Скачать или смотреть Absorption of Digested Fat | Part 10 Lipid Foundations | Macronutrients Lecture 76

Digested lipids are absorbed across both sides of the enterocytes into the lymphatic vessels. Subscribe to Nourishable at    / nourishable  

This video is part 10 of the Lipid Foundations module within a lecture series on the nutrition science of macronutrients.

Lipid Foundations Lecture playlist:    • Lipid Foundations  

Macronutrients Lecture playlist:    • Macronutrients Lectures  

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Lecture Development, Hosting & Post-Production by Lara Hyde, PhD
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Video Production by Robbie Hyde
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Opening Motion Graphics by Jay Purugganan https://www.c9studio.com/WP/

The information in this video is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. All content, including text, graphics, images and information, contained on or available through this video is for general information purposes only.

References
Chapter 6 Lipids in Wardlaw’s Perspectives in Nutrition, 2019 (Editors: Byrd-Bredbenner, Moe, Berning and Kelley, 11th edition)
Chapter 4 - Lipids, Sterols, and their Metabolites in Modern Nutrition in Health and Disease, 2014 (Editors: Ross, Caballero, Cousins, Tucker and Ziegler; 11 edition)

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Lipid absorption requires transferring the lipid across both the luminal and basolateral sides of the enterocyte. The majority of digested fatty acids are 14 carbons and longer, stored inside micelles. These fatty acids can diffuse directly from the micelle across the luminal side into the enterocyte. Short and medium chain fatty acids (4-12 carbons long) will be directly absorbed across the luminal side without micelles. Sterols require a special protein transporter called Niemann-Pick C1 like 1 protein (NPC1L1) for absorption across the luminal side. The enterocyte also has two proteins called ABCG5 and ABCG8 that perform cholesterol efflux and "spit out" these absorbed sterols back into the lumen of the intestine. Approximately 50-60% of cholesterol is absorbed. The drug ezetimibe inhibits NPC1L1 therefore inhibiting cholesterol absorption. Phytosterols compete with cholesterol for absorption through NPC1L1. To get into the body, digested lipids must get across the basolateral side of the enterocyte. Short and medium chain fatty acids diffuse directly across the basolateral side into the blood and travel to the liver through the portal circulation. The majority of dietary fat, including long chain fatty acids and cholesterol, will get repackaged into a large lipoprotein like a water balloon called a chylomicron. This chylomicron will diffuse across the basolateral side of the enterocyte and into the lacteal to travel through the lymphatic vessels before getting deposited into the blood.