Dutch authority detects pharma ingredients in herbal weight loss supps

The paper​, written by experts from the Netherlands’ Food and Consumer Product Safety Authority (NVWA), the National Institute for Public Health and the Environment (RIVM), Wageningen University and the Ministry of Health, Welfare and Sport Nutrition, Health Protection and Prevention Department at the Hague, found 24 out of the 50 samples screened between August 2004 and May 2013 contained active pharmacological ingredients (APIs). This equated to 12 different brand names – the identity of which were kept anonymous in the report.

The tests identified sibutramine (the most frequently detected API), desmethylsibutramine (DMS), didesmethylsibutramine (DDMS), rimonabant, sildenafil (a drug for ‘sexual potency’) and the laxative phenolphthalein - pharmaceuticals sometimes used to treat overweight patients and obesity. These ingredients were not listed on the label.

Of these 24 mislabelled samples, they said 20 of them could result in “potential pharmacological effects”​.

Side effects for sibutramine could include psychiatric symptoms, while for DMS and DDMS past research indicted the possibility of psychotic symptoms, and cardiovascular effects for DDMS. 

The NVWA has taken action, including fines, against the suppliers of the products found to contain hidden APIs. Consumers were also warned against their use through press releases.

Natural doesn’t always mean safe ​

“​Herbal food supplements that claim to induce weight loss are marketed worldwide and are readily available over the Internet. These products generally claim to be ‘all natural’, but there are frequent reports of adulterations with drugs for the treatment of overweight, obesity and constipation such as sibutramine, fenfluramine, rimonabant, orlistat and phenolphthalein,” ​they wrote.

Discussing the findings, a spokesperson for the UK government’s Medicines and Healthcare Products Regulatory Agency (MHRA) told NutraIngredients: “We would always advise caution when buying slimming products, particularly online, and would remind consumers that ‘natural’ does not necessarily mean safe.”​

Internet retailing made up 3.9% of total vitamin and dietary supplement sales in the Netherlands in 2013, up from 2.8% in 2008, according to Euromonitor data. For Western Europe as a whole this stood at 8.4% in 2013 and 5.5% back in 2008. 

They urged consumers to select herbal products from the Traditional Herbal Registration (THR) or by looking for a product licence on packaging, which would indicate it had met quality and safety standards. The spokesperson added that side-effects could also be reported through its Yellow Card Scheme​.

Meanwhile, a spokesperson for the trade association Food Supplements Europe (FSE) said it strongly supported the view that food supplements should be in conformity with the law and be safe and effective for their intended use.

“Food supplements should not contain illegal substances and we support effective enforcement to detect and pursue such practices.”​

The samples were taken strategically based on complaints made to the Dutch and other international authorities, as well as research on internet forums which revealed consumer complaints of side effects.

(Unwittingly) taking a dose ​

Evaluating the potential pharmacological effects of the samples, the researchers said the use of 14 of the supplements would have resulted in daily dose levels of 4–36 mg of sibutramine. Of which 12 would have exceeded the daily recommended dose of the lowest commercially available registered drug which contained 10 mg, the highest of which was 15 mg.  

Since the researchers considered the pharmacological profiles of DDMS and DMS to be similar, they said doses of 0.2 mg a day of both would produce pharma reactions. In five of the samples they detected levels of DDMS that could result in daily intakes of 3.6–16 mg, while three samples showed levels of DMS that would mean intakes of 0.1 - 0.2 mg.

Meanwhile, they concluded phenolphthalein, a suspected carcinogen found in ten of the supplements, and sildenafil, a drug taken for erectile dysfunction, at the doses detected were unlikely to cause pharmacological effects.

However, these risk assessments could be underestimates, since the possibility of effects from doses below these lowest-commercially-available minimums could not be ruled out, they said.  

Source: Food Addit Contam Part A Chem Anal Control Expo Risk Assess​

Published online ahead of print, DOI: 10.1080/19440049.2014.958574​

“Active pharmaceutical ingredients detected in herbal food supplements for weight loss sampled on the Dutch market”​

Authors: N.M Reeuwijk, B.J. Venhuis, D. de ​Kaste, R.L. Hoogenboom, I.M. Rietjens and M.J. Martena