Till now 28 carcinogenic agents have been identified and isolated in smokeless tobacco (oral snuff and chewing tobacco). It is suggested that during the processing stage, quantitative composition of smokeless tobacco go through considerable changes. For instance, starch content of tobacco leaves declines during the curing stage while there is hike of 100% in sugar content.
Listed below are harmful chemicals found in smokeless tobacco:
Polynuclear aromatic hydrocarbons (PAH), particularly benzo[a]pyrene (B[a] P is one such carcinogens found in smokeless tobacco. It is suggested that exposure to PAH can increase the risk of lung and skin cancer.
Volatile aldehydes are the most abundantly found carcinogens in smokeless tobacco (ST). Though acetaldehyde, formaldehyde and croton aldehyde are less carcinogenic, together they can add to the carcinogenic potential in ST. Exposure to volatile aldehyde can cause breast and liver cancer.
Tobacco-specific nitrosamines (TSNAs) are the most harmful carcinogens found in smokeless tobacco. In young tobacco leaves, N-Nitrosamines are found in minute amounts. But, they are actually formed during curing, fermentation and aging of tobacco. N-nitrosamine exposure can cause cancer of oral, esophagus, pancreas, stomach, lung, and bladder.
Other than TSNAs, studies have also reported that smokeless tobacco contains nitrosamino acids. Of the10 nitrosamino acids identified, 3 are not carcinogenic, 4 (nitrososarcosine, 3-propionic acid, 4-butyric acid and N-nitrosoazetadine-2-carboxylic acid) are known carcinogenic and the rest 3 are yet to be bioassayed.
Smokeless tobacco also contains nicotine which is addictive. It is suggested that absorption of nicotine directly into the blood stream is 3 to 4 times higher in case of smokeless tobacco than that caused by cigarettes.
Apart from these cancer-causing agents, smokeless tobacco contains hydrazine, nickel, arsenic, cadmium, radioactive polonium-210 and benzopyrene.