title: Dietary egg white protein inhibits lymphatic lipid transport in thoracic lymph duct-cannulated rats.
abstract: Dietary egg white protein (EWP) decreases serum cholesterol levels. We previously showed that EWP decreased cholesterol absorption in the intestine. Rats subjected to permanent lymph duct cannulation were used to investigate the effects of dietary EWP on lipid transport. They were fed diets with 20% EWP and casein, and their lymph was collected to quantify lymphatic lipid levels. Dietary EWP decreased lymphatic cholesterol transport compared with casein. It was previously shown that EWP excluded cholesterol from bile acid micelles. Therefore, pepsin-hydrolyzed EWP and casein were prepared. EWP was not completely digested. Ovalbumin, which is the most abundant protein in EWP, showed resistance to digestion by pepsin. This study investigated the effects of EWP pepsin hydrolysate (EWP-ph) on cholesterol micellar solubility, cholesterol transfer from the micellar to the oil phase, water-holding capacity (WHC), settling volume in water (SV), and relative viscosity and compared them with the effects of casein pepsin hydrolysate (C-ph). EWP-ph significantly decreased the micellar solubility and transfer rate and increased the WHC, SV, and relative viscosity compared with C-ph. Moreover, the pepsin hydrolysate of ovalbumin, a major protein in EWP, played a role in decreasing cholesterol micellar solubility, leading to the inhibition of cholesterol absorption. In conclusion, dietary EWP decreased cholesterol intestinal absorption by exerting combined effects of these physicochemical properties in the gut.
authors.affiliation: Laboratory of Nutrition Chemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School of Kyushu University , 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Matsuoka
authors.forename: Bungo
authors.initials: B
authors.lastname: Shirouchi
authors.forename: Sayaka
authors.initials: S
authors.lastname: Kawamura
authors.forename: Sanae
authors.initials: S
authors.lastname: Baba
authors.forename: Sawako
authors.initials: S
authors.lastname: Shiratake
authors.forename: Kazuko
authors.initials: K
authors.lastname: Nagata
authors.forename: Katsumi
authors.initials: K
authors.lastname: Imaizumi
authors.forename: Masao
authors.initials: M
authors.lastname: Sato
mesh_terms: D000818:Animals; D001692:Biological Transport; D002404:Catheterization; D002784:Cholesterol / Q000378:metabolism*; D004063:Digestion; D004527:Egg Proteins / Q000737:chemistry / Q000378:metabolism*; D004529:Egg White / Q000737:chemistry*; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism; D008196:Lymph / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012995:Solubility; D013897:Thoracic Duct / Q000378:metabolism*; D014783:Viscosity
chemical_list: D004527:Egg Proteins; D002784:Cholesterol
keywords: cholesterol absorption; egg white protein; ovalbumin; permanent thoracic lymph duct cannulation