Background

Knowledge about biochemical indicators helps health experts make diet and nutrition recommendations to address disease and improve health. The Second Nutrition Report is part of a series of publications that provide ongoing assessment of the U.S. population's nutrition status by measuring blood and urine concentrations.

Inside the Report

The report presents information on 58 biochemical indicators in the U.S. population. CDC scientists measured these levels in the blood and urine of people who took part in CDC's National Health and Nutrition Examination Survey (NHANES) during all or part of the four-year period from 2003 through 2006. The information is presented by age, sex, and race/ethnicity.

Some of the indicators used in this report include:

• Water-soluble vitamins (compounds that can dissolve in water), such as folate, vitamins B6, B12, and C
• Fat-soluble vitamins and nutrients (compounds that can dissolve in fat), such as vitamins A, E, and D; carotenoids; and fatty acids (saturated, monounsaturated, and polyunsaturated)
• Trace elements (dietary minerals that are needed in very small quantities) such as iron and iodine
• Isoflavones and lignans
• Acrylamide hemoglobin adducts

Access the Executive Summary [PDF - 575KB] for a full list of indicators in the Second Nutrition Report.

Purpose of the Second Nutrition Report

This report informs health scientists and policy makers about the levels of biochemical indicators of diet and nutrition in the U.S. population and in selected population groups such as children and women of childbearing age. These data help physicians, scientists, and public health officials assess inadequate or excess intake of specific nutrients. The report also helps:

• Establish or improve data that are used to determine if a person or a group has an unusually high or low level of a nutrition biochemical indicator (population reference level).
• Determine if the nutrition status of population groups—such as minorities, children, women of childbearing age, or the elderly—differs from other groups and if a nutrition status needs improvement.
• Look at nutrient levels over time to detect trends of health significance.
• Assess whether public health efforts to enhance the diet and nutrition of the U.S. population are working.
• Guide future research in nutrition and health.

Interpreting the Data

The measurements presented in this report are the result of cumulative intakes from

• foods, some fortified with micronutrients (e.g., iron, thiamin, riboflavin, niacin, folate, vitamin A, vitamin D), and
• dietary supplements that contain vitamins, minerals, or both.

Biochemical indicators measured in blood and urine can also be influenced by factors other than diet, such as various diseases.

This report presents reference information on selected biochemical indicators. Differences between population subgroups can be assessed by identifying groups with non-overlapping confidence intervals. A confidence interval is a range around a measurement that conveys how precise the measurement is.

It is beyond the scope of this report to explore the reasons for differences in observations derived from descriptive analyses. Also, the current study design does not permit CDC to estimate biochemical indicators by state or by city. For example, CDC cannot extract a subset of data and examine levels of folate in a particular state or city.