According to a Swedish study from Lund University recently published in the American Journal of Clinical Nutrition, it takes a single daily can of soda to increase a man's risk of prostate cancer by 40 percent, compared to a man who never touches the stuff.

So where is the public outcry warning Americans, who are always in search of newer and better drugs anyway, off these lucrative yet carcinogenic vehicles for addictive substances like caffeine, sugar and perhaps worse? They are likely hiding, at least for now, from an industry loathe to let cold-hearted science and much-needed reason lead the way.

"When it comes to studies of soda consumption and chronic disease risk, the only superior alternative to a prospective cohort study would be to conduct a randomized, controlled trial, where you assign one group to drink high amounts soda over 20 years, and the other group to not consume soda," senior researcher Isabel Drake, who led Lund University's soda cancer study, told AlterNet. "This, of course, is unethical and never going to be feasible. There are situations like this one, to assess for causal associations between soda consumption and cancer or other chronic diseases, where observational studies are realistically the best study design to address causal associations."

Causality is the central question when it comes to sodas, whose lineage leads to 18th and 19th century druggists, scientists and other whitecoats. Since then, sodas have metamorphosed from chemical experiments into ubiquitous commodities pounded out by powerhouse multinationals like Coca-Cola and Pepsi, who together lord over about 90 percent of the market. Clocking around $60 billion a year, soda competes for drug market share with cannabis and its godfather, cocaine.

You'll notice that nowhere in that short history lesson did you hear anything about health and wellness. That's because sodas have zero redeeming nutritional value.

But they have had lethal additives like 4-methylimidazole, the ammonia-sulfite caramel coloring that is also a known animal carcinogen. The flavorless die brought nothing to products like Coke, Pepsi, Dr. Pepper and more that carried it, and was toxic enough to activate a new California law requiring disclosure of cancer risk — which, in turn, was enough to motivate Coke and Pepsi to quickly discard it while protesting the controversy as "scientifically unfounded." An appeal to the FDA for ban from the Center for Science in the Public Interest likely helped. But 4-methylimidazole is just one soda headache among many.

"Caramel is one concern that the industry is in the process of largely solving," CSPI co-founder and executive director Michael F. Jacobson told AlterNet. "Also, we have concerns about aspartame, acesulfame-potassium and saccharin, which is rarely used in drinks."

Lund's study is the latest in a roll-call of soda cancer flags. Drake and colleagues followed 8,000 men aged 45-73 for an average of 15 years, and found that 40 percent of those who downed barely 12 ounces of soda a day were likely to contract a disease that kills a million of them a year. Previous research has warned of increased risk of esophageal cancer. University of Minnesota School of Public Health professor of epidemiology Mark Pereira recently led a study finding that 87 percent of his over 60,000 test subjects were likely to develop pancreatic cancer, whose median survival for 80 percent of afflicted individuals hovers between six to 10 months. The soda cancer warning signs continue to siren.

"The important take away from our study is that habitual consumption of soft drinks may be linked to an increased risk of pancreatic cancer," Noel Mueller, University of Minnesota School of Public Health Ph.D. student and first author on Pereira's study, told AlterNet. "In response to any criticisms, I'd like to point out that our results align with a recent Columbia University Mailman School of Public Health meta-analysis of studies on this topic, including ours, which found that soft drink consumption was indeed positively associated with pancreatic cancer risk."

The soda cancer warning signs continue to siren. It's no wonder that fear of a California could-cause-cancer label was enough to motivate soda multinationals into comparatively lightspeed removal of their called-out carcinogens.

It's no wonder that fear of a California may-cause-cancer label was enough to motivate soda multinationals into comparatively lightspeed removal of their called-out carcinogens.

Exploiting causal opportunities like these to bring soda multinationals to heel for their obvious cancer threats is crucial. But good luck finding enlightenment on soda and cancer at the Food and Drug Administration (FDA), the National Institutes of Health (NIH) or its National Cancer Institute (NCI). A NCI spokesperson told AlterNet that he's "pretty sure" they have no conclusive research on the matter. "We have no fact sheet on soda on cancer," he said.

