Stimulation of the apo AI-high density lipoprotein system by dietary soyabean lecithin in humans

Abstract The aim of this work was to assess, the effect of a dietary supplement of soyabean lecithin on the apoprotein (apo) AI–high density lipoprotein system in humans. Adult outpatients (three women and seven men, aged 52 ± 5 years) were selected on the basis of a major type IIA hypercholesterolemia (>6.5 mmol/L). For each subject, a previous control period of 6 weeks consisted in a daily dietary supplement of 3 g soyabean oil (SO) as placebo distributed in two capsules at three main meals. Subjects then were given a daily dietary supplement of 3 g purified soyabean phosphatidylcholine (SPC) for 6 weeks, also distributed in two capsules at the three main meals. The usual basal diet of each subject was monitored every 4 weeks by a 3-day food recall. Between the end of the SO period and the end of the SPC period, plasma level of apo AI significantly increased (from 1.01 to 1.23 g/L), as did unesterified cholesterol (from 1.80 to 2.00 mmol/L). The esterified cholesterol to total cholesterol ratio and apo E level significantly decreased between the beginning and the end of the experiment. Esterified cholesterol and apo B levels remained unchanged. The levels of apo AI or unesterified cholesterol were not correlated to the alcoholic calories or to total or lipid energy. Dietary soyabean lecithin contributed to stimulation of the reverse cholesterol transport by increasing apo AI system and decreasing apo AII and apo E systems. Thus, soyabean lecithin could be considered an effective nutrient useful in the dietary treatment of mild hypercholesterolemia.