Consumers at risk from drug ingredients in herbal food supplements

Consumers are being put at risk from herbal supplements available over the counter that contain pharmacological ingredients not listed on the product label, according to research published in the Journal of the Association of Public Analysts
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(2016;44:051-066). Unlisted ingredients included medications used to treat erectile dysfunction, stimulants and banned substances used in diet pills as well as unauthorised food ingredients.

A group of British food and biomolecular scientists with a special interest in food safety sought out evidence of illegal ingredients discovered in supplements by reviewing cases reported to the European Union’s Rapid Alert System for Food and Feed (RASFF), along with enforcement reports and recalls issued by the US Food and Drug Administration between 2009 and 2016.

When they considered the EU database, the researchers found that the most reported pharmacological ingredients in food supplements were: sildenafil (including analogues) (68 cases); sibutramine and derivatives (63); 1,3-dimethylamylamine (DMAA; 58) synephrine, phenethylamine and derivatives (37); yohimbine (30) and tadalafil (29).

When they examined the FDA database the findings were similar: sibutramine (16 cases); sulfoaildenafil (13); sildenafil (10); tadalafil (9); hydroxythiohomosildenafil (5) and dimethylsildenafil (3).

The researchers also found evidence of food supplements containing permitted food additives in excess of their limits, unauthorised food ingredients, unauthorised nutritionally-related compounds, excess vitamins and one case of the poison strychnine.

The researchers warn that their findings mean that consumers were unknowingly being put at risk.

“Many people consume large quantities of food supplements without knowing the potential interactions with other supplements or drugs that they may be taking in parallel,” the researchers say in their paper. “Food supplements are regulated as foodstuffs and not with the same pre-sales rigour as medicines. Hence, the safety of food supplement consumption is often questionable.”

Tadalafil and sildenafil are usually prescribed for the treatment of erectile dysfunction and if taken with other drugs that contain nitrates can lower blood pressure drastically. Yohimbine, used as an aphrodisiac, can cause bronchospasm and a lupus-like syndrome; the product can also increase blood pressure and induce anxiety, the researchers warn. And studies that have examined the effects of sibutramine have indicated that the drug could be associated with adverse effects such as panic attacks, memory impairments and psychotic episodes, they add.

The researchers go on to say that in order to protect consumer health, adequate methods to be able to analyse these “illegal and potentially toxic” products in food supplements need to be put in place.

They suggest that the first choice for screening food supplements for the top six pharmacological compounds discovered by their review, should be high performance liquid chromatography (HPLC) and mass spectrometry (MS). They suggest that if nuclear magnetic resonance (NMR) spectrometry is available this could be an “excellent first-line method of control for herbal food supplements”.

The Medicines and Healthcare products Regulatory Agency (MHRA), the government body that regulates medicines, medical devices and blood components for transfusion in the UK, says that it is aware of the study. While food supplements are the responsibility of the Food Standards Agency, the MHRA investigates the sale and supply of undeclared pharmaceutical ingredients that may be added to food supplements.

An MHRA spokesperson comments; “The Internet offers access to a vast number of websites offering a wide range of products marketed as ‘slimming pills’ or ‘male enhancement’. Many make attractive claims and offer ‘quick-fix’ solutions; others offer ‘natural’ products. But ‘natural’ doesn’t always mean safe.

“The reality is many of these pills will be untested. That means there’s no way of knowing what’s in them or what they might do to your health – in the short term or long term. Chances are they simply will not work but they may contain potentially harmful ingredients. The consequences can be very serious.”

The MHRA is running a #FakeMeds campaign that highlights some of the dangers around food supplements. Consumers can identify a legitimate supplier by looking for the distance selling logo, adds the spokesperson.