VOA常速英语:Light Cigarettes' Nicotine Punch Same As Regular Smokes

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Smoking has been on the rise worldwide for the past few decades. With this rise has come an increase in the number of people suffering from cancer and heart and lung diseases that are associated with smoking. Many people would like to quit, but it's incredibly difficult, in part, because tobacco is so addictive. And if you're a smoker who has switched to a so-called "light" brand to help you kick the habit, forget it. New research indicates those light brands are just as addictive as regular cigarettes and just as bad for you.

Researcher Arthur Brody, with the University of California at Los Angeles, says the primary addictive substance in tobacco is nicotine. It's only one of thousands of chemicals in tobacco smoke, but when a person lights up, nicotine floods chemical receptors in the brain.

"…nicotine occupies these receptors and desensitizes them, so essentially turns them off," he says, "and so, for some reason, this results in all of the reasons that people smoke. You know - the pleasure that they feel or the reduced anxiety or the little boost in their mood sometimes." 

One strategy people use to quit smoking is to use low-nicotine cigarettes. Brody recently studied these so-called "light" cigarettes and their effects on smokers's brains. First, he had people smoke regular cigarettes while they were in a brain scanner. He could track how many nicotine receptors in the brain were affected.

"If they only took one or two puffs of the cigarette, that occupied 50 percent of this type of nicotine receptor in the brain," Brody says. "Whereas, if they smoked a full cigarette, it occupies about 88 percent... of those receptors."

Then Brody gave people so-called "low-nicotine" cigarettes, which have even less nictoine than light cigarettes.

"Even those little-nicotine cigarettes occupied 77 percent of these receptors," Brody says. "And so the majority of these receptors get occupied very easily with very small amounts of nicotine in cigarettes."

Brody found that even with cigarettes that are supposedly "de-nicotinized," about a quarter of the nicotine receptors in smokers' brains were occupied.

"The problem is that sometimes people buy a light cigarette, and they inhale them more deeply or they smoke more of them," he says, "and so there really is no benefit if they do them that way."

Brody says these findings mean that many smokers who think they're weaning themselves off tobacco by smoking light or low-nicotine cigarettes might not actually be getting any benefit from them. He says that people using these light cigarettes to quit need to be careful about how much they smoke, or they may need to use a method that reduces the amount of nicotine they receive in a more reliable way, such as by using nicotine patches.

Brody's research is published in the International Journal of Neuropsychopharmacology.