One of the core points that we try to promote on SBM is that everything potentially is a toxin. Sola dosis facit venenum – the dose makes the poison – is an adage credited to Paracelcus about 500 years ago. This works both ways – in high enough dose, anything can be a poison, and in low enough dose, anything can be safe. Dosage is everything.

When we refer to things as being toxic or non-toxic, these are relative designations. Something is toxic if it potentially causes bad effects in doses that someone is likely to be exposed to. And something is non-toxic if it can be safely used without being exposed to toxic doses.

Pharmaceuticals are also mainly determined by dose. A drug is a substance that has a biological effect that can be exploited for useful purposes in a dose range that causes acceptable side effects. If the same dose that lowers your blood pressure also destroys your kidneys, that is not a useful drug that will make it to market. It takes on the order of magnitude of $100 million to determine if a substance has that useful dose range.

All drugs are toxins – it is their rational use in targeted patients at highly controlled doses that makes them medicine.

Supplements

What, then, are supplements? “Dietary supplement” is a regulatory term more than a scientific one. The FDA defines a dietary supplement as:

A dietary supplement is a product intended for ingestion that contains a “dietary ingredient” intended to add further nutritional value to (supplement) the diet.

However this is misleading. That is what the definition should be, including vitamins, minerals, and food concentrates or extracts. These are substances taken for their nutritional value. However, the Dietary Supplement Health and Education act of 1994 (brought to you in part by Orrin Hatch from the home state of the supplement industry) engaged in a stunning bit of legislative legerdemain. They snuck in “herbs and botanicals” onto the list of dietary supplements.

This is a brazen deception, because herbs and botanicals are not taken for their nutritional value, no matter what the FDA is legally forced to say. Herbs are taken for their pharmacological effects. Just look up any popular herbal product and see how they are described. I searched for the top ten herbal products, and Prevention.com listed turmeric at the top of their list, writing:

A heaping helping of curry could relieve your pain. That’s because turmeric, a spice used in curry, contains curcumin, a powerful anti-inflammatory that works similarly to Cox-2 inhibitors, drugs that reduce the Cox-2 enzyme that causes the pain and swelling of arthritis, says Lee.

It doesn’t get any clearer than that – they are describing a drug. Oral curcumin supplements are likely worthless by the way, (and IV curcumin possibly lethal) because of low bioavailability. Further, claims are based almost entirely on flawed bioassays, and not actual clinical evidence. If herbs and botanical are drugs, why are they regulated as if they are vitamins? That’s a good question.

Like all drugs, being a useful medicine means there is a dose range in which the substance has a beneficial or useful biological effect with acceptable side effects. Do the most common herbal products have such a dose range? No one knows, because they are not required to provide the kind of scientific evidence that would allow for such a determination. Instead, the public is assured that these substances are safe because they are “natural” and because of traditional use. Neither of these are a reasonable assurance, however.

The result is that the public is lulled into a false sense that herbs are safe. They falsely think they are properly regulated, and that they would not be sold (especially in pharmacies) if they weren’t generally safe. This disconnect between public perception and reality is a dangerous situation, and use of herbs has led to significant health harms.

Rise in supplement toxicity

A recent study published in the Journal of Medical Toxicology tabulates the “out-of-hospital dietary supplement exposures reported to the National Poison Data System from 2000 through 2012.” They found:

There were 274,998 dietary supplement exposures from 2000 through 2012. The annual rate of dietary supplement exposures per 100,000 population increased by 46.1% during 2000–2002, decreased 8.8% during 2002–2005, and then increased again by 49.3% from 2005 to 2012. These trends were influenced by the decrease in ma huang exposures starting in 2002.

The steady rise in toxic exposures to supplements was interrupted briefly when ma huang and other substances containing ephedra were banned by the FDA in 2003. This was based on 16,000 reports of adverse events, including 155 deaths. To my knowledge this is the only such banning of an herbal product by the FDA since the 1994 DSHEA legislation. This shows that proper regulation can have a beneficial effect, protecting the public from the harmful effects of these essentially unregulated drugs.

