Is Kimchi Good For You?

Is Kimchi Good For You?
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Epidemiological evidence that kimchi consumption may significantly increase cancer risk.

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

We know that vegetables reduce cancer risk, but what about fermented vegetables? Kimchi, a Korean dish usually made out of fermented cabbage. Harmful, harmless, helpful?

Harmful, potentially doubling one’s risk of breast cancer. And may increase the odds of getting prostate cancer ten-fold—just a spoonful a day. This is one of the studies that changed my eating habits this year.

You know, it’s funny, every time I come home from the medical library, my family’s like, “What can’t we eat now?” Or they’re like, “Hmm, why is there parsley in everything all of a sudden?”

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

We know that vegetables reduce cancer risk, but what about fermented vegetables? Kimchi, a Korean dish usually made out of fermented cabbage. Harmful, harmless, helpful?

Harmful, potentially doubling one’s risk of breast cancer. And may increase the odds of getting prostate cancer ten-fold—just a spoonful a day. This is one of the studies that changed my eating habits this year.

You know, it’s funny, every time I come home from the medical library, my family’s like, “What can’t we eat now?” Or they’re like, “Hmm, why is there parsley in everything all of a sudden?”

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Doctor's Note

For more videos on fermented foods, see:
Bacterial Vaginosis and Diet
Dead Meat Bacteria Endotoxemia
Carcinogenic Putrescine

For more context, also see my associated blog posts: Soy milk: shake it up! and Breast Cancer and Diet.

If you haven’t yet, you can subscribe to my videos for free by clicking here.

140 responses to “Is Kimchi Good For You?

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  1. Is there more information about this? Is this traditionally made kimchee rather than kimchee made in a manner similar to that of making sauerkraut? For that matter what about sauerkraut and other pickles?

    1. This was for traditional kimchi. I can’t find anything in the literature about sauerkraut either way, but I’ll definitely keep an eye out. It is high in sodium, so if you do eat it I would suggest moderating your intake.

      1. Would really like to learn more about sauerkraut, as it’s a very tasty way to enjoy cabbage. The delicious Spreewald brand (“mild” version) shows 480 mg sodium for a 125 gram serving. Is this really bad?

        I imagine there are lower salt options out there for this food…

      2. Dr. Weil’s website Q & A Library area has a positive review of this food yet warns about the salt levels. Guess I’ll need to look into making my own. :)

        1. So could it be the high sodium levels causing the problem, I wonder? I’d really like to know more and wonder if this translates to sauerkraut as well. I agree it’s a great way to enjoy cabbage and probiotics. I wonder how thorough the study was and if they tried to figure out what aspect of kimchi was harmful.

      3. Most kimchi has a fish sauce added to it…..This may be a contiributing factor to this research. As a vegetarian who thinks garlic is smelly and aweful, I make my own and hope that the jury is still out over vegetarian kimchi

      4. Hi Dr. Gregor, some of the studies I read refer specially to the high salt and N-nitroso compounds which are likely carcinogens. But I don’t think they were very specific. I assume this is done on traditional kimchi which is high on salt and made with fish sauce.

        What about low salt vegan kimchi? Is the risk for gastric cancer coming from all fermented food or only for high salt? And where did N-nitroso come from?

        Wanted to see if you have any new info on this topic?

        Thank you so much for all you do.

    2. Golly, no wonder there are no old folks in Korea…..oh, wait, there are, and few have colon or breast cancer. Must be another Korean dish he’s talking about?

  2. Hi Dr. Greger, Can you please site where you found this information precisely? Are they talking about kimchi/fermented foods made with white vinegar? Or are they made with salt and other spices? I looked up PubMed and I am having trouble finding and understanding it as I am not learned in medical/scientific facts. thanks!

    1. I’m so glad you asked! If you look on this page, right under the video you’ll see a section called Sources Cited. If you click, it will open up and list the hyperlinked citations to all the sources I use for any of the videos on the site.That is something I feel very strongly about. Nutrition information (and everything else in medicine!) should be based on the best available science. Thank you for giving me a chance to point out this feature of NutritionFacts.org for those that might have missed it.

  3. Looking at the abstract for the first study on breast cancer, they only controlled for non-dietary risk factors and vegetable intake. What if those who eat more kimchi also eat more preserved meats? It seems they wouldn’t have caught preserved meats as an independent risk factor in that study. I think the second study found a correlation between prostate cancer risk and all fermented foods. I don’t like to see fermented soy products included here, too! I’m going to hope salt is a culprit, and I’ll keeping eating my tempeh….

  4. Doesn’t traditional kimchi also contain fermented fish? Could this have affected the results? I am confused: I thought fermented vegetables were really good for the immune system and for fighting cancer. I have cancer, so I really need to know whether to eat them or not.

    1. Mary Jurmain,

      there are a variety of vegetables that help prevent cancer and in some cases reverse it. Check out these few videos on what those foods are if you have not already.
      http://nutritionfacts.org/videos/antioxidant-content-of-3139-foods/
      http://nutritionfacts.org/videos/best-fruits-for-cancer-prevention/
      http://nutritionfacts.org/videos/cancer-reversal-through-diet/
      http://nutritionfacts.org/videos/1-anticancer-vegetable/
      http://nutritionfacts.org/videos/veggies-vs-cancer/
      http://nutritionfacts.org/videos/cancer-fighting-berries-2/
      http://nutritionfacts.org/videos/plant-based-prevention/

      Fermenting anything usually involves a preservative which in turn is almost always harmful. The studies do in fact point to pickling foods increasing cancer risk.

