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Vinegar Caveats

As I note in my chapter on greens in my book How Not to Die, vinegar may be one condiment that’s actually good for you. Randomized controlled trials involving both diabetic and non-diabetic individuals found that adding just two teaspoons of vinegar to a meal may improve blood sugar control, effectively blunting the blood sugar spike after a meal by about 20 percent. How? I discuss this in my video Vinegar Mechanisms and Side Effects.

Originally, we thought it was because vinegar delayed the gastric emptying rate, slowing the speed at which a meal leaves your stomach, which makes sense because there are acid receptors in the first part of the small intestine where the stomach acid is neutralized. So, if there is excess acid, the body slows down stomach emptying to give the intestine time to buffer it all. The acid in vinegar was thought to slow the rate at which food leaves the stomach, resulting in a blunted sugar spike. But then, studies were published where taking apple cider vinegar before bedtime resulted in lower blood sugars the next day. How does that work? That’s obviously not some acid-induced stomach-slowing effect. Indeed, anyone who actually went to the trouble of sticking an ultrasound probe on someone’s stomach could have told you that—no difference in stomach-emptying times was found comparing vinegar to neutralized vinegar. So, it’s not just an acid effect.

Back to square one.

Additional studies offered the next clue. Vinegar appeared to have no effect on blood sugars, but this was after giving people a straight glucose solution. Glucose is a byproduct of sugar and starch digestion, so if vinegar blunts the blood sugar spike from cotton candy and Wonder Bread but not glucose, maybe it works by suppressing the enzymes that digest sugars and starches. And, indeed, vinegar appears to block the enzyme that breaks down table sugar. It wasn’t just an acid effect, however. There appears to be something unique about acetic acid, the acid in vinegar. These findings were based on intestinal cells in a petri dish, though. What about in people? Feed people some mashed potatoes with or without vinegar, and glucose flows into the bloodstream at the same rate either way—so, there’s another theory shot down.

Let’s figure this out. If sugar enters the bloodstream at the same rate with or without vinegar, but vinegar leads to significantly less sugar in the blood, then logically it must be leaving the bloodstream faster. Indeed, vinegar ingestion appears to enhance sugar disposal by lowering insulin resistance (the cause of type 2 diabetes), and also appears to improve the action of insulin in diabetics. The mystery of how vinegar works appears to have been solved, at least in part.

So, diabetics can add vinegar to their mashed potatoes—or just not eat mashed potatoes. If you add vinegar to a high-fiber meal, nothing happens, which explains results such as no effects of vinegar in diabetics in response to a meal. That’s no surprise, because the meal in question in the study was mostly beans. If you are going to eat high glycemic index foods like refined grains, vinegar can help—though there are some caveats.

Don’t drink vinegar straight, as it may cause intractable hiccups and can burn your esophagus, as can apple cider vinegar tablets if they get lodged in your throat (not that apple cider vinegar tablets necessarily actually have any apple cider vinegar in them in the first place). Don’t pour it on your kid’s head to treat head lice either. It’s “not harmful except when it leaks on to the face or penetrates the eyes,” and it turns out it doesn’t even work. Vinegar can also cause third-degree burns if you soak a bandage with it and leave it on.

Though as many as a total of six tablespoons a day of vinegar was not associated with any side effects in the short-term, until we know more, we may want to stick with more common culinary type doses, like two tablespoons max a day. For example, drinking 2,000 cups of vinegar was found to be a bad idea.

Other good-for-you condiments include (salt-free) mustard and horseradish. You may be interested in my Second Strategy to Cooking Broccoli video. For more on my book, check out the trailer.

This is the final installment of my five-part series on vinegar. If you missed any, here they are:

In health,
Michael Greger, M.D.

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


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.

45 responses to “Vinegar Caveats

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    1. Paradoxically, ingestion of small amounts of raw apple cider vinegar LOWERS stomach acidity. (The stomach gets the message to “stop making so much acid.”)

      Kombucha contains vinegar too, and billions of bacterial allies per tablespoon besides. Brew it with both green tea and hibiscus flowers using the “continuous brew” method.

      You don’t have to drink kombucha by the bottle ~ a swig a few times a day does the trick.

      Let Food Be Thy Medicine, as Hippocrates used to say.

    2. Hello Heather. Thanks for your comments :)

      Although apple cider vinegar might improve acid reflux symptoms, there’s very limited research, recommendations so far have been due to anecdotal evidence. I believe it hasn’t been conducted a study which supports health claims tied to apple cider vinegar.

      If you want to try apple cider vinegar ask your doctor and discuss with him/her about the potential risks and benefits to try apple cider vinegar.

      Hope it helps.

  1. I just made a batch of fire cider (a longtime folk remedy for cold season with apple cider vinegar infused for a few weeks with hot peppers, rosemary and other herbs, garlic, onion, turmeric root etc.) Any caveats about taking a shot of that every day?

