Physicians' Health Study

Provitamin A carotenoids

α-Carotene, β-carotene, and β-cryptoxanthin


Polyunsaturated fatty acid


Red blood cell


Recommended Dietary Allowance

Risk assessment

Organized framework for evaluating scientific information, which has as its objective a characterization of the nature and likelihood of harm resulting from excess human exposure to an environmental agent (in this case, a nutrient); it includes the development of both qualitative and quantitative expressions of risk

Risk characterization

Final step in a risk assessment, which summarizes the conclusions from steps 1 through 3 of the risk assessment (hazard identification, dose-response, and estimates of exposure) and evaluates the risk; this step also includes a characterization of the degree of scientific confidence that can be placed in the UL

Risk management

Process by which risk assessment results are integrated with other information to make decisions about the need for, method of, and extent of risk reduction; in addition, risk management considers such issues as the public health significance of the risk, the technical feasibility of achieving various degrees of risk control, and the economic and social costs of this control


Ribonucleic acid


Recommended Nutrient Intake


Reactive nitrogen species


Reactive oxygen species


Standard deviation


Standard error

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