      Good luck

  5. Hi “Toxins” (hmm!? Interesting nickname!)

    Thanks for the references, which I will definitely watch again, but I already own and have watched all of Dr. Gregor’s videos, so chances are I have seen all of those clips. I know a fair amount about what I need to eat; I just want to have a very good reason if I’m going to eliminate something else from an already rather restrictive diet (and also before I throw away 30 quarts of fermented green tomatoes). I seem to recall reading something about a study that showed sauerkraut prevented H1N1 from spreading in chickens, or something similarly bizarre. I’ve read Sandor Katz’s book “Wild Fermentation”, in which he talks about how his diet, heavy on fermented foods, has kept him healthy for years in spite of AIDS. And fermented vegetables have a long tradition in many cultures. It’s not that I can’t be convinced that they’re unhealthy, but if I’m going to accept data that goes against the grain of thousands of years of human history and a fair amount of anecdotal data, I’d like more than one study to convince me; I’d like multiple studies and an explanation of the mechanism by which these foods do harm. I hope Dr. Gregor will weigh in on this debate.

    1. Same here Mary Jurmain! I like your thinking. I don’t like a red light on a food with little to no explanation, especially when it may concern (or may not concern) all fermented foods. I’m going to read the study but honestly I much prefer Dr. Greger explaining these studies as he’s able to do so really well for those of us untrained in all the scientific terms.

  6. First of all, a big thanks to you ,Dr. Greger, for providing us with this fascinating website. I love it and check it frequently.
    I was very sad to hear your report of the research regarding Kimchi. Kimchi is made with cabbage, garlic and hot peppers. It sounds like it couldn’t be healthier! What aspect of it might contribute to cancer risk?
    Is occasional eating of canned saurkraut (a few Tbs once or twice weekly), made with cabbage , salt and maybe vinegar probably unwise?

    Also: I typically prepare a salad once a week, such as cucumber salad (made with onions, dill, cucumbers, salt, lemon juice,two packets of stevia, and a little olive oil). Then I eat a little bit each day with fresh lettuce, peppers etc. Do you think this unhealthy because the cucumber salad is not made fresh daily? (It is the only stevia I have all week.)

    Thanks!

  7. I make fermented veggies with Body Ecology Culture Starter. I add no salt or vinegar to my fermented veggies. Do you know any scientific information on eating this type of fermented veggies? I do make sauerkraut with salt, but keep it raw with no vinegar.

    Thanks,
    Deb

  8. I understand for most koreans it’s not a meal unless there’s kimchee on the table.Is there a high rate of prostate cancer in Korea?

  9. well Dr i am ashamed that u call yourself a doctor and dont do all your research like most doctors.. Traditionally prepared kimchi is made from raw cabbage and when fermented properly contains PROBIOTICS.. u can do some google searching and find out how beneficial probiotics are for us.. as a matter of fact, human life as we know it would not exist if it was not for PROBIOTICS…The probiotics found in kimchi and other naturally fermented vegetables ( sauerkraut, pickles, etc.) create by-products like organic acids (helps to preserve veggies and has alkalizing effects on the body) and more enzyme content (easier to digest and better absorption of nutrients).

    1. Most doctors don’t do any research nor do most doctors care for the subject of diet! Nobody here is doubting the benefits of intestinal flora. Dr. Greger has two cited sources showing that pickling food has a negative impact on our health, could you please cite some sources that show otherwise?

      1. Umm, yogurt and dairy doesn’t have HAVE probiotics, they have to be pasteurized. The only reason yogurt and yogurt products have probiotics is because they ADD them. For that matter, dairy is one of the most unhealthy substances you can put in your body (not to mention one of the cruelest and unsustainable industries), so why would anyone want to take a supplement within something that harms their body? There are many dairy free probiotic supplements available that are really good. I take a dairy free probiotic from Garden of Life, there’s also dairy free probiotics in their Raw Fit shake (and other products) which I drink sometimes.
        But the best thing we can do for our good flora is to eat lots of plant foods. Nuts, seeds, beans, legumes and starchy vegetables are particularly good for gut bacteria. The BEST thing for our good flora is to get lots of fiber which it needs in order to survive.

  10. PLUS! Fermented foods, have been used thru the ages to prevent and sometimes even cure illness. For example, sauerkraut was used by the Germans and Europeans to prevent scurvy… Due to its high concentrations of Vitamin C it helps warn off illnesses like scurvy.

    1. Vitamin c is abundant in the plant world and eating a fermented food is not necessary to acquire this easily available nutrient.

    2. xxjane42xx – please cite your sources, rather than just spout conjecture.  If you’ll notice, the information presented in the video is attributed to specific scientific studies.  What is your information based on?

  11. My wife is Korean and her family, ancestors, and everyone I know have been eating Kimchi for ages……not one of them has ever had breast cancer. I think you should search and find out more information. I couldn’t find any sources to support the video which he stated.

  12. *ahem* “The mechanism of deleterious effects of preserved foods remains unclear”. i need to see why and how kimchi can cause an increased chance of cancer.. then ill believe the video. and doesnt one of youre sources claim that cancer is reported to be lower in asian countries than it is in western countries?

    1. There are a number of studies that have found potential mechanisms (e.g. mutagenic substances produced via fermentation, there just haven’t been the studies, animal studies/clinical trials etc, to determine this for sure).

      Nitrite and secondary amines are formed with fermentation:

      1. Nan HM, Park JW, Song YJ, Yun HY, Park JS, et al.: Kimchi and soybean pastes are risk factors of gastric cancer. World J Gastroenterol 11, 3175–3181, 2005

      2. Seel DJ, Kawabata T, Nakamura M, Ishibashi T, Hamano M, et al.: N-nitroso compounds in two nitrosated food products in southwest Korea. Food Chem Toxicol 32, 1117–1123, 1994

      3. Mitacek EJ, Brunnemann KD, Suttajit M, Martin N, Limsila T, et al.:
      Exposure to N-nitroso compounds in a population of high liver cancer
      regions in Thailand: volatile nitrosamine (VNA) levels in Thai food. Food Chem Toxicol 37, 297–305, 1999.

