Apple Cider Vinegar and Belly Fat

In this Article (Index)

• Can apple cider vinegar help you lose weight?
• There is no evidence that ACV will help you lose weight or body fat
• Studies in Humans: evidence of weight loss
• How does Vinegar reduce fat and weight?
• Which are the bioactive compounds in Vinegar?
• Weight loss through ACV induced changes in the gut microbiota
• Risks and adverse side effects of Vinegar
• Closing Comments

Can apple cider vinegar help you lose weight?

According to recent meta-analysis reports combining the results from many separate studies on Apple Cider Vinegar or ACV for short, it isn't the spectacular weight loss aid that the media claims it to be.

Sure, there are studies (more on this below) that show that Apple Cider Vinegar and other vinegars have beneficial effects in obese or diabetic groups. Howver, when subjected to the rigorous statistical tools of a meta-analysis, these claims appear to be inconclusive so until long-term, controlled clinical studies are conducted these controversial and conflicting findings about weight loss will remain unresolved.

There is no evidence that ACV will help you lose weight or body fat

Lunholt, Kristiansen and Hjorth (2020) (1) identified 487 scientific papers on the subject of the effects of apple cider vinegar including its safety, effects on metabolic parameters like cholesterol, blood sugar, triglycerids and body weight in animals and humans and concluded that "due to inadequate research of high quality, the evidence for the health effects of A[apple] V[inegar] is insufficient. Therefore, more large-scale, long-term clinical studies with a low risk of bias are needed before definitive conclusions can be made."

Another meta-analysis by Valdes, So, Gill and Kellow (2021) (2) looked for the impact of dietary acetic acid (vinegar) on metabolic markers such as fasting blood glucose (FBG), triacylglycerol (TAG), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), glycated hemoglobin (HbA1c) -an indicator of diabetes or high-blood sugar, body mass index (BMI) an indicator of obesity, and body fat percentage.
They found that it helps reduce sugar levels (FBG) and triglycerids (TAG) in individuals with type 2 diabetes, and TAG levels in overweight or obese people. However they didn't find significant effects of vinegar consumption on body weight or body fat percentage.

Studies in Humans: evidence of weight loss

The first relevant paper on the impact of apple cider vinegar on weight was published by Kondo et al. (2009) (3).

It involved a 12-week long double-blind trial conducted in Japan involving 175 obese subjects, men and women that were 25 to 60 years old.
The subjects were randomly split into three groups that ingested: 15 ml of apple vinegar (roughly one tablespoon), 30 ml of apple vinegar or a placebo (tasted like vinegar but had no acetic acid). Their body weight, BMI, waist circumference, visceral fat area and triglyceride levels were monitored.

Kondo's team found that "Body weight, BMI, visceral fat area, waist circumference, and serum triglyceride levels were significantly lower in both vinegar intake groups than in the placebo group. In conclusion, daily intake of vinegar might be useful in the prevention of metabolic syndrome by reducing obesity."

The weight loss effects started after the fourth week and those in the high-dose group had a bigger drop in weight, a reduction in waist and hip circumferences and a drop in other variables than the low-dose group signalling a dose dependency effect (more vinger ingested, more pronounced the effect).

The subjects ingesting vinegar lost subcutaneous, visceral and total fat areas compared to the placebo control group.

However, when you look at the numbers, the impact is not so great. The average weight of these overweight Japanese was 165 lb (75 kg), and after 12 weeks those ingesting ACV lost on average 2.2 to 4.4 lb (1 to 2 kg).

Furthermore weight loss was not permanent: "Body weight, BMIs, and waist-hip ratios returned to their initial values" four weeks after the end of the trial.

Konto didn't find any abnormality or adverse effects in liver or kidney function, suggesting that the dose was well tolerated.

Khezri, Saidpour, Hosseinzadeh and Amiri (2018) (4) conducted a similar 12-week long randomized clinical trial. They randomly assigned their 39 overweight participants into two groups. Both groups followed a restricted calory diet (with a 250 kcal/day energy deficit) but one of them added 30 ml (2 tablespoons) of ACV while the other didn't ingest vinegar. They reported that "ACV significantly reduced body weight, BMI, Hip circumference, visceral adiposity index (VAI) and appetite score... Furthermore, Plasma triglyceride (TG) and total cholesterol (TC) levels significantly decreased and high density lipoprotein cholesterol (HDL-C) concentration significantly increased in the ACV group in comparison to the control group."

Techavichian et al (2020) (5) also conducted a blind randomized clinical trial that lasted four weeks and involved 40 overweight subjects, mostly women with an average age of 49.5 years who were also taking medication for high blood pressure, diabetes and high blood-lipids. They were assigned to four groups, each in gesting 30 ml per day of a different type of vinegar. They tested apple cider vinegar, rice vinegar, coconut flower cider vinegar and a coconut flower concentrate drink.

There was no placebo group, son the results are comparisons between groups and identified the effects of the different vinegars as follows:

• Apple cider vinegar significantly reduced waist circumference
• Rice vinegar significantly reduced hip circumference
• Coconut flower cider vinegar significantly improved muscle mass as well as basal metabolic rate, meaning they burned more calories at rest.
• The coconut flower concentrate drink group showed no changes.

As highlighted by the meta-analyses, these studies are relatively short term and involve few participants so their findings suggest an effect, but it can't be conclusively proved.

How does Vinegar reduce fat and weight?

