New perspectives on dietary soybean effects on serum cholesterol and thyroxin
Balmir, Frantzie
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/23699
Description
Title
New perspectives on dietary soybean effects on serum cholesterol and thyroxin
Author(s)
Balmir, Frantzie
Issue Date
1994
Doctoral Committee Chair(s)
Potter, S.M.
Department of Study
Biology, Animal Physiology
Chemistry, Biochemistry
Health Sciences, Nutrition
Discipline
Biology, Animal Physiology
Chemistry, Biochemistry
Health Sciences, Nutrition
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Biology, Animal Physiology
Chemistry, Biochemistry
Health Sciences, Nutrition
Language
eng
Abstract
A series of experiments were conducted in mildly hypercholesterolemic men, rats and hamsters to determine the effects of non-protein components from soy on serum cholesterol and thyroid hormones. In mildly hypercholesterolemic males, 20 g soy cotyledon fiber with or without soy protein was not effective in lowering serum cholesterol levels. Individuals consuming soy/cellulose containing muffins had significantly higher free thyroxin index values than when a low-fat, low-cholesterol diet was consumed. In rats, soy isoflavanoids when added to dietary casein caused a significant lowering of LDL cholesterol relative to casein without isoflavanoids. Animals fed casein that had been supplemented with the crude soybean isoflavanoid extract had significantly higher serum total thyroxin and free thyroxin index values than animals that were given non-supplemented casein. The effects by the exogenous isoflavanoids appeared to be modified by the type of dietary protein. Rats fed soybean diets from which isoflavanoids had been removed showed similar cholesterol and thyroid hormone levels to those observed in animals fed soy diets that contained isoflavanoids. In hamsters, animals fed casein diets that were supplemented with a crude soybean isoflavanoid extract at the level normally found in soy isolate had significantly lower total and LDL+VLDL cholesterol concentrations than animals fed casein without isoflavanoids. When the amount of isoflavanoids added to casein was doubled, both total and LDL+VLDL cholesterol concentrations increased and became intermediate between those observed for casein alone and casein plus isoflavanoids added at the level normally found in soy isolate. This pattern of changes in serum cholesterol was not observed for the thyroid hormones. Serum total thyroxin appeared to increase linearly when increasing levels of isoflavanoids were added to either casein or soy. Results from these studies indicate that while dietary soybeans can cause an increased plasma thyroxin, this does not appear to be related to their effects on serum cholesterol.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
