Food Ingredients That Inhibit Cholesterol Absorption

Abstract

Cholesterol is a vital component of the human body. It stabilizes cell membranes and is the precursor of bile acids, vitamin D and steroid hormones. However, cholesterol accumulation in the bloodstream (hypercholesterolemia) can cause atherosclerotic plaques within artery walls, leading to heart attacks and strokes. The efficiency of cholesterol absorption in the small intestine is of great interest because human and animal studies have linked cholesterol absorption with plasma concentration of total and low density lipoprotein cholesterol. Cholesterol absorption is highly regulated and influenced by particular compounds in the food supply. Therefore, it is desirable to learn more about natural food components that inhibit cholesterol absorption so that food ingredients and dietary supplements can be developed for consumers who wish to manage their plasma cholesterol levels by non-pharmacological means. Food components thus far identified as inhibitors of cholesterol absorption include phytosterols, soluble fibers, phospholipids, and stearic acid.

Keywords: cholesterol absorption; dietary supplement; functional food; nutraceutical.

Fig. 1

Transport of cholesterol (CHOL) and phytosterols (PS) in the intestinal lumen, enterocytes, hepatocytes, and plasma. Dietary CHOL and PS mix with biliary CHOL from the gallbladder to form micelles within the intestinal lumen. The micelles also contain other digested lipids that are transported to the brush border where the lipids are delivered to the enterocyte. Specific transporters, scavenger receptor class B type I (SR-BI) and Neiman-Pick C1 Like 1 (NPC1L1), transport the majority of CHOL and PS into the enterocyte. However, nearly all of the PS is redirected back to the intestinal lumen by the transporters ATP binding cassette (ABC) transporter G5 and G8 (ABCG5 and ABCG8, respectively) for excretion from the body. Some CHOL may also be transported back into the intestinal lumen by ABCG5 and ABCG8, although evidence for this is less conclusive. About half of the CHOL is packaged into lipoproteins and transported into the lymphatic system and eventually the bloodstream for delivery to the liver. Consequently, cholesterol absorption efficiency is generally estimated to be about 50~60%.