Carcinogens in Coffee and Smokeless Tobacco: Truths & Half-Truths

If a health official announced, “The use of coffee, which contains 21 known human carcinogens, is not harmless,” she would be correct... but not entirely so.

A leading expert in carcinogenesis, Bruce Ames, authored a scientific manuscript in 2000 reporting that 21 known carcinogens are found in coffee (abstract here). Roasted coffee contains thousands of chemicals in addition to addictive caffeine. Some of these agents have been shown in laboratory experiments to cause cancer. Professor Ames also reported that humans consume carcinogens every day in foods and beverages that are considered “safe”; the carcinogens are present in such minuscule quantities that they play no significant role in the development of human cancer. He wrote:

“Naturally occurring pesticides that are rodent carcinogens are ubiquitous in fruits, vegetables, herbs, and spices. Cooking foods produces about 2000 milligrams per person per day of burnt material that contains many rodent carcinogens and many mutagens… In a single cup of coffee, the natural chemicals that are known rodent carcinogens are about equal in weight to a year’s worth of synthetic pesticide residues that are rodent carcinogens, even though only 3% of the natural chemicals in roasted coffee have been adequately tested for carcinogenicity.”

Here are some of the cancer-causing agents in coffee: Acetaldehyde, benzaldehyde, benzene, benzofuran, benzo(a)pyrene, caffeic acid, catechol, 1,2,5,6-dibenzanthracene, ethanol, ethylbenzene, formaldehyde, furan, furfural, hydrogen peroxide, hydroquinone, isoprene, limonene, 4-methylcatechol, styrene, toluene, xylene. And there are still about a thousand chemicals that haven’t been tested.

While this is a scary list, health officials are not calling for a ban on coffee. They know that epidemiologic studies show that coffee, while not absolutely harmless, is quite safe to consume.

Let’s get back to that statement at the beginning of this entry. In fact, a Daviess County (Kentucky) health department official was quoted in a news report, saying, “The use of smokeless tobacco, which contains 28 human carcinogens, is not harmless.” She was commenting on Switch and Quit Owensboro, a public health campaign that tells smokers the truth about vastly safer smoke-free cigarette substitutes (here).

The health department official was parroting a commonly used but almost meaningless factoid about smokeless tobacco. It is used by the CDC (here), the National Cancer Institute (here), the American Lung Association (here), and many state agencies (example here ).

The factoid is essentially meaningless because numerous epidemiologic studies have established that cancer risks associated with smokeless tobacco are so low that they are barely measurable.

Coffee contains 21 carcinogens and smokeless tobacco contains 28; both have high levels of an addictive drug (caffeine and nicotine, respectively). Neither coffee nor smokeless tobacco is absolutely safe, but informed public health practitioners know that the health risks with either are minimal. The real risk is in misleading smokers with partial truths.

Tobacco Harm Reduction Debated in the Cincinnati Enquirer

The Cincinnati Enquirer published my guest column last week (here), on the occasion of the Great American Smokeout.

The following day, Dr, Nagla Abdel Karim, an assistant professor at the University of Cincinnati College of Medicine, authored a column criticizing the Owensboro Switch and Quit campaign (here). Her piece illustrates the misinformation that dominates discussion of tobacco harm reduction. Dr. Karim’s statements are worthy of further discussion.

Dr. Karim accurately described Switch and Quit as “an advertising campaign encouraging smokers in Kentucky to make the switch to smokeless tobacco… citing a decreased risk for cancer.” But then she makes a demonstrably false statement: “Unfortunately, this simply isn’t true.”

Is it possible that Dr. Karim believes that the cancer risks from smokeless tobacco are the same as those from smoking? A recent study (here) estimated how smokeless tobacco use might have changed cancer deaths in 2005, a year in which 104,737 American men died from cancers directly attributable to smoking. If all smokers had instead used smokeless tobacco, the number would have been 1,102. The risks from smokeless tobacco are so low that, even if ALL American men were users, there would have been only 2,298 cancer deaths, or 2.2% of the number attributable to smoking.

