One popular myth promulgated by “prohibitionists” is that one or two joints per day are virtually equivalent to an entire pack of tobacco cigarettes per day. In reality, Dr. Tashkin’s research shows that daily marijuana smokers provide less evidence of respiratory damage than pack-a-day cigarette smokers. In addition, there is no evidence linking marijuana to heart disease or to non-respiratory cancers like bladder, colon, and rectal cancer—a distinction reserved, it seems, for smoking tobacco.
Why should marijuana smoking be less physically harmful than cigarette smoking? One big reason is that marijuana smokers tend to consume considerably less smoke. A typical marijuana user smokes around one or two joints per day while a typical tobacco smoker generally goes through a pack or two of 20 cigarettes per day.
Of course, these totals should probably be adjusted for the fact that marijuana smokers usually inhale more deeply, exposing their lungs to a greater amount of smoke per puff. A study by Dr. Tashking and Dr. T.C. Wu discovered that marijuana smokers absorb somewhere between 3 and 5 times as many smoke toxins as tobacco smokers per weight smoked (Tashkin). Thus, one gram of marijuana is equivalent to about three to five grams of tobacco. Marijuana joints range in size from cigar-style leaf “blunts” to slender sinsemilla joints that weigh a fraction of a gram. As a general rule of thumb, you’re going to find higher quality cannabis in smaller joints. With reasonably good quality marijuana, the standard joint will weigh around 0.4 grams—about have the size of a cigarette. Using the abovementioned ratio, the average joint is equal to between 1.5 and 2.5 cigarettes.
A second major difference between tobacco and marijuana is tobacco’s propensity to penetrate more deeply into the lungs. For unknown reasons, particles from marijuana smoke will mostly congregate in the larger, upper air passageways of the lungs and throat and tobacco permeates through to the smaller, lower passageways. According to Dr. Tashkin, one result of this is that marijuana by itself does not appear to trigger emphysema, a progressive and degenerative disease of the lower lungs that is associated with tobacco smoking. Conversely, combining marijuana and tobacco may actually aggravate the risk of emphysema (Tashkin). Marijuana may also be more likely to act as a throat irritant than cigarettes.
One final major distinguishing factor between the two different smokes is their principal active ingredients. Marijuana contains THC and other cannabinoids while tobacco contains nicotine. We’ve seen that there is evidence to suggest that THC and cannabinoids have cancer-suppressive properties. By contrast, nicotine has properties that tend to promote cancer. Furthermore, other nicotine derivatives in tobacco smoke (like NNK and NNN) are well-known potent carcinogens. Lastly, nicotine is an extremely powerful, addictive vasoconstrictor and stimulant known to promote circulatory and heart disease.
According to Professor Melamede, there are certain biochemical reasons to explain why cannabis smoke isn’t as carcinogenic as tobacco smoke (Melamede). First, THC acts to subdue the conversion of PAH in marijuana smoke into active carcinogens, while nicotine appears to have the opposite effect. Second, nicotine often works to inhibit the destruction of diseases cells (apoptosis), while cannabinoids do not. Third, nicotine promotes the growth of tumor-feeding blood vessels (angiogenesis) and cannabinoids, of course, have the opposite effect. Dr. Melamede concludes, “It is possible that as the cannabis-consuming population ages, the long-term consequences of smoking cannabis may become more similar to what is observed with tobacco. However, current knowledge does not suggest that cannabis smoke will have a carcinogenic potential comparable to that resulting from exposure to tobacco smoke.”
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The founder of I Love Growing Marijuana, Robert Bergman, is a marijuana growing expert that enjoys sharing his knowledge with the world. He combines years of experience, ranging from small-scale grows to massive operations, with a passion for growing. His articles include tutorials on growing... [read more]