While it’s been around for over 2,000 years, apple cider vinegar is only now enjoying its 15 minutes of fame. ACV, as it’s known to fans, is increasingly touted as a veritable cure-all for ailments as far ranging as acid reflux and diarrhea to weight problems, high cholesterol and Type 2 diabetes. But if you’d assumed that this modern day surge in ACV’s popularity was due to a spate of new scientific research in support of its medicinal properties … well, you’d be wrong.
All vinegars are produced when specific types of bacteria ferment specific types of alcohol. When red wine is the original alcohol that gets fermented, you wind up with red wine vinegar. Malt vinegar is derived from an ale made from barley, whereas distilled alcohol makes white vinegar. Fermenting apple cider is what gets you ACV. All varieties of vinegar contain a compound called acetic acid in some concentration, usually between 5 and 20 percent.
Acetic acid is – as the name suggests – an acid. This means that the vinegar that contains it will also be acidic. Just how acidic? On the pH scale, where 0 is the most acidic thing possible and 7 is completely neutral, vinegars typically have a value of about 2.5. In comparison, this makes vinegar less acidic than lemon or lime juice (which have a pH around 2) and more acidic than orange juice (which has a pH of 3.3 or higher). Stomach acid is generally more acidic than all of these; it averages around 1.5 on the pH scale. These may seem like minor differences, but be aware that the pH scale is logarithmic – stomach acid with a pH of 1.5 is actually ten times more acidic than vinegar with a pH of 2.5 and a hundred times more acidic than an orange juice with pH of 3.5.
It’s vinegar’s acidic nature that seems to have captured the attention of natural remedy enthusiasts, who tout it as a germ-killing tonic for everything in the digestive tract from sore throats and infectious diarrhea to small intestinal bacterial overgrowth, aka SIBO. The problem with these claims? There is no scientific evidence whatsoever to support them. I combed the research literature to find a single study that even tested any of these claims – and, when I found none, I sent a graduate student intern on the same mission. We both came up empty.
And yet, people continue to turn up in my clinical practice who use ACV to treat acid reflux and related symptoms like heartburn. They believe that they have too little stomach acid and that antacids and prescription acid suppressant drugs make acid reflux worse. As a result, they’re told, they should drink ACV in order to “acidify the stomach.”
But in fact, just the opposite is true. While there hasn’t been a single scientific study testing whether too-low stomach acid levels could actually cause reflux, very well-designed research studies confirm that people with more acidic stomach environments experience more acid reflux into their esophaguses. There’s a reason that doctors who practice evidence-based medicine prescribe antacids when you have symptoms of acid reflux – and it’s not because they’re in cahoots with big pharma or trying to keep secrets from you. It’s because they don’t want you to get esophageal cancer from chronic acid damage to your esophagus.
That’s not to say drinking vinegar may not have any health benefits at all. There is a hint of promising evidence pointing to some potential health-promoting effects of vinegar along metabolic measures like weight loss, lipid levels and blood sugar control. One small study with overweight participants on a weight-loss diet found that those who included an ounce of ACV on top of lunch and dinner salads wound up eating fewer calories (and lost more weight) than participants in a control group who took their salads naked. ACV was credited with having a satiating effect, which other studies have suggested could result from vinegar slowing down the stomach’s emptying rate, helping people feel fuller longer. In fact, a slowdown in stomach emptying could account for the findings of a teensy study of people with Type 2 diabetes, in which adding wine vinegar to a starchy, mashed potato-based meal resulted in lower blood sugar levels compared to that same meal eaten without vinegar on a different day.
In terms of a potential benefit on blood levels of unhealthy lipids, a Japanese study followed 150 obese participants for 12 weeks as they were split into three groups – a placebo group, a group given a low dose (a half-ounce) of regular vinegar daily and a group given a higher dose (1 ounce) of vinegar daily. Even though the groups had no differences in daily calorie intake, diet composition or exercise levels, the high-dose vinegar group lost a modest amount of weight – in the neighborhood of about 5 pounds – while the others did not. Both vinegar groups also had a minor, but statistically significant, reduction in triglyceride levels at the end of the study compared to the placebo group.
My takeaway from all of this? One, there’s nothing magical about ACV when you compare it to other varieties of vinegar. Two, vinegar is by no means a miracle tonic for weight loss, but a daily ounce of any vinegar – particularly with healthy meals – could potentially give a modest boost to your metabolic health. Three, perhaps the British were onto something when they decided that malt vinegar was a good condiment to pair with French fries.
Editor’s note: Madison Wright contributed to research for this article.