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What About the Sodium in Miso?

According to the second World Cancer Research Fund/American Institute for Cancer Research expert report, “[s]alt is a probable cause of stomach cancer,” one of the world’s leading cancer killers. If the report’s estimate of an 8 percent increase in risk for every extra gram of salt a day is correct, then in a country like the United Kingdom, nearly 1,700 cases of stomach cancer happen every year just because of excess salt intake, as you can see at 0:27 in my video Is Miso Healthy?, and, in a country like the United States, it would be thousands more annually.

The risk of stomach cancer associated with salt intake appears on par with smoking or heavy alcohol use, but may only be half as bad as opium use or increased total meat consumption, as you can see at 0:43 in my video. These findings were based on a study of more than a half million people, which may explain why those eating meatless diets appear to have nearly two-thirds lower risk.

We know dietary salt intake is directly associated with the risk of stomach cancer, and the higher the intake, the higher the risk. A meta-analysis went one step further and looked at specific salt-rich foods: pickled foods, salted fish, processed meat, and miso soup. Habitual consumption of pickled foods, salted fish, and processed meat were each associated with about a 25 percent greater risk of stomach cancer. The pickled foods may explain why Korea, where the pickled cabbage dish kimchi is a staple, appears to have the highest stomach cancer rates in the world, as you can see at 1:39 in my video. But researchers found there was no significant association with the consumption of miso soup. This may be because the carcinogenic effects of the salt in miso soup are counteracted by the anti-carcinogenic effects of the soy, effectively canceling out the risk. And, if we made garlicky soup with some scallions thrown in, our cancer risk may drop even lower, as you can see at 2:06 in my video.

Cancer isn’t the primary reason people are told to avoid salt, though. What about miso soup and high blood pressure? Similar to the relationship between miso and cancer, the salt in miso pushes up our blood pressures, but miso’s soy protein may be relaxing them down. If we compare the effects of soy milk to cow’s milk, for example, and, to make it even more fair, compare soy milk to skim cow’s milk to avoid the saturated butter fat, soy milk can much more dramatically improve blood pressure among women with hypertension, as you can see at 2:43 in my video. But would the effect be dramatic enough to counter all the salt in miso? Japanese researchers decided to put it to the test.

For four years, they followed men and women in their 60s, who, at the start of the study, had normal blood pressure, to see who was more likely to be diagnosed with hypertension in that time: those who had two or more bowls of miso soup a day or those who had one or less. Two bowls a day may add a half teaspoon of salt to one’s daily diet, yet those who had two or more bowls of miso soup every day appeared to have five times lower risk of becoming hypertensive. So, maybe the anti-hypertensive effects of the soy in the miso exceed the hypertensive effects of the salt.


Indeed, miso paste, a whole soy food, can be used as a “green light” source of saltiness when cooking. That’s why I used it in my pesto recipe in How Not to Die and in my How Not to Die Cookbook. It can help you in Shaking the Salt Habit.

Not convinced that salt is bad for you? Check out these videos:

Not convinced that soy is good for you? See:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Discuss

Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.


49 responses to “What About the Sodium in Miso?

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  1. But soy sauce didn’t have enough of a soy boost?

    I know that it is the red light and miso is the green light.

    I think soy being in the name makes me wonder what went wrong with soy sauce.

    1. I watched a culinary travel show where they visited a traditional tamari/soy sauce manufacturer. It takes three years to make traditional artisanal fermented tamari and apparently it is nothing like what we know as soy sauce…which is a highly processed, industrial food made in under a month. It is all about price. Traditional tamari is very expensive. I think they mentioned the average modern Japanese person has never tasted real tamari. It is just like the difference between real 10 year aged balsamic vinegar and cheap aetic acid with caramel food coloring. I bet real tamari vs soy sauce in a trial would show tamari wins hands down. BTW, what we in the west know as tamari is likely not the real think either.

      It was sad too, in that show, they were pointing out that extremely few people making tamari this way anymore. The fermentation barrels were over 100 years old I think. That is part of the magic…the microbes that live in the wood. IT is all about quality and who can afford it.

      1. Mims,

        That sounds like the difference between whole grain sourdough bread — which is what I make at home — and commercially sold bread. I grind my grains just before mixing the dough and adding my own culture (it’s now almost 6 years old), the dough undergoes long ferments and proofs, and is not baked until about 24-48 hours after initially mixing the dough.

