Chewing on a stick of gum is supposed to help a variety of things like concentration, appetite, even stress.  But chewing gum isn't necessarily all good for you.

Experts say chewing gum could lead to gastrointestinal problems. When you chew gum, you swallow excess air which can lead to abdominal pain and bloating.

Also, chewing gum may cause you to eat fewer healthy foods. Researchers believe minty gums can give fruits and vegetables a bitter taste, making you want to eat junk food.

Another nasty side effect: gum can release mercury into your body. Research has shown the act of chewing gum can release a small amount of mercury from silver teeth fillings into your system.