How are short and medium-chain fatty acids absorbed?

Short and medium-chain fatty acids are absorbed directly into the bloodstream through intestinal capillaries. Unlike long-chain fatty acids, which are primarily absorbed into the lymphatic system due to their need for micelle formation and chylomicron packaging, short and medium-chain fatty acids can diffuse directly across the intestinal epithelium. Once absorbed, they enter the portal circulation and are transported directly to the liver.

This efficient absorption mechanism is because their smaller size allows them to bypass some of the complex processes that larger fatty acids require. Consequently, they do not need to undergo emulsification or chylomicron formation for absorption, making their uptake into the blood straightforward and rapid, providing a quick source of energy.

The concept of absorption through the lymphatic system applies mainly to longer-chain fatty acids that require a more complex transport system involving lymphatic vessels. Other processes such as transport via proteins or through specific veins highlight alternative mechanisms not involved in the absorption of short and medium-chain fatty acids.