Absorption of Fatty acids and Glycerol and fat soluble vitamins

All these nutrients are absorbed via simple diffusion. Fatty acids and glycerol are insoluble in water, therefore, they cannot reach the blood stream directly. They are first incorporated into small, spherical, water soluble droplets called micelles with the help of the bile salts and phospholipids in the intestinal lumen.

A micelle is an aggregate of many molecules. From the micelles fatty acids, glycerides, sterols and fat soluble vitamins are absorbed into the intestinal cells by diffusion where they are resynthesized in the ER and are converted into very small fat molecules (droplets) called chylomicrons.

The latter are released from the intestinal cells into the lymph present in the lymphatic capillaries, the lacteals. Small quantities of short chain fatty acids are absorbed directly into the blood by diffu­sion rather than into the lymph. Fatty acids, glycerol and vitamins are absorbed in jejunum.