Nutrition: fermented foods

Tuesday 08 May 2018

This month I want to update my nutritional advice about boosting the immune system. It seems the right time of the year to be thinking about this but also any form of treatment for cancer can affect the immune system and many people are looking for ways to support it. It is one of the topics that I am frequently asked about. I last did a blog on the immune system on 10th June 2014. That particular blog focused on the foods that have been shown to boost immunity, which you may like to refer to.

In the following blog I want to enlarge on this information and look at fermented foods and the important role that they can play in supporting our immunity. Fermented foods have come to the forefront recently as research into them has shown their huge immune boosting benefits. Cultures around the world have been eating fermented foods for centuries. Sauerkraut in Germany to Kimchi in Korea and everywhere in between. Sadly with the advances in technology these traditions have been lost to heavily processed convenience foods that give us no nutrition and have been linked to the onset of many diseases.

So what are fermented foods?

These are foods that have been through the process of Lacto Fermentation in which the natural bacteria feed on the sugar and the starch in the food creating Lactic Acid.  

What does the process of fermentation do?

• Preserves the food and extends the shelf life of the food.

• Adds microbes to the gut through the presence of beneficial bacteria that are produced by the fermentation process. In our digestive tract we have billions of bacteria called probiotics or good gut flora (which weighs up to 2kilo!!!). They have numerous health benefits. The main types are Lactobacillus acidophilus and Bifidobacteria infantis. These bacteria can be adversely affected by the use of antibiotics, stress and also chemotherapy.

The benefits of these bacteria are;

1. They help to regulate cholesterol levels.

2.  They act like our own vitamin factory, producing many of the B vitamins and helping to produce other vitamins like vitamin D. They also produce amino acids (protein) and vitamin K which is needed for good bone density.

3. They help the minerals calcium and iron to be absorbed.

4. They do important work in our digestive system, preventing pathogenic bacteria taking hold.

5. They attach themselves to the toxic heavy metals like mercury and lead, preventing them from doing us any harm.

6. They stop the lining of our gut from being damaged. This is important because if it gets damaged substances that are not supposed to be there can get into our bloodstream.  

7. Lastly but by no means least they protect our immune system, so this helps protect us from foreign invaders like pathogens and also helps us to fight cancer. In fact we know that about 80% of our immune cells are located in our digestive tract. So a healthy gut is vital for a strong healthy immune system.

• Fermentation makes food more digestible by producing enzymes that break down the cellulose in plant foods that our digestive systems cannot do and this makes nutrients from the food more available to us. For example sauerkraut has a much higher vitamin C content than standard raw or cooked cabbage.

• Fermentation changes the taste of the food by making the food more tangy or sour and develops the flavour.

• It eliminates anti–nutrients. Natural or synthetic compounds that are called anti-nutrients can interfere with our absorption of some nutrients and can be destroyed by fermentation. For example phytic acid, which is present in grains and pulses, binds minerals such as iron and zinc and reduces their absorption when we eat them. Fermented foods eaten regularly would prevent this.

• Fermentation saves cooking time because the fermentation process renders foods that are tough or difficult to digest or unpalatable raw much more easily digestible. This reduces the need to cook.

So you can see that fermented foods have huge health benefits and also make a change to our diets by giving foods another dimension.

Here is a list of typical fermented foods;

  • Live Bio yogurt. Perhaps the most familiar and well used  fermented food. This can be made using different milks including soya and coconut if you are avoiding milk from animals. Ideal of course used to top berry fruits or good with added nuts and seeds as a snack or breakfast meal or added to a smoothie.
  • Kefir is a delicious probiotic drink. It is made from Kefir grains which you can buy online or use a kefir starter kit. Traditionally it is made from sheep’s milk but is also successful made from soy, coconut, rice or nut milk. Kefir can be used anywhere that buttermilk, yogurt or cream cheese may be used. Other great ways are in a smoothie, served with fruit, and in place of buttermilk in baking.
  • Sauerkraut has been eaten in Russia for centuries. Sauerkraut in German means ‘sour white cabbage’. Homemade sauerkraut is based on shredded cabbage but there are many other variations of pickled fermented vegetables e.g. Kimchi. To aid digestion it is recommended to have 2-3 tablespoons a day. It is simple to make but a process which can quickly be managed.

Note that if you buy fermented foods it is important that they have not been pasteurised as this destroys the natural bacteria that are present.

Make any changes slowly

It is also recommended that if you do want to start using these in your diet, and evidence suggests that this is a good thing, then to introduce them slowly so that the digestive system can get used to them.

PLEASE NOTE  that if you are receiving any form of  treatment, particularly radiotherapy on the abdomen area or for prostate cancer it is important that you inform your medical team before making any changes to the diet or adding extra foods. If you are not receiving treatment then there will be no problems just benefits but, as I have explained, introduce these immune boosting foods slowly. Below is a recipe for Kraut Chi which you may like to try.


1 litre of water.
4 tbsp of water kefir grains.
3 tbsp of cane sugar
300g of white cabbage sliced
1 bunch of spring onions sliced
2 carrots peeled and grated
2cm root ginger peeled and grated
4 tsps of sea salt
1 red chilli finely chopped.


1. Put the water kefir grains and sugar in a jar and stir with a wooden spoon. Set aside for 2-3 days, giving it the odd shake. Strain through a nylon sieve before use.
2. In a large bowl put 2 tbsp of this water and the remaining ingredients. Toss with your hands until well combined.
3. Pack into a 1 litre jar, pressing down if needed. Close the lid and set aside on a work surface for 5 days. By then it should smell vinegary and the vegetables will have softened a bit. It will then ready to eat.
4. The Krauchi will keep for 2 months. Once opened store in the fridge and eat within 1 month.

Remember to have small amounts to start with and build up the portions slowly over time.

Blog originally written by Caroline January 2016 - checked April 2020

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