Dr. Karim wrote that smokeless tobacco “users are at a higher risk for gastrointestinal cancers. This isn’t supposition,” she continued, “it’s been scientifically proven through research studies examining the health effects of smoking and smokeless tobacco.”

She is mistaken. A comprehensive meta-analysis (discussed in detail here) found that smokeless tobacco users had the following relative risks (RR, compared with never users):

Esophagus: RR = 1.13 (CI = 0.95-1.36)
Stomach: RR = 1.03 (CI = 0.88-1.20)
Pancreas: RR = 1.07 (CI = 0.71-1.60)
All Digestive Tract: RR = 0.86 (CI = 0.59-1.25)

It is important to emphasize that there are no elevated risks in this list.

Dr. Karim wrote that a 2007 American Cancer Society study showed that smokers “…who had switched to spit tobacco had a higher rate of death from lung cancer, coronary heart disease and stroke than those who quit using tobacco entirely.”

These claims cannot be validated because the Cancer Society refuses to release the underlying data (discussed here). This is contrary to worldwide medical data sharing practices. Since lung cancer, coronary heart disease and stroke are strongly associated with smoking, the data might show that some Cancer Society “switchers” were actually still “smokers”, undercutting the findings.

Finally, Dr. Karim acknowledges how hard it is to achieve abstinence, and she refers smokers to the government’s abstinence-only website (here). On the homepage is a reference to behavioral tips that are supposed to help smokers when they are desperate for a cigarette -- “being active (walking, jogging, exercising, etc.) drinking water, thinking about something else, and making arts and crafts.”

It is unfortunate that health professionals are invested in worthless behavioral tips for one of the most powerful of human addictions. However, I wholeheartedly agree that smokers should start “thinking about something else,” including switching to satisfying and vastly safer cigarette substitutes.

I would welcome the opportunity to debate this important public health issue with Dr. Karim at a University of Cincinnati College of Medicine forum.

How to Make the American Smokeout Great

This commentary was published by the Cincinnati Enquirer on November 17 (available here).

The American Cancer Society’s 36th annual Great American Smokeout is November 17. After 35 years, we might expect to see better results. There are still 45 million smokers in the U.S., and 440,000 smoking-related deaths every year, according to the CDC (Centers for Disease Control and Prevention). The toll is 7,400 in Kentucky, nearly 18,000 in Ohio.

The Smokeout could be “Great” if the ACS and other public health institutions were more honest with smokers. For years, these organizations have perpetuated the myth that the only way smokers can save themselves is to quit tobacco. Tobacco abstinence has proven not only unachievable for the vast majority of smokers, but also unnecessary.

Nicotine, like caffeine, is addictive but otherwise relatively harmless. Nicotine’s benefits include improved concentration, enhanced performance of some tasks, and elevated mood. Tobacco smoke, however, containing thousands of toxic agents, is a dangerous nicotine delivery system, conferring risks for cancer, cardiovascular disease and emphysema.

Eliminate the smoke, and you eliminate virtually all the risks.

That is the essence of tobacco harm reduction, a public health strategy that educates smokers about vastly safer sources of nicotine, including smokeless tobacco and e-cigarettes.

Decades of medical research have proven that smokeless tobacco use is at least 98% safer than smoking. No tobacco product is absolutely safe, but the ACS and other tobacco prohibitionist organizations cherry-pick scientific studies for isolated epidemiologic findings to make exaggerated claims about health risks. They ignore the overwhelming scientific evidence documenting little or no risk from smokeless tobacco use. In fact, all health risks from smokeless tobacco, including the risk of oral cancer, are so low as to be barely measurable. Statistically, a user has about the same risk of dying from smokeless tobacco as an automobile user has of dying in a car accident.

