Dietary Lipids Are Absorbed In The Intestine By

Long chain fatty acids form a large lipoprotein structure called a chylomicron that transports fats through the lymph system.

Dietary lipids are absorbed in the intestine by. Researchers have identified several new mechanisms by which lipids are taken up by enterocytes and packaged as chylomicrons for export into the lymphatic system or clarified the actions of mechanisms previously known to participate in these processes. The purpose of this review is to update the reader on our current knowledge of the digestion uptake and transport of dietary lipid. 1 department of pathology university of cincinnati medical center 231 albert sabin way cincinnati oh 45267 usa. The intestinal cells absorb the fats.

Intestinal lipid absorption has been shown to exhibit diurnal variations in rodents and humans 8 23 118 129 143. In the small intestines bile emulsifies fats while enzymes digest them. Cholesterol uptake from the lumen by the enterocytes is the rate limiting step in cholesterol absorption 15 and evidence indicates that nieman pick c1 like 1 npc1l1 is involved in this process 16. Lipid absorption in the small intestine involves the digestion products of triglycerides phospholipids cholesterol esters and fat soluble vitamin esters that is free fatty acids small amounts of 2 monoglycerides lysophospholipids mainly lysophosphatidylcholine cholesterol fat soluble vitamins and glycerol molecules that with the exception of short chain and medium chain fatty.

Years ago it was shown that cholesterol but not plant sterols is readily absorbed in the intestine. Hydrophobicity one of the distinctive properties of many dietary lipids that makes triglycerides excellent molecules for energy storage creates problems when such molecules are digested in the gastrointestinal tract absorbed in the small intestine and finally transported in the circulation after absorption or mobilization from body stores. Chylomicrons are formed in the intestinal cells and carry lipids from the digestive tract into circulation. In particular it discusses how intestinal lipid transporters may play a role in the uptake of lipids by the enterocytes and how chylomicrons are formed in the enterocytes and packaged for export into the lymphatic system through exocytosis.

Digestion and absorption of lipids lipids are large molecules and generally are not water soluble like carbohydrates and protein lipids are broken into small components for absorption since most of our digestive enzymes are water based how does the body break down fat and make it available for the various functions it must perform in the human body. Our knowledge of the uptake and transport of dietary fat and fat soluble vitamins has advanced considerably. Another lipid of importance that is absorbed in the small intestine is cholesterol. Cholesterol homeostatis results from a balance of cholestrol synthesis absorption of dietary cholesterol and elimination of cholesterol by excretion in bile.

Absorption of cholesterol is defined as the transport of dietary lipids from the intestinal lumen across the enterocytes into the plasma. Although plasma lipid concentrations are maintained within a narrow physiological range several factors e g plasma clearance cholesterol biosynthesis and hormonal changes can lead to changes in plasma lipids.