Dietary soy beta-conglycinin (7S globulin) inhibits atherosclerosis in mice.
Although beta-conglycinin (7S globulin), a major soy storage protein, stimulates the expression of LDL receptors and the degradation of LDL by hepatocytes in vitro, the in vivo effects of dietary beta-conglycinin on the cardiovascular system are unknown. We assessed the effects of dietary beta-conglycinin and other soy peptide fractions on the development of atherosclerosis in atherosclerosis-susceptible mice. At 6 wk of age, male and ovariectomized female apolipoprotein (apo) E-null mice and LDL receptor-null, apoB transgenic mice were assigned randomly to treatment groups that differed only in the source of dietary protein: 1) casein/lactalbumin, 2) isoflavone-containing soy protein isolate, 3) beta-conglycinin, 4) glycinin (11S globulin, another major soy storage protein), 5) beta-conglycinin-devoid soy protein, and 6) W008 (a peptide fraction produced by hydrolysis and precipitation of soy protein isolate). After 4 mo, aortic atherosclerosis (cholesteryl ester content) and plasma lipoprotein cholesterol concentrations were quantified using GLC. Relative to mice fed casein/lactalbumin-based diets, the extent of atherosclerosis was reduced in ovariectomized female mice fed all soy protein-containing diets. Relative to mice fed isoflavone-containing soy protein isolate, atherosclerosis was reduced only in mice fed the beta-conglycinin-containing diet. Mean reductions were 39 and 67% (all P <0.05) in male and ovariectomized female apoE null mice and 66% (P < 0.05) in male LDL receptor null mice. These effects were unrelated to variation in isoflavone content of the protein source and only minimally related to plasma lipoprotein cholesterol concentrations. We conclude that a diet rich in beta-conglycinin has atheroprotective effects that greatly exceed those of isoflavone-containing soy protein isolate and do not depend on LDL receptors or influences on plasma lipoproteins.
Department of Pathology, Section of Comparative Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA. madams@wfubmc.edu
Michael R
MR
Adams
Deborah L
DL
Golden
Adrian A
AA
Franke
Susan M
SM
Potter
Houston S
HS
Smith
Mary S
MS
Anthony
D000818:Animals; D052179:Antigens, Plant; D001057:Apolipoproteins E / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D001161:Arteriosclerosis / Q000517:prevention & control*; D002784:Cholesterol / Q000097:blood; D002788:Cholesterol Esters / Q000378:metabolism*; D004032:Diet; D004195:Disease Models, Animal; D005260:Female; D005916:Globulins / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D010052:Ovariectomy; D008517:Phytotherapy; D011973:Receptors, LDL / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D055314:Seed Storage Proteins; D012727:Sex Characteristics; D030262:Soybean Proteins / Q000627:therapeutic use*; D013025:Glycine max
D052179:Antigens, Plant; D001057:Apolipoproteins E; D002788:Cholesterol Esters; D005916:Globulins; D011973:Receptors, LDL; D055314:Seed Storage Proteins; D030262:Soybean Proteins; C013894:beta-conglycinin protein, Glycine max; D002784:Cholesterol