6th Grade · Science · Activity · shared by Luke Morgan
Investigate salivary enzymes and carbohydrate digestion, focusing on chemical digestion in the mouth, with this free 6th Grade Science activity.
Case Study: The Mystery of the Dry Mouth Diner
Thirteen-year-old Leo has always loved eating pasta and potatoes, but lately, he has noticed something strange. While his friends talk about how delicious their lunch is, Leo feels like he is chewing on dry paper. He also finds that he gets an upset stomach almost every time he eats a meal high in carbohydrates, like bread or rice. Leo visited a specialist, Dr. Aris, who discovered that Leo’s body does not produce enough saliva. This condition is called xerostomia , or chronic dry mouth.
Breaking down food is a long process that starts in your mouth. Special spots called glands make a watery liquid to help you eat. This liquid contains an important protein called salivary amylase . This protein targets complex energy foods like starch . When you chew, this liquid begins a chemical change that breaks the long chains of food into smaller parts. These smaller parts are a simple sugar called maltose , which your body can use for energy later. Without enough of this liquid, the food bits stay in their long form as they leave the mouth. This can cause a belly ache because the body has to work harder to finish the job. Because the change into maltose never happens in the mouth, the food also does not have its natural sweet taste.
Dr. Aris explained to Leo and his parents that his lack of saliva means the chemical digestion of his food isn't starting correctly. Because Leo has low salivary production, the amylase cannot mix with the starch in his pasta. As a result, the starch stays as long chains instead of turning into maltose . To help, the medical team at the City Health Institute is working on a plan to help Leo manage his digestion issues so he can enjoy his favorite meals again without pain.