Fermented Foods – The First Superfood?

Fermented foods have been around for thousands of years ¹ – traditionally it was a means of preserving food. Our hygienic, hyper-sanitised modern culture has cultivated a morbid fear of bacteria, contamination and food poisoning ². Together with the acceleration and industrialisation of food production, this has contributed to a significant reduction in the diversity of fermented foods being consumed ³.

Lately and fortunately, there has been a revival in the popularity of fermented foods in part due to the resurgence of artisanal processes, but also due to the positive research that have substantiated what our forefathers instinctively knew – that eating fermented foods also provides numerous health benefits ^{3, 4}.

What is it?

Fermented foods are foods that have been naturally processed by friendly bacteria and yeast that convert sugars to organic acids or alcohol under anaerobic conditions (without oxygen). The different types of fermented foods available around the world depend on the different food-microbes combination ⁵. This is not to be confused with foods that have been pickled in acid i.e. vinegar, since this method actively prevents bacterial growth ⁶, and thus does not offer the same health promoting qualities ⁴.

Why is it good for you?

In the fermentation process, these amazing microorganisms not only preserve and improve the safety of the food, enhance the bioavailability of nutrients, degrade toxic components of the food, they also produce certain vitamins, antioxidants and antimicrobial compounds ^{3, 4}. Research has shown links with fermented foods to the prevention of cardiovascular disease, cancer, gastrointestinal disorders, allergic reactions, diabetes, hypertension and heart disease ^{7, 8}. This is in addition to the unique and exciting array of tastes and textures they add to our gustatory experience.

The bacteria responsible for the fermentation process are a great source of probiotic, which is important for gut health. It has been shown that these beneficial bacteria can survive the digestive process ^{9, 10}, and that ingesting fermented foods can increase the number of microbes in the diet by up to 10,000-fold ¹¹. Upon reaching the gut, they work by transiently rebalancing resident gut bacteria to modify gut acidity, produce antimicrobial compounds, compete with pathogens and modify our immune response ^{8, 12}.

These friendly fermenting bacteria produce lactate which has been shown to reduce inflammatory responses ¹³ and oxidative stress in the gut ¹⁴; as well as short chain fatty acids (SCFAs), an energy source for cells lining the gut ⁸. SCFAs are linked to numerous health benefits including inhibiting pathogens, increasing absorption of some nutrients, maintaining gut barrier function, controlling inflammation in the gut as well as protecting against colorectal cancer ¹⁵. Depending on the microbial strain present, B vitamins are also produced ^{16, 17}.

Research has even shown a link in consumption of fermented foods and positive mental health ⁴. A number of pathways have been proposed, but they predominately involve microbial action on brain chemistry ¹⁸; and their influence our own microbiota, which has a direct connection with the brain via the gut-brain axis ⁴.

Types of fermented foods

• Fermented milk products
Yoghurts, cheeses and milk kefir are all fermented milk products that are produced by bacteria and yeasts utilizing sugar in milk (lactose). The most potent is traditionally made milk kefir (from kefir grains), which can contain over 300 microbial species, and is rich in vitamins and minerals19. It has been associated with a multitude of health benefits, ranging from improved digestion and tolerance to lactose, antibacterial, anti-inflammatory and antioxidant activity, improved cholesterol metabolism and wound healing, to the modulation of the immune system and microbiome, and even possible alleviation of allergies and cancers ^{19, 20}.

• Fermented vegetables
For vegans, vegetarians or those that want variation and variety, fermented vegetables including cabbage (sauerkraut and kimchi) and olives, are equally beneficial. Owing to their phytonutrient content, the growth of bacteria in plant and vegetable fermentation enhances their antioxidative and detoxifying abilities ²¹.

Sauerkraut is produced by the fermentation of white cabbage ²². Its many health benefits come from the phytochemicals found in white cabbage as well as the probiotic function gained from the fermentation process. The fermentation of cabbage not only provide additional probiotics, vitamin C, B6, folates and manganese, but has been shown to enhance its anti-inflammatory, anti-oxidative activities ²³.

Kimchi is a spicy Korean dish, commonly comprising of salted and then fermented Chinese cabbage. In addition to its probiotic qualities, it contains other vegetables, garlic, ginger, red pepper powder and green onions that also undergo fermentation that significantly boost its health promoting functionality. Kimchi is low in calories, high in vitamins, minerals and phytochemicals that together have demonstrated kimchi to have anti-cancer, anti-obesity and anti-atherosclerotic qualities ²⁴.

Olives is highly nutritious containing fibres, amino acids, unsaturated fatty acids, vitamins and antioxidants but are inedible without microbial processing ³. The ability of bacteria to colonize the surface of olives and form a film protecting it during digestion means that olives are also probiotic ²⁵.

• Fermented tea (kombutcha)
Kombucha is made from sweetened tea which is fermented with a symbiotic culture of bacteria and yeast (or SCOBY). This fermentation process gives the tea a pleasant sweetish sour effervescent taste, rich in fibre, organic and amino acids, vitamins, antioxidants and minerals ²⁶. Kombutcha’s prominent health benefits include its antimicrobial, probiotic, anti-cancer, detoxification and antioxidative activities ²⁷.

So, it’s official – fermented foods are so beneficial for our health that several prominent groups have recommended that they be part of national dietary guidelines around the world ^{5, 28}.

Some friendly advice before you run out to the supermarkets…commercially produced fermented foods may not necessarily contain the health beneficial live bacteria, as many are heat-treated after fermentation to extend shelf-life and enhance food safety. Furthermore, some products such as commercial pickles and olives are not fermented at all but are placed into brine containing salt and organic acids instead ²⁹.

Natural fermentation on the other hand is inexpensive and easily made at home – all you really need is a jar, some salt or sugar, and trust in the world of bacteria and fungi. Particularly since fresher products contain higher numbers of good bacteria ²⁹, isn’t it time to give this age-old art of fermenting a go?

Need some inspiration? Click on the Recipes page for some of my favourite fermented foods recipes.