A common way of fulfilling a dietary dose of cider vinegar is to utilize it in salad dressing or take a small shot glass of the tonic before a high caloric meal, especially before consuming protein such as beef that requires a longer period for digestion. A Japanese study in 2003 found that the glycemic index (GI) was reduced by over 30% when the simple swap of a pickled cucumber was made for a fresh cucumber (1).

Researchers believe that cider vinegar has antiglycemic properties and plays a pivotal role in regulating sugar levels in type 2 diabetics. Specifically, it is possible that a key component of the vinegar acts as an antiglycemic agent by mocking the chemical pathway of the drug, metformin, used by diabetic patients. Side effects of metformin use include drowsiness, nausea, and diarrhea among other problems (2). Metformin use is also linked to liver disease and heart failure. (3, 4)

Post prandial glycemia is a spike in an individual's blood glucose levels following meals. The simple introduction of vinegar consumption with a meal improved blood glucose sensitivity in several studies. The Diabetes Journal published a study in 2007 assessing the effects of vinegar on waking hyperglycemia in type 2 diabetic individuals, a condition known as "dawn phenomenon" (5).

Noted was a 4-6% reduction in fasting glucose levels when individuals received only 2 tablespoons of apple cider prior to a meal, in comparison to a lower 3-6% fasting glucose reduction when the same individuals received pharmaceutical treatment. Another study showed that women had a 55% reduction in the blood glucose response following a morning meal containing vinegar (6).