Predigestive

Predigestive refers to the initial stages of food breakdown that occur before the main digestive processes in the stomach and intestines. This includes mechanical and chemical processes that begin the transformation of food into absorbable nutrients.

Mechanical predigestion starts in the mouth with mastication, or chewing. This process breaks down large food particles into smaller ones, increasing the surface area available for enzymatic action. The tongue also aids in mixing food with saliva.

Chemical predigestion also begins in the mouth. Saliva, produced by salivary glands, contains enzymes such as amylase (also known as ptyalin), which starts the breakdown of complex carbohydrates (starches) into simpler sugars. Saliva also contains lingual lipase, which begins the digestion of fats, though its activity is more significant in the acidic environment of the stomach. The moisture in saliva lubricates food, making it easier to swallow.

Once swallowed, the food, now a bolus, travels down the esophagus to the stomach. While the stomach is a primary site of digestion, the initial breakdown initiated in the mouth is considered predigestive. The term is less commonly used in scientific literature, with "pre-gastric digestion" or simply "initial digestion" being more frequent. The concept highlights the continuous nature of digestion, beginning even before food enters the main digestive organs.