Surprisingly Cautious News Coverage of Aspartame and Cancer

We fear cancer more than any disease. But, in some ways, that fear is outdated. A diagnosis of cancer is no longer the automatic death sentence many of us still assume. Most cancer screening provides much less benefit, and does more serious harm, than many people realize. And we still stubbornly believe, wrongly, that most cancer is caused by environmental carcinogens. So, when I first heard in late June, via Reuters, that the International Agency For Research on Cancer (IARC) was planning to declare the widely used artificial sweetener aspartame a possible human carcinogen, I thought Here we go again. Another cancer scare. More media alarmism fueling our false fear that cancer is mostly caused by "things out there."

But I was wrong. Yes, there was a big splash of predictably alarmist news coverage when the Reuters story broke. But by the time the official IARC announcement came two weeks later, many health and environment reporters had moved past the OMG! initial reaction and covered it with context and, laudably, caution. Most reported that the IARC has a tiered rating system based on how sure it is…

• 1 – causes cancer in humans
• 2a– probably causes
• 2b – possibly causes (which essentially means maybe, based on some hints from limited research, but we don't really know)
• 3 – not enough evidence to know

…and that aspartame was in Category 2b, along with caffeine, pickle juice, aloe vera, and bracken ferns. James Gallagher, health and science correspondent of the BBC, went even further and, right at the top of one of his reports, essentially cautioned people to not freak out, writing “The 'possibly carcinogenic' label often causes fear and confusion, but just means the evidence is unconvincing.” (The BBC’s NewsNight did an equally responsible piece right after the original Reuters story. There was work like this around the world.)

Even more encouraging, a lot of reporting on the aspartame finding included a key element about how risky something is that rarely shows up in scary news about potential carcinogens: Dose. Dose really matters. (One aspirin is OK, 100 all at once can be fatal.) Many reports noted that the IARC only investigates whether something has a biological carcinogenic effect, but not whether it actually causes cancer at the doses to which we’re exposed. Most stories noted that food safety agencies around the world have studied aspartame for decades and judged it safe for consumption by a 130-pound person as long as they don’t drink more than 12 to 36 cans of diet drinks (depending on the ingredients) a day, every day for the rest of their life. Dose matters.

Yet, that crucial element in careful scientific risk assessment is commonly ignored in risk reporting. It’s nowhere to be found, for example, in most reporting about the latest chemical bogeyman, the PFAS class of industrial chemicals.

So it isn't surprising that news coverage of environmental carcinogens, dramatically playing up the threat of cancer, "The Big C," "The Emperor of All Maladies," but often lacking critical basic information that would put the threat in perspective, has helped create what a 2019 National Cancer Institute survey found, that 70 percent of Americans either strongly or somewhat agreed that “it seems like everything causes cancer.”

It’s beyond modern science to know just how many cancers are caused by environmental carcinogens. Estimates range from a few percent to as high as perhaps 25 percent (if you exclude smoking). Leading cancer biologists believe that cancer is mostly a disease of aging, a killer in large part because we now live long enough that naturally occurring DNA mutations build up over time (exacerbated by poor diet and exercise choices) and allow cells to grow without normal controls. More than half of the people in the United States diagnosed with cancer are at least 65 years old; 87 percent of the people in the United States who die of cancer are 50 and older, and nearly half are 70 or older. In 1900, when the average life span was around 45, cancer was only the 10th leading cause of death in the United States.

But such numbers run squarely against the popular “it seems like everything causes cancer” belief, which is the result of what people have been told about cancer by the news media. So, it is worth noting, and lauding, the uncommonly responsible way the cancer scare about aspartame was handled in many news reports.

Fear of cancer, outdated and excessive in some ways, does great harm, to individuals and to society. The new media have played a major role in creating that fear and causing that harm. (Mea culpa, I did, as an environment reporter for a Boston TV station for 22 years.) Measured news coverage of cancer threats can play a part in slowly helping us bring our fears more in line with the evidence, so while we’re working hard to cure the disease, we can also keep our cancerphobia from doing damage all by itself.