What are the advertised health benefits of apple cider vinegar?
Slow-fermented vinegars like apple cider vinegar, when unfiltered and unpasteurised have what is called ‘the mother’, a cobweb-like build-up of non-toxic, yeast and bacterial sediment, giving apple cider vinegar it’s murky appearance. It can be removed by filtering but when it comes to apple cider vinegar, this is generally what natural health fans look for in the liquid form as it is a sign that the product has not been filtered, pasteurised or overly processed to remove its beneficial qualities.
These beneficial qualities are believed to include various amino acids, antioxidants, vitamins, enzymes and probiotics. There are, however, not many vitamins or minerals other than a very small amount of potassium present in apple cider vinegar which is far below the RDA for adults.
On the other hand, it is a natural antioxidant. An antioxidant is a substance that helps to prevent oxidation of the body’s cells, meaning that it can slow down cell damage.
In addition, probiotics (good bacteria) including live acetobacter, lactobacillus, oenococcus, gluconobacter and komagataeibacter have been identified2. How many of these beneficial bacteria actually survive by the time the end of the bottle is reached is, however, is questionable.
Apple cider vinegar with “the mother” is more expensive than the distilled kind and is believed to be responsible for most of the advertised health benefits associated with it, however, scientific evidence is yet to support all of the claims surround these.
Apple cider vinegar to lose weight
Several studies have been conducted as to whether taking apple cider vinegar (or vinegar in general) to lose weight is as effective as advertised by the health and fitness industries. Here’s what these have to say:
The effects on blood sugar and satiety
Research has revealed that acetic acid (which is generally higher in apple cider vinegar than any of the other types of vinegar) is able to lower the GI (glycaemic index) of foods with a high carbohydrate content3. The glycaemic index refers to a food’s effect on blood sugar (glucose) levels.
Generally, after a carbohydrate-rich meal with a high GI score like bread (as was used in the study), blood sugar levels rise rapidly as carbohydrates are broken down into sugars. The body then releases the hormone insulin in response, facilitating the transport of sugars in the blood to the muscles and fat cells, thus restoring blood sugar levels back to normal. However, insulin levels take longer than blood sugar levels to normalise, and without sugar in the blood to move around, insulin places a demand on the body for more sugar and so hunger and cravings begin. This is why high GI carb-loaded meals often leave you feeling hungry just a few hours after you eat them. It is also why low GI foods are recommended to those on diets, as these do not cause spikes in blood sugar and insulin and therefore help one to feel satisfied for longer.
Now, according to the study’s findings, if vinegar is taken with a high-carb meal like bread, you are likely to feel fuller for longer as the vinegar reduces the initial blood glucose response, delaying glucose absorption (but not preventing it) which helped the test subjects to feel satiated (full).
In general, if the glycaemic load is lowered, your blood sugar levels will remain more consistent, and you are more likely to feel satisfied after eating and, as a result, consume fewer calories for the duration of your day. Whether the caloric deficit will be substantial enough to achieve significant weight loss still requires further investigation.
Suppressing the accumulation of body fat
The main component of vinegar (Acetic acid (AcOH)) proved to suppress the accumulation of body fat in studies conducted on rodents. These animal studies confirmed the below results in regard to the effects of apple cider vinegar and weight loss:
- Promotes fatty acid oxidisation – Research4 conducted on rodents noted that consumption of acetic acid inhibited the accumulation of fat in the body and hepatic lipids (these refer to fatty acids that build up in the liver and contribute to a fatty liver) without changing the weight of skeletal muscle or the consumption of food in the test subjects.
Experts further concluded that acetic acid increases the oxidation5 of fatty acids in the body. This refers to the breakdown of fatty acid molecules to allow for these to be metabolised and used for energy to function.
- Insulin levels decreased – In the same study involving rats (as mentioned above)5, acetic acid reduced the insulin to glucagon ratio (IGR). Insulin and glucagon control blood glucose levels, and the better the ratio of these two hormones, the more effectively blood sugar levels will be controlled. A low insulin to glucagon ratio stimulates the release of nutrients stored in the body, increases glycogenolysis (the breakdown of glycogen, a readily mobile form of stored glucose) and gluconeogenesis (the generation of new glucose, from non-carbohydrate carbons i.e. not from glycogen), and promotes the breakdown of adipose tissue into free fatty acids and glycerol, which helps to prevent fat accumulation in the body.
