'Natural' means safe, doesn't it? [Abstract]

Background: The ready availability of so-called natural remedies from Internet websites, together with mostly unsubstantiated claims as to their efficacy in treating various medical conditions, continues to give rise to serious safety concerns. Although the possibility of acute cyanide toxicity from ingestion of large quantities of apricot kernels is well documented, certain websites are still advocating this practice as a ‘natural’ treatment for cancer - even recommending consumption of 50 kernels daily. Case report: A 48 year-old non-smoking female patient attended the emergency department complaining of nausea, headache, abdominal pain and diarrhoea. She was previously diagnosed with multiple endocrine neoplasia (type IIa) and had undergone a number of neck operations including recent removal of a medullary carcinoma of the thyroid. In an attempt to prevent further recurrence of her disease she had taken advice from a website advocating apricot kernel therapy. Initially she had been ingesting 10 kernels/day but this had been increased to 40/day for the past week. She described having a terrible taste since commencing the therapy and that she now felt very unwell and ‘raw inside’. Examination revealed mild dehydration and an elevated plasma calcium concentration (2.85 mmol/L). Blood cyanide concentration was normal but her serum thiocyanate concentration was 22.6 mg/L (1–4 mg/L in non-smokers), a level consistent with that found in studies of patients ingesting 1500 mg amygdalin (the cyanogenic component of apricot kernels) daily. Following supportive care and intravenous fluids, her symptoms abated and she was discharged. Discussion: Analytical data provided by the Food Standards Agency indicate that bitter apricot kernels on sale in health shops in the UK contain on average 0.5 mg of cyanide per kernel. This patient may therefore have been ingesting approximately 330 microgram/kg cyanide daily - uncomfortably close to the lower acute lethal dose limit in humans of 500 microgram/kg and 28 times the TDI (Tolerable Daily Intake) of 12 microgram/kg/day set by the WHO in 2003. Individuals desperately seeking relief from serious and chronic medical conditions are particularly vulnerable to the exaggerated claims of dangerously irresponsible Internet advertisers and may well find themselves in potentially life-threatening situations. Is there a need for regulation