The Early Show medical correspondent Dr. Emily Senay explains that a lack of thorough study or industry regulation of herbal supplements means that there's a lot of unknowns. She warns consumers need to be careful how they use these products.
A new study by researchers in Minnesota took a look at the 10 best-selling herbs from 1998: chinacea, St. John's wort, ginko biloba, garlic, saw palmetto, ginseng and Siberian ginseng, goldenseal, aloe and valerian.
Researchers searched grocery stores, retail pharmacies, discount stores and health food stores — finding an overwhelming variety of different brands, different ingredients and different doses. Senay says there are at least 880 different variations of the 10 best selling herbs.
The researchers did not analyze the actual ingredients in the products. The study only looked at the labels. They found that the different brands vary widely in their listed ingredients and recommended dosages. Products varied from brand to brand in the amounts and components of the plants used, how they were grown, harvested and prepared. Similar products had differing combinations of added ingredients and different formulations from capsule to extract to tea.
The researchers created a benchmark using information on active ingredients and recommended doses from a textbook on herbal dietary supplements written by researchers and pharmacists. Less than half of the products examined were consistent with that benchmark — these were generally the more expensive brands.
For people thinking about taking a herbal supplement, Senay suggests consulting with a doctor first, andto always keep the physician informed of what is being taken. The bottle should also be show to the doctor so he or she knows exactly what is being taken.
There are also potential risks to consider when mixing medication with supplements. Herbals can affect the potency of other medications or cause unexpected side effects.
There is not much scientific evidence on most of the herbal supplements to show the benefits of them. Preliminary research on St. John's wort for depression and gingko biloba for improvement cognitive function has not shown much of a benefit beyond that of the placebo effect, according to Senay. But the jury is still out until the herbs are tested more thoroughly.