Apple cider vinegar (ACV) is one of the most popular folk remedies I hear about in my practice, and for good reason. There’s some impressive research to back up its health claims.

But first things first: definitions.

Apple Cider Vinegar: Is It All Created Equal?

Apple cider is basically unfiltered, unprocessed apple juice. It becomes vinegar after a double fermentation process: the first process turns the apple’s fructose into alcohol, and the second turns alcohol into the weak acid called acetic acid. The organisms responsible for this include yeast and (beneficial) bacteria: these are “the mother” of the vinegar. Filtered and pasteurized apple cider vinegar will remove the mother. This won’t render it completely useless as a nutritional supplement, but it will remove some of its digestive benefits (see below).

Apple Cider Vinegar and Blood Sugar

There are quite a few studies indicating that ACV slows the rise of post-prandial (after eating) glucose, even up to 31%, and it simultaneously improves insulin sensitivity by up to 34%. Pretty impressive numbers!

The most likely explanation for this I found was that ACV slows the rate of at which the stomach dumps food into the small intestine—which means the glucose in the food will take longer to hit the bloodstream. More acidic foods do this in general; the more acidic the food, the greater the delay in gastric emptying. In theory, therefore, other types of vinegars may have a similar effect. 

Apple Cider Vinegar and Weight Loss

ACV has also been demonstrated to aid in weight loss. I suspect this is also due to the delayed gastric emptying effect, as this study shows that ACV increases satiety (feeling full) after a meal, thus helping you to eat less. This study shows that consuming ACV lowers consumption by on average 275 calories per day. (For a nice object lesson of how much food this actually is, check out these images of 300 calories per day. It’s a little higher than the amount you’d likely save with ACV alone, but you get the idea.)

Apple Cider Vinegar and Your Bowels

Now we come to why having “the mother” is important: as a fermented food with the beneficial bacteria and yeast intact, raw ACV helps to support your microbiome.

Additionally, the acetic acid has antibacterial properties: it protects you against bad gut flora, while helping you repopulate with the good stuff.

The pectin from the apples is a soluble fiber, which also helps to bulk up stools. This helps regulate both constipation and diarrhea.

Apple Cider Vinegar and Acne

As mentioned above, acetic acid is antibacterial. In addition to keeping gut microbes at bay, this study is also one of several that shows that when applied topically, ACV can inhibit Propionibacterium acnes (the bacteria that inflames your pores). This study also shows that ACV improves skin’s texture and overall appearance. So there’s some truth to the recommendation to use ACV as a toner after washing your face.

(Tip on this though: dilute it with water. Straight ACV can be too irritating for all over application. Dilute more for dry or sensitive skin, and less for oily skin, but no less than half and half.)

Apple Cider Vinegar and Stomach Acid

I left this one for last because, while increasing stomach acid is perhaps the best known use for ACV, I was unable to find any studies to support the claim that it does so. That said, I can attest to the fact that a tablespoon of ACV before meals has been clinically useful to my patients with symptoms of low hydrochloric acid (such as feeling that protein sits heavy, reflux or GERD). I suspect that at least part of the reason this works is due to the similarity of pH between hydrochloric acid (pH of about 3) and ACV (pH 2.9-3.3).

The Upshot

Apple Cider Vinegar is a safe home remedy with a lot of potential benefits. If you’d like to try it, I’d recommend between a few teaspoons and a tablespoon before meals, either straight or in water.