        Commercially sold bread has all kinds of additives to help it rise fast, fast, fast, and to flavor it and to preserve it (as well as to add back a few nutrients stripped out of the flour), and can be made in a matter of a few hours (2? 3?), from mixing the dough to baking the loaves. I learned all this when researching the list of ingredients on the back of a package of bread.

        So now, we are spoiled. And would never go back to eating commercially made bread.

    2. Traditionally, soy sauce is made with both fermented soya beans and wheat. Consequently, the amount of soy it contains may not be enough to counterbalance the effects of its high sodium content.

  2. By the way, Dr. Greger’s video over on YouTube is the most amazing video I have seen yet. Slow-paced enough for me to really understand things.

    Wow, that was the voice I was waiting for.

    And, Dr. Greger’s Swine Flu Humane Service video would have been just about all I needed at the beginning of this pandemic.

  3. With all of the doctors and news people and scientists talking, Dr. Greger already had the simple to understand versions almost a decade ago.

  4. The photo shows miso served with tofu. And every time I’ve eaten miso soup, it has been served with tofu (and usually seaweed). Maybe the tofu contributes to the reason that miso soup does not increase the risk of stomach cancer or raise blood pressure, but soy sauce does? Because although miso soup does contain protein, it’s a very low amount.

    On the other hand, soy sauce (and soy oil) do not contain any isoflavones, but miso does. And soy sauce is frequently served without tofu, or any other soy foods.

  5. The problem with these studies is they are not done on whole food plant based populations – people who are healthy. Their response to only salt if everything else is being done right – could be negligible.

    Salt’s ability to interact with other dietary components is the real question here – does it have the same effects on someone eating long term rice, broccoli and beans, as it does someone who is eating kebabs, pizza and burgers? Think we all know intuitively what the answer is, but we need the data to say conclusively.

    1. barry

      No offence but that is conjecture or even wishful thinking.

      I suspect that the Japanese eating traditional foods like miso soup are unlikely to have been eating pizzas, kebabs etc. They are more likely to have been eating a traditional Japanese diet (which appears to have been influenced by Buddhist vegetarian ideas) high in plant foods and low in fat. It appears to have been or be much closer to a WFPB diet than most Western diets and modern (non-traditional) Asian diets.

  6. I was fortunate enough to pick up a copy of Dr. Greger’s book How Not to Diet off my library’s “New Non-fiction” shelf the day before Corona Shut Down Time went into effect. I read it, and am re-reading specific sections, to better absorb the 500+ pages chock full of factual fiber, and flavored with the perfect dash of humor! I’ve been 10 pounds or so from my ideal weight most of my adult life, so I have always loved to read – and sometimes even try to follow – diet books. I’ve been perusing them for about 50 years, so I’ve had a front row kitchen chair on diets ranging from Atkins to Zone, from low carb to high fat and every diet in between. To find a book that sums it all up based on reputable studies has been my little bit of manna (from sprouted wheat berries) from diet heaven! I downloaded the app and am diligently ADDING foods and suggestions. Since I just know my friends will be asking how I lost that last 10 pounds, I’m creating a blog, I’ve always shared all the interesting things I’ve read over the years. But in the time of Corona, it’s not possible to get together with friends or see my coworkers so I decided to start writing about my journey so I can share with my peeps Dr. Greger’s scientific insights. My goal is to implement as many of the Daily Dozen/21 Tweaks as possible to achieve and maintain my 10 pound weight loss. Once I get my website set up, I will post my journey on line as an “Intention” and also for accountability. Corona Time has forced me to slow down and smell the sauteed in broth kale and also gave me plenty of time to put the pieces in place. Thank you, Dr. Greger, for showing up at just the right time for me.

    1. Wendy, I discovered the NutritionFacts.org website about 5 years ago. Immediately changed my diet, based on all his past videos. Lost about 10 lbs and now at the optimal BMI, with all health markers in the recommended range. Never looked back!

      Look forward to seeing your new website.

      1. Hi Darwin,

        Thanks so much for letting me know how well Dr. Greger’s recommendations worked for you. Since I’m just starting, it’s nice to hear how successful it was for you. In my excitement, I didn’t realize I’d posted on the miso post so I appreciate you reading and responding to me. Next week I will launch my journey on a blog site because I really want to get this info out to my friends. Again, thanks!

