Abstract
In a previous paper we reported that the diet containing 1.5% of soy sterols and of unsaponifiable matter separated from soybean oil markedly prevented the increase in plasma cholesterol caused by ingestion of cholesterol. It was presumed that the synergistic effect of the unsaponifiable matter was due to tocopherols present in it.
The purpose of the present paper was to know the effectiveness of tocopherols on plasma cholesterol levels. Rats were given cholesterol and soy sterols with or without tocopherols. After a 30-day feeding period it was recognized that plasma cholesterol fed tocopherols was greatly reduced.
To elucidate the reducing mechanism of plasma cholesterol by tocopherols, sterols excreted into feces were determined. It was noted that there was an increased fecal excretion of cholesterol, while soy sterols in feces were decreased, that is, the absorption of soy sterols was increased. Moreover, we noticed the presence of a large amount of stigmasteral and β-sitosterol in both plasma and liver sterols. It is known that β-sitosterol and stigmasterol are more effective in lowering plasma cholesterol values, compared to ergosterol and campesterol, however, it is also known that the absorption coefficient of β-sitosterol is quite low (less than 5%).
The results indicate that the plasma cholesterol reducing effect of tocopherols is presumably by the increasing absorption of β-sitosterol and stigmasterol and thus absorbed vegetable sterols show hypocholesterolemic effects in rats.
