There are many natural food items that are broadly promoted for their health benefits. Some are simply more nutritious than average foods or are healthier "whole food" sources of particular nutrients than what you might get in other ways. Others of these food items are ascribed an almost mystical sort of benefit, with claims ranging from boosting the immune system to helping weight loss to preventing all-cause mortality.
To temper expectations, it's important to remember that it's extremely unlikely that any given food item is going to have these extreme benefits. If it did, the active ingredients would have been identified and distilled into a medication by now. So, I'm always skeptical when a common ingredient like apple cider vinegar is promoted as having incredible health benefits.
The question, as always, is this: does science back up any of these claims? Is there any good reason to be taking apple cider vinegar as a supplement, or should you keep it where it began: as a tasty ingredient in many recipes and nothing more?
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What is Apple Cider Vinegar, Anyway?
First, let's talk a bit about what apple cider vinegar is.
Apple cider vinegar is a vinegar, which is an aqueous solution made primarily of water and acetic acid. Additional trace compounds add flavoring, usually stemming from the original ingredient that was fermented to produce it.
Apple cider vinegar is produced through the double fermentation process, beginning with apple cider or apple juice. The first round of fermentation converts that juice into an alcohol, as yeast converts the sugars into ethanol. Then, another fermentation process using bacteria converts that ethanol into acetic acid.
The end result is an acidic product with an acid concentration of around 4-7%. More concentrated acetic acid solutions can be created through distillation, and are more commonly used as household cleaners or in industrial processes.
Apple cider vinegar specifically also includes a variety of trace minerals, nutrients, and flavonoids that originated in the apple cider itself. These are left in to flavor and color the resulting vinegar; if they are filtered out, you're left with white vinegar instead.
Additionally, some forms of apple cider vinegar include "the mother" or mother of vinegar. This a cloudy, often stringy mass of yeast, bacteria, apple cellulose, and trace minerals like calcium, magnesium, potassium, and iron; processed vinegar typically filters this out. Some products claim that only vinegar with the mother presents benefits, while others don't make a distinction.
What Are the Potential Benefits of Apple Cider Vinegar?
Depending on who you talk to, apple cider vinegar can be anything from a condiment to a life-saving medicine. What does the science say? The answer is something a lot closer to a condiment.
Apple Cider Vinegar for Blood Sugar Control
The first and most interesting of the potential benefits of apple cider vinegar is as a supplement to help control blood sugar. Blood sugar control is important for overall health and is part of managing diseases such as diabetes, which is extremely common.
The source of the claim that apple cider vinegar can help with blood sugar control came initially from animal studies. These studies, from all the way back in 2000 and 2001, showed that acetic acid inhibits an enzyme responsible for breaking down certain types of complex carbohydrates into simple sugars. This helps minimize the amount of sugar that enters the bloodstream after consuming carbohydrates.
Animal studies are a good place to start, but human studies are required to form any reasonable conclusions. For that, we first turn to a study performed in 2019. This study looked at 70 individuals with type 2 diabetes and hyperlipidemia for an 8-week study.
In this study, the group that was given apple cider vinegar seemed to have better glycemic indices, as well as lower markers for oxidative stress. No effect was observed regarding blood pressure or homocysteine (a marker for cardiovascular disease.)
One study alone isn't necessarily much to go on. A larger meta-analysis of nine studies performed in 2021 found a range of impacts, including a decrease in serum cholesterol, a reduction in fasting blood sugar levels, and a reduction in HbA1C levels. At the same time, no impact was seen on fasting insulin.
Before we get too excited, there's a potential issue with this meta-analysis, which is that the studies involved in the analysis were not all of high quality. Of the nine studies, one was not randomized, three did not provide adequate information on the allocation concealment of the vinegar supplement, and only three were blinded studies. In other words, the data pulled from these studies may not be reliable, and more study is necessary to draw firm conclusions.
It's possible that for people without diabetes, consuming some amount of apple cider vinegar might be able to reduce blood sugar spikes after eating. Additionally, another small study indicated that apple cider vinegar only provided these benefits as a liquid and that capsule ACV supplements did not provide the same benefit.
Apple Cider Vinegar for Weight Loss
Another common claim is that apple cider vinegar can help you lose weight. If this is true, it could be beneficial for individuals looking to drop a few pounds, so where do these claims come from, and how would this weight loss work? After all, there are a lot of different factors that contribute to weight gain and loss, so ACV could operate in a number of different possible ways.
To begin, a study of 155 obese men and women in Japan seemed to suggest that drinking a small amount of apple cider vinegar each day after a meal could help modestly with weight loss. This effect increased between the groups who drank half a tablespoon of vinegar and those who drank a full tablespoon.
One interesting component of this study was an ongoing measurement of fasting blood sugar, insulin sensitivity, and HbA1C, which found no significant changes in these measures, which contradicts the previous benefit's studies.
Another study in Lebanon involving 120 adolescent individuals who were given either one teaspoon, two teaspoons, or a tablespoon of apple cider vinegar in the morning before breakfast showed some amount of weight loss after three months.
As for the specific mechanism by which this works, it seems to be the same mechanism described above: that apple cider vinegar, or more specifically acetic acid, inhibits the enzyme that breaks down carbohydrates into simple sugars.
