The effects of dietary protein source on the development of cholesterol metabolism

A large body of literature exists regarding the effects of dietary protein on blood lipids in adult humans and animals; however, little is known of the action that protein source may have on cholesterol levels in infants. The research of this thesis addresses the following questions; (1) do infant formula proteins affect blood lipids in young animals, (2) is there a permanent response of protein consumed during childhood on adult cholesterol metabolism, and (3) what mechanisms mediate the blood lipid response to dietary protein? In a study which examined the effects of varying casein and whey proteins fed to rabbits during post-weaning, it was determined that a diet of 40% casein and 60% whey protein elevated blood lipids compared to consumption of greater proportions of casein (p $<$.05); however, following a cholesterol challenge (0.4%) in adulthood there was no persistent blood lipid response though hepatic cholesterol biosynthesis was elevated in the 40:60-consumers (p $<$.05). Examination of an earlier period in development using the neonatal piglet as a model showed that consumption of increasing proportions of whey protein decreased blood cholesterol concentrations (p $<$.05), and increased weight gain (p $<$.05). 100% casein consumption also decreased hepatic cholesterol biosynthesis (p $<$.05). Furthermore, glucagon and cortisol were possible mediators of the blood and liver responses, as they were also elevated in 100% casein-consumers (p $<$.001). Another experiment fed hydrolyzed soy protein, and casein:whey ratios of 80:20 or 40:60 to neonatal piglets. Soy-fed piglets had significantly lower blood cholesterol levels (p $<$.10), higher HDL:LDL ratios than casein:whey-fed animals (p $<$.10), and decreased body weight (p $<$.10). The association between these findings and a hepatic mechanism could not be clearly defined. In conclusion, blood lipids in young animals are effected by consumption of the infant formula proteins; hydrolyzed soy, casein, and whey. However, the mechanism whereby protein affects cholesterol concentrations remains to be determined. Furthermore, a direct relationship between blood cholesterol levels during childhood and adult risk of atherosclerosis is unclear.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Nutritional Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Larson, Mary Rose

Contributors dc:contributor

• Erdman, John W.

• Chemistry, Biochemistry
• Health Sciences, Nutrition

Statement dc:rights

• Copyright 1995 Larson, Mary Rose

Language dc:language

eng

Identifier

AAI9543641
(UMI)AAI9543641

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/20317