There is probably no safe level of smoking. Cigarettes are considered Category One (highest level) carcinogens by the WHO. Nitrosamines have been universally condemned as one of the key carcinogens in cigarette smoke (see also here). Pancreatic cancer and acute myeloid leukemia have been linked to smoking.
The odds of a pack a day smoker getting lung cancer after 20 years is 13 times that of nonsmokers (see also here). But despite higher rates of smoking, Asians have relatively low lung cancer rates, possibly due to higher levels of green tea consumption. Also, in terms of lung cancer, smoking just a single joint of marijuana may be as bad as smoking an entire pack of cigarettes.
Benzene, acrylamide, and aluminum are also found in cigarette smoke. And people who smoke double their risk of dying from heart disease (see also here). Smoking may also speed up aging by eating away at our telomeres (the caps on our DNA), which have been thought of as our “life fuses.” Interestingly enough, though, inadequate fruit and vegetable consumption is responsible for almost as many deaths every year as smoking, according to the World Health Organization.
To resist regulation, the tobacco industry has been accused of funding research to downplay the risks of smoking (see also here). And in other research, failure to screen out smokers among coffee drinkers resulted in the incorrect conclusion that coffee was not healthy.
The presence of smokers in the home and meat intake appears to contribute the most to the incidence of asthma in children. Second hand smoke can put an entire household at risk. But COPD patients who eat more fruits and vegetables see slightly improved lung function over a period of years.
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