Intestinal absorption of essential fatty acids under physiological and essential fatty acid-deficient conditions

The adequate supply of essential fatty acids (EFA) to the body depends upon sufficient dietary intake and subsequent efficient intestinal absorption. Lipid malabsorption is not only a leading cause of EFA deficiency (EFAD), but also occurs secondarily to EFAD. Understanding the relationship between EFAD and lipid malabsorption may be helpful in the development and optimization of oral treatment strategies. Sequential steps involved in EFA absorption, including lipolysis, solubilization by bile, uptake into the enterocyte, and chylomicron secretion into lymph are reviewed, both under physiological and EFAD conditions. EFAD in itself affects the deficiency state by impairment of EFA absorption due to its effects on bile formation and on chylomicron secretion. These processes may be interrelated as decreased phosphatidylcholine secretion into the bile (a consequence of EFAD) is known to result in decreased chylomicron assembly and secretion. Possible treatments of EFAD include increasing dietary amounts of triacylglycerols and/or specifically tailoring lipids (structured triacylglycerols, EFA-rich phosphatidylcholines, EFA-ethyl esters). It is forseen that insights into the relationship between lipid malabsorption and EFAD will refine rational approaches to prevent and treat EFAD in specific patient groups.