contaminated dietary supplements

Trawling through my ‘blogging’ folder, wondering what to write about, I came across a paper from the New England Journal of Medicine that discusses problems with contaminated dietary supplements in the US (Cohen, 2009). I’ve previously written about the recall of ‘natural’ treatments for impotence, & Grant’s talked on more than one occasion for the need for ‘truth in labelling’ for such supplements & other forms of complementary & alternative medicine. So I thought it was about time for a follow-up.

Every so often the issue of regulating complementary & alternative health products comes to the fore in NZ. And when it does there are usually fairly strident arguments made against the suggestion. I’ve never really been able to understand why, given the evidence that these products can be adulterated, or aren’t standardised in terms of dosage. I’m also at a loss to see how some (many?) of these products can be described as ‘natural’, and held to be much better for you than those made by ‘Big Pharma", when in fact they’re often (as we shall see) not all-natural & also often produced by the same pharmaceutical companies that make prescription drugs.

Cohen’s paper begins with the cautionary tale of an American police officer who took what was presented as a ‘natural’ weight-loss supplement to help him lose some excess kilos. The supplement also lost him his job – it contained amphetamine, which was detected in a routine urine test & led to him being fired. Apparently, by August 2009 the US Food & Drug Administration had identified more than 140 ‘natural’ products containing active pharmaceutical ingredients, most of them marketed as dietary supplements – & this is regarded as the tip of the iceberg.

Apparently, before 1994 herbal products fell under the rubric of food additives; manufacturers had to prove their products were safe before they could market them. These days, since the 1994 US Dietary Supplement Health & Education Act, it’s assumed that supplements are safe & there’s little control over their marketing. However, it seems that this deregulated environment isn’t well understood by either consumers or doctors. The majority of consumers believe that the supplements they take have been approved by the relevant government agency, & must carry warning labels about any side effects that may exist. (The absence of such warnings is then taken to mean that the product is safe, where in fact they may simply be missing.) Similarly, a survey of doctors in training found that a large minority also believed that the products had to have FDA approval, while most didn’t know that adverse events had to be reported to the FDA.

Cohen’s list of contaminants found in ‘health’ products on the US market is alarming. While poisonous plant materials, heavy metals, & bacterial contamination are commonly found, what’s even worse are the many supplements – touted as ‘natural’ – that contain ‘prescription medications, controlled substances, experimental compounds, or drugs rejected by the FDA because of safety concerns’ (Cohen 2009). They’re most often detected in products sold to enhance sexual or athletic perfomance, or for weight loss but are also found in supplements aimed at people with serious health concerns, such as diabetes. In the light of all this I find it more than a little ironic that a New Zealand natural health products website – arguing against regulation of these products in NZ – says that "the status quo, mirrored in the USA, has been shown over many years to be safe, inexpensive and efficacious. Existing legislation protects consumers from dangerous products and misleading advertising." As Cohen has pointed out, this is a long way from reality. 

Given patients’ tendency not to tell their GPs what supplements they are using (unless the doctor asks fairly specific questions), & the fact that some supplements can act as antagonists to prescription medicines**, & that the contaminants themselves can have serious health effects, such widespread contamination may well represent a significant public health risk in the US (where it’s estimated that 114 million Americans use some sort of dietary supplement: Cohen, 2009)). And in New Zealand. You might argue that ‘our’ products are much better formulated – but remember that many supplements are readily available on-line from overseas sellers, or are imported from overseas and, as the recent withdrawal of sexual enhancement products shows, may be subject to the same serious problems as those discussed by Cohen.

Personally, I think there’s a good argument for regulation of dietary supplements & other over-the-counter health products. You may argue that it’s a case of ‘buyer beware’ & individual freedom to choose – but there’s likely to be a significant cost to the individual and to the public health service when (& it is when, rather than if) things go wrong.

** For example, Oneschuk & Younus (2008) note that while some ‘natural health products’ may have the potential (based on animal & in vitro studies) to help cancer patients manage the side effects of chemo- & radiotherapy, others significantly reduce the effectiveness of chemotherapeutic drugs.

PS (23/06/2010) Anyone interested in a more detailed coverage of the US situation should have a look at Steven Barrett’s post on Quackwatch.

P.A.Cohen (2009) American roulette – contaminated dietary supplements. New England Journal of Medicine 361(16): 1523-1525. doi 10.1056/NEJMp0904768

D.Oneschuk & J.Younus (2008) Natural health products and cancer chemotherapy and radiation therapy. Oncology Review 1: 233-242. doi 10.1007/s12156-008-0028-6 

Leave a Reply

Your email address will not be published. Required fields are marked *