- Metabolism improved – Another study6 conducted in mice found that acetic acid activates the hepatic (liver) enzyme known as AMPK, an enzyme that is activated during exercise in both rodents and humans. When activated, the enzyme stimulates processes that generate energy, increasing glucose uptake and fatty acid oxidation (a process wherein fatty acids are broken down to produce energy), improving metabolic state (the biochemical processes occurring within the body). Thus, acetic acid can increase fat burning and decrease sugar and fat production in the liver.
- Fat storage reduced – A study conducted on obese diabetic rats7, showed that the use of acetic acid, and its effects on metabolism (as mentioned above), may be able to aid in the prevention and treatment of obesity.
- Appetite is suppressed – Research has shown that acetate (a chemical compound derived from acetic acid) can suppress the parts of the brain responsible for controlling your appetite, this can lead to appetite regulation and an associated reduction in food intake which may lead to weight loss.
However, these effects attributed the subject’s lack of appetite to the nausea its consumption induced. As such, it was concluded that its use as an appetite suppressant was inappropriate. 7
The findings of the rodent studies mentioned above are somewhat limited as they have not been replicated in human studies. The appetite control study in humans discredited claims of vinegar being an appetite suppressant due to its nausea inducing qualities. In fact, only one other human study of any significance has been conducted to specifically investigate the effects of vinegar on weight loss, it involved obese subjects in Japan9. The study, which took place over 12 weeks and involved 175 participants, showed that consuming vinegar daily, led to reduced waist circumference and belly fat, lowered blood triglycerides, and ultimately weight loss.
** My Med Memo - Triglycerides are a kind of fat found in the blood. When your triglycerides are high, this may increase the risk of heart disease and is possibly a sign of metabolic syndrome. Metabolic syndrome is a condition that includes high blood sugar (hyperglycaemia), high blood pressure (hypertension), abnormal cholesterol levels and excess body fat around the waist.
The participants in the study were divided into groups with each given specific amounts of vinegar, and each one having different results:
- 1 tablespoon (15ml) vinegar daily mixed in a beverage – This group lost 1.2 kilograms (2.6 pounds) on average
- 2 tablespoons (30ml) vinegar daily mixed in a beverage – This group lost 1.7 kilograms (3.7 pounds) on average
The researchers concluded that the daily intake of vinegar may be beneficial in preventing metabolic syndrome through fat reduction.
Bear in mind, these findings may seem promising, but they are only preliminary and have not been replicated since the 2009 study. Furthermore, results were achieved from a 12-week study, therefore, the long-term effects on the body may be limited. Also, when considering the amount of weight lost over the twelve-week period (on average 1.2kg’s to 1.7kg’s) that makes for between 100g and 140 grams per week, the results suddenly seem far less impressive as most diets have far more effective results.
There is no magic pill to losing weight. In order to achieve noticeable results, you would need to apply a combined approach using one of the several proven methods of diet and exercise, as well as get sufficient sleep.
In general, apple cider vinegar might be a helpful weight loss aid through promoting a feeling of fullness after eating, also known as satiety (whether due to its nausea inducing effects or not) and in aiding in the control of glucose levels. However, it is always best to speak to your doctor or dietician if you want to lose weight healthily.
Apple cider vinegar kills bacteria
Numerous claims regarding apple cider vinegar’s ability to cure the common cold or decrease the time it takes to get over a sore throat and to treat infections and wounds abound. However, the scientific and medical evidence to support these claims is significantly lacking.
A large amount of the research done on the antibacterial effects of vinegar has focused on the ability of vinegar to kill the harmful bacteria found in food.
Vinegar has also been investigated for its efficacy as an antibacterial household cleaner, however, researchers found it to be less effective than other commercially sold cleaners.
With regard to living creatures, the association between immunity and vinegar showed promising results when high doses of apple cider vinegar given to shrimp with the results of the study indicating that apple cider vinegar may be used as a natural immunosuppressant for these crustaceans in order to adjust and enhance and the expression of genes that are immune related10.
These findings, however, have not been proven in humans and as such cannot support the claims as to the effect of apple cider vinegar on preventing or treating illness, throat soreness or boosting immunity.
Apple cider vinegar reduces allergies
There have been claims stating that apple cider vinegar may reduce a wide range of allergies. These claims, however, are not supported by any scientific data. There has been one study conducted on humans which studied the effect of vinegar on allergies11. The study involved seven people with severe allergies to chicken, eggs and lentils and who had suffered from anaphylaxis in the past as a result. Each of the participants underwent skin prick tests which exposed them to foods that were either prepared with or without a white wine vinegar. Foods that were prepared with the vinegar showed a reduced skin reaction in the subjects skin prick tests.