        Wendy

      1. I certainly will, Kate! I plan on being ready to start sharing my journey next week utilizing the Daily Dozen and the 21 Tweaks. I started just a few days ago charting everything with the app and that made it so much easier.

        Thank you, Wendy

  7. The general anti-salt tone in this blog, though accurate it leaves perhaps in many people’s mind that salt is a universal hazard to health. If fact, salt plays a crucial role in maintaining human health. It is the main source of sodium and chloride ions in the human diet. Sodium is essential for nerve and muscle function and is involved in the regulation of fluids in the body. Sodium also plays a role in the body’s control of blood pressure and volume.

    In an effort to shift to a more healthy mostly plant based diet I stopped using salt as a flavor enhancer. I soon started experiencing tremendous leg cramps. After some reflection and research I traced the cramping to a general lack of salt in my diet. Once I added salt to my nutritional plan the leg craps disappeared.

    The lesson learned is the modern diet undoubtedly has too much salt. However a diet with no salt can be left threatening.

  8. Dr., You seem to be a real proponent and champion of soy, even though over 90% of soy is GMO produced. Also, there are numerous sources in print and online that say that soy is detrimental to men’s production of testosterone due to it’s estrogenic effects. The same can be said for flax.
    I would really like to see a video or blog addressing the above and your comments and position on same.

    Thanks,
    Jim Hibbs
    Cotati,CA

    1. In fact, most soy is used as animal feed; The small amount of soy sold for human consumption is pretty much all non-GMO and most appears to be organic.

      Yes, there is a lot of sensational nonsense online and in shock/horror style popular ‘health’ books. But what do actual scientific studies show?

      If you want to see Dr G’s position on these issues, may I suggest that you type ‘soy’ and ‘flax’ in the Search box at the top of the page?

  9. I was recently told by a cardiologist that I should now liberally add salt to my diet. After a blood test, the HDL was at 30 and he said that is too low. My LDL and cholesterol are within range. I have been someone who did not add table salt to meals nor did I cook with salt for most of my adult life.

    Dr. Gregor, what say you to this advice?

    1. Dr Greger doesn’t, to my knowledge, provide individual medical advice online.

      However, your cardiologist’s advice appears a bit odd at first sight. Salt/sodium doesn’t appear to affect HDL levels in people eating even moderately healthy diets.
      https://www.ahajournals.org/doi/10.1161/01.hyp.0000113046.83819.a2

      In any case, raising HDL levels (other than via improving diet and increasing exercise) appears not to have any effect on clinical outcomes anyway
      https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/hdl-cholesterol/art-20046388

      You may also find this article (‘The vegetarian paradox: Low HDL cholesterol levels and low cardiovascular risk’) worth reading
      https://www.mdmag.com/journals/cardiology-review-online/2008/june2008/june-2008-goldberg-commentary

      Obtaining a second opinion, preferably from a plant-based cardiologist, may be your best option if you are uncomfortable with the advice from your current cardiologist.

    2. It appears commenter Mr. Fumblefingers gave you some good advice, but I would add that Dr has had a lot to say both on salt and on HDL. Please check out this topic review and all associated videos on the harmful effects on salt:
      https://nutritionfacts.org/topics/salt/

      He also had addressed why HDL is not such an important health parameter as we once thought;
      https://nutritionfacts.org/video/coconut-oil-and-the-boost-in-hdl-good-cholesterol/

      I think this makes fairly compelling arguments about recommendations to add more salt to your diet. I’d recommend you share this with your doctor and express your concerns for clarification. recommending. You may wish to share this with him

  10. I look at my three containers of miso in the refrigerator and none of them contain soy. They are chick pea or red bean. Do they have the protective effect or no?

    1. There has been an idiotic, paleo driven craze/crusade against any and all soy products, and this is the result.

      Yes, processed soy is no better than any processed food, but this is basically driven by industry that certainly doesn’t want people eating the cattle feed instead the cattle themselves. Unfortunately parts of the “health” and “insurance” industries are also benefiting by keeping people sick and the current food industry in place.

