Respondents were asked to report each dietary supplement they consumed using a unique numeric identifier found on the dietary supplement label called an AUST-L. Where the AUST-L could not be identified, respondents provided information on the supplement name (e.g. Blackmore's vitamin C tablet or Nature's Way fish oil) or the general supplement type (e.g. vitamin C supplement or fish oil supplement). The amount (or dosage) of each dietary supplement consumed was also collected.
The list of dietary supplements reported in the 2011-12 National Nutrition and Physical Activity Survey (NNPAS) then needed to be assigned a nutrient profile and five digit classification code from AUSNUT 2011-13.
Assigning dietary supplements consumed to AUSNUT 2011-13 nutrient data
The ABS provided FSANZ with a list of dietary supplements reported from the NNPAS. FSANZ reviewed the list and identified any medicines that were reported that were not dietary supplements (e.g. they were prescription medicines or were creams for the skin).
The majority of dietary supplements were reported using an AUST-L number and/or the corresponding product name allowing a nutrient profile to be easily assigned.
Where a dietary supplement was not able to be directly matched to an existing product, the dietary supplement was assigned the nutrient profile:
- of the closest dietary supplement, where the product name provided was very similar to a dietary supplement with an AUST-L number
- of a 'not further defined' supplement.
Information on the development of the nutrient profiles for dietary supplements is available here.
Assigning dietary supplements consumed a classification code
Dietary supplements have been classified based on the 'active' ingredients they contain, and more specifically the key nutrient/s they contain. Some supplements classified as calcium supplements also contain magnesium and/or zinc, but at levels of magnesium and /or zinc unlikely to make a major contribution to overall nutrient intakes. In contrast, a product containing several minerals, all present at nutritionally relevant levels, is likely to have been classified as a multivitamin/mineral supplement. Supplements that contain both nutrient and non-nutrient ingredients (e.g. glucosamine with fish oil) have been classified in the most appropriate nutrient classification (e.g. fish oil supplements).
While most supplements also contain 'excipient' ingredients which may contain low levels of nutrients, they have not been taken into account in the classification.