Herbal labeling depends on brand, not benchmarks
consumers may vary substantially in recommended dose and listed
ingredients, researchers report in a new study, which appears to
suggest that doctors can do little to assess how much of an active
ingredient is being ingested.
Different brands of the same herbal products available to US consumers may vary substantially in recommended dose and listed ingredients, researchers report in a new study.
An analysis of the top ten selling herbs showed that label information differed greatly among similar products and fewer than half of those tested provided the dosage and ingredients recommended by certain 'benchmark' standards.
However those products at the higher end of the price scale tended to be most consistent with ingredient benchmarks.
"This study demonstrates that health providers and consumers need to closely examine label ingredients of presumably the same or similar herbal products," write researchers from the University of Minnesota, Minneapolis in the recent issue of the Archives of Internal Medicine.
The journal notes that use of herbal medicines by the public has increased by 380 per cent over the past decade, but over half of such use is not disclosed to a medical physician. The study suggests that consumers would not be able to properly indicate to doctors the amount of active herbals they are consuming.
The Minnesota team carried out a survey of the 10 herbs with the greatest sales in 1998 - echinacea, St John's wort, Ginkgo biloba, garlic, saw palmetto, ginseng, goldenseal, aloe, Siberian ginseng, and valerian.
Products for each of the 10 herbs were analysed in a convenience sample of 20 retail stores in a large metropolitan area. The researchers used a professionals' handbook on alternative medicine for their benchmark, one of the few such publications by scientists with no commercial interest in the industry, according to the study authors.
They report that each herb had a large range in label ingredients and recommended daily dose (RDD) across available products. Strengths were not directly comparable because of ingredient variability, they add.
Among 880 products, 43 per cent were consistent with a benchmark in ingredients and RDD, 20 per cent in ingredients only, and 37 per cent were either not consistent or label information was insufficient.
For example, out of the 92 echinacea products, sold under 27 brand names, two-thirds were inconsistent with the benchmark in both ingredients and dosing recommendations, yet all of the 113 ginseng products were consistent with the benchmark for listed ingredients.
Price per recommended daily dose was a significant predictor of consistency with the benchmark, but not for all products, and store type had no positive association with quality.
There is growing awareness of herb/drug interactions but lack of standardization of herbal ingredients makes it difficult to assess the strength of a herbal product.