      4. Yuan Z and Ding Y: Mutagenesis and anti-mutagenicity in several traditional Zhejiang preserved foods. Carcinogen TeratogenMutagen 15, 91–93, 2003.

      … there are also many studies about the risks of salt and the nutritional deterioration of acid-preserved foods. Many of these studies also control for confounding variables which explain the lower overall cancer rates in Asian countries.

      Dr Greger’s recommendations are based on risk-aversion

  13. I think it might be premature to suggest eliminating all pickled vegetables from your diet based on these two studies, and a cursory review of the literature which indeed provides further evidence for an increased risk of esophageal, gastric and other cancers. Most studies having been done in Asia on relatively small numbers of subjects where the average consumption of pickled vegetables is high may have produced results that would not be seen elsewhere. Indeed, the prostate study demonstrates higher likelihood of getting prostate cancer in those eating the highest quartile of pickled vegetables, which is well above what I believe would be the norm for most Americans, with no suggestion of a dose response curve. Therefore, it might be more appropriate to suggest avoiding high intake levels of pickled vegetables and admit that we don’t have enough data to determine the effect of lower levels of intake. However, I agree that until health benefits of pickled vegetables are proven, they should not contribute a large percentage of vegetable consumption.

  14. I was wondering if you had any information on capers? The kind you find pickled in jars. I’ve heard the berry is high in antioxidants but then I only see them sold pickled, and it seems that this might not be a good thing. Thanks for all of your hard work!!

  15. I couldn’t read the Yu study, so I didn’t know if they differentiated between vegan and non-vegan (e.g., shrimp paste, anchovy, fish paste); traditional kimchi in Korea isn’t vegan.

    As a vegan who has finally found a source of vegan kimchi, this information–if true–makes me sad.

    1. Could Dr Greger or Joseph Gonzales answer Bee’s question please – I also would like to know the answer to this and, if they are ok to eat, in what amounts and frequency would be considered healthy?

      1. No studies I am aware of look at the kind of products you describe and it’s role on dysbiosis. This review may offer some insight. If you eat fermented foods like sauerkraut I suggest keeping intake low and yes a salt-free version perhaps is better. I have never seen those but another site user posted about it in a recent video. Let me know if you want me to find the comment maybe you guys can connect?

        PS: I have replied to all other question you had on kimchi. I hope the are helpful.

        Thanks, BenJ
        Joseph

  16. I checked out this site and it says that Korea had low prostate cancer rates but
    as they become more westernized their rates are increasing. http://www.ncbi.nlm.nih.gov/pubmed/16741923

    This comparison of prostate cancer death rate by country http://www.worldlifeexpectancy.com/cause-of-death/prostate-cancer/by-country/

    lists the U.S.
    is 103 whereas South Korea, the birthplace of kimchi, is low at 165.
    I look forward to learning more on this because I make my own kimchi and I love it.

  17. Seems like some studies are schlock-Fermented and organic foods are still healthy to consume. I sometimes really question the surdies you accept as fact…

  18. Jesus Christ. Is is so bad? I think this biased video forgot to mention that Kimchi is rich in vitamin A, thiamine (B1), riboflavin (B2), calcium, and iron,[15][16] and contains a number of lactic acid bacteria, among those the typical species Lactobacillus kimchii.[17][18][19] Health magazine named kimchi in its list of top five “World’s Healthiest Foods” for being rich in vitamins, aiding digestion, and even possibly reducing cancer growth.[20]
    (wikipedia)
    If anything, Just look at the difference between the obesity levels between USA and Korea ._.

  19. I don’t know where you found the information or the idea that kimchi increases the probability of breast cancer. Neither do I know how familiar you are with the food itself. But i do want to point out to you that first of all, Koreans have been eating kimchi for centuries; however, studies have shown that only recently (since the early 1990s) have breast cancer incidents been steadily increasing. If Koreans have been eating kimchi for centuries, why should this problem start arising now? Maybe instead of targeting kimchi specifically, look at the broader picture and trends. For example, did you know that the increase in cancer incidents coincides with the timing that Western diets were introduced to Korea? Moreover, not only breast cancer but cancer rates in general has increased in Korea after the introduction of Western Diet. And something else i think you should know. According to breast cancer statistics in Korea, despite the increase of breast cancer incidents, Korea still has lower breast cancer incidents (26.2 per 10000) compared to the world average of 37.4 per 100000.

  20. I think Dr Greger does us a great service by informing us of the latest dietary research. However quickly leaping to conclusions and giving broad recommendations based on insufficient research, or a very narrow interpretation of that research is a big problem in what he does, it discredits everything he says, and this video is a perfect case in point.

    Based on two small Korean studies, he’s telling people to never eat Kimchi because he thinks it will cause cancer. I looked at the studies and they do not seem tightly controlled or conclusive at all, and have no mechanism proposed (as others have pointed out).

    I am increasingly taking all of Dr Greger’s recommendations with a grain of salt (and in this case, a lot of salt, along with some fermented vinegar..)

