Food supplement contamination with illegal ingredients is an increasing global problem. Contaminants that could cause serious health risks such as pathogens, heavy metal, pesticides residues, and mycotoxins are making their way into the final products. To help solve this problem, laboratory tests and surveys can assist regulators in proactively protecting consumers and businesses.
We spoke to Dr Michael Walker, scientist and analyst from the LGC Government Chemist programme, and co-author of the paper, ‘A Review of Methods for the Simultaneous Detection of Illegal Ingredients in Food Supplements’ about tackling the problems of food fraud in food supplements.
LS: Can you describe to us what a food supplement is?
Dr Michael Walker (MW): Most of us will be familiar with food supplements but a good definition is “a concentrated source of substances with nutritional or physiological effect intended to supplement the normal diet and sold in dose form”. Food supplements include a spectrum of dietary ingredients such as herbs, botanicals, vitamins, minerals and enzymes or extracts from organs or glands.
LS: What are the current regulations around food supplements?
MW: General food law (e.g. the Food Safety Act 1990) applies and the product must be safe and authentic. In the UK the Food Supplements Regulations 2003 permit the sale of food supplements provided they comply with certain conditions laid down in EC Directive 2002/46. These include that the product must be pre-packed and labelled ‘food supplement’. If they contain vitamins and minerals these must be approved and listed in Directive 2002/46. The labelling must comply with general food labelling law, e.g. Regulation 1169/2011 on the provision of information to consumers and in addition must be labelled with:
• any characterising vitamins or minerals or other substances with a nutritional or physiological effect and their amounts
• the portion of the product recommended for daily consumption
• a warning not to exceed the stated recommended daily dose
• a statement to say food supplements should not be used as a substitute for a varied diet
• a statement to say the product should be stored out of the reach of young children.
Food law, Regulation 1924/2006, also prohibits any claim that a food or food supplement can prevent, treat or cure any disease, and health claims must be approved by EFSA and the Commission to prevent spurious claims. This protects consumers and responsible businesses. In the USA the relevant law is the ‘Dietary Supplement Health Education Act’ of 1994.
LS: What are the most common contaminants found in food supplements?
MW: From our survey food supplements have been found to contain excess food additives, and contaminants such as pathogens, heavy metal, pesticides residues, and mycotoxins. Other findings include unauthorised novel food ingredients, unauthorised nutritionally related compounds (for example bis (picolinato) oxo vanadium, betaine, and metal amino acid chelates and excess vitamins. There were also some instances of the main psychoactive compound in cannabis, tetrahydrocannabinol (THC) and one instance of the poison strychnine.
The other worrying class of contaminants were undeclared pharmacological ingredients. We found that between 2009 and 2016 the top five were sildenafil and its analogues, sibutramine and derivatives, 1,3-dimethylamylamine (DMAA), yohimbine, and tadalafil. Other interesting adulterants exhibiting frequent notifications included the biogenic amine synephrine and derivatives, and phenolphthalein both of toxicological concern and implicated in attempted weight loss.
LS: In what ways can scientists combat food fraud such as supplements containing hidden dangers?
MW: First of all scientists can collate and publish their findings in the peer reviewed literature. We saw in our research that scientists in Italy have been particularly active in publishing the analysis of illegal ingredients in food supplement. Secondly scientists should not be reluctant to engage with the media about their findings. Science journalists such as the team in Technology Networks, and the Science Media Centre are excellent bridges between scientists and the media and hence the general public who need to be better informed about the insidious dangers in some supplements. I also recommend any active scientist to get to know their own Press office
A heavy responsibility rests with official control scientists, in the UK these are the Public Analysts. One of the reasons we carried out our own research was to provide a readily accessible compendium of approaches that can be used to test for illegal pharmaceuticals in supplements. Each lab has to validate the methods so that sound results are obtained in their hands, which makes it expensive to introduce new methods, and regulators should be alive to the problems that poses in times when funding is scarce.
LS: Can you explain further the type of tests carried out to tackle the problem?
MW: In the UK individual Local Authorities, the Food Standards Agency and the Medicines and Healthcare Products Regulatory Agency, MHRA, have been active in combating problems with food supplements. For example FSA have worked hard to counteract the sale of DNP, 2,4-dinitrophenol, a “fat burning” product that has caused deaths. In 2015 and 2016 MHRA seized tens of thousands of dosage units of unlicensed slimming tablets containing banned pharmaceutical ingredients and unlicensed erectile dysfunction medicines. In late 2016 MHRA ran a campaign to warn consumers about the sale of diet pills products which contain unlicensed medicines.
To give teeth to enforcement officers product testing is necessary. Many approaches are straightforward LC methods with standard columns, gradient elution and detection by UV, fluorescence, DAD or MS. Mass spectrometry obviously provides more confidence in confirmation of the molecular identity of the compounds detected. In our paper we have listed LC analytical conditions and suggested a first choice LC-MS/MS screening method for yohimbine, sildenafil, vardenafil and tadalafil by triplequad in ESI positive mode. If high field NMR is available, which it often is in your nearest university chemistry department, this is an excellent first-line method of control for herbal food supplements.
The full report can be found here
Dr Michael Walker, Referee Analyst from the LGC Government Chemist Programme, was speaking to Louise Saul, Science Writer for Technology Networks