Apple cider vinegar, a product of fermented apple cider, is not only a kitchen staple but a highly regarded health food. While most of its health claims are based on anecdotal evidence or its reputation as a folk remedy, there are a limited number of studies -- including animal studies -- that have helped support or refute the claims. If you are considering treating a medical condition with apple cider vinegar, consult with your doctor first for advice and treatment recommendations.
Among vinegar's health claims, the impact on diabetes and blood sugar control is one of the most studied. One small study published in the January 2013 issue of "Journal of Diabetes and Endocrinology" added 1 tablespoon of vinegar to the daily diet of people with type 2 diabetes, and after 30 days -- without any other treatment changes -- an 18-point drop in fasting blood sugar was noted. While this study was not specific to apple cider vinegar, the concentration of acetic acid -- the active compound researchers link to its health benefits -- is similar among different types of vinegar. But not everyone with diabetes may benefit, as vinegar may delay gastric emptying and aggravate gastroparesis, a diabetes complication characterized by slow stomach emptying.
Apple cider vinegar is often regarded as an aid for weight loss. The majority of weight loss studies have been completed in animals; however, there have been some small studies completed in humans. One such study published in the August 2009 issue of "Bioscience, Biotechnology, and Biochemistry" found that a daily intake of 1 or 2 tablespoons of apple cider vinegar helped obese Japanese adults lose weight over the 12-week study. According to an article published in the May 2014 issue of "Journal of Food Science," vinegar's acetic acid appears to help weight loss by causing greater satiety, or fullness, and facilitating a reduction in calorie intake.
Although not specific to apple cider vinegar, soaking dentures in a 10 percent vinegar solution for 45 days lowered the levels of the fungus Candida albicans and reduced the rates of mouth inflammation, according to a study published in the December 2008 issue of "Journal of Applied Oral Science." Claims of treating halitosis, or bad breath, with apple cider vinegar are not supported by current research. Since the acid level of the vinegar could damage the enamel in teeth if not rinsed away, using vinegar to treat bad breath could do more harm than good.
The acetic acid content of apple cider vinegar makes it a candidate for killing germs. Research published in the March-April 2014 issue of "mBio" discussed vinegar's ability to kill or significantly reduce levels of mycobacteria -- a family of bacteria that causes infections such as tuberculosis -- when these germs were exposed to vinegar with at least 6 percent acetic acid for 30 minutes. Apple cider vinegar, like most vinegar, contains at least 5 percent acetic acid, so more research is needed to clarify the effectiveness of different types of vinegar. According to the Centers for Disease Control and Prevention, vinegar is not registered as a disinfectant with the Environmental Protection Agency because it does not kill Staphylococcus aureus, but undiluted vinegar may be effective against certain strains of Escherichia coli.
Apple cider vinegar has been shown to be effective in lowering blood pressure in animal studies, but this has not been studied in human trials, according to a May 2006 review article in "Medscape General Medicine." Apple cider vinegar is also claimed to lower cholesterol. While animal studies have found small successes, a human trial referenced in the April 2013 issue of "World Journal of Cardiovascular Diseases" did not find any improvement in cholesterol levels in study participants who consumed 2 tablespoons of apple cider vinegar for 8 weeks.
Apple cider vinegar has been regarded as a treatment for acne; however, there are no scientific studies to back up this claim. There is also speculation that it may be useful to remove warts. No studies confirm this and in fact, an article in the January 2012 issue of "Virology Journal" concluded that apple cider vinegar was not successful in treating warts. Apple cider vinegar is also recommended as a treatment for age spots when applied topically. Currently, there is no research to support this claim and because of the acidity of vinegar, topical treatments could cause irritation.
Warnings and Precautions
Despite the many touted health benefits of apple cider vinegar, a surprisingly limited number of research studies exist to back up these claims. While including 1 to 2 tablespoons of vinegar may add flavor and potential benefits to blood sugar or weight control, caution applies if using vinegar as a supplement. Consult your doctor if you are considering using vinegar to manage any health conditions or if you take any prescription medications. While vinegar is generally considered safe, undiluted liquid vinegar or supplements have rarely been linked to throat injury due to the acidity. Apple cider vinegar has not been extensively studied for its use as an alternative treatment and is not listed with the National Center for Complementary and Integrative Health. At the present time, more human studies need to be conducted to confirm the health benefits of apple cider vinegar.