The Food Chemistry Division (Working Group on Nutrition Issues) of the German Chemical Society (GDCh) has published a new version of its vitamin conversion tables. These revised tables replace the previous versions from 2001/2006 and reflect the current state of scientific knowledge as well as the applicable European legal framework for food and dietary supplements.
As a result, calculations based on the new tables may differ from those obtained using earlier versions, even when analytical measurement results remain unchanged. The tables continue to serve as a technical reference for converting analytical results into values relevant to nutritional declaration and evaluation.
The conversion factors for vitamin E have been revised in the updated GDCh vitamin conversion tables. This revision specifically affects the conversion of DL-α-tocopherol, the synthetic form of vitamin E, into α-tocopherol equivalents, which are used as the reference for vitamin E activity. As a result, synthetic DL-α-tocopherol and DL-α-tocopherol acetate are now assigned a significantly lower vitamin E activity.
It should also be noted that all tocopherols and tocotrienols, other than α-tocopherol, are no longer considered to exhibit vitamin E activity. This change is particularly relevant for vegetable oils, tocopherol mixtures and enriched foods in which other tocopherol forms were previously used for calculation purposes.
These revisions can result in calculated vitamin E contents that are more than 30% lower than values determined using earlier conversion tables, even though the underlying analytical measurement results remain unchanged. While laboratory results are not affected, calculation outcomes and declared values change accordingly and should be considered for product evaluation and labeling.
For companies, the revised GDCh vitamin conversion tables may require a review and adjustment of existing processes and documentation. In particular, the following should be reviewed:
Depending on the product and vitamin forms used, this may mean additional work, such as adjusting specifications or declarations. At the same time, the updated tables improve the traceability and consistency of vitamin information and can help reduce long-term discrepancies and follow-up queries.
Although the GDCh vitamin conversion tables are not legally binding, they are increasingly used in practice as an authoritative technical reference. Addressing these changes at an early stage supports a structured and efficient implementation of any necessary adjustments.
Contact us for support with vitamin analysis in food and technical advice on nutritional declarations to help ensure product quality.
