I am not a huge kimchi eater. I eat it on occasion (and have had some tasty kimchi pancakes to boot), but it’s not a staple in my diet. Nevertheless, when I heard about the link between kimchi and stomach cancer, it made me nervous. There are so many health benefits to eating probiotic fermented foods, that I was confused when I heard about a potential serious harm that could come from the same source. If kimchi was deadly, what did that mean for other ferments?
In this 2-part series, I’m going to take a look at the link between stomach cancer and how it relates to both fermented foods such as kimchi, as well as cured meats. (You can read about part two here)
Big ol’ disclaimer (and a small aside):
I read these disclaimers all the time on websites that say “this is just my opinion and I am not a doctor.” I know it’s mostly just people protecting their butts, but it bothers me, because it implies that we as average citizens are unable to do our own research and educate ourselves without the help of a doctor. Because here’s the deal: I am a doctor. This isn’t my field, and I’m not even a medical doctor (I studied chemistry), but I know what it takes to do a literature review. The only thing standing in the way of the average person’s desire to do a decent review is access to scientific journals.
Anyway. My point is that as concerned citizens, we should be able to do our own research and take every opportunity to stay scientifically literate.
But now here comes the disclaimer. Because this isn’t my field of study, I am not up to date on the latest research. I don’t know the most influential papers or the researchers who are making waves. I have dedicated a decent amount of time to looking into this subject, but not nearly enough time to be exhaustive. I mean, comparatively, the time and thought I put into my dissertation was enormous. I haven’t read nearly the same amount of papers for this review or reflected on or engaged in discussion with anyone else about this topic. These are just my thoughts.
Plus, I have a major bias. I don’t want there to be a strong link between stomach cancer and fermented foods. So as I researched, I crossed my fingers and held my breath and hoped I would find evidence to defend the foods I love.
Stomach cancer (also known as gastric cancer) is a pretty rare form of cancer in the US. It affects only about 0.9% of men and women during their lifetime (compared to 12.3% of men or women who are diagnosed with breast cancer during their lifespan). It’s also on the decline in the US. Since the 1930s it’s gone from being the leading cause of cancer deaths to the 8th most common cause of cancer deaths in the US.
But other countries do not have such low rates of stomach cancer. Korea has the highest rates of stomach cancer, with incidences as high as 7.6% for some populations. Other countries with high rates of stomach cancer include Japan, China, Mongolia, and Guatemala, among others. Across the world, it is the fifth most common cancer, affecting primarily developing nations.
Doctors and scientists don’t have a clear understanding of why cancer cells develop in the stomach. That’s part of the mystery of cancer and each individual’s personal journey. But we do know some risk factors, which include family history, smoking, eating salty, smoked, or fermented foods, eating processed meats, and infection of H. Pylori bacteria, among others.
Fermented Vegetables vs. Salt Intake
This sounds like bad news to kimchi-loving, vegetable-fermenting enthusiasts. But there’s hope, I promise. You see, there’s a reason behind why kimchi may be correlated with cancer rates. It may not be the fermented food itself that is affecting cancer rates, but rather the high levels of salt intake instead. In fact, kimchi may actually have anti-cancer properties, but the high levels of salt inherent to it negate the positive effect by damaging the stomach lining.
For the average Korean, kimchi accounts for 20% of salt intake. And average salt consumption is not on the low end, either. Average salt intake in Korea is almost three times higher than the recommended intake of less than 5 g per day. From what I’ve seen, there isn’t significant evidence to suggest that anything inherent to fermented foods is the cause of stomach cancer rates. Some sources suggest that kimchi might be a source of carcinogenic nitrosamines (more on that in part two of this series), but at least one study found that mere trace amounts of nitrosamines were formed during kimchi fermentation. Instead, salt (which could be found in almost any food source) is the likely culprit. High amounts of salt damage the stomach lining and can slowly lead one down the path to stomach problems.
Uruguay, for example, is a country with high rates of stomach cancer as well as salt intake. I couldn’t find any information about whether they consume copious amounts of fermented foods as well, but correlations have been linked between their intake of salt and rates of stomach cancer. In fact, the concern over salt consumption is so serious that salt shakers have actually been banned from restaurant tables in Uruguay.
When I first heard about the link between kimchi and stomach cancer, I was mostly just confused. It didn’t seem plausible to me that a food so greatly revered, and so full of probiotic and nutritional goodness, could be a cause of death and sadness. I delved into this research, admittedly, with a bias on the side of kimchi. But I also genuinely wanted to understand what it was about kimchi that seemed to be associated with stomach cancer.
After doing this research, my takeaway is that there is nothing inherent to kimchi to fear. For that matter, I am not concerned about other vegetable ferments, either. Personally, I don’t have an excessive salt intake, and vegetable ferments aren’t contributing significantly to that salt intake either. I use my vegetable ferments as condiments, anyway. They add flavor and seasoning to my meals, but certainly don’t add a significant amount of salt.
There are, I suppose, good and bad sides to everything. If we believe in something strongly, it is hard to see the bad in it, and vice versa. But moderation is good in life. The ideal level of moderation is variable, particularly depending on whether it is in regards to a vice or a passion. But I feel assured that kimchi is mostly good, mostly healthy, mostly blameless. Anything that generates such fervent passion from a nation is bound to be worth trying. (And if you feel like trying it, here is our tasty version of the recipe.)
Stay tuned for part two of this series, which will be up within the week. It’s up now. I’m going to look at nitrites and cured meats and reflect on their health implications.
Thanks for sticking with me! I wish you all well,