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:

How Much Vinegar Every Day?

Consuming vinegar with a meal reduces the spike in blood sugar, insulin, and triglycerides, and it appears to work particularly well in those who are insulin resistant and on their way to type 2 diabetes. No wonder the consumption of vinegar with meals was used as a folk medicine for the treatment of diabetes before diabetes drugs were invented.

Many cultures have taken advantage of this fact by mixing vinegar with high glycemic foods. For example, in Japan, they use vinegar in rice to make sushi, and, in the Mediterranean, they dip bread into balsamic vinegar. Throughout Europe, a variety of sourdough breads can lower both blood sugar and insulin spikes. You can get the same effect by adding vinegar to boiled white potatoes then cooling them to make potato salad.

Adding vinegar to white bread doesn’t just lower blood sugar and insulin responses—it increases satiety, or the feeling of being full after a meal. As you can see in my video Optimal Vinegar Dose, a study found that if you eat three slices of white bread, it may fill you up a little, but in less than two hours, you’re hungrier than when you began eating. If you eat that same amount of bread with some vinegar, though, you feel twice as full and, even two hours later, still feel nearly just as full as if you had just eaten the three pieces of bread plain. But this remarkable increase and prolongation of satiety took nearly two tablespoons of vinegar. That’s a lot of vinegar. What’s the minimum amount?

It turns out that even just two teaspoons of vinegar with a meal can significantly decrease the blood sugar spike of a refined carb meal, a bagel and juice, for instance. You could easily add two teaspoons of vinaigrette to a little side salad or two teaspoons of vinegar to some tea with lemon. Or even better you could scrap the bagel with juice and just have some oatmeal with berries instead.

What if you consume vinegar every day for months? Researchers at Arizona State University randomized pre-diabetics to take daily either a bottle of an apple cider vinegar drink—a half bottle at lunch, and the remaining half at dinner—or an apple cider vinegar tablet, which was pretty much considered to be a placebo control: While the bottled drink contained two tablespoons of vinegar, the two tablets only contained about one third of a teaspoon. So in effect, the study was comparing about 40 spoonfuls of vinegar a week to 2 spoonfuls for 12 weeks.

What happened? On the vinegar drink, fasting blood sugars dropped by 16 points within one week. How significant is a drop of 16 points? Well this simple dietary tweak of a tablespoon of vinegar twice a day worked better than the leading drugs like Glucophage and Avandia. “This effect of vinegar is particularly noteworthy when comparing the cost, access, and toxicities” associated with pharmaceutical medications. So the vinegar is safer, cheaper, and more effective. This could explain why it’s been used medicinally since antiquity. Interestingly, even the tiny amount of vinegar in pill form seemed to help a bit. That’s astonishing. And, no: The study was not funded by a vinegar company.

What about long-term vinegar use in those with full-blown diabetes? To investigate this, researchers randomized subjects into one of three groups. One group took two tablespoons of vinegar twice a day, with lunch and supper. Another group ate two dill pickles a day, which each contained about a half tablespoon’s worth of vinegar. A third group took one vinegar pill twice a day, each containing only one sixteenth of a teaspoon’s worth of vinegar. I wasn’t surprised that the small dose in the pill didn’t work, but neither did the pickles. Maybe one tablespoon a day isn’t enough for diabetics? Regardless, the  vinegar did work. This was all the more impressive because the diabetics were mostly well controlled on medication and still saw an additional benefit from the vinegar.


Make sure to check out my other videos on vinegar’s benefits:

This vinegar effect seems a little too good to be true. There have to be some downsides, right? I cover the caveats in Vinegar Mechanisms and Side Effects.

There are a few other foods found to improve blood sugar levels:

The best approach, of course, is a diet full of healthy foods:

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:

The Benefits of Vinegar Beyond Weight Loss

A double-blind, placebo-controlled, randomized study found that body weight and belly fat were significantly reduced by adding just a single tablespoon of vinegar to one’s daily diet. Is there any benefit to vinegar consumption if you’re not overweight? Well, the subjects’ triglycerides normalized, and, for those taking the larger dose of two tablespoons per day, there was a dip in blood pressure. Those effects may have just been because of the weight loss, though. Other than taste, is there any benefit to normal-weight individuals sprinkling vinegar on their salads? What about vinegar for controlling blood sugar? That’s the topic of my video Can Vinegar Help with Blood Sugar Control?.

