How long does digestion take?
Digestion, the entire process from swallowing food to expelling it, is assumed to last from 2 to 5 days. Experts at the Mayo Clinic believe it takes 6 to 8 hours for food to pass through the stomach and small intestine, and an average of 36 hours for food to pass through the large intestine. Many factors, including the type of food, affect the length of digestion. Foods rich in protein and fat (meat, fish) take longer to digest than carbohydrates. Gender and age also matter. In women, it takes longer to digest than in men. The process also slows down with age.
How are foods digested one after the other?
Digestion involves numerous enzymes (mainly amylases, peptidases, lipases), saliva and hydrochloric acid. Thanks to this, minerals, vitamins and water can enter the body. Digestion begins in the mouth. The enzymes secreted by the salivary glands and lingual glands break down carbohydrates and fats. Swallowed food goes to the throat, from where it is transported (also through the esophagus, which travels the food) to the stomach.
The stomach is lined with a mucosa, in which there are gastric glands that secrete gastric juice – the human body produces 1.5-2.5 liters of juice daily (its secretion is caused by the sight or smell of food!).
In the composition of gastric juice you can find:
- digestive enzymes:pepsin, which breaks down long chains of proteins, thus initiating the process of their decomposition, rennet, which cuts the protein contained in milk,
- mucus:protects the gastric membrane against self-digestion (creates a protective layer 1 mm thick),reduces the friction that occurs when food moves,
- hydrochloric acid:activates pepsin and produces an acidic environment appropriate for its action, it kills microorganisms that got into the stomach with food.
Interesting fact: liquid foods pass through the stomach without stopping, medium-heavy meals stay in it for 1-2 hours, and very hearty meals – even for 5-7 hours. The muscles of the stomach cause the food to mix with the gastric juice. Digestive enzymes also start working, turning the swallowed food into chyme. The contractions of the stomach then move it into the duodenum.