-IBIS-1.7.0-
rx
fats
Lipid transport and storage
nutrition


definition

Lipid transport and storage

White fat – Most of our fat is stored as white fat. It is not very metabolically active.

Brown Adipose Tissue (BAT or Brown Fat) – We are born with a higher percentage of brown fat which is metabolically more active. As we age, brown fat slowly gets replaced with less active white fat. Evidence today indicates that we can actually change the type of fat in the body by the types of carbohydrate that we consume.

Chylomicrons – Once fatty acids and glycerol are absorbed into the epithelial cells, they recombine to form triglycerides. These triglycerides, inside the epithelial cells at the endoplasmic reticulum, then combine with cholesterol, phospholipid and protein to form chylomicrons. Once formed, they circulate in the lymphatic system where they eventually return to the blood via the thoracic duct. (See diagram concerning triacylglycerol digestion, absorption and metabolism)

HDL – High density lipoprotein is considered protective against heart disease. It is composed of more protein than fat and cholesterol and, thus, it is very dense. HDL transports fat and cholesterol from the peripheral circulation back to the liver to be metabolized. The higher the level of HDL in the blood, the lower the risk of heart disease. Some HDL (HDL3) moieties are not considered protective.

LDL – Low density lipoprotein is considered to be atherogenic. It is composed of a higher percentage of cholesterol and fat than protein, thus, it tends to be lighter in density. LDL transports cholesterol from the liver to the peripheral circulation where it can accumulate in the blood vessel walls.

Apolipoprotein A – These are the beneficial lipoproteins found in the HDL cholesterol. They have been found to be inversely correlated to heart disease even more than HDL.

Apolipoprotein B – These are the apolipoproteins that have been found to be more highly correlated to heart disease than LDL cholesterol.

(Marz, p. 46)

 

 

footnotes

Marz, Russell. Medical Nutrition From Marz. Second Edition. Portland, OR. 1997.