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.

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  • aeason

    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?

    • Michael Greger M.D.

      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.

      • TobiasBrown

        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…

      • TobiasBrown

        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. :)

      • Rosemary Guy

        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

  • Eric Needs

    This is a shame.

    • Michael Greger M.D.

      My thoughts exactly–used to eat the stuff all the time!

    • oaklandeasy

      Don’t buy it.

  • Hm……made with Organic Cabbages?? I wonder why?? Please find evidence and reverse this decision :)

    • Michael Greger M.D.

      This is on my pubmed alert list.

  • Deer

    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!

    • Michael Greger M.D.

      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 for those that might have missed it.

  • VegeMarian

    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….

  • 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.

  • 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.

  • pk

    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.)


  • debcasey

    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.


  • tc247

    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?

  • xxjane42oxx

    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).

    • Toxins

      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?

    • gallifreygirl2007

      THANK YOU JANE! my exact thoughts as well!

    • Joel Santos

      Hi dr greger what do you think about gochujang?

    • Metamech

      Completely agree. Koreans eat kimchi religiously and they are extremely healthy.

    • Jane you should go get ur probiotics from Yogurt and dairy products and stop reading this site.

  • xxjane42oxx

    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.

    • Toxins

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

    • 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?

  • dm47

    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.

    • Michael Greger M.D.

       If you click on the Sources Cited link up above you’ll find the sources linked there.

  • *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?

    • mike

      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

  • John Duda

    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.

  • Michael Greger M.D.

    Also be sure to check out my associated blog post Breast Cancer and Diet!

  • 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!!

  • Easter Cat

    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.

  • D504
  • D504

    kinda conflicts with mainstream theories of whether it healthy? 

  • Bee

    I thought that eating fermented foods helps with dysbiosis?  Are the raw/salt-free sauerkrauts ok to eat (like Rejuvenative Foods brand)?

    • BenJ

      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?

      • Joseph Gonzales, R.D.

        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

  • Marty

    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.

    This comparison of prostate cancer death rate 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.

  • Ted

    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…

  • 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]
    If anything, Just look at the difference between the obesity levels between USA and Korea ._.

    • GirlScout

      Look up Korea and stomach cancer and kimchi.

  • ….

    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.

  • Dan A

    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..)

  • gallifreygirl2007


    • gallifreygirl2007

      World’s Healthiest Foods: Kimchi (Korea)

  • rachel

    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 is made of glass and it keeps the
    air out. namaste;, rachel

  • bernard

    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!????”

  • Tomek

    And what would you say about this article: ?

  • Tomek

    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.

  • michelleden

    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

  • Christie

    Someone just showed me this article:

  • Planteater

    Not all fermented foods are pickled and not all pickles are fermented. If you buy kimche in a jar, it may not have been fermented (no probiotics), may have been pasteurized (no probiotics), and will probably have preservatives. I wish this study had made fermented kimche to compare to the store bought.

    • planteater

      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?!

      • DanielFaster

        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.

    • 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!

  • Jennifer

    Sad face! I love kimchi, assumed since it was cabbage with spices that it would be good for you. :(

  • Sara

    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:

    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.

  • Sarah Elaine Gallagher Layton
    • JacquieRN

      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.

    • Lovegan

      Your source is an anti-vegan corporate-funded front group “Animal lovers, animal watchers, animal eaters, animal owners, animal professionals, and the animal-obsessed should all feel welcome in this corner of the blogosphere.” 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, funded by the food-and-beverage industry to counter scientific evidence about the dangers of mercury levels in fish;, 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]

      • Laine

        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.

        • Tom Goff

          It’s very easy to make insulting stereotyping comments as you do. But do you have any actual evidence to justify your beliefs?

  • Adrian Hansen

    The causes of cancer are still a mystery, so just take this ‘research’ with a ‘grain of salt ‘ !

  • vegan minstrel

    Wondering if the chile pepper ingredient could be a factor. Though it’s been shown to have anti-cancer properties, a 2010 study showed capsaicin to be carcinogenic for skin cancer:

    As for sauerkraut, anyone concerned about it having too much sodium can make their own with potassium chloride.

  • James N

    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!

    • 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!

  • Cheryl

    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?

  • Eric Salisbury

    “what can’t we eat now?”, “why is there parsley in everything all of a sudden?” ROTFL! *Good healthy laughs* :)

  • Joel Santos

    Hi dr greger. Are there any studies on gochujang? Is it okay to still use it?

  • Anna Steele

    Does this mean pickles and sauerkraut are bad for you? If not, what’s the difference?

  • ldombovic

    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.

    • Joseph Gonzales R.D.

      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.

  • Caroline

    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):

    “… 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.”

    “… Nitrate levels are high in kimchi.
    The full article can be found here:

  • gary55305

    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.

  • Helen Butt

    Are there any updates on the fermentation/pickling issue? I’m wondering whether I should be avoiding this type of food.

    • Joseph Gonzales R.D.

      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.

      • Helen Butt

        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.

  • kamojett

    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.

  • Cheryl

    It’s been 5 years; any new news on this?

  • Charma1ne

    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?

  • DJWONG13

    Hi Dr. Greger, I was wondering if Kimchi is bad for you, are pickles bad for you as well? And what about fermented foods such as miso?

    • Or how about olives? Aren’t olives fermented using a similar process? What about miso and tofu?

      • Joseph Gonzales R.D.

        Thanks for keeping me on my toes! Let me know what questions may have been skipped :-)

    • Joseph Gonzales R.D.

      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.

  • JoshS

    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.

  • Healthynut

    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?

  • oaklandeasy

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

  • Brett

    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?

  • Marvin

    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 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

  • johan003

    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?

  • Lonnie Lewis

    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.

  • Luis A Ortega

    I wonder if it has to do with the fish sauce or shrimp sauce koreans add. What about vegan kimchi?


    Sigh… inspired by this delicious NPR article on Kimchi’s connective power
    I sought out and savored kimchi for lunch… then made a really bad decision and looked it up in my online nutritional bible. So sad. Maybe 4x a year?

  • Kim

    I just made five jars of vegan Kimchi. Unless you can prove otherwise I’m going to blame the fish sauce used in traditional Kimchi.

  • Lynn Albrink-Witt

    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?

    • Christine Kestner

      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!

  • Martin K

    Yet in South Korean, where kimchi is eaten at several meals each day, women have a very low rate of breast cancer: Might be that they have a good diet that counteracts the negatives of kimchi, or the studies could be flawed.

  • OV

    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.