  21. I tend to believe there are additional factors involved besides people
    consuming more pickled vegetables. Perhaps the people consuming them made them in a certain way that created scum or mold? or with certain ingredients like fish, contaminated seaweed, dairy? I do not know these specifics.
    I DO know that I am a vegetarian/vegan for 25 years who has fallen in love with healthy fermented vegetables including sauerkraut and Kimchi (which i make myself). Why do I mention “healthy”? because what most people do, and is “tradition”, is to use a german or polish type ceramic pickling crock. These may be traditional but they usually allow air in them which creates scum or mold and people think it is healthy and beneficial to simply “skim off” the scum or mold and the rest is healthy to eat (yuk). What they are making is “rotten” vegetables. Healthy “Fermented” vegetables should have no foul odor that smells rotten.
    I use a fermenting vessel that is fool proof if you follow directions
    carefully. The http://www.pickl-it.com is made of glass and it keeps the
    air out. namaste;, rachel

  22. Don’t believe everything you hear on the internet, there are so many disinformation out there.

    Kimchi and other fermented vegetables contains essential probiotics which everybody nowadays (in chemical loaded environment) are lacking of.

    However on the opposite side, fermented vegetables contains Acetaldehyde compound which can be detrimental to our health if consumed in large quantity. Therefore Fermented food is a double edge-sword, it is good to our health if consumed in moderation, but bad if we overconsumed.

    The notion of Kimchi is bad overall and must be avoided is ludicrous, our ancestors had been fermenting vegetables for thousands of years before the invention of refrigerator. How else can they eat their vege during winter months?

    If Kimchi is bad overall, one must question, “how to these Koreans, survived 2000 years of Kimchi without dropping dead all over from Breast Cancer!????”

  23. However, I think it’s a great source of information, but it may be that some fermented veggies (especially Kimchi) would have a very different risk associations with the cancers and other health issues, depending on the context of the study as there are a lot of cancer types. I mean that according to some research they can slow or even inhibit some types of cancer, on the contrary, other research may prove that it’s completely different with other cancers.

  24. This seems to directly oppose your conclusions and is very indepth study. Better than some of the studies you cited, in fact… It’s google-able.

    Dietary factors and gastric cancer in Korea: A case-control study

    Hyun Ja Kim1, Woong Ki Chang2, Mi Kyung Kim1, Sang Sun Lee3, Bo Youl Choi1,†,*

    Article first published online: 2 NOV 2001

    DOI: 10.1002/ijc.10111

    1. Go to the grocer and try to find a jar of pickles, kimche or sauerkraut that is also fermented and doesn’t have preservatives. It’s nearly impossible. These studies did NOT look at traditional kimche because it was not fermented. If you want to look at benefits of true fermented veggies, it would be best to disregard this study because it only looks at preserved foods. Who wants to eat that?!

      1. I’m reposting a comment from another thread since I agree with you and think the topic is treated too superficially on this site – I’d really like to see it explored a bit more:
        I’m keen on fermented plant-based foods like miso, natto, amazake, kombucha, homebrew beer and lacto-fermented veggies – I think it may be a bit oversimplistic to lump all these together, see http://kimchicancer.blogspot.c… which notes a protective effect for some fermentates and a cancer increased risk with others, e.g. radishes.

    2. Fact is, once a fermented food is jarred or canned under heat, the probiotics are killed and it it is worthless as a source of them, preservatives or not. Also, I think it needs to be reiterated that “pickling” can refer to simply adding vinegar to ingredients, again, rendering a food worthless as a source of probiotics! Cultured, lacto-fermented vegetables indeed have a long and illustrious history and regardless of what a few recent questionable studies show, I’ve been consuming them for my 60+ years and will continue to, especially in light of the newish volumes of info (and LOTS of personal experience) regarding the importance of the microbes in our gut as our “second brain”. Like anything else, be moderate, a good overall diet is the most important thing!

  25. May this be related with the high content of histamine we can find fermented foods? – As I know high levels of histamine can raise estrogens levels and give symptoms all around the body. I found this very interesting:

    http://ajcn.nutrition.org/content/85/5/1185.full

    High histamine content may be one of the reason processed meat, fish and dairy are particularly harmful and also linked to increased allergies.. ??
    I’d love to know more about that, and to know which other foods may contain a lot of it. I’ve read about brewer’s yeast, soy products and balsamic vinegar for instance.

    1. Not enough said for me. The article you linked to is simply a reminder of how easy it is to attack another person on the web. It is one thing to disagree and present scientific evidence but it is another thing to call people names and just slam other well meaning organizations that do base their work on research with significant improvement in people’s lives. Even the Harriet Hall in her article linked to at Science-Based Medicine has “cherry picked”, didn’t stick to facts, used gross generalizations, omissions when citing a study and veered off from scientific objectivity. Would Harriet Hall MD actually speak to Michael Greger MD, C. Esselstyn MD, Neal Barnard MD, Dean Ornish MD, John McDougall MD, etc. that way or tone – I can bet not.

    2. Your source is an anti-vegan corporate-funded front group http://www.humanewatch.org/why “Animal lovers, animal watchers, animal eaters, animal owners, animal professionals, and the animal-obsessed should all feel welcome in this corner of the blogosphere.”

      http://www.sourcewatch.org/index.php/HumaneWatch.org

      HumaneWatch.org is a website created by millionaire Washington, D.C.-area lobbyist Rick Berman and his corporate-funded front group, the Center for Consumer Freedom (CCF) to attack and attempt to de-fund the Humane Society of the United States (HSUS). Berman typically targets activist charities that criticize big business, or lobby for policies that conflict with the views of big business. The HSUS lobbies for policies that mandate humane treatment of animals in commercial animal industries, like puppy mills, dairy and confinement meat industries. In addition to attacking HSUS, CCF is known for attacking other public interest and pro-consumer groups like Mothers Against Drunk Driving, the U.S. Centers for Disease Control. [1]

      Other CCF-funded projects include FishScam.com, funded by the food-and-beverage industry to counter scientific evidence about the dangers of mercury levels in fish; CSPIscam.org, which is dedicated solely to criticizing the Center for Science in the Public Interest; and SunlightScam which represents indoor tanning manufacturers, distributors, and facility owners, and which claims tanning is not dangerous in any way.[2]

      1. If they’re attacking the CDC I’m all for them honestly, as that is one of the most backwards and corrupt organizations in America – one that is most definitely NOT for the good of our health. I see you’re pro vegan, which likely contaminates you as a source in my books, as many (not all) are zealots without sound reason. So, apparently we’re at an impasse.