However, these findings are likely due to the acidic properties of vinegar and its potential to denature proteins in a similar manner to that of the stomach in the process of the digestion of food. As a result, it is uncertain as to whether the denaturation of proteins caused by vinegar before the foods were ingested by the subjects would have a different result when compared to protein denaturation occurring in the stomach. The study was also severely limited by the number of participants, restricting the findings.
Apple cider vinegar improves fertility
A number of people suggest that apple cider vinegar is able to improve fertility. To date, there has only been one human study conducted to possibly prove these claims. The study12 involved seven Japanese women suffering from PCOS (polycystic ovary syndrome), which is the main cause of irregular menstrual periods. Women with the disorder have issues with fertility and need to take medications to treat infertility and promote ovulation and possible pregnancy. As a result, non-pharmaceutical options of treatment for this syndrome will be beneficial.
The women involved in the study ingested 15grams of vinegar every day for a period of 90 to 100 days. The results were promising as four out of the seven women were able to regain their menstrual period/cycle which is thought to be a result of vinegar’s ability to normalise insulin resistance, a common symptom of PCOS. However, due to the size of the study, more research is needed before the effect of apple cider vinegar on fertility can be proven.
Apple cider vinegar lowers blood sugar levels and combats diabetes
The most promising health benefit of apple cider vinegar and perhaps the most researched is that of the ability of vinegar to combat diabetes through the regulation of blood sugar levels.
A number of studies have shown vinegar to be successful in controlling blood sugar spikes through increasing insulin sensitivity in those with diabetes, particularly type 2.
Type 2 diabetes is a condition wherein blood sugar levels are elevated either due to the body not being able to produce enough insulin or if it is insulin resistant.
One such study13 conducted by researchers from Arizona State University found that participants with type 2 diabetes taking 20 grams of apple cider vinegar with 40 grams of water, along with one teaspoon of saccharine (artificial sweetener), lowered their blood sugar levels after meals.
Further research found that ingesting apple cider vinegar before going to sleep was able to aid in moderating blood sugar levels when waking up, this is the time when blood sugar levels are at their lowest14. Bear in mind, these studies were conducted on those who had well-controlled type 2 diabetes and only included a small group of people (19 and 11 respectively).
Until larger, more controlled clinical trials are conducted, it is not advisable to assume that apple cider vinegar is a sure-fire way to treat diabetes.
Apple cider vinegar reduces risk of heart disease
According to the World Health Organisation (WHO), the world’s leading cause of death is currently cardiovascular disease15, this includes stroke and heart disease.
Some of the risk factors associated with heart disease include:
- High blood pressure (hypertension)
- High cholesterol
Some researchers believe that apple cider vinegar can improve these conditions and therefore, lessen the risk factors of heart disease.
A study16 conducted on rats found that vinegar is beneficial for maintaining a healthier blood pressure level for those suffering from high blood pressure (hypertension). It was noted that the acetic acid found in vinegar was able to lower cholesterol, as well as triglyceride levels.
These findings are somewhat limited as they are based on animal studies, as a result, we cannot be certain of the effects of apple cider vinegar and heart disease in humans.
Further research found that apple cider vinegar with ‘the mother’ contains an antioxidant known as chlorogenic acid. This antioxidant is known to affect the blood vessels, reduce blood pressure and prevent LDL (low-density lipoprotein) cholesterol particles, also known as ‘the bad kind’ of cholesterol, from oxidisation which occurs when these particles interact with free radicals. Oxidised LDL may lead to inflammation of the arteries that supply blood to the body’s tissues and organs, causing tissue damage and hardening of the arteries (atherosclerosis), and increasing the risk of a heart attack or stroke.
An observational study conducted by Harvard17 found that women who ate oil and vinegar salad dressing on their salads five to six times a week experienced lowered risk rates of heart disease compared to those who didn’t. However, it is not clear as to whether these benefits are a result of vinegar or not, as other factors were not taken into consideration such as diet, personal health conditions etc.
Further human studies will need to be conducted in order for the above-mentioned findings to be confirmed.
Apple cider vinegar may be able to kill cancer cells or slow the progression of cancer
Cancer is a disease that is characterised by the uncontrollable growth of abnormal cells. The disease develops as these abnormal cells multiply uncontrollably and destroy body tissue.
There is a great deal of hype around the properties of apple cider vinegar and the effect it may have on cancer.
Some studies have noted that vinegar may be able to shrink tumours and destroy cancer cells. These studies were all conducted in test tubes or on rats, this limits the findings to the effect of vinegar on humans considerably.
Epidemiological studies were also conducted, this kind of study analyses the patterns, causes and effects in the form of observation of health and disease conditions in specific populations. These studies found that ingesting vinegar is linked to decreased risk of oesophageal cancer in China18, however, increased vinegar consumption, amongst other foodstuffs, was also linked to an elevated risk of cases of bladder cancer in Serbia19.
