Thursday, April 20, 2006

Cyanide Alert - Bitter Apricot Kernels and More

Cyanogenic glycosides are present in a number of food plants and seeds. Hydrogen cyanide is released from the cyanogenic glycosides when fresh plant material is macerated as in chewing, which allows enzymes and cyanogenic glycosides to come together, releasing hydrogen cyanide.

Bitter apricot kernels (which have recently become available as a health food on the UK market) when ingested, can produce cyanide. Apparently the dosage sheet accompanying the product indicates that consumers could take a maximum of 10 kernels a day -- this is five times the limit recommended by the Food Standard Agency's (FSA) scientific committee on toxicity of chemicals in food, consumer products and the environment (COT). COT considers a safe intake is equivalent to one to two kernels a day.

As well as bitter apricot kernels, low levels of cyanide are also present in almonds, sweet apricot kernels and in the stones of other fruits such as cherries.

A number of other cyanogenic glycosides are present in foods including linamarin (cassava, lima beans), prunasin (ferns) and sambunigrin (elderberries).

Cyanide is one of the most potent, rapidly acting, poisons known. Cyanides inhibit the oxidative processes of cells causing them to die very quickly.

Because the human body rapidly detoxifies cyanide, an adult human can withstand 50 -60 ppm for an hour without serious consequences. However, exposure to concentrations of 200-500 ppm for 30 minutes is usually fatal. Aside from death, acute cyanide toxicity at small doses can cause headache, tightness in throat and chest, and muscle weakness. The effects of chronic (long-term) exposure to cyanide are less well known. (Source -

In closing, I'd like to leave you with a comment from the website:

"While we usually think of toxic substances as coming from man-made sources, many occur naturally. For example, toxic mussel outbreaks in the ocean have claimed lives and caused illness because the mussels consumed contained an algal toxin. Fresh water is not without toxic substances, either. For example, a group of fairly common organisms called cyanobacteria produce toxins called microcystins. Deaths of cattle, wildlife, and family pets have been traced to drinking water containing microcystins, as have several liver-related illnesses in humans. Although naturally occurring toxins are all around us, if one is educated to where and how they occur, steps can be taken to avoid them."

Apricot kernels withdrawn over cyanide concern - Europe
Cyanogenic glycosides -