]


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  1. Hello
    I’d like to introduce a fermented food to my daily diet. I eat yogurt so figured this could be an easy switch. Which would you recommend? And would this be enough? I normally eat 2 small pots a day, usually activia so something similar to that would be great. Thanks!

    1. Hi Katie
      Thanks very much for your message. It’s good to change up the yoghurt strains you are eating, so aim to get different brands of live yoghurt on a weekly basis. You can also try Kefir which tastes similar and has been fou=nd to be more effective at building a diverse and well-populated gut microbiome. Try adding apple cider vinegar to your salad dressings – a teaspoon of kimchi or sauerkraut on your plate beside your vegetables as a condiment works well too. I hope this is helpful. Lucinda

    2. Hi Katie,

      Lucinda is right, an easy switch would be kefir. It is also delicious when you blitz it with berries!

      • 1tbs kefir grains – https://happykombucha.co.uk/collections/live-kefir
      • 250ml fresh whole milk (I use organic cow’s milk)

      • Mesh strainer / sieve
      • Mason jar or any other glass container / jar
      • Rubber spatula / wooden spoon
      • Muslin cloth and rubber band

      1. Put the grains into the clean glass jar.
      2. Add milk. Leave 1/2 an inch of room at the top. If you want thicker kefir, add a little cream. The more cream you add, the thicker your kefir will be.
      3. Cover jar with a muslin cloth and leave at room temperature for 12-24 hours (the warmer the room, the quicker for fermentation). This is the stage when the grains culture the milk.
      4. Stir the mixture regularly to allow the grains to come into contact with all the milk.
      5. You will know when it’s ready as it will start to look think and clumpy.
      6. When this happens, pour the kefir out into a strainer set onto of a Pyrex measuring cup or glass bowl.
      7. Next use your rubber spatula / wooden spoon to gentle stir the kefir until it passes through the mesh

      I like to let my kefir chill in the fridge then it is perfect to drink.
      **Best before: Use within 21 days

      The leftover grains in the sieve can then be gently washed in a little fresh milk and the processes repeated.