[Effect of dietary protein on serum lipid profile in hypercholesterolemic people]

To observe the effect of soy protein on the concentration of serum lipids in hypercholesterolemic people and the correlation between dietary protein and serum lipids.

Ninety healthy hypercholesterolemic volunteers were given beverages contained either 24 g of casein or 18 g of soy protein plus 6 g of casein by random daily for 8 weeks without change of their habitual life. Body height, body weight, waist and hip circumference and serum lipids were measured before and after the study.

(1) The body weight and body mass index of subjects in the soy group were decreased slightly but significantly (P < 0.05), while the waist-to-hip circumference of subjects in casein group was decreased (P < 0.05). (2) ApoB and TC/HDL-C ratio were significantly reduced after consuming soy protein beverages for 8 weeks (P < 0.05), while in casein group, TC, LDL-C and ApoB were reduced significantly (P < 0.05). (3) The reduction in TC concentration was negatively correlated with the quantity of dietary protein intake (r = - 0.419, P < 0.01), whereas it was positively correlated with the quantity of vegetable protein intake (r = 0.521, P < 0.01).

The effect of soy protein on serum lipids could be influenced by the source and quantity of dietary protein.