Nutrients and related substances can produce adverse health effects when the intake of them exceeds certain levels.Their potential hazards can be identified and characterized by risk assessments.The specificity that certain amount of nutrients is uniquely essential for maintenance of normal body functions should be fully considered in the new risk assessment model.The Tolerable Upper Intake Level(UL) for nutrients and related substances is the internationally accepted risk assessment method.FAO and WHO defined a risk assessment value termed the Highest Observed Intake(HOI) for nutrients without established adverse effects.For nutrients and related substances that do not have threshold level for adverse health effect,and the intake levels of them associated with an overlap of risk and essentiality,new risk assessment methods should be explored on the basis of UL model.Risk assessments on the above nutrients and related substances are reviewed in this paper.