    2. I can’g look at the labels of your 3 containers of miso, but from what I’m reading, it appears miso always is made out of soy, although they may have these other ingredients like chick pea or red bean. Check out this article and see if this indicates that your miso DoeS contain soy plus these other ingredients: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0208821
      Isolation of immune-regulatory Tetragenococcus halophilus from miso
      “Miso, which is a Japanese traditional fermented ingredient of soy paste, is of three main types: bean miso, rice miso, and barley miso, based on the materials of the molts. Bean miso is made from soybeans, salt, water, and Aspergillus oryzae together with some strains of LAB and yeast during the process of the brewage [17]. The LAB in miso belong to T. halophilus, which are salt-tolerant bacteria. The nutritive value of miso is excellent due to its abundant amino acids and vitamins. Furthermore, miso is a beneficial food for human health. Miso lowers the risk of cancer, hypertension, inflammation, lifestyle-related diseases, and prevents aging.”
      Hope this is helpful

  11. Imagine the benefits of low salt miso!

    I find that the old adage that salt is just a way to cover bad cooking, poor quality, stale, flavorless food and a lack of good spices is generally true.

    Use of tart “umame” and savory spices like tamarind, sumac, limes, fruit and berries in savory food, and celery seed, cumin, turmeric, etc. goes a long, long way to reducing dependence on salt.

  12. Vegetarians so often are talking about diet of our ancestors, but they never ate soy products
    Eating soy beans have side effects, hormone load, and are not easily to digest even after processing
    Yes. they are processed food,

    1. People have been cultivating soy for many thousands of years. According to Wikipedia

      ‘Soybeans were a crucial crop in East Asia long before written records began.[61] There is evidence for soybean domestication between 7000 and 6600 BC in China, between 5000 and 3000 BC in Japan and 1000 BC in Korea.[62]’
      https://en.wikipedia.org/wiki/Soybean

      And people wouldn’t have started farming them in the first place if they weren’t already recognised as a long-established and valuable wild-picked food source.

      Yes, they have to be cooked to make them properly edible but so what? Humans have to cook meat to make it safe to eat and properly digestible but you guys never accept that as an argument for not eating meat.

  13. The leap from ´koreans have high stomach cancer rates’ to ´it’s because of the kimchi’ is completely unscientific. Is there a study to prove that kimchi causes stomach cancer? Real kimchi is a live fermented food like kosher pickles and sauerkraut and miso. It is not a « pickle » like vinegar based pickled products. It is live.

    Now they do often add fish products in it, so as a vegan I don’t buy « traditional » korean kimchi, but rather the more « fusioned » vegan kimchi. And it is a healthy food, like miso.

    More likely koreans high cancer rates are due to their very high animal protein and egg consumption. Korean barbecue anyone?

    It is disappointing that you would make that leap without any evidence, even if you do present it as simply a supposition. That is bad faith, since you have established yourself as a source that always only puts forth suppositions based on peer-reviewed data.

    Koreans have high cancer rates. Koreans eat kimchi. Sure okay. Koreans also eat lits of chestnuts and rice. But more importantly Koreans eat lots and lots of meat. Based on everything since the China study, we can more logically assume that animal protein is the culprit, rather than spicy fermented cabbage with an tiny amount of fish in it.

    Very disappointing. I suggest some sort of retraction.

    1. Why not do some research before making comments like these? it would reveal scientific studies like eg

      ‘CONCLUSION: Kimchi, soybean pastes, and the CYP1A1 Ile/Val or Val/Val are risk factors, and nonfermented seafood and alliums are protective factors against gastric cancer in Koreans. Salt or some chemicals contained in kimchi and soybean pastes, which are increased by fermentation, would play important roles in the carcinogenesis of stomach cancer. Polymorphisms of the CYP1A1, CYP2E1, GSTM1, GSTT1, and ALDH2 genes could modify the effects of some environmental factors on the risk of gastric cancer.’
      https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4316045/

    2. It is sloppy to put “pickles” together without making a distinction between vinegar pickles and naturally fermented vegetables. They are not the same thing. Is the problem the vinegar, or the probiotics?

  14. I’ve been wondering about all the unprounouncable additives in some vegan foods. I know fresh is best but sometimes we just want the convenience of something that can just be warmed up. What harm do they do?

