Conference Examines Efficacy, Safety of Medicinal Herbs
Denise Grady
Chatting with the man who sat next to her on an airplane a year and a half ago, Dr. Leonore Arab could not help noticing that his skin had a telltale orange tinge. As they talked, he revealed that he was thirty-eight and had lung cancer, and in addition to undergoing standard treatment had consulted an “herbalist,” who had told him to drink three glasses of carrot juice a day, eat little else, and take herbs and other supplements, including beta carotene, a yellowish-red nutrient that is converted into vitamin A in the body.
The carrot juice alone contained enough carotene to turn his skin orange, a harmless though certainly odd looking condition. But the herbalist’s advice was not harmless. Indeed, Dr. Arab, a professor of epidemiology and nutrition at the University of North Carolina at Chapel Hill, found it troubling.
“It was heart-rending,” she said, adding that she did not want to destroy his hopes, but felt an obligation to tell him that he might be harming himself.
She warned the man, as gently as possible, that research had linked beta carotene to an increased risk of lung cancer in men who smoked, and that the substance might not be safe for someone who already had lung cancer. In addition, she told him, cancer patients needed far more nourishment than they could get from a diet of carrots, juice, herbs, and vitamins.
That experience, and similar encounters with other patients taking herbal products with unknown ingredients and unknown effects, recommended by people with unknown credentials, led Dr. Arab to organize a scientific meeting on the subject.
The two-day conference, “The Efficacy and Safety of Medicinal Herbs,” March 2-3 in Chapel Hill, North Carolina, was among the first in the nation to gather mainstream researchers from respected universities and to apply rigorous scientific standards to evaluating studies of herbal products. Duke University and the National Institutes of Health were cosponsors, along with the University of North Carolina.
But the scientific scrutiny is a bit late. “The train has left the station,” Dr. Arab said, noting that Americans were already engaged in a vast, uncontrolled experiment. They spend $4 billion dollars a year on herbal remedies, which are not regulated by the Food and Drug Administration.
“People are not turning to health professionals,” Dr. Arab said. “They go to magazines for information.” Many do not even tell their doctors what they are taking.
But even if people did ask their doctors about herbs, most doctors could not answer. There is little information about herbs in the nation’s scientific literature, and American medical schools do not teach students about them. Speakers at the conference included several researchers from Germany, where herbal medicines have been studied more extensively than in this country and are regulated like drugs by the government, which monitors growing, harvesting and processing. Popular herbs got mixed reviews at the conference. More than twenty controlled studies of mild depression have shown that St. John’s wort works as well as some prescription drugs, with fewer side effects. The herb is the best-selling antidepressant in Germany, and health insurance covers it there as well as in Switzerland and Austria. It is also widely used by Americans who want to treat their own depression, but Dr. P. Murali Doraiswamy, a psychiatrist at Duke University who spoke at the conference, had reservations about it.
He said some of the studies were too small to be reliable, that long-term data were lacking, and that the herb had not been compared with the most effective prescription drugs like Prozac and Zoloft. Scientific reviewers called St. John’s wort promising but unproven, he said, adding that many of his own patients had tried it, but often irregularly and at incorrect doses. Because depression is a serious illness and a major cause of suicide, he said the trend to self-medicate was worrisome.
Recently, cases have been reported in which St. John’s wort has had dangerous interactions with other drugs, including those used to treat H.I.V. infection and to prevent rejection in transplant patients.
Several studies of St. John’s wort are now in progress, one sponsored by the National Institutes of Health and one by Pfizer Inc., the drug company. In the meantime, Dr. Doraiswarny said, the jury is still out.
The herb saw palmetto, taken by many men to relieve symptoms of prostate enlargement like frequent urination, got a more positive report. Dr. Timothy J. Wilt, of the Veterans Affairs Center for Chronic Diseases in Minneapolis, evaluated eighteen studies and found that saw palmetto worked better than a placebo and as well as a prescription drug for the condition, finasteride, also called Proscar. The herb had fewer side effects and cost $15 a month, compared with $68 for the prescription drug. But Dr. Wilt said long-term studies were needed to find out whether saw palmetto would keep working and whether it might help men avoid or delay prostate surgery.