Energy products (such as drinks containing yohimbe and caffeine) still account for the majority of adverse events from toxic exposure to “supplements.” These products can cause cardiac arrhythmias, seizures, and even death.

In the study 60% of calls were for children under 6 (who, unsurprisingly, should not be consuming energy drinks) who had accidental exposures. However, 95% of the serious adverse outcomes occurred in those 6 years or older. In the older age groups more exposures are also intentional, 65% in teens and 40% in adults. So a large percentage of the serious adverse outcomes were due to intentional use of herbal products.

Poor quality control

The false assurance of safety based on the notion that these products are “natural” results in deeper problems as well. The supplement industry is generally poorly regulated. Supplements often contain contaminants, unlisted fillers, and even use fillers to substitute for the alleged active ingredients. You may think you are getting Gingko, but in fact you’re getting alfalfa and rice flour. Some of those substitutes may cause allergies. Supplements often have drug-drug interactions. Ingredient levels vary incredibly. Bioavailability is anyone’s guess. Supplements also often illegally and secretly contain real drugs.

So, even if an herbal product has some beneficial effect in highly controlled clinical trials, where barcoding is used to assure purity and dosage is carefully measured, you cannot apply these findings in the real world. When you buy an herbal product you essentially have no idea what you are getting.

There documented case of mislabeling and inappropriate use leading to serious toxicity. For example:

In Belgium in the early 1990s, the TCM herb Stephania tetrandra was used for weight loss. Aristolochia fangchi was mistakenly used instead, and this resulted in more than 100 cases of renal failure and more than 20 cases of urothelial dysplasia. Similar problems were later reported in the UK. The culprit is thought to be the aristolochic acid found in Aristolochia fangchi. In TCM practice, Stephania tetrandra and Aristolochia fangchi were never meant to be used for weight loss.

Herbs are drugs

None of this is to say that herbal products are more or even as potentially toxic as prescription drugs. I think in general herbs and botanicals are less toxic than prescription drugs because they have lower dosage and lower bioavailability. These features also lower the potential for a beneficial effect, however – they go hand-in-hand.

My real point is that herbs are drugs. Do not be deceived by the massive lobbying and propaganda campaign of the supplement industry. The notion that herbs are “natural” means literally nothing. Anecdotal evidence from traditional use is also a poor guide. Unless you track toxicity closely, you will notice only the most immediate and obvious toxic effects, and you will have no idea about any long-term or chronic effects.

The only facts that matter are those that relate to the pharmacological properties of herbs and botanicals. What is their therapeutic window, what are the active ingredients, their doses, bioavailability, half-life, routes of elimination, purity, consistency, and drug-drug interactions? This is the kind of information you discover when you do careful scientific research into the properties and biological effects of herbs and/as drugs. You can know these things when an industry is properly regulated for quality control and transparency.

Instead of knowledge, information, and transparency, the supplement industry offers deceptive marketing about being “natural.” They misinterpret basic science, ignore major concerns about their products, and half the time don’t even respond to FDA inquiries about their alleged deficiencies.

Current supplement regulations in the US (and many countries) are overtly anti-consumer and pro-industry, and are the direct result of aggressive industry lobbying and having powerful senators in their pockets. The rise in calls to poison control for supplements are just one manifestation of this situation. The fix is also pretty clear. We simply need to regulate the industry the way the public wants and thinks they already are being regulated.

Posted by Steven Novella

Founder and currently Executive Editor of Science-Based Medicine Steven Novella, MD is an academic clinical neurologist at the Yale University School of Medicine. He is also the president and co-founder of the New England Skeptical Society, the host and producer of the popular weekly science podcast, The Skeptics’ Guide to the Universe, and the author of the NeuroLogicaBlog, a daily blog that covers news and issues in neuroscience, but also general science, scientific skepticism, philosophy of science, critical thinking, and the intersection of science with the media and society. Dr. Novella also contributes every Sunday to The Rogues Gallery, the official blog of the SGU.