Cholesterol=poison? As low as possible?. . Definition. Conversely, hypolipidemia can be defined as plasma cholesterol concentrations less than 3.4 nmol/L(130mg/dl)Plasma lipid levels vary among individuals of different population owing to genetic and dietary factors.For example, the mean plasma cholesterol concentration for Western men is 210 mg/dl, whereas for Japanese men it is 165 mg/dl -Williams Textbook of Endocrinology tenth edition 1167 .