Dear Doctor: What are the benefits of apple cider vinegar? I hear about it on social media, but I don’t understand how vinegar can lead to weight loss or help me control my blood sugar.
My mom is a big proponent of apple cider vinegar. She likes to put it on her salads, vegetables or just drink a spoonful of it. I am somewhat dubious about her claims of its health benefits, but I am also skeptical of my own reticence not to accept her belief.
Vinegar is created by the fermentation of many natural substances, including grapes, sugar cane, rice and, in this case, apples. The fermentation process produces acetic acid of various concentrations and, with apple cider vinegar, the acidity is fairly high – at a pH of about 3 on a scale of 0 to 14 (a pH of 1 to 7 is acidic). Apple cider vinegar also contains many polyphenols, or plant-based compounds. These antioxidant compounds have been shown to decrease blood pressure in laboratory animals, improve the ability to metabolize sugar, and have beneficial effects on cholesterol.
Now let’s analyze the potential medical benefits of apple cider vinegar. In one interesting study, researchers removed the ovaries of mice to increase their oxidative stress and to mimic menopause; then they fed the mice a high-cholesterol diet. One group of mice was given apple cider vinegar while another group was not. The mice given apple cider vinegar had improvements in their cholesterol; a decrease in the oxidation of LDL, the so-called “bad,” cholesterol; and an increase in the antioxidant glutathione. However, there were only 10 mice in each of the groups. So the numbers don’t carry much power.
In a French study of rats fed a high-fat diet and apple cider vinegar, researchers found a decrease in blood sugar and benefits in all cholesterol numbers – triglycerides, LDL cholesterol and HDL cholesterol. Researchers also found in the apple cider vinegar group a decrease in food intake and a decrease in body weight. The authors proposed that apple cider vinegar had an effect of reducing appetite. Again, the number of rats in the study was small, with only six rats in the apple cider vinegar group.
Obviously, rodents are not humans, but that said, many studies in humans have shown that vinegar reduces the glycemic response and the glycemic index of sugars and carbohydrates. Vinegar itself may help lower blood sugar, but the mechanism of action is not understood.
Along those lines, a 2004 study looked at 11 patients who had insulin resistance and 10 patients who had type 2 diabetes. Compared with a placebo, apple cider vinegar improved patients’ insulin sensitivity, meaning that it improved insulin’s ability to bring sugar out of the bloodstream and into the cells of the body. Also, apple cider vinegar decreased the rise of both sugar and insulin when the subjects were given a bagel and orange juice, normally insulin- and glucose-spiking foods. Lastly, in a Swedish study of 12 healthy males given bread both with and without white vinegar, those who consumed the vinegar showed a lowering of blood sugar and insulin. Also the group who consumed the vinegar felt full more quickly.
So the benefit of apple cider vinegar may be in vinegar itself, not anything specific to the vinegar from the fermentation of apples. The studies above are not long-term studies in humans, so it’s difficult to make a conclusion about long-term benefits of apple cider vinegar or any other vinegar. However, the next time my mom feeds me a salad drenched in apple cider vinegar and quotes to me its health benefits, I may have to hold my tongue. She may be right.
Robert Ashley, MD, is an internist and assistant professor of medicine at the University of California, Los Angeles.
Ask the Doctors is a syndicated column first published by UExpress syndicate.