What is the role of bicarbonate in the digestive system?

Bicarbonate plays a crucial role in the digestive system primarily by neutralizing stomach acid as it enters the small intestine. When chyme, which is the partially digested food mixed with gastric juices, moves from the stomach into the duodenum (the first part of the small intestine), it is highly acidic due to the presence of hydrochloric acid.

The introduction of bicarbonate, secreted by the pancreas, helps increase the pH in the small intestine, creating a more alkaline environment. This neutralization is vital because it protects the intestinal lining from damage caused by the acidity and also creates an optimal pH for the digestive enzymes that function best in a neutral to slightly alkaline environment. These enzymes are crucial for further breaking down food particles into their component nutrients, facilitating proper digestion and absorption.

While bicarbonate does not directly emulsify fats, inhibit enzymes, or aid in nutrient absorption in the same way, its primary function is to ensure a safe and effective environment for digestion to occur.