Industry releases white paper questioning NY AG testing methodology

WASHINGTON — Four dietary supplement trade associations on Wednesday released a white paper that identifies five potential weaknesses of the New York Attorney General's recent investigation into botanical dietary supplements. 

1. 
   Were the DNA barcoding methods inappropriately used on extracts? According to the investigation, which reportedly used DNA barcoding methods, “a large number of the tests did not reveal any DNA from a botanical substance of any kind." However, DNA in botanical dietary supplements containing extracts is of relatively poor quality — or absent altogether. If specific DNA authentication methods were not used targeting short DNA fragments, a high rate of false negative results would have been highly probable;


2. 
   Did the laboratory performing the test have sufficient knowledge of the complexities of testing botanical dietary supplements? Specialized training and extensive experience in the field of plant species identification, on top of a solid understanding of the various processing and extraction techniques used by each manufacturer, are necessary to obtain reliable results from testing botanical dietary supplements; 


3. 
   Were adequate procedures used to avoid contamination of samples in the testing facility? The NY AG study reported that, “contaminants identified include rice, beans, pine, citrus, asparagus, primrose, wheat, houseplant, wild carrot and others." Additionally, garlic was identified in a number of samples not listed to contain that species. While rice and wheat are not wholly unexpected fillers in botanical dietary supplements, the widespread discovery of plants not typically known as adulterants such as asparagus, houseplants and garlic across independent samples from different suppliers suggests the possibility of environmental and/or cross contamination between samples in the laboratory;


4. 
   Were validated reference sequences and appropriate analytical tools used to identify species? Most of the species under investigation by the NY AG cannot be accurately identified without a proprietary database of reference sequences, as several of the species under investigation — including St. John’s wort and Echinacea — do not have publically available reference sequences from the genes necessary to identify them; and


5. 
   Were valid conclusions made from the results? The NY AG made public pronouncements with potentially far-reaching legal and market implications that a majority of the dietary supplement products were devoid of the labeled ingredients and contained a myriad of unlabeled ones. However, these conclusions are not valid for a number of reasons. First, the absence of DNA cannot by itself indicate whether a botanical product originated from a plant, because the DNA can be removed while retaining the phytochemicals from the plant source; additional testing must be employed when no DNA is identified to provide conclusive results. Second, because some DNA testing methods are capable of detecting trace levels of DNA, the amount of plant material that is present cannot be extrapolated (only that it is present in the sample), and the significance of the species found cannot be determined. Moreover, the source of the contaminants cannot be concluded — they could have arisen from the lab itself, or from any one of a number of steps in the process from harvest to milling and packaging.