Endogenous phytosterols cannot be synthesized and can only be supplemented by exogenous sources. However, the absorption rate of sterols is low, basically 0.4%~4%. This article will introduce you to the absorption process of phytosterols and the factors that affect absorption.
Absorption of Phytosterols
Studies have shown that the absorption process can be divided into 3 stages as shown below:
①Phytosterols form mixed micelles with bile acids and free fatty acids in the intestinal lumen;
②The mixed micelles are close to the epithelial cells. The phytosterols are freed from the micelles and absorbed into the cells by the relevant transporters on the cell membrane;
③ The sterol that enters the cell is esterified under the intracellular ACAT enzyme (cholesterol acyltransferase). Then forms chyle with triglyceride and apolipoprotein under the action of MTP (triglyceride transfer protein), which is secreted into the cell. blood circulation system.
Factors Affecting Absorption
In general, it decreases with increasing C atoms (campesterol > β-sitosterol > stigmasterol). The absorption rate of phytosterols in different origins is also different. Such as plants produced in high temperature areas, the proportion of campesterol content is increased, so the absorption rate is also higher. From the perspective of absorption process, esterification is the basis of absorption. The absorption of esterified sterols is 5 times that of non-esterified sterols. Whether the double bond on the carbon atom at the 5th position is saturated also affects the absorption rate, eg campesterol > campesterol. But beta-glutanol is hardly absorbed. Absorbed plant sterols are selectively distributed to various parts of the body, with the highest content in the liver, adrenal glands, and gonads, so they can promote growth and regulate the endocrine.