Vinegar has been used for wounds and other ailments since the time of Hippocrates, but is there evidence to back up these uses? Read on for more about the potential health benefits of vinegar.
What is Vinegar?
Historically, vinegar has been used as a preservative or as an acid for cooking. Like some of the other foods we love, such as cheese, yogurt, and wine, vinegar is also made with the help of microorganisms that ferment sugars and convert them into acetic acid [1].
Vinegar is a liquid consisting of about 5 to 20 percent acetic acid, water, trace elements, and, in some cases, flavorings. It has been used as a treatment for many different ailments since the time of Hippocrates, around 420 B.C. [1].
Diluted acetic acid by itself is not considered vinegar because vinegar contains other minerals, vitamins, and amino acids. Other bioactive products in vinegar include gallic acid, catechin, epicatechin, and caffeic acid.
Types of Vinegar
Vinegar is made from different fruits, rice, barley, and other foods that are high in sugar. Some examples are rice wine vinegar, apple cider vinegar, white distilled vinegar, balsamic vinegar, and fruit vinegar. Depending on the type, they can have different levels of acidity.
Different vinegar types are more popular in different countries and areas of the world. The one common theme amongst all vinegar is its beneficial properties and antioxidants.
How Vinegar Works
Vinegar is made by the fermentation process involving the yeast, Saccharomyces cerevisiae, and Acetobacter bacteria.
For antihypertensive effects, the proposed mechanism is that acetic acid acts directly on renin activity, which causes a decrease in Angiotensin II. This subsequently reduces blood pressure [2].
The method through which vinegar improves glycemic levels is not fully known. However, researchers believe the mechanism occurs after the translation of sucrase/lactase/maltase enzyme complexes [1].
The acetic acid in vinegar reduces blood sugar content by activating AMPK, an enzyme [3].
Vinegar is thought to affect glucose levels by delaying the rate of gastric emptying. The acetic acid in vinegar also seems to suppress disaccharidase activity and increase glucose-6-phosphate levels in skeletal muscle. Therefore, it is thought that vinegar may also prevent carbohydrate breakdown, similar to the prescription drug acarbose (Precose) [4].
Potential Health Benefits (Possibly Effective)
While the benefits in this section have multiple clinical trials behind them, it’s important to note that the FDA has not approved any vinegar product for any medical purpose or health claim. Vinegar is a safe component of many foods, but we still recommend talking to your doctor before using vinegar as a supplement.
1) Blood Glucose
In insulin-resistant subjects, vinegar improved post-meal insulin sensitivity by 34 percent. In patients with type II diabetes, insulin sensitivity improved by 19 percent [5].
In another study of eleven healthy adults, the addition of vinegar to a high-glycemic meal significantly reduced post-meal blood sugar [6].
Two tablespoons of apple cider vinegar at bedtime helped to reduce fasting blood glucose levels in eleven patients with type II diabetes [7].
In rats, blood glucose levels were significantly reduced when vinegar was fed in conjunction with corn starch. In humans, the results were not as pronounced. However, the area under the insulin response curve was reduced by 20 percent after the subject was administered 50 g of sucrose and 60 mL of vinegar [1].
In theory, vinegar could be a potential treatment to slow the progression of diabetes. In a cell study, vinegar increased insulin-stimulated glucose uptake, allowing insulin to do its job better and enhancing carbohydrate metabolism [8].
Additional human trials will be required to determine whether vinegar can really help control blood sugar, especially in diabetic patients.
2) Antimicrobial Activity
Diluted vinegar (2 percent acetic acid solution at a pH of 2) can effectively treat ear infections, including otitis externa, otitis media, and granular myringitis [9, 10].
Bacterial
Vinegar is slightly effective at inhibiting the growth of Staphylococcus aureus and Pseudomonas aeruginosa on wounds as a surface cleaning solution. However, many experts advise against using vinegar to clean a wound because the acidic solution may do more harm than good to the injured tissue [1].
In the context of killing microbes, vinegar may be most useful for cleaning vegetables before food preparation [1].
Viral
Vinegar is used in remote, poorly sourced locations as a mechanism for screening women for Human Papillomavirus (HPV) infection [11].
When the acetic acid in vinegar comes in contact with the viral lesions associated with HPV, it alters them, allowing midwives to detect infection with 77 percent sensitivity [12].
A preliminary study suggests that local excision plus a brief application of 99 percent acetic acid with rapid neutralization with sterile water under local anesthesia was effective in treating multiple genital warts in women with an acceptable rate of recurrence of 13.3 percent [13].
These treatments are used in remote locations with poor access to conventional healthcare. Better and more reliable treatments are available at medical facilities across North America, Europe, and many other parts of the world. Do not, under any circumstances, attempt to treat genital warts with vinegar.
Yeast Infections
Vinegar may help fight candida vulvovaginitis and oral candidiasis [14].
Some people use vinegar to suppress lice, nail fungus, and warts. However, very little evidence supports these uses, and more effective treatments are available. Do not attempt to treat these conditions with vinegar [1].
Potential Benefits (Insufficient Evidence)
The benefits in this section have been observed in at least one clinical study, but the results have yet to be reliably repeated. Again, the FDA has not approved vinegar for any medical purpose or health claim. If you want to use vinegar as a complement to other, better-studied strategies, talk to your doctor to determine whether it could be appropriate.
