Other names: cider vinegar, ACV, acetic acid
Apple cider vinegar is a type of vinegar made by the fermentation of apple cider. During this process, sugar in the apple cider is broken down by bacteria and yeast into alcohol and then into vinegar. Apple cider vinegar contains acetic acid (like other types of vinegar) and some lactic, citric and malic acids.
Unlike white vinegar, apple cider vinegar is a light yellow-brown color and is often sold unfiltered and unpasteurized with a dark, cloudy sediment called mother of vinegar (consisting mainly of acetic acid bacteria) settled at the bottom of the bottle.
Unfiltered and unpasteurized apple cider vinegar is sold in health food stores, online and in some grocery stores.
Although other types of vinegar — such as white vinegar, balsamic vinegar, red wine vinegar and rice wine vinegar — are used mainly in cooking, apple cider vinegar is used primarily for health purposes. Hippocrates was said to have used it as a health tonic and American soldiers are said to have used it to combat indigestion, pneumonia and scurvy.
But it wasn’t until the book Folk Medicine: A Vermont Doctor’s Guide to Good Health, written by D.C. Jarvis, M.D., was published in 1958 that the medicinal use of apple cider vinegar took off. Jarvis recommended apple cider vinegar as a cure-all, explaining that it was unusually rich in potassium (compared to other food sources, it is not). He said that mixing the apple cider vinegar with honey, a mixture he called “honegar,” enhanced the healing power of the vinegar. Jarvis also wrote that apple cider vinegar could destroy harmful bacteria in the digestive tract and recommended as a digestive tonic to be consumed with meals.
Although the year it was released it didn’t attract much attention, the following year, Folk Medicine became a bestseller and stayed on the bestseller list for months. According to Time magazine, it sold more than 245,000 copies in a single week and received many testimonials by people who felt they benefited from the apple cider vinegar and honey mixture.
In the 1970s, apple cider vinegar became popular once again, this time by proponents who had read Jarvis’ book and suggested that apple cider vinegar along with kelp, vitamin B6 and lecithin could help people lose weight by speeding metabolism and burning fat at a faster rate.
Why Do People Use Apple Cider Vinegar
Perhaps the most intriguing aspect of apple cider vinegar’s possible health benefits is its effect on blood glucose levels. Several small studies suggest that vinegar (both apple cider vinegar and other types) may help to lower glucose levels.
For example, a preliminary study by researchers at Arizona State University, published in the journal Diabetes Care, examined people with type 2 diabetes. Study participants took either two tablespoons of apple cider vinegar or water with one ounce of cheese at bedtime for two days. The researchers found taking two tablespoons of apple cider vinegar at bedtime had a favorable impact on blood glucose levels the next morning. Prior to the study, the average fasting blood glucose level was 137 mg/dL. It decreased by 2% with the cheese and by 4% with the vinegar, a statistically significant difference. In people with a fasting glucose level above 130 mg/dL prior to the study, the vinegar reduced glucose levels by as much as 6%. The study was very small and the duration was short, so more research is needed.
Other studies have found that vinegar can lower the post-meal rise in glucose. The acetic acid in vinegar is thought to slow starch digestion and reduce the glycemic index of starchy foods. For example, a small study compared the effect of vinegar with white bread on blood glucose and insulin levels. Researchers found that those who took vinegar with white bread had lower post-meal blood glucose and insulin levels and it also appeared to increase satiety ratings.
Apple cider vinegar has become popular as a “fat-burner” and as a natural appetite suppressant. In fact, there’s even an apple cider vinegar diet, which involves taking one to three teaspoons of apple cider vinegar or apple cider vinegar pills before each meal.
The earliest proponent of apple cider vinegar for weight loss was Jarvis, who wrote that people who consumed apple cider vinegar regularly would burn fat instead of store it. Although some say that the pectin, enzymes, vitamins, or potassium may help with weight loss, there is no reliable research showing that either apple cider vinegar or the combination of apple cider vinegar, kelp, vitamin B6 and lecithin can influence metabolic rate or the help us “burn fat” faster than we normally would.
One small study in 2005 found that those who ate a piece of bread with a small amount of white vinegar felt more full and satisfied than those who ate the bread alone. It’s possible that vinegar may affect satiety by lowering the glycemic index of carbohydrates eaten at a meal. More research is needed.
Alkaline Acid Balance
Some alternative practitioners suggest apple cider vinegar as part of a diet to restore alkaline acid balance. The theory behind the alkaline diet is our blood is slightly alkaline, with a normal pH level of between 7.35 and 7.45. Our diet should reflect this pH level and be slightly alkaline. All foods we eat, after being digested and metabolized, release either an acid or alkaline base (bicarbonate) into blood. The foods that people tend to overeat –- grains, meat, dairy products — all produce acid.
