Serious risks? Report highlights ‘hidden ingredients’ in herbal supplements

The review, which examines the detection of illegal ingredients in botanical and herbal supplements, finds these supplements often contain hidden ingredients and banned pharmaceutical compounds.

However, industry associations have responded to the report by noting that incidents of non-compliance, contamination and spiking with pharmaceutical ingredients are ‘isolated’ and generally related to finished products that are imported in to the EU from elsewhere.

Led by first author Dr Michael Walker from the UK Government Chemist Programme at LGC, the team found that over-the-counter supplements – especially ones advertised to treat obesity and erectile dysfunction problems - are often labelled as fully herbal but sometimes include potentially dangerous pharmaceutical ingredients, which are not listed on the label.

“Our review looked at research from right across the globe and questioned the purity of herbal food supplements,”​ said study co-author Professor Duncan Burns from Queens University Belfast. “We have found that these supplements are often not what customers think they are – they are being deceived into thinking they are getting health benefits from a natural product when actually they are taking a hidden drug.”​

“These products are unlicensed medicines and many people are consuming large quantities without knowing the interactions with other supplements or medicines they may be taking,”​ he said. “This is very dangerous and there can be severe side effects.”​

CRN UK told NutraIngredients it is working closely with UK authorities on the issues brought up in the report, but added that food supplements already must comply with around 20 categories of food laws in addition to laws and regulations relating to specific ingredients.

“Reputable manufacturers comply with these laws,”​ said the CRN UK in a statement – noting that it’s website​ contains information on how to spot whether a food supplement is compliant or not, which will be valuable for both retailers and consumers.

A common occurrence – or rare findings?​

Dr Robert Verkerk, founder, executive and scientific director at the Alliance for Natural Health (ANH) International, agreed with the CRN UK – noting that while “it’s no bad thing that government chemists’ flag the issue of adulteration of supplements (…) this is a non-issue for reputable companies, manufacturers and contract manufacturers in the UK and through most of Europe.”​

He added that while the paper refers to products picked up by RASFF​ throughout the EU and to ‘frequently reported’ adulterants, it gives no indication of the total number of samples analysed – “let alone the total number of food supplements sold in the EU.”

“In anyone’s book, it would be hard to think of these as common occurrences​,” said Verkerk. “Rare findings would be more like it.”​

The ANH executive added that rare occurrences of ‘cowboys’ are typical in any industry – and that the food and supplements sectors are not alone.

“Many years of monitoring in the UK, Holland, Belgium, Germany and elsewhere has shown that most of these adulterated products come into the EU from the East – and yes, there is always work to be done in terms of improving both monitoring and enforcement to deal with the very small number of cowboy operators that do present a genuine risk to public health,”​ he said. “But as far as the vast majority of food supplement companies are concerned, especially those based within the EU which spend a great deal of effort checking on the quality of raw materials and employing rigorous HACCP and GMP procedures in manufacture, it is disingenuous to have them tarnished with the same brush.”​

Report findings​

The report, published in the Journal of the Association of Public Analysts, raises questions about the safety of slimming supplements containing after several were found to contain sibutramine – a pharmaceutical ingredient that was licensed as Reductil until 2010, when it was withdrawn across Europe and the US due to an increased risk of heart attacks and strokes.

Several recent occurrences in this area, including arrests by Dutch authorities​ this month and a warning by the UK regulator last year​, refer specifically to ‘illegal’ weight loss pills that have been found to contain sibutramine. 

Furthermore, the new report found that Tadalfil and sulfoaildenafil were among the most frequently undeclared ingredients in products for erectile dysfunction.

When taken with other medicines containing nitrates, they can lower blood pressure drastically and cause serious health problems, warned the researchers.

“This is a real issue as people suffering from conditions like diabetes, hyperlipidemia and hypertension are frequently prescribed nitrate containing medicines. If they are also taking a herbal supplement to treat erectile dysfunction, they could become very ill,”​ warned Burns.

“People who take these products will not be aware they have taken these substances and so when they visit their doctor they may not declare this and it can be difficult to determine what is causing the side effects,”​ he said. “It is a very dangerous situation.”​

Other ingredients found by the report include the banned stimulant DMAA, in addition to yohimbine and synephrine.

Testing strategies​

Report co-author Professor Declan Naughton, from Kingston University London said the report highlights the vital role research and, in particular, techniques like datamining, can play in informing regulators about current trends in supplement contamination.

“This is very important to ensure effective testing strategies and, ultimately, to help keep the public safe,”​ he said.

Walker added that laboratory tests described in the report should help regulators to tackle the problem proactively to protect consumers and responsible businesses.

When asked whether an industry-wide safety mark, or quality assurance logo, was something that could help to overcome the issues of ‘cowboys’ selling herbal supplements that contain illegal pharmaceutical ingredients the CRN UK told NutraIngredients that while discussions between various associations, lasting several years, had explored the option, it was deemed not feasible.

“We have looked at this in great detail (…) However, the administration and resources to assess and authorise the quality mark, with the many thousands of products on the market, meant that the manufacturers would have to pay a considerable sum for the service,”​ said CRN UK – adding that smaller companies would suffer significantly.