Q. Can I eat vinegar to prevent diabetes and lose weight?

A. Research has shown that vinegar improves blood sugar and insulin responses to high-carbohydrate meals. This is why it may help prevent diabetes as well and control weight.

During digestion, carbohydrates in foods such as rice, bread or noodles break down into a sugar called glucose. When glucose reaches the bloodstream, the hormone insulin sends it to muscle, brain and liver cells to be used for energy or stored for later use.

During the early stages of diabetes known as pre-diabetes, insulin is unable to move all of the sugar into the cells. This causes an abnormally high spike in blood sugar levels after meals. Repeated spikes can lead to full-blown diabetes.

University of Arizona researchers studied the effects of vinegar on these blood sugar spikes. Participants were given a mixture of vinegar, water and artificial sweetener before eating a high-carbohydrate meal. Healthy nondiabetic participants were compared with those with diabetes and pre-diabetes. Blood sugar readings and insulin responses improved in all groups after drinking the vinegar mixture. Those with pre-diabetes had the best results of all.

In a four-week followup study, the same researchers gave participants two tablespoons of vinegar before two meals daily. They wanted to study the longer term effect of vinegar on blood sugar and also on cholesterol. Cholesterol didn't improve, however the participants who drank vinegar lost an average of 2 pounds — some even lost 4 pounds.

Recently, Swedish researchers studied healthy volunteers. They found that in addition to improving blood sugar and insulin responses to carbohydrates, two to three tablespoons of vinegar before meals increased satiety or feelings of fullness. This may explain its role in weight control.

All of the studies on vinegar to date have used only a small number of participants and have been of short duration, making it difficult to draw long-term conclusions. Even so, it is inexpensive and safe to use vinegar. Use vinegarette on salads or as a marinade for vegetables. Eat namasu or pickles. Drink vinegar and water before meals.

Steer clear of commercial vinegar supplements as they have very little acetic acid. Acetic acid is the ingredient responsible for the antidiabetic and satiety affects of vinegar.

Remember vinegar is meant to supplement a healthy diet and exercise program, not as a replacement for it.

Amy Tousman is a registered dietitian with the Health Education Center of Straub Clinic and Hospital. Hawai'i experts in traditional medicine, naturopathic medicine and diet take turns writing the Prescriptions column. Send your questions to: Prescriptions, Island Life, The Advertiser, P.O. Box 3110, Honolulu, HI 96802; fax 535-8170; islandlife@honoluluadvertiser .com. This column is not intended to provide medical advice.