  26. I wonder if the fish content of kimchi has anything to do with the formation of carcinogens. I just made a huge batch of vegan kimchi and wonder if I should throw it out now. I wish I had found this video first!

    1. Don’t throw it out! People have been eating this for thousands of years! There may be more to these studies than meets the eye or else it would have been apparent long ago! Seriously, think about it! Even too much water can kill you! Relax…it’s a condiment, not a daily meal!

  27. This would suggest that non-preserved fermented foods can provide beneficial bacteria, without increasing cancer risk. Kombucha is too risky, how about vegan yogurt or kefir? There is evidence for the benefit of fermented food, but now against preservation. Perhaps due to salt or acidity?

    1. It’s probably funded by the dairy people. Because they claim yogurt have the same nutritional content (which they don’t because it’s coated in sugar and kimchi has so much more good) and vegans are eating kimchi for the same reasons as people eat yogurt. It’s just scare tactics

  28. I am curious if there is any more information on pickled and fermented products on this website. I can see that Kimchi and Kombucha aren’t too good for you. I can also see that pickling food may not be great. Is there such thing as a healthy pickled item? Also, what fermented products are good for you? I saw that tempeh was quite healthy (and it’s fermented). Thank you kindly.

    1. Apple cider vinegar is still okay, but don’t mess with the pills. Are kimchi and sauerkraut harmful? It seems a little bit of sauerkraut is okay, but there is not much research. Lastly, I like this powerpoint from a dietitian from the Fred Hutchinson Cancer Center in Seattle presenting at AICR on fermented and picked foods on cancer risk. Yes, tempeh is fermented and very healthful. The problem with pickles and sauerkraut is their salt content. Perhaps limiting these foods would be a good idea? If I come across more research I’ll post here.

  29. Perhaps related, these studies on the relationship between kimchi and gastric cancer risk point out that not all varieties of kimchi have a positive correlation with cancer. (I’m hoping that my own home-fermented vegetables are beneficial):

    https://cancerkimchi.wordpress.com/
    CANCER AND KIMCHI BY DR. JOSEPH C KIM

    “… Different types of kimchi and stomach cancer
    “There are many different types of kimchi. Let’s look at these 3 types and see how they are linked to gastric cancer:

    Baiechu kimchi (prepared with salted Chinese cabbage and red pepper, etc.),
    Kkakduki (a kind of kimchi prepared with salted radish and red pepper, etc.),
    Dongchimi (a kind of kimchi prepared with radish and a large quantity of salt water)

    To assess gastric cancer (GC) risk in relation to dietary intake in Korea, a case-control study was performed. Trained dietitians interviewed 136 patients diagnosed with GC, and the same number of controls were selected by matching sex, age and hospital. A significant decrease in GC risk was observed with increased intake of Baiechu kimchi (prepared with salted Chinese cabbage and red pepper, etc.), Baiechu kimchi-stew, garlic, mushroom and soybean milk. On the contrary, a significant increase in the risk of GC was observed with increased intake of cooked rice with bean, charcoal grilled beef, pollack soup, Kkakduki (a kind of kimchi prepared with salted radish and red pepper, etc.), Dongchimi (a kind of kimchi prepared with radish and a large quantity of salt water) and cooked spinach. In food groups, increased intake of soybean products was associated with decreased risk of GC. Intake of citrus fruits rather than total fruits was shown to have a protective effect on the risk of GC, but was not significant. In this study, intake of total vegetables was shown to have a protective effect, whereas high nitrate-containing vegetables increased the risk of GC. In conclusion, our study suggests that the risk of GC decreased with high consumption of fresh vegetables and fruits, whereas high consumption of foods rich in nitrate and carcinogenic substances produced during the cooking process increased the risk of GC.”

    Also:
    “… Nitrate levels are high in kimchi.
    The full article can be found here:
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2766547/

  30. If you look at Table 1 in the study, where they analyze what foods the cancer population regularly ate vs what foods the control population ate, there is a VERY INTERESTING difference. While both groups ate about the same number of total calories a day and about the same BMI, the cancer group ate a mean of 499 (sd 320) grams of FRESH fruits and vegetables a day, while the control group at 865 (sd 477). That is a BIG difference that must be considered. Is the cancer the result of eating pickled vegetables, or the result of NOT eating fresh fruits and vegetables? NO WAY TO KNOW from this study.

    1. Hey Helen. Apple cider vinegar is still okay, but don’t mess with the pills. Are kimchi and sauerkraut harmful? Seem a little bit of sauerkraut is okay, so perhaps with things like capers a little is fine to consume. I like this powerpoint from a dietitian from the Fred Hutchinson Cancer Center in Seattle presenting at AICR on fermented and picked foods on cancer risk.

      He has videos on most all of those foods, just search for topics and they should all appear! I don’t think all fermented foods are off the list. Apple cider vinegar, tempeh, miso, and the ethnic breads like dosa (which is what just lentil and rice flour). I think the major worry is sodium content from these foods (kimchi), ethanol from beer, and lactic acid build-up from kombucha. Hope that helps.

      1. Thanks. I guess then that eating small amounts of sauerkraut or pickles occasionally is not going to be a problem unless the salt content is unusually high. I wonder whether rinsing pickles or sauerkraut removes much of the salt.