  15. All the studies you refer to on the dangers of sodium were done on meat eaters. As a vegan of 50 years I believe salt has a totally different effect on me because all the fats I consume are water soluable unlike animal fats so the salt stays in the animal fat and in the body longer then a vegan because we can flush out our bodies often. I love the good kind of salt and at 72 have no problems and feel great.

    1. I’m confused since my understanding is that fats aren’t water soluble, whether animal or plant, unless specially treated.

      Also, not everybody is salt sensitive. You may just be one of the lucky ones and your diet is irrelevant.

      Anyway, congratulations on being healthy at 72. It’s a fabulous achievement. Good luck for the future.

    1. I now aim for adding a 1/4 teaspoon of salt per kilogram of vegetables. In practice, I just add a 1/4 teaspoon of salt to whatever I cook.

  16. This is an interesting study done on Japanese miso and blood pressure. The notable parts of the study are that: 1)consumption of miso (despite the high sodium content) seems to not have an affect on daytime blood pressures, and a decrease in nighttime blood pressure; 2)the miso used was provided by a Japanese company and created by them with an ace inhibitor; 3)the conflict of interest section needs to be deciphered by nutritionfacts professional staff; 4)here’s a doozy, this created miso RAISES LDL-C levels significantly!!! What The Heck!!!; and 5)this is a recent study having been published in August of 2019. Any kind of help would be greatly appreciated nutritionfacts! Aloha from Honolulu, Hawaii!!! Ken

  17. Oops here’s the study, please put into search string on pubmed:

    Long-term intake of miso soup decreases nighttime blood pressure in subjects with high-normal blood pressure or stage I hypertension

  18. Just wanting a health moderator from nutritionfacts to have a look at the study and comment on the increase in ldl in the above study:

    “Long-term intake of miso soup decreases nighttime blood pressure in subjects with high-normal blood pressure or stage I hypertension.”

    I’m not wanting to swap one risk for another. Yeah I can eat salty with miso because it doesn’t raise blood pressure, but I DO NOT want increased ldl cholesterol. Any help would be great! Mahalo in advance! Ken Young

    1. I looked up the study you mentioned ( https://www.nature.com/articles/s41440-019-0304-9 )
      and the only comment I could find related to cholesterol was this “Miso intake did not influence lipid or glucose metabolism.” Most studies of soy protein show a reduction in cholesterol as this study https://www.ahajournals.org/doi/full/10.1161/01.cir.102.20.2555 states: “Although there have been some conflicting results in studies in adults with elevated serum cholesterol levels, most studies report total and LDL cholesterol reductions after the addition of soy protein to a diet that is low in saturated fat and cholesterol.” It appears the miso will not be a “swap” of on risk for another but indeed will be heart healthy both in terms of cholesterol AND blood pressure. Hope that helps

  19. Aloha Nurse Joan! Thank you so much for the reply! On my iPhone, I have a “find on page” function that allows me to search for key words. I typed in “LDL” and it took me to this spot in the study, this is a copy paste of it:

    “Biochemical analysis showed that miso intake significantly increased low-density lipoprotein cholesterol (LDL-C) levels, which was not observed in the control group; LDL-C levels at week 8 were significantly higher in the miso group than in the control group (Table 4).”

    I did find your quotation in the study which is a complete paradox. Can you please advise? Is it an error on the researchers’ part?

    Mahalo again, Ken

  20. Can a health moderator please have a look at this study?

    https://www.nature.com/articles/s41440-019-0304-9

    It says both, “Miso intake did not influence lipid or glucose metabolism,” and, “Biochemical analysis showed that miso intake significantly increased low-density lipoprotein cholesterol (LDL-C) levels, which was not observed in the control group; LDL-C levels at week 8 were significantly higher in the miso group than in the control group .”

    Both in the same study! Which is it?! Thank you for all you do! Ken

    1. Hello Ken,

      This seems like a mistake to me. If you look at table 4, you can see that the Miso group started with a higher baseline LDL level, although after the intervention saw a slight decrease. I am not sure why the authors claimed there was an increase as that is not what the results show.

      I hope this helps,
      Dr. Matt

  21. I’m such a mental nut sir! I looked at the table prior (obviously not well), missed that. I stand corrected sir! Yes levels went down, but yes the study made a mistake too I guess. Thank you for your prompt reply doc, a big mahalo from Honolulu, Ken

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