The best evidence concerns gum’s ability to prevent cavities by boosting saliva flow and neutralizing acid produced by mouth bacteria. Sugar-free gums are best for this, notably those with the sugar alcohol xylitol, which suppresses the growth of cavity-producing bacteria. Still, gum can’t replace brushing and flossing.
Can gum sweeten your breath? Wrigley’s Eclipse gum now contains magnolia bark extract, which reduces the bacteria in saliva that cause bad breath, according to company testing published in the Journal of Agricultural and Food Chemistry in 2007. But most gums are just a temporary fix at best, masking odors without addressing the underlying cause. Sugary gums might make matters worse. Rinsing your mouth with water after eating, if you can’t brush, may be just as good as gum.
Gum chewing burns only about 11 calories an hour. But if it keeps you from eating a candy bar, that’s a big plus. Studies on whether gum reduces appetite have produced conflicting findings. A study published in the journal Appetite found that when women chewed gum (15 minutes, once an hour, for three hours), they ate about 30 fewer calories when subsequently offered a snack, compared to when they hadn’t chewed gum. But each piece of gum had 5 to 10 calories, so the women didn’t actually cut down on calories significantly. Would sugarless gum have had the same effect? Maybe, maybe not.
Early research found that gum chewing improved performance on memory tests. But other studies have failed to find any brain benefit—or have noted that gum sometimes worsens performance. A study in Appetite found that gum improved performance on certain cognitive tests, but only when it was chewed before, not during, the tests. The benefit lasted just 15 to 20 minutes. According to the researchers, gum doesn’t help thinking—and possibly even impairs it—during a task because of “interference.” Some people can’t think (or walk) and chew gum at the same time.
According to a recent review in the Archives of Surgery, chewing gum after intestinal surgery reduces the time it takes for normal bowel function to return—a critical step in recovery. It’s thought to mimic eating, which promotes the wavelike muscle contractions in the intestines needed to move food through. Chewing gum also seems to decrease stomach acidity, but studies are mixed about whether it helps with actual heartburn symptoms. It may be worth a try.
Can chewing gum slow aging, treat impotence, make you smell better? If only. Gums with wacky ingredients and far-out claims are all over the Internet, many developed in Japan. They boast of platinum nanoparticles for anti-aging effect, herbs said to have a Viagra-like effect and ingredients that supposedly alter body odor. There are gums with ginseng to boost immunity, and with ginger to cure seasickness. None are proven (or likely) to work, but they make good party conversation.
Contrary to myth, swallowed gum does not take weeks, months or even years to digest (it passes out in stool unchanged, in normal transit time). But constant chewing can wear down tooth enamel, and too much sugarless gum can have a laxative effect, due to the sugar alcohols. There’s no evidence that chewing gum causes temporomandibular disorder (TMD), but it can worsen jaw pain if you already have it. Most important, no matter what the claims, no gum can take the place of brushing, flossing and regular dental check-ups.