The NCI does have a factsheet on Diet and Nutrition that sheds light on other areas like artificial sweeteners, fluoridated water and cruciferous vegetables. But most compelling is the NCI's facstsheet on cancer and obesity, which it warns is associated with increased risk of cancers of the esophagus, breast, endometrium, colon, rectum, kidney, pancreas, thyroid, gallbladder… "and possibly other[s]." The NCI also notes that obesity comes complete with a higher risk of coronary heart disease, stroke, high blood pressure, diabetes, and a number of other chronic diseases, all for an "markedly" increased share of Americans consuming themselves to death.

But the indispensable link missing from that causal chain is the obvious link between soda and obesity. It's not rocket science: If soda is a major obesity threat, and obesity is a major cancer threat, then soda is a major cancer threat.

Like soda and cancer, soda and obesity used to be a hot-button issue. That is, until enough time, science and activism passed. But as one can tell by high-profile blowback from Michael Bloomberg, who banned sales of large sodas while calling it the "single biggest step any city has ever taken" to "curb obesity," or Michelle Obama, who called obesity America's "number one greatest national security threat," administering global policy these days on soda and obesity is no longer political suicide. It's a shared reality received at last from power players who champion initiatives with motivational grabbers like "Let's Move!"

This is perhaps why a spokesperson for the American Medical Association responded to AlterNet's questions about soda and cancer with a reminder of its positions on soda and obesity, which like autism and other medical spectrums shelter less processable truths.

"Causal inference is the holy grail of epidemiology," Mueller said.

"You make a good argument that the causal link between soda and obesity, and obesity and cancer, could potentially be enough to establish causality," Drake told AlterNet. "Because of the direct link between diet and obesity, obesity is of course an easier sell."

Jacobson agreed. "Probably by far the biggest risk is due to the fact that drinking too much soda promotes obesity, and obesity promotes several types of cancer," he told AlterNet. "Coffee, decaf, tea, seltzer, flavored waters and water are certainly safer than liquid candy."

"Since cancer is affected by other environmental factors, and to a much greater extent genetic factors, there is probably not enough evidence to say there is a direct causal link, but potentially enough evidence to say that a poor diet increases risk of disease," said Drake.

"It's premature to say whether obesity may be on the causal pathway between soda and pancreatic cancer," Mueller dissented. "However, in my mind, despite the theoretical shortcomings for causality, there is a strong enough case to be made that sugar-sweetened beverages offer no redeeming nutritional qualities and, as such, there is a policy case to be made that their consumption, in excess, should be limited."

But these seem like semantic scientific arguments. The druggists and other whitecoats who created sodas, as well as the power suits who capitalize on their formidable market in industry and government, can mount infinitely regressive causality arguments until their nest eggs are well feathered by soda cancer's complexities. But the hyperconsuming public they've encouraged will inevitably wake to a day when those same parties, who once told them it was just fine to drink Cokes to teach the world to sing, are instead saying they should worry about having only months to live, because they drank too many Cokes a day to teach the world to sing.

"With all usual scientific caution being said, since we do not have the possibility to perform randomized clinical trials investigating the long-term impact of soda consumption, we do have to rely on the evidence at hand," Drake added. "And given that it can be stated with certainty that there are no health benefits with drinking soda — in fact, evidence suggest negative impact on health — public health measures should be taken, perhaps to a much greater extent than they are today, to limit consumption."

In other words, until both its pushers and users acquiesce to new economic and political normals, soda is to be known as a side route to cancer.

Until then, the soda industry plans on cashing as many checks as it takes to keep its product on the tip of your tongue. Or issuing them, in the case of pop diva Beyonce, who scored $50 million large to hawk Pepsi to her image-conscious base. That industry chess move might not be worth the money: With increasingly lethal public health risk comes slipping soda sales and changing demographics and tastes. Youth addicts who once turned to tankers of sodas are turning to coffee for caffeine and sugar fixes, or even back to water to purify their bodies and consciences.

All of this makes soda a 20th century commodity on inevitable life support in our still-new millennium. Let's drink to that.