    1. Hello Erin! Thanks for your comments and sharing your recipe :)

      How much vinegar do you add to the fire cider? According to some of Dr. G videos: “Although as many as six tablespoons a day of vinegar were not associated with any side effects, two tablespoons per day are recommended. Vinegar should not be ingested straight as it may burn the esophagus and cause intractable hiccups.” So, I think if you stick to that doses there shouldn’t be any problem.

      To find out more about vinegar check Dr. G videos on the topic >>

    1. I, too am interested in an answer to Brian’s question. Also, in how best to take it.

      Should I drink 2 T in a glass of water before bed, or split it into multiple servings during the day?


    2. I linked to a paper mentioned in an earlier vinegar video which found 2 teaspoons with a high carb meal reduced the glucose spike in type 2 diabetics. The effect of 2 tbsp faded out by 5 hrs. They found 4 teaspoons had less effect than 2. It’s far from clear what is optimum but read the paper and you’ll maybe decide 2 teaspoons is worth sticking with.

    3. To quote from near the end of the blog:
      “until we know more, we may want to stick with more common culinary type doses, like two tablespoons ***max a day***.”

  2. Acetic acid present in vinegar is well known to break the integrity of the gastric mucosal barrier allowing the back diffusion of hydrogen ions into the gastric mucosa thus causing gastric erosions, ulcerations and ulcer complications (bleeding and perforations). In the 1970’s Dr. Horace Davenport has shown this negative effects of short chain fatty acids (e.g., acetic, proprionic and butyric acids) on the integrity the gastric mucosa in dogs. Likewise, other barrier breakers such as NSAIDs, bile acids in combination with acid are well known to induce gastric ulcers and ulcer complications. Therefore, chronic safety studied in animals are needed to establish whether the use of vinegar is safe, especially in patients at risk of ulcers such as those with H. pylori infection and in rheumatic patients receiving NSAIDs and steroids.

    1. There isn’t any research yet.

      When they try to figure it out for things like acid reflux, here are the types of sentences you get.

      “Apple cider vinegar might improve acid reflux in people not taking medications and with minimal risk. But although there’s a lot of anecdotal evidence, there’s very limited research. In fact, no research supporting this claim has been published in a medical journal.”

    2. Although lists of common triggers might be of some use, trigger foods for LPR or GERD are highly individualistic. In my experience, the worst culprits for LPR (the form I have had) are not specific foods but eating too much, inadequate chewing, high fat meals, and eating fewer than 3-4 hours before bedtime.

      1. gengo-gakusha, I agree with you totally on the idea of trigger foods and the eating too much, too close to bed time, sitting after meals, high fat meals or oil added foods for acid reflux.
        What I wanted to know from the scope was 1. did i have risk of barrett’s esophagus? 2. acid reflux? 3. celiac disease? 4. inflammed leaky gut? 5. any mechanical problem causing the reflux? 6 ulcers? and I got the answers to that, plus some. Keeping a food diary helped to recognize some trigger foods.

      2. Which is why if a reasonable practice doesn’t have concrete proof of efficacy, I am my own “guinea pig”. We are all somewhat different so I figure there is one quick way to test the theory for, and on myself. I don’t even care if it is a placebo effect, which contrary to the scientific view, I think can be an inconspicuous little miracle reminding us that mind and body are one.

    3. Hi Diane. Many thanks for your comments.

      Although apple cider vinegar might improve acid reflux symptoms, there’s very limited research, recommendations so far have been due to anecdotal evidence. I believe it hasn’t been conducted a study which supports health claims tied to apple cider vinegar.

      If you want to try apple cider vinegar ask your doctor and discuss with him/her about the potential risks and benefits to try apple cider vinegar.

      Hope it helps.

  3. Thank you for your comments Esam Dajani. I can not share the enthusiasm for vinegars, or kombucha seen in these forums. Trying dilute shots of either feels like pouring alcohol on an open wound. And indeed, 2 scopes on separate occasions confirmed severe GERD and I have adjusted my diet accordingly. I don’t however see the need to torture, maim or mutilate yet more animals in testing what should be common sense – using people (who insist on using these products) would make more sense.

    1. Barb,
      And yet I continue to read that reflux/gerd can be caused by too little stomach acid! It becomes so frustrating to know what the real answer is. Has Dr. Greger ever suggested a tried and true test to determine if there is too much or too little acid that may be causing the problem or are we just supposed to use trial and error to determine which it is. Are you following a low FODMAP plan?

      1. Barb, I made a statement like yours after another video presentation of Dr. Greger with regard to being frustrated and not knowing what the real answer is. It was not well-received…Here everyone has an opinion and back it up with medical citations that get challenged by others with opinions and their medical citations. Its a mixed bag with personal experiences and testimonials that vary wildly from one person to the next. Use common sense and if you experiment, do it gently.

