Apple cider vinegar diet: Does it really work?

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People search for information on a wide variety of health topics in Google and other search engines. That’s no surprise.

But I was surprised to learn that "apple cider vinegar weight loss diet" (or sometimes called the apple cider vinegar detox) was among the fastest-rising health topic searches for Google in 2017. And then I found out that apple cider vinegar has been used medicinally for centuries!

Why the renewed interest? And, more importantly, does it work?

What is the apple cider vinegar diet?

Apple cider vinegar comes from apples that have been crushed, distilled, and then fermented. It can be consumed in small quantities or taken as a supplement. Its high levels of acetic acid, or perhaps other compounds, may be responsible for its supposed health benefits. Although recommendations for "dosing" vary, most are on the order of 1 to 2 teaspoons before or with meals.

What can the apple cider vinegar diet do for you?

For thousands of years, compounds containing vinegar have been used for their presumed healing properties. It was used to improve strength, for "detoxification," as an antibiotic, and even as a treatment for scurvy. While no one is using apple cider vinegar as an antibiotic anymore (at least, no one should be), it has been touted more recently for weight loss. What’s the evidence?

Studies in obese rats and mice suggest that acetic acid can prevent fat deposition and improve their metabolism. The most widely quoted study of humans is a 2009 trial of 175 people who consumed a drink containing 0, 1, or 2 tablespoons of vinegar each day. After three months, those who consumed vinegar had modest weight loss (2 to 4 pounds) and lower triglyceride levels than those who drank no vinegar. Another small study found that vinegar consumption promoted feeling fuller after eating, but that it did so by causing nausea. Neither of these studies (and none I could find in a medical literature search) specifically studied apple cider vinegar.  A more recent study randomly assigned 39 study subjects to follow a restricted calorie diet with apple cider vinegar or a restricted calorie diet without apple cider vinegar for 12 weeks.  While both groups lost weight, the apple cider vinegar group lost more.  As with many prior studies, this one was quite small and short-term.

In all, the scientific evidence that vinegar consumption (whether of the apple cider variety or not) is a reliable, long-term means of losing excess weight is not compelling. (On the other hand, a number of studies suggest that vinegar might prevent spikes in blood sugar in people with prediabetes and type 2 diabetes by blocking starch absorption — perhaps that’s a topic for another day.)  Even among proponents of apple cider vinegar for weight loss or other health benefits, it’s unclear when to drink apple cider vinegar (for example, whether there is particular time of day that might be best?) or how much apple cider vinegar per day is ideal.

Is there a downside to the apple cider vinegar diet?

For many natural remedies, there seems to be little risk, so a common approach is "why not try it?" However, for diets with high vinegar content, a few warnings are in order:

• Vinegar should be diluted. Its high acidity can damage tooth enamel when sipped "straight" — consuming it as a component of vinaigrette salad dressing is a better way.
• It has been reported to cause or worsen low potassium levels. That’s particularly important for people taking medications that can lower potassium (such as common diuretics taken to treat high blood pressure).
• Vinegar can alter insulin levels. People with diabetes should be particularly cautious about a high vinegar diet.

So what?

If you are trying to lose weight, adding apple cider vinegar to your diet probably won’t do the trick. Of course, you’d never suspect that was the case by the way it’s been trending on Google health searches. But the popularity of diets frequently has little to do with actual evidence. If you read about a new diet (or other remedy) that sounds too good to be true, a healthy dose of skepticism is usually in order.