Sirotkin (2021) reviewed the literature on the subject and summarizes the possible ways that vinegar can produce weight loss (6)

• As it lowers blood sugar and fats it reduces their impact on the hunger center in the central nervous system, reducing apetite. Though Darzi (2013) attributes it to the nausea that vinegar provokes (7)
• It extends the sensation of satiety by slowing the gastric emptying rate (the time it takes food to move from the stomach to the small intestine) (12)
• By reducing levels of leptin it promotes satiety (13)
• It acts upon an enzyme called AMPK (5′adenosine monophosphate-activated protein kinase) and stimulates genes that promote the burning of fat, or fatty acid oxidation (8)
• AMPK also slows the production of sugar in the liver while vingegar reduces the production of fat (lipogenesis) (3) and its storage by the body and liver

Which are the bioactive compounds in Vinegar?

A team led by Ok, E. (8) studied the effect of pomegranate vinegar or PV and acetic acid at low and high doses in obese rats and found that they lost weight, ahd had lower liver fat and blood triglycerides.
But the interesting point is that they found that the effects on fat and body weight decrease "were more potent at the low-dose than the high-dose, but the effects of low-dose PV showed slightly more or equal potency than high-dose acetic acid"

They conjectured that there may be something in the chemical composition of the pomegranate vinegar other than acetic acid that was responsible for this more potent effect than the purified acetic acid. They noted that PV has a wide range of phytochemicals (chemical compounds produced by plants) adding that "future studies are needed to identify the principal bioactive components in PV" to pinpoint those that enhance its benefic effects.

Some phitochemicals found in Vinegar

Ousaaid et al. (2021) (9) compared different "fruits vinegars" and provided information on their biochemcial components. Their analysis included artisanal or traditional recipes, industrial products and a wide range of fermented fruits as sources (grapes, dates, apples, blueberries, pomegranates, etc).

Vinegar's main component is water, making up between 95 and 98% of the liquid. Then comes the acetic acid that can range from 2 to 6% of the vinegar. The remaining coponents are a cocktail of bioactive ingredients in very small amounts: organic acids, polyphenolic acids, and minerals (sodium, calcium, potassium, phosphorus).

Acetic acid makes up about 93% of the acid content, but there are many more acids: succinic, malic, tartaric. They provide the aroma to the vinegar. Acetic Acid is the key component that stimulates the AMPK mechanism mentioned further up, but other chemicals also play a role.

Chlorogenic acid (despite its name, it has no relationship with chlorine), is the main phenolic acid and Santana-Gálvez, Cisneros-Zevallos and Jacobo-Velázquez (2017) (10) highlight its "activity against obesity" as shown by animal studies, together with caffeic acid, also present in vinegar, it "significantly lowered ... body weight, visceral fat mass, plasma leptin and insulin levels, triglycerides in liver and heart, and cholesterol in adipose tissue and heart... Human studies have also revealed anti-obesity effects of chlorogenic acid-rich foods."

ACV also contains gallic acid, p-hydroxybenzoic acid, catechin, syringic acid, and p-coumaric acid. Of these, gallic acid has been shown by Doan et al. (2015) (11) to play a role in the AMPK activation and protected obese mice from "diet-induced body weight gain without a change in food intake."

Fruit vinegars are good sources of antioxidants and other phytochemicals that promote anti-inflamatory effects (13).

Weight loss through ACV induced changes in the gut microbiota

A study with mice by Beh et al. (2017) (13) has found that vinegar modifies the gut microbiota, reducing some types of microorganisms and promoting the growht of others. This effect reducest the Firmicutes population, one that is predominant in obese mice and also the Allobaculum, Sarcina, Clostridium populations. Adding vinegar to the mice's diet also increased the populations of Verrucomicrobia, Proteobacteriaphylum, and the beneficial Bacteroides, Lactobacillus, Parabacteroides, Akkermansia, Flavobacterium and Oscillospira.

Studies in humans have linked human obesity with an increased Firmicutes and decreased Bacteroidetes and Verrucomicrobia populations in the gut. Vinegar reverses this trend. The Firmicutes have the ability to ferment non-digestible carbohydrates and release their energy that is absorbed by the body and stored as fat.

Akkermansia, whose populations grow in the presence of vinegar, promote weight loss and reduced inflammation (14).

Risks and adverse side effects of Vinegar

Vinegar contains acids and should always be considered as a corrosive agent that can provoke acid burns. Chang et al. (2020) (15) report of esophageal damage in a teenager caused by vinegar and caution that "continuous consumption of vinegar beverages can cause acidic burns and destroy the surface of the upper gastrointestinal tract, leading to esophageal ulcers... [vinegar] can cause severe injury to the gastroesophageal mucosa."

Techavichian et al (2020) recommen that "people with a history of gastro-esophageal reflux disease, peptic ulcer or gastritis should be careful about consuming cider vinegar as it could irritate the gastro-intestinal tract" (5).

Closing Comments & Conclusions

Acetic acid appears to have some beneficial effects on weight control in obese subjects. However, they have not been conclusively proved. The antioxidants and other plant produced chemical compounds also have an effect on your gut microbes and metabolism. This same effect can be obtained by eating fresh fruit and vegetables and avoiding the adverse side effects of vinegar and acetic acid.

Due to its sugar lowering effect, people with diabetes should consult with their physician before taking vinegar supplements or adding additional vinegar to their diets, as it may interfere with their current medication. Hlebowicz (2007) pointed out that "vinegar affects insulin-dependent diabetes mellitus patients with diabetic gastroparesis [a condition that affects the stomach muscles and prevents proper stomach emptying.] by reducing the gastric emptying rate even further, and this might be a disadvantage regarding to their glycaemic control." (12)