3) Weight Management
Vinegar (apple cider vinegar) may increase feelings of satiety, indicating its potential usefulness in weight control. Satiety is a feeling of fullness and satisfaction: the opposite of hunger.
In a double-blind clinical study, vinegar intake reduced body weight, body fat mass, and serum triglyceride levels in obese Japanese subjects. A daily intake of vinegar, therefore, may be helpful in the prevention of metabolic syndrome by reducing obesity [15].
According to one study in animals, cider vinegar induced a significant reduction in weight gain [16].
It also helped increase serum HDL levels and decreased triglycerides and LDL levels in diabetic rats [17].
In mice, acetic acid also prevented body fat and liver lipid accumulation, possibly by up-regulating the expression of genes that are involved in burning fats for energy [18].
4) Heart Health
The acetic acid in vinegar significantly reduced blood pressure and renin activity (associated with blood pressure) in hypertensive rats [16].
Studies have also reported that vinegar administration inhibited the renin-angiotensin system (hormone system) in non-hypertensive rats [19].
Trials investigating the effects of vinegar ingestion on the renin-angiotensin system have not been conducted in humans, and there is no scientific evidence that vinegar ingestion alters blood pressure in humans. More research is required to determine whether vinegar really has a significant effect on reducing blood pressure [1].
Animal Studies (Lacking Evidence)
No clinical evidence supports the use of vinegar for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.
We recommend talking to your doctor about other, better-studied options to achieve the health goals discussed in this section.
5) Antioxidant Activity
Vinegar is a source of dietary polyphenols, which are antioxidants and defend against oxidative stress [1].
For example, kurosu, a traditional vinegar produced from unpolished rice, suppressed lipid peroxidation in mice treated topically with hydrogen peroxide-generating chemicals [20].
Animal and cell experiments have also indicated that both grain and fruit vinegar could potentially improve antioxidant capacities and reduce oxidative damage [21, 22].
Apple cider vinegar induced a protective effect against erythrocyte, kidney, and liver oxidative injury and lowered the serum lipid levels in mice fed a high cholesterol diet. The authors suggested that it may scavenge free radicals, inhibit lipid peroxidation, and increase the levels of antioxidant enzymes and vitamins in cells [23].
6) Cholesterol
Rats that were fed apple cider vinegar for 19 days had a drastic reduction in total cholesterol and triglyceride levels [24].
An antioxidant called chlorogenic acid in vinegar can prevent LDL cholesterol particles from becoming oxidized, helping to lower LDL levels and cholesterol [25].
In animals, apple cider vinegar significantly reduces hemoglobin A1C (HbA1C), lowers low-density lipoprotein (LDL) cholesterol and triglycerides, and increases high-density lipoprotein (HDL) cholesterol. In another animal model, apple cider vinegar decreased triglycerides and very-low-density lipoprotein (VLDL) cholesterol [17].
7) Digestion
Vinegar may modulate acid/alkaline balance and promote the growth of healthy bacteria in the stomach. In animals, the ingestion of vinegar increased the quantity of minerals and vitamins absorbed from food, possibly because several vitamins and minerals are better absorbed at lower pH (higher acidity) [26].
8) Cognitive Decline
Kurozu, a traditional rice wine vinegar, shows a tendency to suppress cognitive dysfunction and amyloid accumulation in mice. This particular study found that vinegar might help the production of proteins like HspA1A, a protein similar to HSP70, which helps reduce amyloid formation in the brain [27].
A Japanese study found that vinegar consumption might improve cognitive function in rat models of Alzheimer’s disease and other dementias [28, 29].
Cancer Research
A case-control study demonstrated that vinegar ingestion was associated with decreased rates of esophageal cancer [30].
An extract from Japanese rice vinegar containing ethyl acetate inhibited azoxymethane-induced colon carcinogenesis in male rats in comparison to control rats. After 40 days, the rats had significantly smaller tumor volumes, as well as longer lifespans [31].
Rice shochu vinegar also stimulated cytotoxic activity (toxicity) in natural killer cells and stopped tumor growth in mice [32].
A mouse model vinegar produced from RSDS (rice-shochu post distillation slurry) stimulated natural killer cell cytotoxic activity against human leukemia cell lines [33].
Certain types of vinegar are also being investigated for their potential against leukemia, colon, lung, breast, bladder, and prostate cancer cells [34, 35].
Side Effects & Precautions
Although vinegar’s use is considered safe by default, there are rare reports of literature regarding adverse reactions to vinegar ingestion [36].
- According to one case-control study in Serbia, vinegar ingestion was associated with a 4.4-fold greater risk for bladder cancer [37].
- Hypokalemia (low levels of potassium in the blood) was observed in a 28-year old woman who had reportedly consumed approximately 250ml of apple cider vinegar daily for six years [38].
- Apple cider vinegar might lower blood sugar levels in people with diabetes. Therefore, blood sugar levels need to be monitored closely. Talk to your doctor before using vinegar as a supplement if you have diabetes [8].
- Although vinegar is able to treat many infections, there are usually other more effective options. We recommend strongly against attempting to use vinegar to treat any medical condition [1].
