The Science of K4

The Science of K4 Information

Kaye van der Straten is the originator of K4 Kombucha and Cultured Foods and is passionate about the health benefits of kombucha, turmeric, garlic and ginger. She is a postgraduate qualified biologist, a curious foodie and is challenged by autoimmune disease. Her diverse attributes have come together to create the K4 range of delicious wellness foods that are a treat to eat.  

Herbs, roots, leaves, fruits and vegetables that are rich in antioxidants placed in a circle on a white background, surrounding a mortar and pestle filled with ground spices

What are antioxidants and what are the health benefits?

Antioxidants are one of those health “buzz words” we hear thrown around. But what are antioxidants, and why are they so good for us?

Simply put, antioxidants are molecules that reduce cell damage under the right conditions, particularly damage that is caused by the presence of oxygen. But why would the presence of oxygen cause cell damage when oxygen is everywhere on earth? 

It’s a very good question. When our bodies work to break down oxygen, there are some by-products of that process that we don’t need. These by-products are called “free radicals” (cool name, ey?). Free radicals are attractive in the molecular world, they steal electrons from other molecules in your cells, and set off chemical chain reactions that cause cell damage and cell death. 

This is a natural process that happens regularly in our bodies, and is one of the primary causes of inflammation and ageing. We don’t want to subject ourselves to free radicals too often or in great concentrations, or we may end up facing health consequences.

That’s where nature has found a way. Although our bodies naturally produce several enzymes which constantly work to reduce the free radicals circulating within our bodies, we don’t manage to catch them all. Enter antioxidants – the super-heroes of our food and the super-heroes our internal molecular world. They work to destroy free radicals by terminating the chain reactions before the vital parts of our cells are damaged. 

What foods are rich in antioxidants?

Antioxidants can be a wide range of different molecular substances, some that we are familiar with in our daily lives, others not so much. A basic (and not complete) list of antioxidants are:

  • Vitamins – A, C, E and K
  • Minerals – copper, manganese, iodide and zinc
  • Amino acids – alpha lipoic acid, glutathione
  • Enzymes – coenzyme Q10, DHEA, melatonin, catalase, glutathione
  • Plant nutrients – carotenoids, flavonoids, polyphenols, resveratrol, glucosinolates and phytoestrogens

An image of the written names of foods rich in antioxidants, written in different colours, sizes, directions and fonts.

Plant nutrient antioxidants are found in many foods that we eat daily, and some are richer than others. A list of foods rich in antioxidants (also not complete – there are well over 3000 foods known to contain antioxidants!) are:

  • Green and black tea, cacao, cocoa and coffee
  • Herbs and spices (turmeric (which has some other great health benefits too), chilli, garlic, clove, peppermint, cinnamon, allspice, oregano, thyme, sage, rosemary, saffron, dragon’s blood, triphala, amalaki, arjuna, goshuyu-tou)
  • Berries (gooseberries, bilberries, rosehip, blackcurrants, baobab, wild strawberries, goji, cranberries)
  • Vegetables (curly kale, red cabbage, broccoli, artichoke, okra, beetroot)
  • Fruits (pomegranates, apples, apricots, olives, dates, mango, citrus, plums, guava)

Which teas are the richest in antioxidants?

We know that green and black teas are rich in antioxidants, particularly in polyphenols. Of all the teas, green tea is the richest source of polyphenols. The science around the health benefits of green tea is tight and widely accepted.  Some of the research findings (from animal and human studies) for green tea include:

  • Prevention of oxidative stress
  • Anti-inflammatory, antifungal, antiviral and antibacterial effects
  • Prevention of hepatoxicity
  • Some protection against degenerative disease
  • Immune system modulation
  • Cancer prevention effects
  • Lowering blood pressure and thereby reducing the risk of stroke and heart disease

Which is why we choose to brew K4 Kombucha only from premium Darjeeling green tea. K4 Cultured Foods are all about getting the best of the best, in flavour and health benefits. Our cultured foods and drinks are created by applying the traditional practice of fermentation to select functional foods (foods that have known benefits to improving human health). By culturing (or fermenting) foods in this way, we enhance the nutrient bioavailability within these foods.

A workers hands over a drum of green tea leaves, the tea leaves are in and under his hands

What are the health benefits of kombucha?

But what happens to green tea antioxidants when it is cultured into kombucha – do the levels of antioxidants change?

Recent research demonstrated that the polyphenol levels of green tea increased after the green tea was cultured into kombucha. And, when the researchers tested the free radical scavenging activity of the polyphenols, it was higher in the kombucha than in the uncultured green tea. 

In the same research paper, the authors treated high cholesterol rats with kombucha and then looked for the curative effects on their cholesterol levels.  Their findings showed that kombucha improved the liver-kidney function of high cholesterol rats. There is a caution though – this only a single study and these effect haven’t yet been tested in humans.  Further studies are needed before we can confidently say that the same effects happen for humans also.

What does this mean for you and your glass of kombucha?

Now you know that the science says kombucha is rich in antioxidants, particularly if you are selecting a green tea based kombucha. You can have confidence that culturing kombucha creates a drink that is not only delicious for your taste buds, but good for your body too.  

So, whether you want to swap out your evening alcoholic tipple, or just try something new – why choose anything else!

A woman with dark hair and a beautiful wide brim hat holds a glass of dusky pink Kombucha in her hands and smiles while looking beside and past the camera

“What the Science Says” articles are based on the author’s review of published scientific journal studies.  All journal studies used in the compilation of this article are included in the References section. 


Bellassoued, Khaled et al. "Protective Effect Of Kombucha On Rats Fed A Hypercholesterolemic Diet Is Mediated By Its Antioxidant Activity". Pharmaceutical Biology 53.11 (2015): 1699-1709. Web. 9 May 2017.

Carlsen, Monica H et al. "The Total Antioxidant Content Of More Than 3100 Foods, Beverages, Spices, Herbs And Supplements Used Worldwide". Nutrition Journal 9.1 (2010): n. pag. Web. 9 May 2017.

Chacko, Sabu M et al. "Beneficial Effects Of Green Tea: A Literature Review". Chinese Medicine 5.1 (2010): 13. Web. 9 May 2017.

Chan, EricW.C et al. "Antioxidant And Antibacterial Properties Of Green, Black, And Herbal Teas Of Camellia Sinensis". Pharmacognosy Research 3.4 (2011): 266. Web. 9 May 2017.