Look, if vinegar -- specifically apple cider vinegar -- was as beneficial to your health as suggested by the many claims you run across, it would have been marketed long ago by Eli Lilly instead of H.J. Heinz. That doesn't mean that all the claims are bogus. But you must filter out the myths -- and take the rest with a couple of grains of salt -- and at least four parts of water.
Claim: It Controls Diabetes
A study at Arizona State University tested whether a 2-tbsp. dose of vinegar taken at bedtime could lower waking glucose levels. The hypothesis was based on some limited studies that had indicated a similar amount of vinegar at mealtimes reduced glucose levels. In the test, individuals taking the vinegar showed a 4 to 6 percent reduction in glucose concentrations, much as with the mealtime tests. But remember, all the studies have been small and the glucose reductions haven't been great enough to "control" diabetes. Apparently, it might help a little and probably won't hurt, although a Mayo Clinic report found mixing vinegar with insulin might decrease potassium levels.
Claim: It Facilitates Weight Loss
Vinegar is reputed to both suppress appetite and speed up metabolism. Mayo Clinic nutritionist Katherine Zeratsky says there's little scientific support for such claims. Still, vinegar could contribute to weight loss if you substitute it for salad dressing. Vinegar has a lot fewer calories.
Claim: It Reduces Cholesterol
A study on rats by some Japanese scientists found that vinegar reduced cholesterol levels and triglycerides by a statistically significant amount. But it's worth noting that rats have a different digestive process from humans, and there has not been a test to see if vinegar has a similar benefit in people. It probably wouldn't hurt to up your vinegar intake, but there are other homeopathic remedies that already have proved they can help lower cholesterol in tests using humans.
Claim: It Prevents Pregnancy
The suggestion that a vinegar and water douche soon after sex can prevent pregnancy is most certainly a myth. Sperm swim really, really fast. Even if there were some reason to believe that the douche might actually create a cleansing tidal wave -- and there's not -- your tsunami would need to start in a couple of seconds, not even a minute or so, to have any chance of success.
Claim: It Combats Acne
Vinegar vs. acne is worth a try, but the results depend on the pH -- a measure of acidity -- of your skin. Apple cider vinegar absorbs excessive skin oil, kills bacteria and lowers the pH level of your skin. All those typically lead to good results in the war on pimples. Wash your face with soap and water, then use a cotton ball to apply a mixture of one part vinegar to three parts water. Rinse it off after 10 minutes. Follow the procedure three times a day, and for severe acne cases, leave the mixture on overnight.
Claim: It Fights Constipation -- or Diarrhea
Doctors don't prescribe vinegar for digestive problems, but that doesn't mean it won't help in mild cases. For constipation, mix 2 tbsp. of vinegar with 8 oz. of either apple juice or prune juice. Apple cider has lots of pectin, a water-soluble fiber that boosts digestion. Pectin -- plus vinegar's bacteria-killing abilities -- also contributes as a remedy for diarrhea. For a day, drink 2 tbsp. of vinegar mixed into 8 oz. of water three times.
Claim: It Boosts Energy
Revolutionary war hero Francis "Swamp Fox" Marion supposedly sipped vinegar water because it gave him more energy. More likely, he drank it because vinegar helped purify water he got from questionable supplies. But to replace electrolytes lost during strenuous exercise, try a mixture of water, salt and vinegar. If that sounds suspiciously like pickle juice, that's because it is. In fact, a Texas company picked up on the rumored popularity of pickle juice as an electrolytic-replacement drink and began marketing a version. It has lots of sodium and potassium, but no calories.