The effect of vinegar on blood glucose levels is perhaps the best-researched and the most promising of apple cider vinegar’s possible health benefits. Several studies have found that vinegar may help lower glucose levels.
- A 2007 study of 11 people with type 2 diabetes found that taking two tablespoons of apple cider vinegar before bed lowered glucose levels in the morning by 4%-6%.
- A 2005 study in the European Journal of Clinical Nutrition found that vinegar supplementation lowers glucose and insulin responses and increases satiety (fullness) after meals containing carbohydrates.
There have been quite a few studies over the last 20 years investigating the effect that vinegar has on carbohydrate digestions, glycaemic index of food and satiety after a meal. Japanese studies have shown that eating pickled cucumbers with white rice (which ordinarily has a glycaemic index of 100, the same as sugar) reduces the glycaemic index of the rice by 30% – some studies even state up to 35%.
Whilst the earlier studies all used normoglycaemic participants or subjects who were known to have normal glucose metabolism, recent studies have been conducted on subjects with impaired glucose metabolism, such as diabetes and insulin resistance.
A study by Carol Johnston et al published in 2004 found that supplementing with vinegar at mealtimes increased insulin sensitivity by 34% in subjects with IR and 19% in subjects with Type II diabetes.
The degree to which vinegar increases insulin sensitivity and lowers blood sugar after a meal has been found to be dependant upon the dose – the more vinegar you consume, the stronger the action. Whilst this does not mean you should consume an unreasonable amount of vinegar it does mean that different people may need more or less vinegar than others, depending upon the severity of their insulin resistance and their diet. Most studies have used between 20 ml and 30 ml of vinegar with meals to achieve these effects.
It should be noted that vinegar that has been neutralised through adding either salt or baking soda to it does not appear to have any effect on insulin sensitizing or blood glucose levels after a meal. So adding salt to a vinegar based salad dressing may inactivate the benefits.
If you find that drinking vinegar which has been diluted in just plain water is still too acidic for you, you could try adding a little stevia or honey to it, although don’t forget to account for the sugar in honey if you are keeping track of the carbohydrates you consume.
Researchers have speculated that vinegar may be as effective as metformin or acarbose in treating diabetes and that vinegar may even increase the chances of a person returning to a normal, glucose tolerant state, due to it’s insulin sensitizing effect.
Current studies using animals have found that supplementing the diet of spontaneously hypertensive rats with vinegar reduced their blood pressure and appeared to increase the rate of calcium absorption from their food.
A few laboratory studies have found that vinegar may be able to kill cancer cells or slow their growth. One such animal study found that sugar cane vinegar encourages a process called apoptosis or programmed cell death in leukaemia cells and another that rats whose drinking water was supplemented with vinegar prior to being injected with various cancer cells had a much lower rate of tumour occurrence and progression.
A study by the Henan Tumour Institute of an area in China where people had one of the highest rates of oesophageal cancer in China, Linzhou City, found that those people whose diets included vinegar had a much reduced chance of the cancer when compared to others within the same city.
Vinegar contains polyphenols, compounds which are synthesized by plants to help protect themselves from oxidative stress and which are causing interest in coffee, chocolate, tea, wine fruits & vegetables. When polyphenols are ingested by humans, they have a strong antioxidant and therefore anti-cancer property.