Cyanides food sources

People who eat large amounts of cyanide may have symptoms including deep breathing and shortness of breath, convulsions, and loss of consciousness, and may die. Use of cassava roots as a primary food source in tropical Africa has led to high blood cyanide levels. 

Small but significant levels of cyanide are present in normal blood plasma at concentrations of 0-14 pg %. (Feldstein and Klendshoj 1954). Vitamin B12 contains cyanide, with the source of cyanide attributed to breakdown of cyanogenic foods by bacteria in the gut. 

The primary route of exposure to thiocyanates for the general population appears to be from ingestion of foods in which thiocyanate occurs naturally (e.g., cabbage, kale, spinach, kohlrabi). Estimates of the thiocyanate concentration in the total diet of an adult in the United States were not located in the available literature however, these would be expected to be quite low. Exposure to cyanide also is a source of thiocyanate exposure because thiocyanate is a major metabolite of cyanide in the human body. 

At one time amygdalin, sold as Laetrile, was promoted as a treatment for cancer, presumably based on the hope that the cancer cells would be poisoned by the released cyanide.1 The tubers and leaves of the cassava plant provide a major source of food in many tropical countries. However, unless the cyanogenic glycosides are removed by boiling the tubers and pulping the leaves cassava is... 

A potential source of cyanide poisoning is cassava, a starch from the root of Manihot esculenta, used as food in much of Africa. The root contains cyanogenic linamarin, which is normally removed in processing the root for food. Widespread cases of a spinal cord disorder called konzo and characterized by spastic paralysis have been attributed to ingestion of linamarin from inadequately... 

Cyanide and thiocyanate are normal constituents of blood (77). Sources of cyanide include some foods, for example, cyanogenic glycosides in bitter almonds, fruit seeds, and a number of plants, cigarette smoke, and smoke from fires. The blood concentration of cyanide in healthy subjects was... 

Retrospective identification of cyanide poisoning in a CW context would be complicated by exposure from other sources, which include cigarette smoke, smoke from fires and some foods, e.g. cyanogenic glycosides in bitter almonds, fruit seeds and a number of plants. Quoted blood concentrations in non-smokers vary from a few ng/ml to >100 ng/ml. In nine fire victims, the concentrations determined were 687 597 ng/ml (Ishii et al., 1998). In smokers, cyanide levels in blood may rise to 500 ng/ml. 2-Aminothiazoline-4-carboxylic acid was detected in the urine of moderate cigarette smokers at concentrations between < 44-162 ng/ml (Lundquist et al., 1995). 

The greatest source of cyanide exposure to humans and range animals is cyanogenic food plants and forage crops, not mining operations. 

---