Proponents of the alkaline-acid theory believe that a diet high in acid-producing foods leads to lack of energy, excessive mucous production, infections, anxiety, irritability, headache, sore throat, nasal and sinus congestion, allergic reactions and makes people prone to conditions such as arthritis and gout. Despite being an acidic solution, some proponents of apple cider vinegar believe it has an alkalinizing effect on the body, which is why one to two teaspoons of apple cider vinegar in water is recommended as a daily health tonic. Although it’s a popular remedy, the effectiveness of the remedy and the theory haven’t been researched.
A home remedy for dandruff is to mix 1/4 cup apple cider vinegar with 1/4 cup water. The vinegar solution is thought to restore the restore the pH balance of the scalp and discourage the overgrowth of malassezia furfur, the yeast-like fungus thought to trigger dandruff.
The vinegar mixture is usually poured into a spray bottle and spritzed on the hair and scalp, avoiding the eye and ear area. A towel is then wrapped around the head and left on 15 minutes to an hour. After that, the vinegar can be washed from the hair. Alternative practitioners often recommend it once to twice a week for dandruff.
A 2006 study found that rats fed acetic acid (the main ingredient in vinegar) had significantly lower total cholesterol and triglyceride levels. Large, human trials are needed to see if the same results occur in humans.
Apple cider vinegar in water is a popular home remedy for acid reflux. It’s based on a theory by some alternative medicine practitioners that heartburn and reflux are actually symptoms of insufficient stomach acid caused by aging, poor diet or overusing antacids or other medications. Alternative practitioners usually rely on laboratories that conduct alternative tests to assess stomach acidity prior to any treatment. Critics say that insufficient stomach acid, or hypochlorhydria, isn’t a common condition and that it isn’t a known cause of acid reflux or heartburn.
Apple cider vinegar isn’t recommended as a home remedy for acid reflux or heartburn, because it may damage the delicate lining of the digestive tract and it could possibly worsen the problem. If you have acid reflux or heartburn, see a qualified health practitioner for a proper diagnosis and treatment.
Apple cider vinegar is a home remedy for acne. A typical application is one part apple cider vinegar to three parts water and the solution is dabbed onto the pimple. Although some people swear by it, caution should be used because there have been case reports of skin damage and burns from using full-strength vinegar on the face.
Preliminary studies suggest that the acetic acid in vinegar may help to lower blood pressure. How it might work is unclear, although studies suggest that it may increase levels of nitric oxide, a compound in the body that relaxes blood vessels, or it might inhibit an enzyme called angiotensin-converting enzyme from producing angiotensin II, a hormone that causes blood vessels to constrict or narrow.
Side Effects and Safety Concerns:
Undiluted apple cider vinegar, in liquid or pill form, may damage the esophagus and other parts of the digestive tract. Apple cider vinegar drinks may damage tooth enamel if sipped.
One case report linked excessive apple cider vinegar consumption with low blood potassium levels (hypokalemia) and low bone mineral density. People with osteoporosis, low potassium levels and those taking potassium-lowering medications should use caution.
People with allergies to apples should avoid apple cider vinegar.
Apple cider vinegar tablets may become lodged in the throat or esophagus and cause serious damage to those tissues.
Vinegar applied to the skin may cause burns and scarring.
Excessive doses of apple cider vinegar have been found to cause damage to the stomach, duodenum and liver in animals.
The quality of apple cider vinegar tablets varies. A 2005 study compared eight brands of apple cider vinegar supplements and found that the ingredients didn’t correspond with the ingredients listed on the packaging, and that the chemical analysis of the samples led researchers to question whether any of the products were actually apple cider vinegar or whether they were just acetic acid.
Possible Drug Interactions:
Theoretically, prolonged use of apple cider vinegar could lead to lower potassium levels, which could increase the risk of toxicity of cardiac glycoside drugs such as Lanoxin (digoxin), insulin, laxatives and diuretics such as Lasix (furosemide).
Because apple cider vinegar may affect blood glucose and insulin levels, it could theoretically have an additive effect if combined with diabetes medications. Apple cider vinegar may also lower blood pressure, so it may have an additive effect if combined with high blood pressure medications.
Resources:Fushimi T, Suruga K, Oshima Y, Fukiharu M, Tsukamoto Y, Goda T. Dietary acetic acid reduces serum cholesterol and triacylglycerols in rats fed a cholesterol-rich diet. Br J Nutr. (2006) 95.5: 916-924.
Ostman E, Granfeldt Y, Persson L, Björck I. Vinegar supplementation lowers glucose and insulin responses and increases satiety after a bread meal in healthy subjects. Eur J Clin Nutr. (2005) 59.9: 983-988.
White AM, Johnston CS. Vinegar ingestion at bedtime moderates waking glucose concentrations in adults with well-controlled type 2 diabetes. Diabetes Care. (2007) 30.11: 2814-2815.