I regularly eat homemade kimchi, a Korean fermented food. I love the flavour and know it is doing me good, but what are fermented foods and why are they so healthy?
What is fermentation?
Fermentation is an ancient technique of preserving food. It is a natural process where microorganisms (yeast and bacteria) convert carbohydrates (starch and sugar) into alcohol or acids. The alcohol and acids not only act as a natural preservative and give fermented foods a distinctive sharp, tart flavour but also promote the growth of probiotics and enzymes which have many health benefits.
Why is it so healthy?
Fermented foods are rich in probiotic bacteria, increasing the diversity of our microbiome (the collection of all microbes, such as bacteria, fungi, viruses, and their genes, that naturally live on our bodies and inside us).
Research shows that the gut microbiome is important for our immune health and also our mental health.
Fermenting breaks down a food’s fibre, increasing the digestibility of the ingredients.
Brassica vegetables (cauliflower, cabbage, broccoli, Brussel sprouts, collard greens) when cut release the chemical sulforaphane (a potent antioxidant) that is destroyed during cooking but thrives when fermented (Although note a quick steam is fine, also chop your veg 30 minutes before eating to help this process).
It also supports stomach acid levels, acting as digestive enzymes.
It increases the concentration of nutrients in foods i.e., most B vitamins (folic acid and B12) plus vitamin K and vitamin C (when cabbage is fermented for sauerkraut the vitamin C content doubles).
Fermented foods:
Sauerkraut: German – pickling finely shredded cabbage.
Kimchi: Korea – fermented mixed vegetable dish variations; such as cabbage, radish and cucumber, combined with chilli, garlic.
Sourdough: Europe/US - method of breadmaking using wild yeast.
Kefir: Eastern Europe – fermented milk, similar flavour to yoghurt.
Kombucha: China/Russia – fermented black or green tea.
Kvass: Russia –compared to a sweet, non-alcoholic beer made from soaking rye bread in water, yeast and flavourings.
Plus: Yoghurt, Tempeh, Natto, Cheese, Miso, Salami, Beer, Wine, Olives, Crème fraiche.
Note: It is advised to start by incorporating small quantities (a tablespoon) of fermented foods to the diet and gradually increase the intake. This is to avoid gastrointestinal discomfort from the shift in gut flora. To benefit from the health properties of fermented foods, it is best to eat them regularly.
References:
Tim Spector, Food for Life The New Science of Eating Well; 2022
Helpsheet: Fermentation; Clinic in a Box; College of Naturopathic Medicine
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