      2. hi Lida, I am not sure if I can answer your question clearly or not, but the way I saw it, the matter was hinged to getting a correct diagnosis. So, I went to an Ears, nose and throat specialist tovbe scoped and diagnosed. I took their handout, but there were more acid foods that were triggers for me I had to avoid. I was scoped a second time shortly before going off the proton pump inhibitors. My stomach was a mess. When they do a scope, they also biopsy checking for various things along the way. In my case I was glad I went that route to get a diagnosis.

        I started wfpb just before giving up oroton pump inhibitors. I had the Fodmap handout but the doc said start at the top of the list, and see how you feel. Didn’t take long. Milk/dairy at the top, wheat next, and I was pretty much alright. My list of ‘ avoid foods’ is not in concrete. Tomatoes can be iffy for example, same with lemon juice on foods. Toothpaste and mint products are terrible, and I lose my voice with chocolate. (just examples)

        To my knowledge Dr Greger has not mentioned a tried and true test for acid or lack of acid in the stomach. But he is addressing nutritional topics as opposed to diagnosing medical issues. What did your doc say? Dodn’t they suggest a referral to a gastroenterologist or ENT?


        1. Hi, Barb
          I had an endoscopy which showed esophogeal erosion and my gastroenterologist wanted me to use PPI’s long-term but I agreed for only a month and then went off gradually as he suggested. Unfortunately, continue to have digestive issues and find that I cannot adopt all of Dr. Greger’s daily dozen into my diet. The gastroenterologist suggested the FODMAP diet and taking zantac when there was a flare-up. I am in the process of trying to establish a non-reactive eating plan. This requires a lot of trial and error which can be extremely uncomfortable or downright painful. As healthy as legumes are, I have a hard time tolerating them. I am, therefore, on a modified WFPB diet avoiding many foods which others find they can tolerate and enjoy.
          My quest continues and while I understand that Dr. Greger can’t offer medical advice, I do think he can continue to indicate the various caveats to foods that might be healthy for some but not for others. I don’t think he has dealt that extensively with reflux and gerd issues. Honestly I think whenever he promotes a food for being stellar he also needs to indicate for whom this may not be the case.


          1. Great, thanks for clarifying Lida. I was in about the same position. I did have fairly long list of healthy foods I could not eat though doing a healing protocol since helped a lot. I still refrain from highly acidic foods like vinegar, citrus fruits, salsa and many tomato products, and many herbal teas that have low acidic ph. If your throat/stomach still feels raw, I wouldn’t be using vinegar !

    2. Barb,
      I agree completely with your comment on animal testing. It’s also hard on teeth enamel, which for older people like me is a concern (too much vinegar in my youth, perhaps…:-).

  4. In the rural midwest in the late 50’s and early 60’s, my mother used two tablespoons of vinegar mixed with water as a hair conditioner. After shampooing, she would end with a vinegar rinse. It was excellent for removing soap from the hair and made our hair shiny and healthy. We also used the vinegar-water mixture as a final rinse when we were getting cattle ready to show at the county and state fairs.

    1. Nancy H, I’ve used baking soda in shampoo to remove build-up from shampoos & conditioners but have never used vinegar. I’ll try it sometime. No reason why it shouldn’t work just as well.

    2. Thanks for the reminder… my mother and aunts in the midwest used the same vinegar rinse and were known for their beautiful and shiny hair.
      I have spent so much money on 15 different conditioners over the years and just last week remembered the vinegar rinse and tried it with great results, shiny, soft and natural. I use natural coconut or jojoba oil on the ends if needed. And it saves me so much money.

    1. I think this is a clue: (not that apple cider vinegar tablets necessarily actually have any apple cider vinegar in them in the first place)

  5. I am still a bit confused, if vinegar is an acid how can it be good for your liver? In Anthony Williams book “Liver Rescue” he writes that vinegar is not agreeable to the liver and should be avoided. And doesn’t lemon juice do everything the vinegar does and is helpful to the liver?

    1. Lemon juice has a ph of around 2 which is as acidic, or more acidic, than vinegars. some vinegars register at 2.2, whereas some balsamic vinegars are closer to 4 on the ph scale –

      And no, lemon juice does not do what vinegar does with respect to effects on the endothelium, blood sugar levels, blood pressure. There are videos that correspond to these articles, linked above. They help may clarify some questions for you.

    2. Hi sunnyveo. Many thanks for your comments.

      I did a quick search, and apparently, vinegar might help with liver function. Some animal studies done on this topic conclude “The fruit vinegars regulate lipid metabolism and decrease liver damage in high-fat-fed rats”, others suggest that might be hepatoprotective in cases of diabetes mellitus.

      More info:

      Apparently, there’s not so much research on that, but so far there’s been a good result and can be good for the liver, but take into account that these are animal models and people which already have a disease. Not sure if the same effect would be for a healthy person.

      Hope it helps.

  6. Why not use a vinegar and water solution in a final rinse for a rention enama? I can see how this would be easier on the body and quickly absorbed.

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