Safety of herbal medicine

29 November 2002

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Published in The Age

Herbal medicines have an ancient reputation for treating a range of human ailments, and even in the twenty-first century are used by the majority of the world’s people. Yet media reports of dangers from herbals persist. These frequent alarms, says Australian Medical Association spokesperson Dr Rosanna Capolingua, “are not overdone”:

“The consumption of natural therapies has increased so much that now we’re starting to see side-effects, and in some cases disasters occurring. It’s a real wake-up call.”

Recent stories have told us that St John’s Wort could affect fertility, that herbal Noni juice contains enough potassium to threaten kidney patients, and that vitamin supplements could spread mad cow disease.

But US medical herbalist Dr Alan Tillotson points out that the St John’s Wort scare originated in a lab experiment on human sperm and hamster eggs. “The lead author of the study, Richard Ondrizek, MD, was upset and ‘flabbergasted’ that his research was being used in the media to promote the idea that these herbs could cause infertility in humans.”

He adds that Noni juice actually contains less potassium than cucumber and oats, and that 60% of the US population takes vitamin supplements - and there’s yet to be a report of mad cow diease there.

Dr Tillotson pokes plentiful fun at what he calls “hysterical phytophobia in a tongue-in-cheek article: MD hysteria against herbs reaches epidemic proportions: threatens nation’s health. (Phyto is a prefix relating to plants.)

Herbal critics, Tillotson writes, “seem unable to mathematically calculate the vast numerical difference between the thousands of victims of modern pharmaceutical medicine and the handful of victims of natural medicines. For example, the worst estimates of ‘dangerous herbs’ is that they may kill 50 Americans a year, while pharmaceuticals routinely kill 140,000 (according to the Journal of the American Medical Association in 1997), making herbs approximately 2,800 times safer than pharmaceuticals”.

“Anything seeingly adverse to herbs,” Tillotson told The Age, “is blown out of proportion.” He believes the problem stems from our social conditioning in favour of Western medicine, and from drug companies employing “thousands of public relations and advertising people to promote their products. Some of them use their media contacts to promote garbage issues”.

The Age asked the AMA’s Dr Capolingua about the 18,000 Australians who die annually of “preventable hospital mishaps”: didn’t this put the occasional problem with herbals in some perspective?

“I don’t think we should be falsely reassured by making comparisons,” she responded.

A lot of the research into herbal toxicity “is test tube research which has little relevance to normal human use,” says Kerry Bone, a former member of the complementary medicines evaluation committee of the Therapeutic Goods Administration (TGA).

Occcasionally a herb does proves toxic. Most problems come when herbs are misidentified or adulterated, according to Bone, who says that the worst cases are from Asia, where herbal medicines have been illegally adulterated with pharmaeutical drugs. He points to Cow’s Head brand tung shueh, which when analysed in 1996 contained several mainstream anti-inflammatories.

In general, though, Bone believes that much-vaunted “dangerous” herbal interactions with mainstream drugs are definitely overblown:

“I have seen little evidence of it in my practice. Pharmacologist Dr Clyde Jensen, who was head of the National College of Naturopathic Medicine in the US, did a survey of his college’s clinics’ cases for evidence of herb-drug interactions. Not one was credibly observed, over five years in these busy clinics.”

“But anything we put into our bodies has an effect,” says the AMA’s Dr Capolingua, “whether it’s from a plant, or made in a laboratory. Often because something is natural, we get lulled into a false sense of security. Patients have every right to see an alternative therapist. But patients need also to understand what to expect - and not to ask too much. And to ask questions about safety and efficacy, like they would of me if I was writing a prescription.

“The difference with conventional medicine is that we’ve done the clinical trials. In the alternative therapies, we need more clinical trials. We need to know when therapies such as herbs are safe and useful. I mean, people take garlic. It lowers lipid levels, which is a good thing. But do they realise it also increases bleeding time, and that you’re not supposed to take it before an operation, because you can bleed considerably in theatre?”

Dr Capolingua also points to frequent uncertainty with herbals over appropriate dosages: “We need a lot more research, basically.”

Herbs - like the pharmaceuticals which are often synthesised from them - are drugs, and occasionally their effect is adverse. Dr Stephen Myers and Anna Drew point out in a 1997 article in the Medical Journal of Australia that the bark extract Yohimbine - used for male impotence - “can cause hypertension and anxiety in a predictable, dose-related manner”.

Wholesale disasters, whilst rare, do occur. One of the worst arose when the Belgian slimming treatment ingredient Stephania tetrandra  was substituted with Aristolochia fangchi, which led to renal failure in 80 women, half of whom are now terminal.

Australia’s response to the disaster was comprehensive: “Although no medicines containing Aristolochia are permitted in Australia,” says TGA spokesman John Noble, “routine testing by the TGA found it was present in some medicines due to misidentification of the herb. The TGA’s Office of Complementary Medicines worked closely with the Australian industry to remove the affected goods from the market, and to improve the botanical identification processes used by herbal manufacturers. In addition, every batch of medicine that is likely to contain the herb must now be tested and approved before release for supply in Australia.”

Despite the occasional such episode, Melbourne pharmacist Lesley Braun believes the media overdoes herb safety issues: “Most likely due to a lack of understanding about some of the fundamental principles, and also because sensational headlines attract readers”.

Braun believes some solutions exist at government level. The TGA’s present systems for registering medicines “recognise pharmacists and medical doctors but not naturopaths or herbalists - who are likely to have many more years of training and experience in using complementary medicines. This is naïve and unrealistic.

“ADRAC - the body that collects adverse reaction reports to therapeutic substances, including complementary medicines - is not efficient either. Naturopaths and herbalists do not have direct access to the reporting system, meaning there may be adverse reactions to complementary medicines that are unlikely to be reported to ADRAC.

“There is a case for developing a new scheduling category that includes complementary medicine practitioners, and recognizes that the safety of some complementary medicines would be enhanced if prescribed after a professional consultation with these experts.”

More broadly, Dr Alan Tillotson say that “education and education and education” is the way to counter anti-herbal hysteria. And that there’s an urgent need for this:

“All herbs combined - hundreds if not thousands of them - claim less lives than aspirin alone. Prescription drugs kill tens of thousands of people who get them only under direct medical supervision, and for many diseases where herbs could cure just as well if not better - such as hepatitis. The safety ratio between the two types of medicines is astounding."