  31. I’m no expert on health, diet or food preparation. That said, I was under the impression that pickling and fermenting were two very different processes, a fact that hasn’t been brought up in any of the comments or in the video. My understanding is that pickling uses vinegar to preserve food, while fermenting which is used to make sauerkraut etc. is a natural process using lactic acid bacteria. Although I don’t know the details for kimchi specifically I do know that in Canada commercial brands of sauerkraut are often pasturized and/or contain vinegar. The pasturization will kill any beneficial probiotics. And it is possible vinegar will do the same. I only eat unpasturized sauerkraut.
    So in my mind it’s hard to continue this conversation without making a distinction between fermenting and pickling, pasturized and unpasturized. Also important to note is that “Traditional” doesn’t always mean traditional. Commercial so called “traditional’ products often use non traditional methods and ingredients. Like when I try to buy a traditional cider or perry from the UK and I find out they include glucose/fructose. Since when is that traditional? 1990? And not that you care but it makes them taste like crap.

  32. Is this research still current or has it been superseded by new research? I recently read an article extolling the benefits of eating kimchi and especially the preventative effects on diseases such as Alzheimers. Could someone help please?

    1. I kind of hit on all of this comment below. Often I have replied to similar questions further down in the thread. Kimchi is still bad, and pickles can be too. The problem is the massive sodium content. Miso still has sodium, but since it offers other health benefits it’s a bit different. Of course, all of this depends on how much sodium is consumed daily.

  33. The question is: What kind of kimchi? The one with fish sauce? The one with vinegar or additives/process like can goods? Or the home made (raw) only vegetables with little to no sea salt? My wife only puts a little sea salt and vegetables.

  34. The studies referenced below the video talk about pickled vegetables, not cultured like sauerkraut. The other study talks about relationship of cancer and cured/preserved foods like meat and smoked fish. As far as I am aware, pickled vegetables are made with substantial amounts of vinegar, whilst sauerkraut and I presume kimchi are cultured in their own juice, water and salt which produces friendly bacteria. That being said, kimchi is fairly spicy which may damage the sensitive lining of the stomach. I recall of increased risk of stomach and esophagial cancer among Indian population due to very spicy foods, perhaps that can be another contributing factor to increased cancer risk. I still can’t put sauerkraut on that list along with pickled foods. Any englightement?

  35. There are more studies that say that kimchi prevents the growth of cancer. This website is full of poop if they’re saying otherwise.

  36. I’ve been under the impression that fermented plant foods are good for us, promoting good bacteria and all. After watching your videos on kimchi and kombucha, I am confused. Can you clarify whether fermented plant foods are good or harmful?

  37. First I checked your book, How Not to Die (I have a copy) looking for kimchi and then, since your site is my go to site, I found the above video. I was surprised and looked at the references. Though an amateur, I noticed that the one specifically devoted to prostate did not mention kimchi but rather talked about pickled foods and “three items (salted mustard greens, salted fish and salted pork meat) showed significant mutagenic activity in cell micronucleus test (Yuan and Ding, 2003).” Now this article is dated as is the video. I am wondering whether you still hold the same views. I have found a more recent (Dec 2014) article http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4285955/ titled Cancer Preventive Potential of Kimchi Lactic Acid Bacteria (Weissella cibaria, Lactobacillus plantarum) from the Journal of Cancer Prevention. I was wondering whether you could help me out here as I have several bottles of high quality tasty organic kimchi patiently waiting for me in the refrigerator. Thanks, Marvin

  38. I always see news items saying that pickled foods are associated with cancer, but I have never seen an explanation of exactly what in pickled foods causes this. Is it the salt? Is it the vinegar? Or in the case of Kimchi, is it the excessively high heat/spice from peppers? Has anyone figured this out?

    1. I found this really helpful (this paper lists that there are many benefits to fermented foods but compounds in pickled foods (not sure about all pickled foods) that may enhance a compound with potential carcinogenic properties): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3904694/

      “In this discussion, we may unwittingly give the impression that fermentation is exclusively a beneficial application to food and beverage production. Such is not the case and not all forms of fermentation or fermented foods can be painted with the same brush. For example, certain microorganisms (for example, fungi) associated with pickled foods may enhance the production of N-nitroso compounds with potential carcinogenic properties [164]. Also, although agmatine and other polyamines found in fermented meats, fish, and certain beverages have been shown to have a variety of experimental benefits related to brain health [165,166], a safe level of intake remains unknown [165]. However, as outlined in our review, there is more than ample justification to follow the microbe-nutrition and gut-brain research pathways into convergence. The clinical world of mental health involves one where consumption of convenient, high-fat, or high-sugar foods is the norm; these foods, at odds with our evolutionary past, are not only undermining optimal nutritional status, they have untold effects on the microbiome and ultimately the brain. Hopefully, further research will continue to illuminate the ways in which the clay fermentation pots of our ancestors might be connected to the emerging discipline of nutritional psychiatry.”

      Someone else in the comments section pointed out that in one of the cited sources under the video, some decrease in cancer risk were observed with consumption of fermented and/or pickled foods.

      Personally I don’t think the studies referenced under the video are that sound.

  39. Dr. Greger, it has been five years since you presented on the effects of Kimchi. Do you have any new information about Kimchi or any other fermented plant based foods.

  40. Could this be evaluated again? I think it should be pointed out what kind of kimchi we are talking about. I make sauerkraut myself, which seems to be a similar process just without the fish sauce. However, store bought, including fish and with preservatives etc may have different effects? It’s the same way we can’t call almond milk just almond milk – it’s different if I buy Silk from the store or make my own just containing almonds and water, isn’t it?

