Absorption of Nutrients from the Intestinal Lumen
Let's dive into how our body absorbs three crucial nutrients - glucose, amino acids, and fatty acids - from our intestines into our bloodstream. This process is fascinating and crucial for athletes and active individuals!
Glucose Absorption
The Process
- Active Transport
- Glucose molecules are absorbed through a process called sodium-dependent glucose transport
- Requires energy (ATP) and sodium ions
- Uses special protein carriers called SGLT1 (Sodium-Glucose Transport Proteins)
The presence of sodium is crucial for glucose absorption - this is why many sports drinks contain both glucose and sodium!
- Movement Across the Intestinal Wall
- Glucose moves from the intestinal lumen into intestinal cells
- Then exits through the other side into the bloodstream via GLUT2 transporters
- This is facilitated diffusion (doesn't require additional energy)
Amino Acid Absorption
The Process
- Active Transport System
- Similar to glucose, amino acids use sodium-dependent transport
- Different carrier proteins specific to different amino acids
- Requires energy (ATP)
Different amino acids compete for the same transport systems, which is why balanced protein intake throughout the day is important for athletes.
- Secondary Transport
- Some amino acids can also be absorbed through:
