APPLE CIDER VINEGAR - What Should I Know About It?

By Cathy Wong, ND

Alternative Medicine Expert

Updated June 21, 2014. 
Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Apple cider vinegar is a type of vinegar made by the fermentation of apple cider. During the fermentation process, sugar in the apple cider is broken down by bacteria and yeast into alcohol and then into vinegar. Like other types of vinegar, apple cider vinegar contains acetic acid and it also contains some lactic, citric and malic acids.

Health Benefits of Apple Cider Vinegar:

To date, few studies have tested the health effects of apple cider vinegar. Here's a look at some key findings from the available research:

1) Diabetes

Some preliminary research suggests that vinegar (both apple cider vinegar and other types) may benefit people with diabetes. For example, in a 2007 study published in Diabetes Care, researchers found that type 2 diabetes patients who consumed two tablespoons of apple cider vinegar at bedtime showed favorable changes in blood sugar levels the following morning.

In an animal-based study published in thePakistan Journal of Biological Sciences, scientists found that diabetic rats fed an apple-cider-vinegar-enhanced diet for four weeks experienced an increase in HDL ("good") cholesterol (as well as a reduction in their levels of triglycerides, a type of harmful blood fat).

2) Weight Loss

There is limited scientific support for the claim that apple cider vinegar can promote weight loss. However, one small study (published in Bioscience, Biotechnology, and Biochemistry in 2009) found that obese people who consumed acetic acid daily for 12 weeks experienced significant decreases in body weight, abdominal fat, waist circumference, and triglycerides. In tests on mice, another 2009 study (published in the Journal of Agricultural and Food Chemistry) found that acetic acid may help prevent the buildup of body fat and certain liver fats. It's unknown whether these studies tested the use of acetic acid derived from apple cider vinegar or from other vinegar types.

3) High Blood Pressure

Acetic acid may help lower high blood pressure, according to an animal-based study published in Bioscience, Biotechnology, and Biochemistry in 2001. Again, it's unknown whether this study tested the use of acetic acid derived from apple cider vinegar or from another vinegar type.

4) High Cholesterol

Published in the British Journal of Nutrition, a 2006 study found that rats fed acetic acid for 19 days had a significant reduction in total cholesterol and triglyceride levels.

5) Dandruff

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 or twice a week for dandruff.

6) Acne

When using apple cider vinegar to treat acne, some alternative practitioners recommend mixing one part apple cider vinegar with three parts water. The solution is then dabbed onto the pimple. Since there have been case reports of skin damage and burns from using full-strength vinegar on the face, it's important to take caution when using this remedy.

7) Alkaline Acid Balance

Some alternative practitioners recommend using apple cider vinegar to restore alkaline acid balance. The theory behind the alkaline diet is that our blood is slightly alkaline (with a normal pH level of between 7.35 and 7.45) and that our diet should reflect this pH level. 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 increased risk of 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. As such, they recommend one to two teaspoons of apple cider vinegar in water as a daily health tonic. Although this is a popular remedy, its effectiveness hasn't been researched.

Other Common Uses For Apple Cider Vinegar:

Proponents claim that apple cider vinegar can also help with the following health conditions:

• allergies
• arthritis
• chronic fatigue syndrome
• flu
• gout
• heartburn
• sore throat

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.

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.

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.

Where to Find Apple Cider Vinegar:

Unlike white vinegar, apple cider vinegar is a light yellow-brown color and is often sold unfiltered and unpasteurized with a dark, cloudy sediment settled at the bottom of the bottle. Known as "mother of vinegar," this sediment consists mainly of acetic acid bacteria. Unfiltered and unpasteurized apple cider vinegar is sold in health food stores, online and in some grocery stores.

Apple cider vinegar is also sold in tablet form. However, it should be noted that the quality of apple cider vinegar tablets may vary. For example, 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. What's more, the chemical analysis of the samples led researchers to question whether any of the products were actually apple cider vinegar or simply acetic acid. In addition, apple cider vinegar tablets may become lodged in the throat or esophagus and cause serious damage to those tissues.

History of Apple Cider Vinegar:

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 (although 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.

In the 1970s, apple cider vinegar became popular once again, this time with the help of 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.

Using Apple Cider Vinegar for Health:

If you're considering the use of apple cider vinegar for a specific health problem, it's important to consult your doctor before using it.

Sources:

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.

Hlebowicz J, Darwiche G, Björgell O, Almér LO. "Effect of apple cider vinegar on delayed gastric emptying in patients with type 1 diabetes mellitus: a pilot study." BMC Gastroenterol. 2007 Dec 20;7:46.

Kondo S, Tayama K, Tsukamoto Y, Ikeda K, Yamori Y. "Antihypertensive effects of acetic acid and vinegar on spontaneously hypertensive rats." Biosci Biotechnol Biochem. 2001 Dec;65(12):2690-4.

Kondo T, Kishi M, Fushimi T, Kaga T. "Acetic acid upregulates the expression of genes for fatty acid oxidation enzymes in liver to suppress body fat accumulation." J Agric Food Chem. 2009 Jul 8;57(13):5982-6.

Kondo T, Kishi M, Fushimi T, Ugajin S, Kaga T. "Vinegar intake reduces body weight, body fat mass, and serum triglyceride levels in obese Japanese subjects." Biosci Biotechnol Biochem. 2009 Aug;73(8):1837-43.

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.

Shishehbor F, Mansoori A, Sarkaki AR, Jalali MT, Latifi SM. "Apple cider vinegar attenuates lipid profile in normal and diabetic rats." Pak J Biol Sci. 2008 Dec 1;11(23):2634-8.

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.

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