And an ingredient called xylitol has been shown to add an extra dose of cavity-fighting power. The benefits of that may extend beyond the mouth: A growing body of research suggests that good oral health decreases the risk of heart disease, premature birth and diabetes.
Last February, in a study published in the journal Archives of Surgery, California researchers found that, among 34 people who received colon surgery, those who chewed gum during recovery were able to leave the hospital sooner. Abdominal surgery can stop or slow the workings of the intestines, and people can't usually eat right away. Chewing gum instead may, like chewing food, stimulate the release of gut-healing hormones.
There are mental benefits too, Wrigley's Leveille says. He cites a Chinese study of nine people that found chewing gum boosted blood flow to the brain by as much as 40%. And a Britain-based study on 75 people, published in the journal Appetite in 2002, found that chewers did better in a word memory test.
From a list of 15 words, gum chewers recalled eight or nine words right away and seven words 25 minutes later. Nonchewers and people who pretended to chew remembered six or seven words at first and five words later. Although the scientists don't know the reason, they hypothesize that the act of chewing increases a person's heart rate and delivers more oxygen to the brain.
Weight loss is another hot area of research. People have long claimed that chewing gum helps them avoid snacking, Leveille says, but data are scarce -- and conflicting. For example, in a 2006 study published in Appetite, University of Liverpool researcher Dr. Marion Hetherington found that among 60 people, those who chewed gum snacked on 36 fewer calories three hours after a meal and reported craving fewer sweets.
But a soon-to-be-published paper by Purdue University nutritionist Richard Mattes found no such link. In his trial, 47 people chewed gum either when they were hungry, two hours after lunch, or not at all. At the end of the day, all groups had eaten about the same number of calories. "I think this topic is best characterized as understudied," Mattes says.
Could one maybe add something to gum to damp the appetite? Some small brands offer gums with chromium, touted as an appetite suppressant, and British scientists recently received funding to research a hormone called pancreatic polypeptide in injection and gum form. However, even though the body produces the hormone in response to food, there is no scientific evidence to back either one as a weight loss aid, says Gayl Canfield, a registered dietitian at the Pritikin Longevity Center & Spa in Aventura, Fla.
