Kimchi and Your Health: The Good and the Bad

Kimchi is a dietary staple of Korean diets, and for good reason. The fermented cabbage is a well-known probiotic and supposed superfood. Health Magazine once listed it as one of the five healthiest foods in the world, alongside Greek yoghurt and Spanish olive oil.

Its benefits are so touted, one might wonder if kimchi can actually live up to the hype.

Let’s take a look at the research to find out.

The good

Kimchi consists of salted and fermented vegetables, typically baechu cabbage, with added garlic, ginger and chili. This fermentation process is carried out by lactic acid bacteria (LABs) like Leuconostoc, Lactobacillus and Weissella. Many of these LABs are considered probiotics, which are known to benefit the human gut microbiome and have even been linked to weight loss.  

Published in 2020, one trial of 114 adults found that, after 12 weeks of either taking kimchi-derived probiotic supplements or placebos, the kimchi-consuming participants lost, on average, 0.2 kg of fat mass while the placebo group gained, on average, 0.6 kg of fat mass. The kimchi group also had significantly slimmer waist circumferences by the end of the study.

There’s evidence that kimchi’s beneficial bacteria also combat harmful bacteria present in the human gut. Published in 2016, one controlled clinical trial found that, compared to the 6 women who were fed 15 g of kimchi per day, the 6 women who consumed 150 g a day showed a notable decrease in potentially harmful bacteria like Listeria and Clostridium.

Another study published in 2021 made similar findings. After eating 100 g of kimchi every day for 10 weeks, 32 people experienced a dramatic reduction of the “bad” gut bacteria Helicobacter pylori. In several cases, the bacteria seemed to have been eliminated from the participants’ guts by the end of the trial.  

Elsewhere in the body, kimchi’s fat-fighting qualities are most apparent in the blood.

Published in 2013, another trial comparing the effects of high and low kimchi consumption found that a higher intake improved serum lipid profiles and fasting glucose levels. Both portion sizes lowered concentrations of total glucose, total cholesterol and low-density lipoprotein (or LDL, often dubbed the “bad” cholesterol).

Published in 2018, another trial of high kimchi consumption (210 g/day) found that the Korean side dish seemed to significantly improve body fat percentage and skeletal muscle mass. The participants’ levels of beneficial bacteria like Faecalibacterium and Bifidobacterium also increased by the end of the trial while levels of harmful bacteria like Clostridium and Escherichia coli fell.

Beyond its effect on obesity, kimchi may also have benefits for people living with irritable bowel syndrome. Published in 2022, one trial of 90 participants with the condition found that three varieties of kimchi all had significant improvements in abdominal pain or inconvenience, desperation, incomplete evacuation and bloating.

Even those without irritable bowel syndrome have reported gastrointestinal benefits after adding kimchi into their diets. Published in 2019, one trial found that, after eating 75 g of kimchi twice each day for 14 days, the 20 participants with a history of digestive problems felt a significant reduction in their abdominal pain, heartburn, acid reflux, bloating and belching. 

The bad

Not everyone who eats kimchi experiences such gastrointestinal improvements, though. Indeed, for a minority of people, the Korean cabbage dish can seemingly cause and worsen symptoms like bloating.

The same 2020 study that evidenced kimchi’s fat-fighting qualities, for instance, also noted that some participants experienced adverse gastrointestinal discomfort, although these symptoms were mild.

Bloating is a common reaction to all kinds of fermented foods due to the temporary increase in gas caused by the probiotic bacteria killing harmful gut bacteria.

Fermented foods like kimchi also naturally contain biogenic amines, like histamines, which are created by certain bacteria to break down the amino acids in fermented foods. Because amines stimulate the central nervous system, the compounds can increase or decrease blood flow, which can trigger headaches and migraines in some people with histamine intolerance. Other symptoms of histamine intolerance include itching, runny nose, fatigue, hives and digestive symptoms including diarrhea, nausea and vomiting.

If not fermented or stored properly, kimchi can also pose a food poisoning risk. In 2013 and 2014, two large outbreaks of E. coli in South Korean schools were respectively associated with contaminated kimchi.

Lastly, while kimchi’s health boons are undeniable, some positive findings from certain studies have occasionally been called into question by others.

For instance, though a 2021 study found that kimchi reduces and even eliminates levels of the harmful bacteria H. pylori in the gut, one study published in 2004 found that participants still had H. pylori four weeks into a high-kimchi diet. It’s worth noting, however, that the 2021 study was conducted over a long period of time, 10 weeks.

Another study, published in 2020, added some nuance to kimchi’s bowel benefits. In a trial involving rectal cancer patients, the researchers found no significant effect of kimchi-derived probiotics in comparison with a placebo.

Final thoughts

Thanks to its probiotic contents, kimchi is a healthy, gut-boosting side dish that can, if eaten regularly, even help consumers lose excess weight. Reductions in gastrointestinal symptoms like bloating and abdominal pain are also possible, though the food might also cause the same symptoms in individuals with susceptibilities like histamine intolerance.