Nicotine is a psychoactive drug with many stimulant properties. It is a toxic substance found in tobacco as well as in other plants, including some that are eaten as food. Nicotine-containing foods include eggplant, green tomatoes and cauliflower, although the amounts are much lower than what's found in tobacco.
The lethal dose of nicotine is 60 mg, and cigarettes contain between 0.5 and 2 mg of nicotine. About 20% of that is ingested from smoking, a little more if tobacco is chewed in the form of chewing tobacco or sniffed in the form of snuff.
Tobacco use was encouraged in the first half of the 20th century, with claims of its ability to aid concentration and relaxation. It was marketed to women in connection with the women’s movement, as a symbol of freedom, and also as a weight control aid. Around 40% of Americans smoked in the 1960s, then in the latter part of the 20th century, the health hazards of smoking, particularly its causal role in lung cancer, became more well-known, and the number of smokers dropped to about 28% in the early part of the 21st century. Some demographic groups, most notably teenagers, have higher rates of smoking. Smoking among various ethnic groups varies from country to country -- despite all the education on the harms of smoking, it is still driven by peer pressure in many sub-cultures.
In 1988, the addictive nature of nicotine was formally recognized in the Surgeon General’s report. It acknowledged that cigarettes and other forms of tobacco are addictive, the addiction is caused by the drug nicotine, and the pharmacological and behavioral processes that are involved in nicotine addiction are similar to those that cause addiction to drugs such as heroin and cocaine.
It is estimated that in the early 21st century, tobacco is the leading preventable cause of death, accounting for about 45,000 deaths per year in the United States. That is more deaths than all other drugs combined. The most common illnesses caused by tobacco are:
- Lung disease, including COPD, chronic bronchitis, emphysema, and lung cancer. In addition to lung cancer, tobacco causes cancer of the mouth and throat.
- Cardiovascular disease, including stress and damage to the heart, arteriosclerosis (hardening of the arteries), and atherosclerosis (build-up of fatty deposits in the arteries).
- Thinning of the skin.
- Parent-to-child transmission – increased risk of low birth weight in babies and increased risk of cancer in the children of male smokers.
Nicotine replacement therapy or NRT is one of the most effective ways of quitting smoking. Nicotine is delivered to your body without inhalation, so it reduces many of the risks associated with smoking. There are several different formulations of NRT, including transdermal nicotine patches, which allow nicotine to be absorbed through the skin; nicotine gum and lozenges, which allow it to be absorbed through the mouth and digestive system; and nicotine vapor inhalers, which allow the nicotine to be inhaled without the harms of smoke inhalation. However, the body is still affected by the toxicity of nicotine itself.
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