    1. Hi, Lynn. I am Christine, a NF volunteer moderator. I agree that there is a difference between more processed store-bought foods and less processed, homemade ones. This does not appear to be a factor in the cited studies. I hope this helps!

  41. After reading the study on Prostate cancer noted decrease in risk for some consumption:
    0.10–4.00 grams per day for Fermented soy products has OR of 0.77 and for Pickled vegetables consuming between 1.56–4.11 grams per day has OR of 0.91.

    On the breast cancer study from the abstract: “These results suggest that not only the amount of total vegetable intake but also the amounts of different types of vegetable (i.e., pickled or nonpickled) and their proportions relative to total vegetables are significantly associated with the risk of breast cancer.”
    This suggests that participants were eating less healthy food such as fresh vegetables and consuming a preserved product that is likely associated with other confounders in an overall less healthy diet.

    Overall, these studies are not as reliable in the big scheme of trials.
    However, a good pondering start and alerted me that store bought kimchi maybe a bad choice. A vegan kimchi maybe a better choice and in small amounts as a condiment.

    Thank you for all your work.

    1. You can take a very high quality probiotic as well as fermented foods while you are taking your antibiotic. Typically the best probiotics must be refrigerated and you should look for one with 50-90 Million active units. If you add them to food make sure they are not heated or you will kill them off. Also making sure you are eating a diet high in fiber will provide what is known as the “pre-biotic” that the probiotic bacteria require to be healthy and do their job.

  42. I have been a big fan of fermented goods, but am getting away from them–thanks to you. One product I am using is Gochu Jang, or fermented Soybeans. Does anyone know if this too is bad?

  43. Looks like there’s a lot of health benefits to fermented foods: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3904694/

    lots of interesting stuff in the above link, this particularly stood out to me: “Researchers have examined the in vivo properties of an herbal blend typically used in traditional medicine to treat inflammatory disorders, comparing its effects in the unfermented and fermented form. Blood LPS levels were significantly lower when treated with the fermented blend, as was C-reactive protein, a primary marker of systemic inflammation. There was also a significant reduction in LPS-induced intestinal permeability and a significant rise in stool Lactobacillus species, neither of which was noted with the unfermented blend”
    “Similar research has been documented with fermented and unfermented herbs used for gastrointestinal disorders, that is, more pronounced anti-inflammatory activity and minimization of LPS-induced gene expression with the fermented blend [150]. In separate work involving a singular traditional food or medicinal agent, the anti-inflammatory botanical Sophora flavescens, researchers, again using LPS as the inducing agent, found a more pronounced anti-inflammatory and antioxidant activity with the fermented form”

    One of the cited sources under this video, which I only quickly browsed through, talked about interviewing patients and asking them their eating habits. To me it seems unreliable. For example, say someone eats a lot of fermented cabbage, well in my experience, that usually means they’re pairing it with sausage. And as others have mentioned, some foods are fermented with fish sauce. And what about those consuming fermented soy products? Soy is one of the biggest GMO crops, so chances are they’re consuming genetically modified, non-organic soy. It just didn’t seem thorough enough to me for any relevant validity from my perspective. Especially considering that some of the in vivo results of fermented plant foods have shown positive results in different ways.

    1. Here it explains why perhaps PICKLED fermented foods may be associated with cancer: “In this discussion, we may unwittingly give the impression that fermentation is exclusively a beneficial application to food and beverage production. Such is not the case and not all forms of fermentation or fermented foods can be painted with the same brush. For example, certain microorganisms (for example, fungi) associated with pickled foods may enhance the production of N-nitroso compounds with potential carcinogenic properties [164]. Also, although agmatine and other polyamines found in fermented meats, fish, and certain beverages have been shown to have a variety of experimental benefits related to brain health [165,166], a safe level of intake remains unknown [165]. However, as outlined in our review, there is more than ample justification to follow the microbe-nutrition and gut-brain research pathways into convergence. The clinical world of mental health involves one where consumption of convenient, high-fat, or high-sugar foods is the norm; these foods, at odds with our evolutionary past, are not only undermining optimal nutritional status, they have untold effects on the microbiome and ultimately the brain. Hopefully, further research will continue to illuminate the ways in which the clay fermentation pots of our ancestors might be connected to the emerging discipline of nutritional psychiatry.”

  44. Dr. Greger, there is clearly a lot of controversy and confusion on this issue. We would appreciate an update of your 2010 kimchi video.

  45. Hi there!

    I have been reading the good doctor’s book, How Not To Die, and I have found it to be a wealth of information, but this concern about kimchi has me questioning this study and the study in the book.
    Kimchi, despite the sodium content, has a lot of health benefits like other fermented foods.
    I think the one thing that the study both in the book and this video misses is that Korea has one of the highest levels of both stress and alcoholism in the world. Both of these factors are contributors for cancer in general, not just stomach cancer.
    Did either of these studies control for these factors or did they just correlate the kimchi consumption with breast or stomach cancer without taking these factors into consideration?

    Thanks!

    A

  46. Thank you for your question. The studies mentioned in the video relate to breast and prostate cancer. From what I can tell from the statistical analysis, the breast cancer study did control for alcohol and smoking intake but not for stress (this would be difficult to do when asking people to recall events from the previous year). The prostate cancer study does not mention controlling for smoking.

  47. I have always hated the smell of vinegar in many food due to the fact, when I was premed student at UCSC, my best friend, Morris who was
    finishing up his PhD, had a lab partner who was doing postdoctorate work and was using acetic acid. The lab reaped with stinky smell of vinegar.
    Also, I knew a man who 35 years ago probably one of the first manufacturer of RAW fermented cabbage. The smell from his processing
    kitchen was nauseaing also. Anyway, I developed a very negative association with smell of fermentation. although I had enjoyed my cancer hot dog every night with sauerkraut back at UCB. Anyway, the increase throat cancer is not a surprise, since BEER, a fermented product do that too.