In general, though, studies have shown that apple cider vinegar may provide a protective function and aid in the prevention of certain kinds of cancer, however, it is premature to recommend this as a means of treatment based on the research that has been conducted.
2. NCBI. 2016. Diversity of the microbiota involved in wine and organic apple cider submerged vinegar production as revealed by DHPLC analysis and next-generation sequencing. Available: https://www.ncbi.nlm.nih.gov/pubmed/26897250 [Accessed 10.11.2017]
3. NCBI. 2005. Vinegar supplementation lowers glucose and insulin responses and increases satiety after a bread meal in healthy subjects. Available: https://www.ncbi.nlm.nih.gov/pubmed/16015276 [Accessed 17.10.2017]
4. NCBI. 2009. Acetic acid upregulates the expression of genes for fatty acid oxidation enzymes in liver to suppress body fat accumulation. Available: https://www.ncbi.nlm.nih.gov/pubmed/19469536 [Accessed 10.11.2017]
5. NCBI. 2005. Effect of acetic acid feeding on the circadian changes in glycogen and metabolites of glucose and lipid in liver and skeletal muscle of rats. Available: https://www.ncbi.nlm.nih.gov/pubmed/16277773 [Accessed 08.11.2017]
6. NCBI. 2006. Acetic acid activates hepatic AMPK and reduces hyperglycemia in diabetic KK-A(y) mice. Available: https://www.ncbi.nlm.nih.gov/pubmed/16630552 [Accessed 08.11.2017]
7. NCBI. 2007. Improvement of obesity and glucose tolerance by acetate in Type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Available: https://www.ncbi.nlm.nih.gov/pubmed/17485860 [Accessed 08.11.2017]
8. NCBI. 2014. The short-chain fatty acid acetate reduces appetite via a central homeostatic mechanism. Available: https://www.ncbi.nlm.nih.gov/pubmed/24781306 [Accessed 17.10.2017]
9. NCBI. 2009. Vinegar intake reduces body weight, body fat mass, and serum triglyceride levels in obese Japanese subjects. Available: https://www.ncbi.nlm.nih.gov/pubmed/19661687 [Accessed 16.10.2017]
10. NCBI. 2017. Dietary effect of apple cider vinegar and propionic acid on immune related transcriptional responses and growth performance in white shrimp, Litopenaeus vannamei. Available: https://www.ncbi.nlm.nih.gov/pubmed/27840173 [Accessed 08.11.2017]
11. NCBI. 2010. Vinegar decreases allergenic response in lentil and egg food allergy. Available: https://www.ncbi.nlm.nih.gov/pubmed/19879037 [Accessed 10.11.2017]
12. NCBI. 2013. Intake of vinegar beverage is associated with restoration of ovulatory function in women with polycystic ovary syndrome. Available: https://www.ncbi.nlm.nih.gov/pubmed/23666047 [Accessed 08.11.2017]
13. American Diabetes Association. 2004. Vinegar Improves Insulin Sensitivity to a High-Carbohydrate Meal in Subjects with Insulin Resistance or Type 2 Diabetes. Available: http://care.diabetesjournals.org/content/27/1/281 [Accessed 16.10.2017]
14. American Diabetes Association. 2007. Vinegar Ingestion at Bedtime Moderates Waking Glucose Concentrations in Adults With Well-Controlled Type 2 Diabetes. Available: http://care.diabetesjournals.org/content/30/11/2814 [Accessed 08.11.2017]
15. World Health Organisation. 2017. Cardiovascular disease. Available: http://www.who.int/cardiovascular_diseases/en/ [Accessed 27.10.2017]
16. NCBI. 2001. Antihypertensive effects of acetic acid and vinegar on spontaneously hypertensive rats. Available: https://www.ncbi.nlm.nih.gov/pubmed/11826965 [Accessed 10.11.2017]
17. NCBI. 1999. Dietary intake of alpha-linolenic acid and risk of fatal ischemic heart disease among women. Available: https://www.ncbi.nlm.nih.gov/pubmed/10232627 [Accessed 16.10.2017]
18. NCBI. 2003. Risk factors for oesophageal cancer in Linzhou, China: a case-control study. Available: https://www.ncbi.nlm.nih.gov/pubmed/12875624/ [Accessed 16.10.2017]
19. NCBI. 2004. Non-occupational risk factors for bladder cancer: a case-control study. Available: https://www.ncbi.nlm.nih.gov/pubmed/15237578/ [Accessed 16.10.2017]