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 too, 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 KEY WORDS: * atherosclerosis * mice * soy protein * 7S globulin * lipoproteins