Chances are, if you’ve ever been to a Korean BBQ with your mates, you’ve probably been served Kimchi. Kimchi is a traditional South Korean side dish made from salted and fermented vegetables, mainly from napa cabbage and Korean radishes; seasonings include chilli powder, onion, garlic, ginger and spring onion. Kimchi is a staple in Korean diets and there are many hundreds of varieties and family recipes available. Although all halmeonis (Korean for grandma) will reckon theirs is the best!
Kombucha, on the other hand, refers to the fermented drink made from a base of tea, sugar, bacteria and yeast. Yum! To make kombucha, you need what is often referred to as the ‘Kombucha Mushroom’, a symbiotic colony of bacteria or yeast (“SCOBY”)—which looks like a rubbery pancake. This is added to tea and sugar and allowed to ferment and the yeast in the culture eats up all the sugar, turning it into carbon dioxide and making kombucha fizzy. The longer the SCOBY is left to ferment, the more vinegary the kombucha will taste. Yikes.
Fermentation, simply put, is the chemical breakdown of a substance by bacteria, yeasts or other microbes. Usually, this process involves effervescence (a fancy word for bubbling), gives off heat and is what turns sugar to acids, gases, or alcohol. Many things in our daily lives undergo fermentation such as beer, wine, vinegar, soy sauce, buttermilk, sour cream and of course we’ve just mentioned kimchi and kombucha. Humans have long been fermenting foodstuffs as a form of extending their shelf life, and in an effort to preserve food to last tough times.
So, what do kimchi and kombucha have in common? As it turns out, quite a lot if you see past the bacteria. Both are made from the process of fermentation, have slightly fizzy flavours and are acquired tastes (unless you grew up on the stuff). And maybe most importantly, it is the bacteria present that is thought to contribute to the health benefits of both kimchi and kombucha.
Kimchi is rich in dietary fibre, vitamin C, beta carotene, minerals (sodium, potassium, calcium, iron and phosphorous) and beneficial phytochemicals (thiocyanate, beta-sitosterol, indole compounds), and probiotic lactic acid bacteria such as Lactobacillus plantarum and Lactobacillus brevis. Some of the benefits of kimchi include its anti-oxidative, anti-inflammatory, anti-tumour, anti-mutagenic and anti-microbial activities, as well as immune promotion. A 2011 study of overweight and obese people (N = 22) who ate 300 g/day of fermented kimchi for 4 weeks found that the kimchi had quite a few positive effects. These included a reduction in body weight, BMI, body fat and decreased waist-hip ratio, total cholesterol, blood glucose and insulin levels.
Kombucha contains both bacteria and yeast. These microbes convert the sugar in tea to acetic acid, lactic acid, gluconic acid and ethanol, the acids give kombucha that nice zingy flavour. These acids are beneficial as they prevented other unwanted (and possibly dangerous) microbes from growing. Within the body, the acids act as a natural ‘cleanser’, act to reduce inflammation, lower blood pressure and maintains blood sugar levels. Kombucha also contains vitamins B and C, which act as coenzymes to trigger chemical reactions in our body which otherwise may not occur—so you could say they are important! Kombucha also contains minerals (copper, iron, zinc) and tea polyphenols such as catechins, theaflavins and thearubigins. And, due to the tea polyphenols present, kombucha is a rich source of antioxidants.
Although kombucha is not as well studied in humans, cell culture and rat studies are out there. Studies have found kombucha to help in preventing the growth of cancer cells and inhibiting their survival. However, it is important to note that these studies involved growing cells in a lab. Recently, a study involving rats fed cholesterol-rich diets, high thiobarbituric acid reactive substance levels (byproduct formed from fat degradation—tells us about oxidative stress) and kombucha tea as a treatment, found that kombucha was effective in combatting liver and kidney toxicities. Another rat study found that kombucha has a hypoglycaemic or blood glucose-lowering effect in diabetic-induced rats. Consumption of kombucha is also thought to improve digestion through its probiotic action.
Now, don’t get put off when eating kimchi and drinking kombucha by thinking of all the bacteria and microbes found in them, just think what good it will do your gut—which already has its own millions of microbial colonies living inside it, known as your gut microbiome, but that’s a tale for another time!