How are short-chain fatty acids absorbed in the body?

Short-chain fatty acids (SCFAs), which are typically defined as fatty acids with fewer than six carbon atoms, are absorbed through the intestinal epithelium in a straightforward manner. They can diffuse directly across the cell membrane of enterocytes due to their small size and relatively hydrophobic nature, allowing them to cross lipid bilayers without the need for additional transport mechanisms.

This direct absorption is facilitated by the concentration gradient, where SCFAs move from an area of higher concentration in the intestinal lumen to an area of lower concentration within the enterocytes. Once absorbed, SCFAs can enter the portal circulation and be transported to the liver for further metabolism.

Other options, such as micelle formation, active transport, or facilitated diffusion, are more relevant to the absorption of long-chain fatty acids or other larger molecules that require assistance to cross the membrane, thereby further underscoring why direct absorption is the correct understanding for short-chain fatty acids.