Apple cider vinegar
ACV is used in salad dressings, marinades, vinaigrettes, food preservatives, and chutneys, among other things. It is made by crushing apples and squeezing out the liquid. Bacteria and Yeast are added to the liquid to start the alcoholic fermentation process, and the sugars are turned into alcohol. In a second fermentation process, the alcohol is converted into vinegar by acetic acid-forming bacteria (acetobacter). Acetic acid and malic acid give vinegar its sour taste.
Vinegar (and other acidic liquids) have long been proposed as agents to enable weight loss, one proposed mechanism is that it prolongs the sensation of satiety after eating. A 2009 study on mice showed that consuming acetic acid (the active component in ACV), upregulates the expression of genes for fatty acid oxidation enzymes in the liver causing a suppression in body fat accumulation.
In a double-blind experiment, obese Japanese were assigned to three different groups based on similar body weights, body mass indexes (BMI), and waist circumference. Each group drank a 500 ml drink containing either 30 ml, 15 ml, or 0 ml of vinegar daily for 12 weeks. Those in the 30 ml and 15 ml groups had lower BMI, visceral fat area, waist circumference, serum triglyceride, and body weight than the control group of 0 ml. The 12-week weight losses were modest: 1.2 kg in the 15 ml group and 1.7 kg in the 30 ml group. These two groups consumed fewer calories than the control group, so the effect may have been due to an impact on appetite. It was concluded that consumption of vinegar might reduce obesity.
Apple cider vinegar tablets can also be taken, although there is much evidence against there being value in taking the tablet version, as ACV pills are not well regulated, and may vary dramatically in terms of vinegar content from brand to brand.
People have also been know to take it for indigestion believing the acid helps breakdown protein.
A report regarding an Austrian patient who had consumed excessive amounts of apple cider vinegar (up to 250ml per day) for six years suggests that long-term, high dosage intake of apple cider vinegar can lower potassium levels in the body as well as reduce bone density (osteoporosis); it is theorized that excessive intake of vinegar can cause hypokalemia, hyperreninemia, and osteoporosis. Apple cider vinegar contains chromium which can alter insulin levels and it is therefore recommended that people who have diabetes should talk to their doctors before using ACV. ACV is highly acidic; in one recorded instance, a woman received esophageal burns after an ACV pill got caught in her throat.