It’s time to tell smokers the truth. The ACS grudgingly acknowledges on its website that “[smokeless tobacco] is less lethal than smoking cigarettes.” (here) The organization’s chief epidemiologist served on a review panel for a National Cancer Institute study that concluded “…[smokeless] products pose a substantially lower risk to the user than do conventional cigarettes.” (here) Still, the ACS objects to smoke-free product substitution by smokers.

Switching from cigarettes to smoke-free tobacco is not an industry ploy; it’s endorsed by two prestigious medical organizations, the British Royal College of Physicians and the American Association of Public Health Physicians. The Royal College concluded “...that smokers smoke predominantly for nicotine, that nicotine itself is not especially hazardous, and that if nicotine could be provided in a form that is acceptable and effective as a cigarette substitute, millions of lives could be saved.” (here)

Tobacco harm reduction has saved many lives in Sweden, where men smoked less and used more smokeless tobacco over the past century than in any other Western country. The result: Swedish men have the lowest rates of lung cancer – indeed, of all tobacco-related deaths – in the developed world. If the rest of the European Union smoked at the rate of Swedish men, there would be 272,000 fewer dead smokers in the EU each year. (here )

Tobacco harm reduction can also work in the U.S., if the ACS and other health organizations start telling smokers the truth about safer cigarette substitutes. The ACS message for this year’s Smokeout is “Help create a world with less cancer and more birthdays.” That’s the basic theme of tobacco harm reduction: If you’ve tried and failed to stop smoking, make the switch to any smoke-free tobacco product and enjoy a healthier, longer life.

Smoking Cessation Medicines Trigger Suicidal Behavior and Depression

Anti-tobacco extremists say that safer tobacco products aren’t necessary because FDA-approved medicines are effective. They ignore scientific evidence of those medicines’ paltry success rate (pharmaceutical nicotine works for only 7% of smokers), and of their significant side effects. For example, varenicline (Chantix) and bupropion (Zyban) carry FDA black-box warnings concerning depression and suicidal or self-injurious behavior.

A study published in PLoS One (here) concludes that “Varenicline shows a substantial, statistically significant increased risk of reported depression and suicidal/self-injurious behavior. Bupropion for smoking cessation had smaller increased risks.” The study’s first author is Thomas Moore from the Institute for Safe Medication Practices; his coauthors are from medical schools at Wake Forest, Harvard and Johns Hopkins Universities.

Moore et al. looked at cases of depression or suicidal/self-injurious behavior in the FDA Adverse Event Reporting System from 1998 to 2010. As a negative control for short-term medication, they compared behavioral episodes during varenicline and bupropion use to those during use of three common antibiotics. Because quitting smoking has also been associated with behavioral problems, Moore also used pharmaceutical nicotine as a “cessation” control.

Compared with antibiotic use, varenicline users were 37 times more likely to experience depression or suicidal/self-injurious behavior (odds ratio, OR = 37, confidence interval, CI = 28-49). The OR for bupropion was 13 (CI = 9-17), and the OR for nicotine was 4.3 (CI = 3.1-6.2).

Compared with nicotine (which controlled for behavioral problems due to quitting smoking), the OR for varenicline was 8.4 (CI = 6.8-10.4) and the OR for bupropion was 2.9 (CI = 2.3-3.7).

Moore also discussed other safety concerns: “While suicidal/self-injurious behavior and depression appear to be prominent side effects of varenicline, they are by no means the only safety issues. Varenicline has been associated with aggression and violence in three studies and carries a warning about this behavior. Its effect on vision, cognition, and motor control and other risks have led to its being banned for airline pilots, air controllers, military pilots and missile crews, and restricted for truck drivers. Varenicline is also associated with an increase in the risk of serious cardiovascular events. In addition, it is associated with hypersensitivity, angioedema and potentially life-threatening severe cutaneous adverse events [references omitted].”

Moore warns doctors prescribing varenicline about “…the value judgment of how to weigh the possible benefits of 52 weeks of smoking abstinence for 1 or 2 out of every 10 patients treated against the risk of less frequent adverse events such as violent and suicidal behavior that can have immediate, catastrophic and irreversible effects on self, family, and career. In the meantime, safer alternatives now exist and should be preferred.”

