What is the Difference Between Digestion and Absorption?

The difference between digestion and absorption lies in the processes they involve and their outcomes:

• Digestion is the chemical breakdown of ingested food into absorbable molecules. This process begins in the mouth and continues as food travels through the small intestine. Digestion involves breaking down large food molecules, such as proteins, lipids, nucleic acids, and starches, into smaller subunits that can be absorbed by the body.
• Absorption refers to the movement of nutrients, water, and electrolytes from the lumen of the small intestine into the cell, then into the blood. The absorption process moves the products of digestion (molecules) across the gastrointestinal (GI) tract. Absorption can occur through various mechanisms, such as active transport, passive diffusion, facilitated diffusion, co-transport (or secondary active transport), and endocytosis.

In summary, digestion is the process of breaking down food into smaller components, while absorption is the process of taking up the nutrients from these smaller components and transporting them into the bloodstream to nourish the body's cells.

Comparative Table: Digestion vs Absorption

Here is a table outlining the differences between digestion and absorption:

Digestion involves breaking down food into smaller components, which can be either mechanical (through chewing and mixing) or chemical (using enzymes and other chemicals to break down the food). On the other hand, absorption is the process of taking up the nutrients from the digested food and passing them through blood vessels or lymphatic vessels to be used by the body. About 95% of nutrient molecules are absorbed in the small intestine, while some substances like water, minerals, and vitamins are absorbed in the stomach and large intestine.