Simple sugars are very easy for the body to push into the blood, circulate around the body, and use for both energy and the production of fat for energy storage. Meanwhile, carbohydrates are more difficult for the body to use in this manner but can still be processed for energy more slowly. The result is that food is digested more slowly, providing you energy for longer and reducing your cravings for more food later. This reduction in hunger helps reduce the "calories in" side of the weight equation.
One note here before we move on is that in the studies that show apple cider vinegar helping to reduce appetite, this effect seems to be primarily short-term in nature. In other words, it works for a few weeks or even a few months, but it quickly tapers off, and the benefit disappears. That said, very few if any long-term studies have been performed to show results either way.
Less Proven Benefits of Apple Cider Vinegar
There are quite a few additional benefits purported to come from daily consumption of apple cider vinegar.
These include:
- Aiding in digestion. Some claims have floated around on social media that apple cider vinegar can reduce bloating and gas and aid in general digestion to help reduce unpleasant side effects like gas and heartburn. Very little has been done to study this effect, and in the one study that has looked into it, only some people reported a temporary reduction in heartburn, and others reported an increase in heartburn symptoms. Vinegar, being an acid, stands to worsen stomach and esophagus issues as well.
- Balancing bodily pH. Some apple cider vinegar products promote the ability to counteract an imbalanced bodily pH level through the introduction of acetic acid. No study has shown this to be true; blood pH levels are carefully regulated by your internal organs. There is also no current evidence to suggest that a more acidic pH level would be beneficial, even if it worked.
- Effects on mood. Depression and other mood disorders are difficult to treat. There are some animal studies that suggest acetic acid might interact with the metabolism of amino acids including tryptophan, glycine, and serine, all of which are used in the creation of mood-regulating neurotransmitters. However, no studies have proven a link between vinegar and these neurotransmitters, or that the end result is beneficial if it exists.
- Cold, flu, COVID, and other disease prevention or treatment. Acetic acid has antibacterial properties – it is, after all, used as a cleaner in higher concentrations – so a common "home remedy" is to drink, gargle, or otherwise rinse with apple cider vinegar to help treat or prevent respiratory, throat, or other illness. There is no evidence to suggest that this works.
In general, the list of benefits of apple cider vinegar is quite limited, and human studies have been small, inconsistent in quality, and difficult to rely upon for true recommendations.
Are There Drawbacks to Apple Cider Vinegar?
Any benefit, however minimal, may be worth exploring if the supplement in question is otherwise harmless. However, if there is any risk of serious side effects, much greater caution is necessary. Where does apple cider vinegar fall on this scale?
Unfortunately, vinegar of any sort is at its heart acetic acid, and acids are acids. Apple cider vinegar, then, has a few drawbacks.
The first is that apple cider vinegar can potentially cause indigestion or upset stomach. If you already have any sort of stomach ulcer, esophageal damage, or other digestive issues, acetic acid can exacerbate the issue. This is why most studies use a very diluted supplement, typically a tablespoon at most of apple cider vinegar in an 8 oz. glass of water.
Another issue is that prolonged exposure to acid will erode tooth enamel. Tooth decay is caused by the production of acid locally by the bacteria on your teeth, after all. Adding more acid, especially on a continuous, daily basis, can lead to further erosion of your teeth. This is an easy-to-counteract side effect – all you need to do is rinse after taking any vinegar – but it's still worth mentioning.
Another potential issue is the concentration of the vinegar. Most apple cider vinegars are between 4 and 7 percent acetic acid. This is generally recognized as safe, which is why it's a food item, but higher concentrations – anything 20% or more – are considered poisonous.
Speaking of, one massive question that has not yet been tested or answered is whether or not the apple cider part of apple cider vinegar is meaningful. What I mean is that the active ingredient in these studies is acetic acid, which is present in all vinegars. Is there anything special about apple cider vinegar, or would red wine vinegar, balsamic vinegar, or plain white vinegar do just as well? We just don't know.
As with all supplements, just because I discuss them does not mean I recommend them. I don't take apple cider vinegar myself, nor do I include it in MicroVitamin. I don't think the results are significant enough to seek it out. Enjoy it on a salad as part of a healthy diet, and that's good enough.
Sources:
- ConsumerLab Apple cider Vinegar Report: https://www.consumerlab.com/reviews/apple-cider-vinegars-review/apple-cider-vinegar/
- Operation Supplement Safety from USU: https://www.opss.org/article/apple-cider-vinegar-dietary-supplements
- The effect of apple vinegar consumption on glycemic indices, blood pressure, oxidative stress, and homocysteine in patients with type 2 diabetes and dyslipidemia: A randomized controlled clinical trial: https://pubmed.ncbi.nlm.nih.gov/31451249/
- The effect of apple cider vinegar on lipid profiles and glycemic parameters: a systematic review and meta-analysis of randomized clinical trials: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8243436/
- Apple cider vinegar for weight management in Lebanese adolescents and young adults with overweight and obesity: a randomized, double-blind, placebo-controlled study: https://nutrition.bmj.com/content/early/2024/01/18/bmjnph-2023-000823
- Safety and side effects of apple vinegar intake and its effect on metabolic parameters and body weight: a systematic review: https://pubmed.ncbi.nlm.nih.gov/32170375/
- The Effects of Vinegar/Acetic Acid Intake on Appetite Measures and Energy Consumption: A Systematic Literature Review: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9193460/
