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Aug. 22, 2000 -- Convinced of the medicinal value of various roots and leaves, growing numbers of health-conscious consumers are snapping up botanical supplements, say the authors of a new article appearing in the American Journal of Clinical Nutrition.
"Yet, scientific research is still confined to only a handful of the hundreds of substances sold in health food stores," write lead author Andrea Borchers, PhD, a nutritional researcher at the University of California, Davis, and colleagues.
Seven of the 10 top-selling botanicals in the U.S. were used as medicines by Native Americans, and many of these supplements' purported benefits are based on what these early Americans used them for. But little is known about exactly how they used these substances -- their plant-collecting procedures, the precise plant parts they used, or their methods of preparation, Borchers says.
The original North American residents' use of medicinal botanicals was "by no means random, but highly selective," Borchers tells WebMD. They made extensive use of some plant families and virtually avoided others. In fact, they took different plant parts for the treatment of different ailments, combined several botanicals for specific therapeutic purposes, and recognized toxic plants both as poisons and as medicines.
"The fact that Native Americans have used so many botanicals in a really expert way is a good indication that there are some very promising substances among the things they used. But so far there's very little scientific research on any of these compounds," Borchers says.
Two herbs that have received some study are Echinacea (purple coneflower) and Urtica dioica (stinging nettle), and Borchers and colleagues say there are indications that both do have medicinal effects.
"There's pretty good evidence that all species of Echinacea work in reducing symptoms of common cold or flu or upper respiratory infections," Borchers says. "But that's not a totally consistent finding. What's complicating the picture is that testing has involved different types of extracts, either from different species or from different parts of the plants in the studies. If they use roots, they get a different chemical structure than if you use the upper parts of the plant."
Scientists still speculate on precisely how Echinacea works in the system, she tells WebMD: "It seems to affect the immune system ... and thereby helps the body fight off a cold or flu."
If you're looking for a botanical rather than drugs to knock down the flu, try Echinacea, Borchers says. "It's been shown to be quite safe because it has been used in large studies with minor side effects. And it might actually help."
As for stinging nettle, commonly used to relieve arthritis, Borchers says that preliminary studies indeed point to an anti-inflammatory effect. "The picture is much less clear because investigations have been done in animal studies only. There's always the question to what extent do animal studies translate into humans."
But "some results tend to confirm what Native Americans found" -- that stinging nettle did work. "There are some indications that it directly inhibits some of the enzymes that cause inflammatory responses," she tells WebMD.
Coming up with a standard dose for these botanicals has become a big issue among American manufacturers in recent years. Because so little is known about the effective components in Echinacea, companies are having a hard time establishing a standard dose, Borchers says. "They don't know exactly what the ultimate active ingredients are," she says. "And there are still questions about as to what extent these ingredients are actually absorbed.
"European companies have been in this business a lot longer, and they have pushed for standardization for 15 or 20 years now. This is a very personal opinion here, but if you go with a European brand, at least you would get what they say is in there, hopefully," Borchers tells WebMD.
If you're committed to American-made products, the best you can do is find a brand name with a good reputation, she advises. "There's talk about standardization of extracts and more control by the FDA," but until then, it's important to look for something else to base your purchasing decision on, Borchers says.
She also points to web sites, include those run by Consumer Reports and ConsumerLab, which provide information on the chemical composition of various extracts "so you can make sure you get something that actually contains Echinacea. Ultimately, it's 'consumer beware,'" she says, "Keep up on the latest in research."
Also, if you're taking other medications and want to try an herbal, "there's the issue of drug interaction, as with St. John's Wort, which had negative interactions with transplant and HIV drugs," she says. "Testing of drug interactions is in its infancy, but if people are taking different things, they need to be aware of different side effects of what they are taking."
Steven Foster, author of 101 Medicinal Herbs, has followed the research on Echinacea for the past 20 years. While researchers have learned much about the mechanisms by which Echinacea works in the body, he agrees that much is still unknown about the best recommended dosage and the best type of preparation, whether it's tincture, tea, capsule, or extract.
"Echinacea is worth taking, especially at the onset of symptoms when you feel like you're coming down with something," he says. But don't mistake it for a cold preventative, he advises.
"People are making the mistake of taking Echinacea like vitamin C, where you take it continually during cold and flu season," he says. "The thing about it is, it basically works by stimulating the immune system. It works on a real short-term basis and requires repeated doses.
"If you took Echinacea for two months every morning, after two or three weeks the immune system stops responding to the stimulation. There have been three clinical studies published that proves this point. Don't take it for more than two or three weeks."