Any fruit or food containing sugar can convert to vinegar, according to the website VerstileVinegar.org. Fruit or sugary foods convert to vinegar in a two-stage process: yeasts first transform the the sugar to alcohol, followed by a stage in which bacteria act on the alcohol to make acetic acid. In addition to its acetic acid content, vinegar is a complex food containing a variety of vitamins, minerals and other substances from its original source that lend distinct properties to the final product. Some of the health benefits of vinegar are documented in research.
Apple cider vinegar fed to diabetic and non-diabetic rats for four weeks resulted in significant changes in blood lipids, according to a 2008 "Pakistan Journal of Biological Sciences" study. Researchers observed a significant reduction of low-density lipoprotein, or LDL cholesterol, and a significant increase of high density lipoprotein, HDL cholesterol, in normal rats. Apple cider vinegar also reduced serum triglyceride levels and increased HDL in diabetic animals.
A study in the 2010 "Food and Chemical Toxicology" found that compounds called melanoidins in balsamic vinegar feature antioxidant properties that protect lipids from oxidation. The study, which did not use human or animal subjects, simulated the process of digestion on turkey meat. Researchers report encouraging prospects for the use of melanoidins as antioxidants in cardiovascular disease prevention.
Blood Sugar Management
Vinegar given to human subjects reduced the spike in blood sugar following a high glycemic index meal, according to a 2010 "European Journal of Clinical Nutrition" study. Participants were fed a meal of mashed potatoes with low-fat milk on two different days -- one meal with vinegar and one without. The vinegar-containing meal resulted in a lower overall increase in blood glucose. The study also looked at the effects of vinegar on a meal not categorized as high glycemic index and found no change in blood glucose or insulin values compared to the same meal without vinegar, leading the researchers to conclude that vinegar only effects blood sugar following a high glycemic index meal and can be useful in the management of blood sugar.
A study of the effects of white rice vinegar on rats that were induced to have diabetes had promising results. The 2010 "Acta Diabetologica" study fed rats a vinegar-containing diet for one month and reported lower fasting and random blood glucose, higher fasting serum insulin and improved function of the beta cells of the pancreas. Changes in the liver including improved glycogen storage and improvement in diabetes-related fatty changes were also noted.
Metabolic syndrome is a group of symptoms, including increased blood pressure, elevated insulin and cholesterol levels and abdominal fat deposits, that increase the risk for cardiovascular disease, stroke and diabetes, according to the Mayo clinic. In a study in the 2010 "Journal of Nutrition" rats were fed diets that induced metabolic stress including elevated abdominal and hepatic fat deposition, collagen deposition in heart and liver, abnormal cholesterol levels, impaired glucose tolerance and hypertension. After 16 weeks, the group fed olive leaf extract along with the poor diet had better cardiovascular and metabolic signs than the group that did not receive the olive leaf extract.