ABSTRACT
Two weeks of feeding soy peptides containing 2% collagen peptides increased the levels of type I and III tropocollagen and their mRNAs. In contrast, the diet did not increase the mRNA levels of rat hyaluronan synthases, serine palmitoyltransferase (the rate-limiting enzyme of ceramide synthesis), and 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (the key enzyme of cholesterol synthesis). These results suggest that feeding of soy peptides with collagen peptides specifically enhanced the tropocollagen level in the skin.
Subject(s)
Collagen Type III/biosynthesis , Collagen Type I/biosynthesis , Peptides/administration & dosage , RNA, Messenger/biosynthesis , Skin/drug effects , Soybean Proteins/administration & dosage , Tropocollagen/biosynthesis , Administration, Oral , Animals , Diet , Gene Expression/drug effects , Glucuronosyltransferase/genetics , Glucuronosyltransferase/metabolism , Hyaluronan Synthases , Hydroxymethylglutaryl CoA Reductases/genetics , Hydroxymethylglutaryl CoA Reductases/metabolism , Male , Rats , Rats, Wistar , Serine C-Palmitoyltransferase/genetics , Serine C-Palmitoyltransferase/metabolism , Skin/metabolismABSTRACT
The changes in body fat ratio and serum lipids induced by the ingestion of beta-conglycinin were examined in 41 healthy female university student volunteers. The trend of change in body fat ratio following the ingestion of beta-conglycinin differed between students with a baseline body fat ratio over 25% and those less than 25%. In the former group, the ingestion of beta-conglycinin suppressed the increase in body fat ratio. Moreover the six subjects who had a high total cholesterol level (5.72 mmol/L or higher) tended to have reduced levels of serum triglyceride, free fatty acid, total cholesterol and lipoprotein (a) after the ingestion of beta-conglycinin, although those levels did not change significantly. The number of subjects was only six, therefore it was inferred that significant changes were not observed. Thus, ingestion of soybean beta-conglycinin suppressed the increase in body fat ratio in individuals with a high baseline body fat ratio and reduced relatively high serum levels of lipids. Those results suggest that if soybean beta-conglycinin is ingested continuously (5 g daily), it will be effective in keeping body fat ratio and serum lipid levels normal and eliminating excessive lipids from the body.
