Lupin protein attenuates the development of hypertension and normalises the vascular function of NaCl-loaded Goto-Kakizaki rats

The beneficial cardiovascular effects of soy protein have been studied intensively in recent years. Another protein-rich legume is lupin, which has been shown to have similar effects to those of soy in lowering serum cholesterol levels. In this study we compared the effects of lupin and soy protein on hypertension and vascular functions in spontaneously diabetic Goto-Kakizaki (GK) rat, which develop hypertension when fed a high-salt diet. The rats were fed with a 6% NaCl diet containing either lupin or soy protein isolate (20% weight/weight) for two weeks. In the end of the study the SBP was 18.6 mmHg lower (p<0.001) in the lupin group, and 12.0 mmHg lower (p<0.01) in the soy group than in the control group. Lupin and soy treatments normalised the decreased vasocontraction observed in the NaCl-fed control group, but only lupin treatment improved the impaired endothelium-dependent vasorelaxation. The attenuation of hypertension is likely to be mediated by the corrected vascular dysfunction, whose precise mechanism and the possible clinical relevance remains to be studied further.