Ginseng does appear to have antioxidant properties, according to studies by Dr. David Kitts of the University of British Columbia in Vancouver. Antioxidants are thought to prevent certain types of cell damage associated with artery disease and aging, but their usefulness has not been proved and it is not clear whether they are safe for cancer patients, Dr. Arab said.
Another herb, comfrey, was condemned by Dr. Felix Stickel, of the University of Erlangen in Heidelberg who said the herb had been banned in Canada and Germany because it can cause liver failure. It has not been banned in the United States, though manufacturers have voluntarily removed it from products like herbal teas because its toxicity is widely known. Previously, it had been recommended both here and overseas to treat inflammation and constipation.
Other herbs received cautiously positive reviews. Dr. Arab reported that epidemiologic studies, in which researchers survey people’s diets and health, indicated that eating cooked or raw garlic–but not garlic supplements–was linked to a decreased risk of stomach and intestinal cancer.
Dr. Edzard Ernst of the University of Exeter in England analyzed a series of studies of the herb feverfew, and concluded that it could be somewhat helpful in preventing, though not treating, migraine headaches.
Ginkgo biloba appeared to slow mental decline slightly in a third of patients in a placebo-controlled study of 137 people with dementia, Dr. Pierre LeBars of New York University said. The study, the first to show any benefit, was published in 1997 in The Journal of the American Medical Association. But the herb did not improve memory in healthy people. Dr. LeBars said more studies were needed to find out if it would really be of use in treating dementia. The form used in the study differed from the version usually sold in this country.
Certain echinacea extracts are accepted as treatment for colds in Germany, reported Dr. Rudolf Bauer of Heinrich-Heine University in Dusseldorf, who described several controlled studies showing that the herb could shorten the duration by a few days and ease symptoms. But there are three different species of echinacea and many different processing methods, and the effectiveness of different products may vary, he said, adding there was no evidence that any form of the herb could prevent colds or other infections.
Positive findings on herbs would be great news if Americans could obtain reliable products with known doses of substances that have medicinal effects. But what is actually in many of the items sold as dietary supplements in the United States is anybody’s guess: some may actually contain none of what is promised on the label.
Dr. Varro E. Tyler, a distinguished professor emeritus of pharmacognosy at Purdue University, called the status of medicinal herbs in the United States a “scandalous situation” that has left the public bewildered, scratching their heads and trying to figure out things like which of a dozen different echinacea products might work. He also warned that anybody can call himself or herself an “herbalist” and offer all sorts of advice to the public.
Dr. Tyler, who has written more than thirty books about herbs, describes them as “dilute drugs,” and he said they should be regulated as drugs by the FDA so that manufacturers are required to produce uniform batches with known ingredients.
But under the 1994 Dietary Supplement Health and Education Act, herbal medicines are classified as supplements, not drugs, which means there is no monitoring of quality control by a drug agency. The act also prevents manufacturers from saying on labels that their products can prevent or treat specific diseases or symptoms.
As a result, Dr. Tyler said the market has been flooded with “junk products” that are a waste of money. He denounced the growing trend to add herbs like St. John’s wort and echinacea to iced tea, soft drinks, and other foods. The herbs are drugs and should be treated with respect, he said, and do not belong in canned soup any more than Prozac does.
He faulted greedy manufacturers and the FDA. He said that to approve an herbal product as a drug, the federal agency insisted that its manufacturer provide the same proof of safety and efficacy as other new drugs. But that requirement is unrealistic, he said, because the testing process can cost hundreds of millions of dollars, and herb manufacturers do not attempt it, because their products are generally not patentable and they will never recoup the costs.
Since herbs have been around for so long and the vast majority have few or no side effects, Dr. Tyler said the rules should be relaxed for them, to require strong proof of safety and “reasonable” proof of efficacy, which he said could be obtained with two well-designed, placebo-controlled trials that would cost a few million dollars, instead of hundreds of millions. He predicted that FDA-approved herbal drugs would be so popular that people would flock to them, forcing manufacturers to submit to the process to be competitive.
But a spokeswoman for the drug agency said that changing the standards for approval would take an act of Congress.
Denise Grady is a reporter for The New York Times, where this article originally appeared Reprinted by permission.
COPYRIGHT 2000 Committee for the Scientific Investigation of Claims of the Paranormal
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