Kimchi is a beloved Korean dish that's becoming known all over the world. Made of fermented vegetables and flavored with spices, it sure seems healthy. But should discerning diners read between the lines? First, let's learn about what the dish actually is because even some people who've enjoyed the delicacy may not know what's inside.
What Is Kimchi?
Kimchi has a very long tradition in Korea. "The first known records of the dish date from 2,500-3,000 years ago, when it was simply a preparation of salted vegetables, made during harvest season to prevent food waste and keep the family fed in winter," explains Dr. Julia Skinner, founder and director of Root, an Atlanta-based food history and fermentation company. "As time went on and more foods were introduced, the dish's ingredient list expanded, to include different spices and a wider array of vegetables and aromatics."
The primary ingredient in kimchi is cabbage, but it can be made with other vegetables like daikon radishes, red peppers and even the occasional fruit, like apples, says Skinner. She notes that flavoring options have expanded, from plain salt to fish sauce, and from dried pepper flake to gochujang (red chili paste). Although these ingredients give kimchi its initial flavor, the science behind the dish is what makes it stand out.
"Kimchi is a lacto-fermented food, which means that it is softened and soured by lactobacilli (a genus of anaerobic bacteria that eat the starches in the food when it is submerged in brine)," Skinner explains in an email. "This gives it its sour tang as well as some of its nutritional benefits."
Fermentation was originally developed to preserve perishable products, like fruits and veggies. Modern refrigeration has largely negated the need for that purpose, but other benefits of fermentation (it allows for the growth of gut-beneficial microorganisms) keep the practice alive.
Although fermentation sounds complicated, it's actually easily done from even a home kitchen. The first step in the process is brining, also known as salting. This draws the water out from the ingredients, and takes 12 to 15 hours. It also helps the flavor of the seasonings penetrate. The concoction is then rinsed, drained and stored at around 50 degrees Fahrenheit (10 degrees Celsius). A number of healthy bacteria are known to spring forth from this method, including L. mesenteroides, S. faecalis, Lb. brevis, Lb. plantarum and P. cerevisiae.
Fermentation isn't a one-size-fits-all situation, as kimchi's process is spontaneous, whereas a culture is added to cheese and yogurt. "The microbes that do the fermenting live on the surface of the vegetables used to make the kimchi. This also means that each fermentation and each microbial community will be somewhat different from batch to batch," says Bob Hutkins, food science professor at the University of Nebraska and author of the second edition of "Microbiology and Technology of Fermented Foods."
Health Benefits of Kimchi
Calorie-conscious people are likely to fall head over heels for kimchi, as the dish is very low in calories and fat. It also boasts an impressive nutrient profile, rich in fiber, vitamins and minerals. Current evidence indicates that kimchi is effective at warding off cancer, obesity and constipation, and reducing cholesterol. It is also full of health-improving antioxidants and anti-aging properties.
A lot of this is due to the aforementioned microbes. "When you eat kimchi, you are also consuming billions of these microbes, and these microbes are thought to contribute to additional health benefits once they reach the gastrointestinal tract," Hutkins says. "For example, kimchi microbes have been reported to have anti-inflammatory and antimicrobial effects."
However, consumers shouldn't equate kimchi to probiotics, he cautions. "The latter are defined as microbes having a known health benefit, which, by implication, means the specific microbe has been characterized and used in a clinical study," Hutkins says. "Thus, while many of the kimchi bacteria are very closely related to known probiotic strains, kimchi cannot be considered the same as probiotic."
Health Risks of Kimchi
Kimchi is not the best option for people with a few food-related issues. First, it contains quite a bit of salt, so people at risk of high blood pressure, stroke or heart disease should probably steer clear. (A daily serving of kimchi has 1,232 mg of sodium. The World Health Organization recommends people consume no more than 2,000 mg of sodium per day).
Many kimchi recipes also contain a significant amount of garlic, which can cause unwanted reactions in people with irritable bowel syndrome (IBS). "This is because garlic contains FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols)," says Sophie Bibbs, IBS and low FODMAP nutrition coach, in an email. "Complicated name, but these are basically all sugars that aren't properly absorbed by the gut, triggering symptoms such as bloating, constipation, diarrhea and gas in people with IBS. They are found in a wide variety of foods, but are in a very high concentration in garlic, so kimchi can be very aggravating."
The most serious kimchi-related concern, however, is most likely to strike people who eat a large amount of the dish, not uncommon in Korea, where kimchi is often served atop steamed white rice daily. In fact, 20 percent of Korean sodium intake is attributed to kimchi, and studies have linked high consumption of kimchi with an increased risk of gastric cancer, the most commonly diagnosed form in the country. The concern is so real that experts are urging caution and moderation with this traditional dish. "Public health officials in Korea have been advocating for reducing salty food consumption. Given how important kimchi is to the culture, one strategy is simply to reduce the amount of salt in kimchi," Hutkins says.
Fortunately for the occasional kimchi eater, this scary possibility is highly unlikely, Hutkins explains. "In Korea, where kimchi is a staple and is eaten two to three per day, average daily consumption in Korea is around 100 grams, way more than in the U.S. So the risk for the normal consumer would be negligible, and far out-weighed by the benefits."
If you opt for store-bought kimchi, there are a couple of caveats to note, Hutkins says. First, some recipes include bone broth, which could be a problem if you're vegetarian or vegan. Also, you might not get what you're looking for with the store-bought variety. "Some brands are heat-treated for shelf-life reasons, so the microbes are inactivated," he explains, noting that there are active options to choose from. "One way to tell – if the product is on the shelf at room temperature it's been heated."
That last bit of info may prompt you to make it yourself. If so, why not try one of these kimchi recipes. Chances are, you'll like it!