Unwritten is that one of those safer alternatives is smoke-free tobacco. While no tobacco product is absolutely safe, smoke-free alternatives deliver satisfying doses of nicotine, which is an important modulator of mood, well-being, and other behavioral performance measures.

FDA Petition: End Smokeless Tobacco Misinformation

The federal government requires the printing of three fallacious warnings on smokeless tobacco (ST) products . As I noted in an earlier post (here), one of the warnings – “This product is not a safe alternative to cigarettes” – is especially deceptive; it implies that smokeless tobacco is just as dangerous as smoking.

On July 28, RJ Reynolds filed a citizen petition with the FDA, challenging this warning (here). Reynolds requested that the agency change the text to:

“No tobacco product is safe, but this product presents substantially lower risks to health than cigarettes.”

The petition states, “the public has been misinformed by the public-health and tobacco-control communities – including government health agencies – about the relative risks presented by cigarettes and ST products. A significant part of that affirmative misinformation is the challenged warning, which has appeared in other contexts before its inclusion in the [Tobacco Control Act] in 2009. Government-mandated warnings on ST products reach audiences beyond the purchasers of these products, through press reports, websites of and publications by organizations that follow the Government’s lead, word of mouth and otherwise. The challenged warning has been on ST products since February 1987, undoubtedly, it has contributed to the widespread misunderstanding, including among smokers, that ST products present as much risk to health as cigarettes do.

“FDA should not participate in further perpetuation of that misinformation by retaining the text of the challenged warning. When advising the public, and when requiring others to advise the public, about the relative risks of cigarettes and ST, the Government should, in suitably brief form, tell the whole truth, not mislead by telling only part of the truth.”

The petition documents, with scientific and legal evidence, the inaccuracy of the warning, which has been required since 1987. One of the strongest arguments is that it perpetuates the common misperception, documented in several published studies (including ours, here), that ST is equally or more dangerous than cigarettes. As a result, the warning “may lead some consumers to simply continue smoking after failed attempts at abstinence because they will be resigned to the belief that the use of [ST products] is just as harmful as smoking.”

The petition notes that the 2009 Tobacco Act gave the FDA authority to change the warnings in order to “promote greater public understanding of the risks associated with the use of smokeless tobacco products,” while “the current misleading warning affirmatively fosters public misunderstanding of those risks.” (Emphasis in original.)

I have lectured on tobacco harm reduction for over 17 years; one of the most common objections from opponents is that Americans can’t handle the truth that the health risks of smokeless tobacco are barely measurable. Because consumers might make bad decisions, health professionals are encouraged to perpetuate a lie.

The Reynolds petition destroys this specious argument. Its concluding paragraphs are exceptionally powerful, so I reproduce them here:

“One way or another, sooner or later, the public will learn the truth about the relative risks presented by cigarettes and ST products. When that truth becomes widely known, what will the members of the public think of the public-health authorities who had deceived them into believing that there is no relevant difference between the risks presented by cigarettes and those presented by ST products? And how much will their trust in public-health authorities on other matters – e.g. diet, exercise, alcohol – have been undermined by the deception about tobacco?

“[Sissela] Bok’s overall conclusion [from the book, Lying: Moral Choice in Public and Private Life, here] is that, for many reasons, lying to provide a benefit for the recipients of the lie is wrong. Her final words are: ‘Trust and integrity are precious resources, easily squandered, hard to regain. They can thrive only on a foundation of respect for veracity.’ For FDA, an agency whose mission is to be accomplished through the application of sound scientific principles and whose statutory charge here is to promote the greater public understanding of the risks associated with the use of ST products, there can be only one answer. Tell the whole truth.”

The Reynolds petition is scientifically credible and morally compelling. The FDA must correct the egregious misinformation that it requires on one fourth of all ST products sold in the U.S.