Blog Post

Apple Cider Vinegar and Health: An Evidence-Based Look

Apple Cider Vinegar

Apple cider vinegar is often promoted as something that can help with a wide range of areas of health.

There are some people who tout it as a miracle that can help with absolutely everything. Others claim it does absolutely nothing. As with a lot of areas of nutrition, the answer is somewhere in the middle.

This post will go through a lot of the areas people normally talk about in relation to apple cider vinegar. And whether there is evidence to support those claims.

Weight

The most frequent thing people seem to talk about is that they think apple cider vinegar can help with weight-loss.

Firstly, understanding the fundamental principles of weight-loss works is an important filter for whether something will help you lose weight.

The main principle is the concept of calories in vs calories out. No matter how we look at it, consistent weight-loss over time requires a calorie deficit.

Obviously there can be short term fluctuations due to a variety reasons, including water weight changes.

But over time, calories in vs calories out is the mechanism that controls weight.

So, when applying that filter, in what way would apple cider vinegar impact weight management?

It has no real mechanism for increasing energy expenditure, so the calories out portion is unaffected.

For it to work, it would need to impact the calories in portion.

One obvious aspect is that apple cider vinegar contains almost no calories. Therefore, adding it could displace other calories in some way. For example, adding it to a salad instead of a higher calorie dressing could save calories.

But honestly, most people are referring to the benefits of having a shot of it in the morning.

From that perspective the only option left as an explanation for the small weight loss that is seen in some studies is that it induces a bit of nausea. And this nausea can lead to a reduced calorie intake.

Regardless of what you think of the theoretical reasoning, we have research available to see the results in practice.

The main study people refer to is a 12-week Japanese study with 155 participants. This resulted in a weight loss of 1.7kg over 12 weeks. Within 4 weeks post-trial they had regained 1.4kg as well, which is worth mentioning as well.

Firstly, that small loss is not really anything to write home about. It also had the flaw where participants intake was self-reported. There are massive issues with self-reported intake, which is obviously an issue.

Beyond that though, even this small result appears to be the most compelling evidence of weight loss that has been found in the research.

This is an area that has also been studied for >10 years as well. There have been no significant results to make it seem like apple cider vinegar leads to significant weight loss.

Blood Glucose Levels and Insulin

Apple Cider Vinegar

Blood glucose levels is the biggest area where apple cider vinegar appears to have benefit.

Apple cider vinegar includes 5-6% acetic acid. And the proposed mechanism is that the acetic acid delays gastric emptying.

Delayed gastric emptying means that it is easier for insulin to keep blood glucose levels within range. Therefore, insulin levels do not need to rise as high and blood glucose levels also will not get as high.

Having apple cider vinegar (or any vinegar) near the time of the meal is necessary for the effect to take place. Having it in the morning likely has no impact on a meal later in the day.

In terms of the research, it appears to improve insulin sensitivity by 19-34% when consumed near a high carb meal. Another small study showed that vinegar reduced blood glucose levels by 31.4% after the consumption of 50g of white bread.

For somebody looking to control their blood glucose levels, apple cider vinegar could be a valid option.

Even for people with Type 2 Diabetes, which is where I think it would be most effective, it still is not one of my front-line suggestions. There are so many things that can be done to help manage blood glucose levels. But apple cider vinegar does appear to be beneficial for this purpose.

Cholesterol

Cholesterol is a bit more complex. The most common study I people reference is an animal study that showed a reduction in LDL cholesterol and triglycerides.

Animal studies are notorious for being poor when it comes to relevance in terms of nutrition for humans.

From my perspective, they are useful for helping to identify which areas we should be thinking about. But due to different metabolisms, it is worth being aware that a lot of animal research does not translate the same way in humans.

And since cholesterol is an easy thing to measure in humans, it is also an easy topic to study. We do not need to base decisions off animal research on this topic since we can easily study it in humans.

There are two main human studies that I am aware of. Technically they show promise from a cholesterol perspective. But it is not at the stage where I think it is a valuable option.

One study had 39 participants who were put onto a 250kcal deficit, with the intention of weight loss. Half the participants also had 30ml of apple cider vinegar daily. Cholesterol was reduced more in this group than in the control group.

Another study had 19 patients with high cholesterol who were instructed to consume apple cider vinegar daily. There was no control group and no specific dietary intervention. Cholesterol dropped relatively significantly.

This leaves a lot open to interpretation. Optimists can look at this and see that there is some positive research, and it is worth considering.

From my perspective though, none of those studies really had large sample sizes and they were relatively poorly controlled from a dietary perspective.

That is not really a large criticism. These studies were not designed to definitively answer the question of whether apple cider vinegar improves cholesterol.

But food for thought, it has been a long time since either of these studies have been conducted. It does not seem like researchers are rushing to get more studies done on this topic with greater dietary control and larger sample sizes.