  48. Hello Dr. Greger,

    There is a huge confounding factor that needs to be accounted for. Korean kimchi is not vegan; it contains salted shrimp and either anchovies or fish sauce. Could it be that the bacterial fermentation of these animal products is producing TMAO or other harmful substances? This notion that kimchi could be a risk factor for stomach cancer doesn’t sit well with me. Bacterial fermentation is one of the few vegan ways to get all of one’s B vitamins without resorting to animal sources. Also, kimchi and other bacterially fermented foods seem to boost the immune system’s function, or so I’ve heard. As a folk remedy, kimchi juice is suggested as a remedy for various ailments, and Korea did some study where the found that chickens that age kimchi (leave it to Korea to feed chickens this stuff!) were resistant to bird flu.

    Are there any studies comparing vegan kimchi to traditional shrimp and fish sauce enhanced kimchi? Until this is done, I don’t think it is fair to write off kimchi entirely.

    Kimchi isn’t made the way saurkraut is made. Anyone who simply spices saurkraut and calls it kimchi is doing it wrong. Onions and pears or apples are grated or food-processed along with spices and garlic to act as fermentation accelerants. Kimchi ferments to completion in a week, but saurkraut, which is made with nothing but salt (and maybe some water to top it off if the person making it is impatient) takes a month or more. The bacterial profiles of the two are significantly different. I wouldn’t be surprised if the addition of fish sauce and tiny salted shrimp changed the bacterial cross-section of kimchi to include more bacteriodes, but I don’t know for sure what is going on. This ought to be studied.

    1. Thanks for your comment Berkana.

      A 2014 meta-analysis has indeed shown that salt intake increased the odds of gastric cancer by 92% and kimchi increased the odds by 121%. This should be concerning and although there other reported benefits of fermented kimchi consumption, I am not sure if it’s benefits outweighs its risks.

      I could not find studies differentiating variety of kimchi.

      Hope this answer helps.

  49. HI Dr Greger
    thank you for this- I am confused tho- the study shows kimchi as doubling chance of breast cancer and yet you say Sauerkraut is good. Aren’t these two products fundamentally the same? they are both made of fermented cabbage- only difference I see in ingredients is spicing. I am guessing the spicing is not what increases the risk. I have been told many times to put sauerkraut in my diet and I also see you support it- what is the difference.

  50. Hi Rockbox,

    I am a volunteer for Dr. Greger. Thank you so much for your question. This is a good one.

    The researchers in this study suggest that it may be because of the high salt content, nitrites, and secondary amines, which are all independently linked to higher cancer risks. So if you are preparing your own Kimchi limit the added salt and preservatives. The same thing goes for sauerkraut.

    I hope this helps to answer your question!

  51. Any chance we could get an updated, more detailed video on this topic? Almost 7 years on I would imagine there are some new studies out.

      1. Adam,

        Thank you for passing along the request to Dr. G. I am seeing numerous, more recent studies that tout the benefits of kimchi in removing BPA from the body and thus reducing prostate and breast cancer risk.

        Best,
        Kimberly

  52. dang… but what’s the mechanism? the high salt? animal products in traditional kimchi?

    i was just planning to make some extremely low sodium kimchi … one recipe called for a whopping 28k mg for one head of cabbage

    i’m aiming for like 3500mg which is half a tablespoon … don’t know how well it would turn out but this video makes me reconsider for the moment

  53. Wow. This knocked me for a loop. And it wasn’t a Fruit Loop.
    But could it be that traditional kimchi is made with fish sauce, anchovies, etc. AND white sugar so maybe these produce carcenogenic icky stuff?
    I never liked it before, but now I get my kraut and kimchi from a local organic place, and it’s all vegan. Salty as hell. But used as a condiment…Nom.

    1. I’m kind of assuming that it is in fact due to the presence of animal products in traditional Kimchi- and the bacterial action on them, and their byproducts, that are the culprit. I’ve gotten really into lacto-fermentation within the last year, and have made Kimchi several times, although it has been just veggie based. But it really shocked me to learn this about Kimchi, so maybe it’s more of a hope on my part, that the cancer causing effects can be attributed to whatever animal additives are found in traditional Kimchi. I’ve also made Sauerkraut (red cabbage), that is delicious, but now I’m questioning all things fermented… I’ve done a little searching online, after seeing Dr. Greger’s video on this, but haven’t found much in the way of negative findings on fermented foods, in general- perhaps other than the salt content.

      1. Yeah I have the same question: the bad stuff is the high salt and animal products. I am unsure about if fermented foods are 100% safe and even beneficial like it claims everywhere. But if we already eat a lot of fiber from a plant based diet that feeds the good bacteria in gut. How much more benefits do we really get from eating fermented foods? Say we make our own so no animal products and low in salt.

  54. Those are great points. While the salt in fermented foods like Kimchi does not have the same deleterious effects as salt outside of this setting (such as increased risk of stomach cancer), that’s not to say you must consume fermented foods. You’re correct that eating a diverse, whole food, plant based diet serves as a “prebiotic”, feeding healthy bacteria. We’re still learning about the microbiome, but providing prebiotics in the form of whole plant foods seems to be a good idea for the microbiome and has many, wide-ranging demonstrated health effects outside of the microbiome.

  55. What is it exactly in the Kimchi that causes cancer? Might it be the additives and not the fermented vegetables themselves??
    I know Kimchi in the store usually has a high amount of salt and preservatives… But it could definitely be made without these things. I wouldn’t say these studies alone are sufficient to say all Kimchi is harmful, but rather to check the labels if you buy it in store.

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