If you feed people a half cup of table sugar, as their blood sugars spike, their artery function can become impaired. The higher the blood sugars go, the more the arteries take a hit. There’s a drug, though, that can block sugar absorption. By blunting the blood sugar spike with this drug, you can prevent the arterial dysfunction. This demonstrates that it’s probably good for your heart if you don’t have big blood sugar spikes after meals. In fact, how high your blood sugars spike after a meal is a predictor for cardiovascular mortality. So do people who eat lots of high glycemic foods, like sugary foods and refined grains, tend to have more heart attacks and strokes? Yes. They also appear more likely to get diabetes—but maybe people who eat lots of Frosted Flakes and Wonder Bread have other bad dietary habits as well?

The diets that have been put to the test in randomized controlled trials and proven to prevent diabetes are the ones focusing on cutting down on saturated fat and ramping up the consumption of fiber-rich whole plant foods, such as fruits, vegetables, and whole grains, without specific regard to lower or higher glycemic loads. The drug has been put to the test, though, and blunting one’s mealtime blood sugar spikes does seem to reduce the risk of developing diabetes, as well as reduce the risk of heart attacks and high blood pressure. So is there any way to prevent these blood sugar spikes without having to take drugs? Well, one way would be to not sit down to a half cup of sugar!

Yes, the drug can slow the progression of your atherosclerosis. You can see in my video Can Vinegar Help with Blood Sugar Control? how the arteries going to your brain narrow somewhat more slowly with the drug than without it. But wouldn’t it be better to eat a diet that actually reverses heart disease and diabetes? The healthiest diet to prevent the meal-related blood sugar and fat spikes—the oxidation and inflammation—is a diet centered around whole plant foods. But what if you really want a bagel? Instead of spreading drugs on it, spreading on some almond butter may help blunt the blood sugar spike from refined carbs. Another option is to dip your baguette in some balsamic vinegar.

“The consumption of vinegar with meals was used as a home remedy for diabetes before the advent of pharmacologic glucose-lowering therapy”—that is, before drugs came along—but it wasn’t put to the test until 1988. After all, how much money can be made from vinegar? Well, according to The Vinegar Institute, millions of dollars can be made! But a single diabetes drug, like Rezulin, can pull in billions—that is, until it was pulled from the market for killing too many people by shutting down their livers. The drug company still made out like a bandit, though, having to pay out less than a billion to the grieving families for covering up the danger.

There’s no liver failure from schmearing peanut butter on a bagel, though, and it cuts the blood sugar response in half. Similarly, drinking four teaspoons of apple cider vinegar diluted in water gives the same blunting of the spike—with the additional advantage over the peanut butter of lowering insulin levels in the blood. This is something peanut butter apparently can’t do. But putting peanut butter on your bagel is presumably better than having a bagel with lox because fish causes triple the insulin response. Red wine also increases insulin levels, though not as much as fish does, and also shoots up triglycerides. Non-alcoholic red wine, however, doesn’t cause the same problem.

What about vinegar? Not only may a tablespoon a day tend to improve cholesterol and triglycerides over time, vinegar can drop triglycerides within an hour of a meal, as well as decrease blood sugars and the insulin spike, potentially offering the best of all worlds.


Was that bursting with information or what? It’s because of everyone’s kind support that I was able to hire more than a dozen researchers to help me plow through the literature. I’m extremely grateful so many of you were able to see the potential and help NutritionFacts.org become what it is today. Onward and upward!

What’s that about belly fat being reduced? Check out other videos in my series on vinegar:

Did I say reverse diabetes? Reverse heart disease? For examples, see:

Sharing information that can help people prevent and reverse common diseases is my life’s work. Check out the full story in my series of introductory videos.

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: