Effects of Dietary Casein, Soy, and Methionine-Supplemented Soy on Serum Lipids Level in Rats

  • Choi, Mi-Ja (Department of Food and Nutrition, Keimyung University) ;
  • Jung, So-Hyung (Department of Food and Nutrition, Keimyung University)
  • Published : 2002.09.01


The objective of the current study was to determine the influences of dietary proteins and methionine on plasma lipid concentrations. Thirty growing male Sprague-Dawley rats were fed diets similar in all respects except that dietary protein was from either casein, soy protein isolate, or soy protein isolate supplemented with L-methionine (0.24 %). The animals were fed experimental diets ad libitum for nine weeks. Plasma total-cholesterol concentrations were unaffected by the protein source or methionine supplementation. Plasma triglyceride concentrations were lower in rats of methionine supplemented soy protein diets (76 mg/dL) than in the rats fed casein or soy diet (120 mg/dL, 109 mg/dL, respectively). These results indicate that soy protein reduces plasma triglycerides relative to casein in rats fed cholesterol free diets, and that methionine-supplemented soy diets decrease plasma triglyceride concentrations more than soy protein alone.


  1. Meinertz H, Nilausen K, Faergeman D. 1989. Soy protein and casein in cholesterol-enriched diet: effects on plasma lipoproteins in normolipidemic subjects. Am J Clin Nutr 50: 786-793
  2. Terpstra A, HM, Van Tintelen G, West CE. 1982. The effect of semipurified diets containing different proportions of either casein or soybean protein on the concentration of cholesterol in whole serum, serum lipoproteins and liver in male and female rats. Atherosclerosis 42: 85-95
  3. Terpstra, AHM, Laitlnen L, Stucchi AF, Nicolosi RJ. 1994. The effects of semipurified diets containing two levels (20% and 40%) of either casein or soybean protein isolate and concentrate on plasma lipids in hamsters. Nutr Res 14: 885- 895
  4. Terpstra AHM, Holmee JC, Nicolosi RJ. 1990. The hypocholesteroemic effect of dietary soybean protein vs casein in hamsters fed cholesterol-enriched or cholesterol-free semipurified diets. J Nutr 121: 944-947
  5. Forsythe WA. 1986. Comparison of dietary casein or soy protein effects on plasma lipids and hormone concentrations in the gerbil. J Nutr 116: 1165-1171
  6. Potter SM, Bakhit R, Essex-Sorlie D, Weingartner K, Chapman K, Winter L, Nelson A, Nelson R, Ham J, Savage W, Prabhudesai M, Erdman JW. 1993. Depression of plasma cholesterol in men by consumption of baked products containing soy protein. Am J Clin Nutr 58: 501-506
  7. Sirtori CR, Zucchi-Dentone C, Sirtori M, Gatti E, Descovich GC, Gaddi A, Cattin L, DaCol PG, Senin U, Mannarino E, Avellone G, Colombo L, Fragiacomo C, Noseda G, Lenzi S. 1985. Cholesterol-lowering and HDL-raising properties of lecithinated soy proteins in type II hyperlipidemic patients. Ann Nutr and Metab 29: 348-357
  8. Carroll KK. 1991. Review of clinical studies on cholesterol- lowering response to soy protein. J Am Diet Assoc 91: 820- 827
  9. Wong WW, Smith EO, Stuff JE, Hachey DL, Heird WC, Pownell HJ. 1998. Cholesterol-lowering effect of soy protein in normocholesterolemic and hypercholesterolemic men. Am J Clin Nutr 68: 1385S-1389S
  10. Tonstad S, Smerud K, Hoie L. 2002. A comparison of the effects of 2 doses of soy protein or casein on serum lipids, serum lipoproteins, and plasma total homocysteine in hypercholesterolemic subjects. Am J Clin Nut 76: 78-84
  11. Hermansen K, Sondergaard M, Hie L, Carstensen M, Brock B. 2001. Beneficial effects of a soy-based dietary supplement on lipid levels and cardiovascular risk markers in type 2 diabetic subjects. Diabetes Care 24: 228-233
  12. Carroll KK, Kurowska EM. 1995. Soy consumption and cholesterol reduction: review of animal and human studies. J Nutr 125: 594s-597s
  13. Fillios LC, Mann GV. 1954. Influence of sulfur amino acid deficiency on cholesterol metabolism. Metabolism 3: 16-26
  14. Seidel JC, Nath N, Harper AE. 1960. Diet and cholesterolemia; V. Effects of sulfur-containing amino acids and protein. J Lipids Res 1: 474-481
  15. Leveille GA, Shockley JW, Sauberlich HE. 1962. Influence of dietary protein level and amino acids on plasma cholesterol of the growing chicks. J Nutr 76: 321-324
  16. Sugiyama K, Ohkawa S, Muramatsu K. 1986. Relationship between amino composition of diet and plasma cholesterol level in growing rats fed a high cholesterol diet. J Nutr Sci Vitaminol 32: 413-423
  17. Sugiyama K, Kushima Y, Muramatsu K. 1985. Effects of sulfur-containing amino acids and glycine on plasma cholesterol level in rats fed on a high cholesterol diet. Agri Biol Chem 49: 3455-3461
  18. Morita T, Oh-hashi A, Takei K, Ikai M, Kasaoka S, Kiriyama S. 1977. Cholesterol-lowering effects of soybean, potato and rice proteins depend on their low methionine contents in rats fed a cholesterol-free purified diet. J Nutr 127: 470-477
  19. Moundras C, Remesy C, Leyrat MA, Cemine C. 1988. Methionine deficiency in rats fed soy protein induces hypercholesterolemia and potentiates lipoprotein susceptibility to peroxidation. Metabolism 44: 1146-1152
  20. Serougne C, Rukaj A. 1983. Plasma and lipoprotein cholesterol in rats fed L-amino acid-supplemented diet. Ann Nutr Metab 27: 386-395
  21. Anderson JW, Johnstone BM, Cook-Newell ME. 1995. A meta-analysis of the effects of soy protein intake on serum lipids. N Engl J Med 333: 276-282
  22. Nilausen K, Meinertz H. 1999. Lipoprotein (a) and dietary proteins: Casein lowers lipoprotein (a) concentrations as compared with soy protein. Am J clin Nutr 69: 419-425

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