Lupin protein compared to casein lowers the LDL cholesterol:HDL cholesterol-ratio of hypercholesterolemic adults.

BACKGROUND: Lupin protein had hypocholesterolemic effects in laboratory animals. However, the effect in humans has not been elucidated till now. AIM OF THE STUDY: To investigate the effect of lupin protein on circulating cholesterol in plasma and lipoproteins of hypercholesterolemic subjects. SUBJECTS AND METHODS: A randomised, double-blind, placebo-controlled, parallel trial (23 females and 20 males completed the trial) was conducted to compare the effects of lupin protein versus casein as control protein on plasma lipids and amino acids. Thirty-five grams of the test protein were consumed daily for 6 weeks. RESULTS: Both lupin protein and casein resulted in a reduction of circulating plasma cholesterol (-0.50 +/- 0.64 and -0.47 +/- 0.79 mM; P < 0.05) from baseline to week 6. The reduction of plasma cholesterol was mainly caused by a reduction of LDL cholesterol in the lupin protein group (-0.31 +/- 0.46 mM; P < 0.05), while in the casein group HDL cholesterol significantly declined (-0.17 +/- 0.15 mM; P < 0.05). Comparing the lupin protein group with the casein group yielded a difference in the net changes from baseline to week 6 in the LDL:HDL cholesterol-ratio of -0.24 (95% CI: -0.007, -0.479; P < 0.05). No significant differences in net changes were observed for plasma concentrations of triglycerides, glucose, homocysteine, taurine and most of the amino acids. CONCLUSIONS: Lupin protein compared to casein slightly lowered the concentration of LDL cholesterol in hypercholesterolemic subjects, without altering HDL cholesterol. No or minor effects of lupin protein were observed on circulating glucose, homocysteine and plasma amino acids.