Echinacea products sold in retail stores often do not contain what the labels claim, according to researchers whose findings prove just how vulnerable consumers are to deceptive labeling.
A team from the University of Colorado Health Sciences Center, Denver found that in a sample of 60 supplements marketed as echinacea products, 10 per cent showed no noticeable presence of the plant.
Sales of echinacea, commonly used to treat colds and flu, represent 10 per cent of the dietary supplement market in the United States, but the plant can be sold in different forms - capsules, liquid - and different varieties are supported by varying levels of scientific evidence.
The researchers assessed both the quality and quantity of contents in echinacea-only preparations available from retailers in the Denver, Colorado area in August 2000. They report on their findings in this week's Archives of Internal Medicine.
They used thin-layer chromatography (TLC) to determine species and measure quantity, and from there, to check that the species had been accurately labeled. They also divided standardized, nonstandardized samples.
Of the 59 samples, six (10 per cent) preparations contained no measurable echinacea. The assayed species content was consistent with labeled content in only 31 (52 per cent) of the samples. Of the 21 standardized preparations, nine (43 per cent) met the quality standard described on the label, significantly undermining the value of so-called 'standardized' natural remedies. Finally, the team report that labeled milligrams were weakly associated with their findings.
The authors concluded that many products on the market do not live up to labeling claims. They add: "A claim of 'standardization' does not mean the preparation is accurately labeled, nor does it indicate less variability in concentration of constituents of the herb."