K. Yamamoto’s scientific contributions

Objectives: To evaluate the effects of the miso soup containing soy protein hydrolyzate with bound phospholipids (c-SPHP) on the serum cholesterol levels in hypercholesterolemic subjects in a randomized double-blind study was carried out over a three-month period. Methods: Subjects were Japanese adult male volunteers whose serum total cholesterol levels were between 200-280mg/dL. The subjects were divided into two groups randomly. Each test diet was orally administered in a miso soup form that contained c-SPHP or casein hydrolyzate (placebo). The subjects were given one test diet daily (c-SPHP 3g/day). The study consisted of a two-week pre-feeding period, a three-month feeding period, followed by a two-week post-feeding period. Results: After three months of miso soup ingestion, serum total cholesterol of c-SPHP-miso soup group (n = 11) decreased significantly compared with the placebo group (n = 11) (p < 0.05) and from the initial level (7.6%, p < 0.01). LDL-cholesterol tended to be lower level compared with the placebo group. There was not a significant difference in HDL-cholesterol level throughout the study. Conclusions: This study suggests that miso soup, containing c-SPHP, has also remarkable improving effects similar to c-SPHP on the serum cholesterol levels in hypercholesterolemic subjects.

Objectives: To evaluate the serum cholesterol lowering effects of soy protein hydrolyzate with bound phospholipids (c-SPHP) in tablet form, a randomized double blind placebo-controlled study in mildly hypercholesterolemic subjects was carried out over a twelve-week period. Methods: Subjects were Japanese adult volunteers with mild hypercholesterol. Seventy-five subjects were randomly divided into three groups and each group was given c-SPHP tablet at the dose of 0, 1.5, or 3g per day, respectively. Placebo group received casein hydrolyzate tablets. Tablets were given twice daily. The study consisted of a one-week pre-testing period, a twelve-week testing period, followed by a four-week post-testing period. Results: After twelve weeks of tablet ingestion, serum total cholesterol and LDL-cholesterol levels of c-SPHP-tablet (3g per day) group (n = 25) decreased significantly compared with the placebo group (n = 25) and from the initial level (p < 0.05). No significant difference in HDL-cholesterol level was observed throughout the study. Conclusions: This study suggests that tablet form of c-SPHP (3g per day), has remarkable effects to reduce serum cholesterol levels in mildly hypercholesterolemic subjects.