Task 3: Key Concepts about Identifying Dietary Supplement Variables and File Locations

NHANES dietary supplement variables cover items related to the use of vitamin, mineral, herbal, and other dietary supplements.  Some variables relate to the participants and the supplements they may have taken; other variables relate to the supplements and their formulations and ingredients.  These variables, and information about them, are stored within the Dietary component, contained in five data files:


Variables in File 1
Participant sequence number (SEQN)
Any dietary supplements taken in the past 30 days?
Total number of supplements taken
Any non-prescription antacids taken?
Total number of antacids taken


Variables in File 2
Participant sequence number (SEQN)
Supplement ID number
Supplement name
Was container seen?
Matching code
How long supplement taken (days)?
How often taken past month? (quantity)
How often taken past month? (unit)
How much taken each time? (quantity)
How much taken each time? (unit)
Antacid reported as a dietary supplement


Variables in File 3
Supplement ID number
Supplement name
Supplement information source
Formulation type
Serving size quantity
Serving size unit
Alternative serving size
Count of vitamins in supplement
Count of minerals in supplement
Count of amino acids in supplement
Count of botanicals in supplement
Count of other ingredients in supplement


Variables in File 4
Supplement ID number
Supplement name
Ingredient ID
Ingredient name
Ingredient operator (<, =, >)
Ingredient quantity
Ingredient unit
Ingredient category
Blend flag


Variables in File 5
Ingredient ID number
Ingredient name
Blend component ID
Blend component name
Blend component category



For more detail on the dietary supplement variables, go to Information about Dietary Variables.  Please note, however, that the most complete descriptions of these variables can be found in the Analytic Notes section of the “Docs” file.  You can find this link on the Dietary Supplement Use line of the 2003-2004 Dietary Files page. 

You cannot determine whether a dietary supplement variable is appropriate to use in your analysis without consulting the data file documentation.  You will use this information when downloading data files and documentation and when performing your analyses. 

Read the documentation.



Dietary supplement data are part of the Dietary component of NHANES 2003-2004.  Other variables necessary for your analysis may be located in other parts of the dataset.

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