Vanessa’s Law expansion puts natural health products in their place

Before I was a pharmacist, I was a wide-eyed biochemistry student fascinated by how medicines are discovered and used. I’d spend hours poring over articles about promising molecules and compounds, wondering how they might revolutionize our lives.

Then I’d send the article to a pharmacist and a physician I knew and be utterly deflated by the skepticism I was met with. In hindsight, they were both consistently correct, but I couldn’t understand what part of their training was giving them this insight. Now that I’m a pharmacist myself, I understand – as helpful as clinical knowledge and critical appraisal are, what I was missing mostly was history.

Training the next generation of pharmacists and physicians isn’t just about teaching diseases, prevention and treatment, it’s also about teaching how our knowledge got to where it is today and how we safeguard against errors we’ve made before.

One safeguard, “Vanessa’s Law,” mandates hospitals to report serious adverse events that may have originated from medications and medical devices. It also gives Health Canada more tools to act quickly and decisively if a major risk is identified. It’s an imperfect but important tool. This year, Vanessa’s Law was expanded to include natural health products (NHPs). The protests from their manufacturers were not unexpected, but it only takes a brief history lesson to realize why NHPs should have been included from the beginning.

In the 1940s, several studies identified an exciting new vitamin called folic acid. Its deficiency was quickly linked with several illnesses. One small study showed it could treat anemia of pregnancy. A few rodent studies even displayed anticancer properties. It’s no wonder then that in 1945, Sidney Farber and his team ran a trial to test folic acid supplementation to see if 90 late-stage cancer patients could benefit. But what Farber and his team found was dramatic: patients instead had rapid progression of their disease with a major rise in mortality.

Farber’s study highlighted the role of folic acid in cellular replication and led him to make a breakthrough discovery using antifolate drugs that have gone on to become a cornerstone of chemotherapy. But it also highlighted the importance of proper human trails and the risks of extrapolating from incomplete data.

In the pharmaceutical world, tens of thousands of molecules and compounds are studied; only a small fraction ever make it to clinical (human) trials. These are promising molecules with robust mechanisms of action and exceptional scientists behind them. Still, over the three phases of trials that are needed for approval, another 90 per cent will fail. Drug development is largely a graveyard of “promising molecules” that most of the public will never hear about. As imperfect as our approval and monitoring system for prescription medicines is, it shields many Canadians from ineffective and unsafe products.

Natural does not mean safe. Folic acid is natural. So is cyanide.

Unlike prescription medications however, NHPs (e.g., supplements, herbal remedies) are not subjected to the same rigorous processes. Natural does not mean safe. Folic acid is natural. So is cyanide. Too often, supplements are reviewed by extrapolating from limited data sets or even intuitive reasoning based on their proposed mechanism.

This was a mistake we had already made with antioxidant supplements. In the early 1990s and 2000s, we knew antioxidants mopped up Reactive Oxygen Species (ROS) that were clearly bad for you. ROS could cause cellular mutations and were implicated in cardiovascular disease, dementia, cancer and even aging. Every pre-clinical study (e.g., lab studies in animals or cell lines) seemed to show a new way that ROS could hurt humans. Given what we knew, it made intuitive sense to take antioxidant supplements for prevention. It was – and still is – an extremely profitable industry.

But when clinical trial results finally started coming in, studies showed no benefit in cardiovascular disease, dementia or any overall mortality. Most troubling were a few studies looking at cancer and overall mortality. Here, several studies linked a handful of antioxidant supplement types with increased prostate cancer and increased risk of death (ranging from four to sixteen per cent).

With the benefit of hindsight (and better studies), we can see why our intuition was wrong: ROS can be bad, but they’re also a tool used by the immune system and can limit cancer growth. We probably shouldn’t try to get rid of ROS completely by flooding people’s systems with antioxidant pills.

As NHPs have become a multi-billion-dollar industry, it can be difficult for its consumers to separate hype from reality. In fact, a 2021 report from the Office of the Auditor General found that 88 per cent of the natural health products reviewed were advertised with misleading product information. This included incomplete listing of ingredients and incorrect dosage information. We also still see reports of toxicity, liver injury and supplements tainted with everything from arsenic to progesterone.

Vanessa’s Law won’t eliminate these risks. We also can’t reasonably expect every company with an herbal product to spend years and hundreds of millions of dollars running clinical trials. But we know our existing system is insufficient. Our interpretations of pre-clinical data are often too optimistic. The expansion of Vanessa’s Law is a crucial first step toward better safety monitoring and better protecting Canadians.

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Amir Imani 


Amir Imani PharmD, RPh, is a Hospital Pharmacist and Instructor at the University of Toronto’s Leslie Dan Faculty of Pharmacy.

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