If it were likely that apple cider vinegar helps cholesterol, I would wager that researchers would be all over it. It would be a solid way to make a name for themselves. This is even more relevant since there is no strong mechanism to explain it.

Or alternatively, apple cider vinegar companies would be funding research like crazy, to help promote their own products for these purposes.

Since that is not happening, I assume that other people in this space are looking at it the same way I am and interpreting this as a sign that it really does not do that much for cholesterol.

Cancer

Apple Cider Vinegar

There are only two studies that look at vinegar consumption and cancer in humans. And none specifically on apple cider vinegar, to the best of my knowledge.

These studies also did not really show anything promising. Particularly since they were conflicting. One showed a small decreased association with cancer. Another showed a small increased association with cancer.

The proposed mechanism behind why a lot of people think apple cider vinegar helps reduce cancer risk is the theory that the body’s pH plays a role.

This theory is based on the belief that a less acidic body will make it harder for cancer cells to survive.

This is backed by some research outside of humans. In humans, it is clear that this whole alkaline diet concept does not have merit for reducing the risk of cancer.

Beyond that, there is no research on apple cider vinegar and cancer anyway. Therefore, somebody who is promoting it is promoting it without any research backing behind it.

If there was a theoretical mechanism alongside anecdotal evidence, people would likely start dedicating time and money towards researching this area.

Digestion

Some people claim apple cider vinegar improves digestion.

This is another complex one. Because how do we measure “digestion.” It’s a tricky one.

Once again, there is legitimately no research on this topic.

The only mechanism that makes sense to me is that the delayed gastric emptying could play a role.

But in other cases, delayed gastric emptying is actually associated with bloating since food is in the stomach for longer. Typically, people would associate bloating with poor digestion.

The other thing that some of the benefits of apple cider vinegar are proposed to be due to is the “mother.” This is a cloud of bacteria that you can see in a bottle of apple cider vinegar.

The “mother” is a probiotic which could potentially play a role. But there is no research supporting this concept. And there are also heaps of other probiotic options.

And it is still important to create a good environment for probiotics to survive and thrive in your system. This occurs through prebiotic consumption.

So apart from those two mechanisms mentioned above, there is not much to support this concept beyond individual experiences and beliefs. That’s not to say it’s not possible for it to help digestion. But from my perspective, there are so many other options I would look at first.

Tooth Enamel

One time where the pH of the food actually comes into play is tooth enamel.

Apple cider vinegar is acidic to the point that it can negatively impact tooth enamel if not diluted.

This can lead to sensitivity, decay and cavities.

This is so clear-cut that it would be unethical to study in humans as part of a randomized controlled trial. But in-vitro studies have demonstrated this effect clearly.

The easy way to avoid this impact is to dilute the apple cider vinegar in some way. Instead of having a straight shot, diluting it with some water. Or at minimum, rinse your mouth afterwards.

Oesophagus

Similarly, to tooth enamel, there is reason to believe that there is potential for straight apple cider vinegar to be harmful to the oesophagus.

Vinegar appears to be one of the most common causes of throat burn in children due to accidental ingestion.

This does not directly translate to apple cider vinegar though.

Although there is a case report of a women who had an apple cider vinegar tablet stuck in her throat. This led to burns causing issues as much as 6 months later.

Theoretically, although the impact is likely small, daily consumption could contribute to issues that build over time.

There does not seem to be a lot of clear evidence that a daily shot of apple cider vinegar has negative impacts on the oesophagus.

From a cautious perspective though, it could be worthwhile diluting it to reduce the likelihood of there being a downside.

Summary

The body of evidence appears clear that apple cider vinegar can help keep blood glucose levels lower.

This can be particularly relevant for those with Type 2 Diabetes.

If I am working with a client who wants to try it, I think it’s worthwhile assuming it is diluted. IF the client dislikes the taste of apple cider vinegar and struggles with it, I would probably use that willpower elsewhere. There are plenty of options when it comes to reducing blood glucose levels.

For all the other benefits proposed, the evidence in support does not seem that strong. If somebody feels they get benefits, all the power to them. I would not go out of my way to get somebody to stop doing it.

If somebody starts preaching about all these benefits to other people as if they are facts, that is where I see the issue. At this stage, the evidence does not seem to support a lot of the claims that are being made.

By Aidan Muir

Aidan is a Brisbane based dietitian who prides himself on staying up-to-date with evidence-based approaches to dietetic intervention. He has long been fascinated by all things nutrition, particularly the effects of different dietary approaches on body composition and sports performance. Due to this passion, he has built up an extensive knowledge base and experience in multiple areas of nutrition and is able to help clients with a variety of conditions. One of Aidan’s main strengths is his ability to adapt plans based on the client's desires. By having such a thorough understanding of optimal nutrition for different situations he is able to develop detailed meal plans and guidance for clients that can contribute to improving the clients overall quality of life and performance. He offers services both in-person and online.