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When Everything Causes or Prevents Cancer

How Critica Approaches Getting Some Facts
July 17, 2019 | Comments

It seems that if we read enough newspapers and magazines and follow a sufficient number of social media sites we will ultimately conclude that everything we eat, breathe, or touch is capable of causing cancer. What do we do when something we like to eat or use to clean our homes, for example, is suddenly reported to be a carcinogen? Stop using it or ignore the frightening news flash? And how should we react when a “natural” product is touted as preventing or curing cancer? Go out and buy it in bulk right away?

         One thing many people do in such a case is to enter the substance alleged to cause or cure cancer into a search engine and see what’s out there about it. We all know, however, that this method is as easily misinforming as enlightening because search engines do not discriminate between true and false information. A Google search for example will give you the most common sites others have looked at, not the ones that give the most accurate information.

         At Critica, we are often asked “is this true?” when one of these reports about a cancer-causing or curing agent is reported in the popular media. While we pride ourselves at having done considerable research on the safety of specific things like vaccines, guns, fossil fuels, tick-borne diseases, shock treatment, GMOs, and nuclear energy, we are hardly experts on every substance that supposedly causes or prevents cancer. So what do we do when someone asks us questions like these four:

  1. “does bleach really cure autism?”
  2. “does bleach cause cancer?”
  3. “do dandelion weeds kill cancer cells.”
  4. “do brussels sprouts and broccoli prevent cancer?”  

Often, it is our intrepid Critica COO, Catherine DiDesidero, who first encounters such claims and turns to the scientists among us for answers.

Bleach Does Not Cure Autism

         The first of these four questions is the easiest.  We were appalled to learn that some parents have given bleach to thousands of their children with autism, believing it is somehow a “cure.” Apparently, a former real estate agent named Kerri Rivera has managed to convince parents that chlorine dioxide, a mixture of sodium chlorite found in bleach and acid, is an effective treatment for autism. She and others promulgating this dangerous myth have managed to “infiltrate more than a dozen private Facebook groups for parents of autistic kids”.

The fact is that consuming significant quantities orally of chlorine dioxide, sodium chlorite, or bleach in general is extremely toxic and potentially fatal. It is fairly easy to get this information from reliable sources, like the websites of the Food and Drug Administration (FDA), Centers for Disease Control and Prevention (CDC), and the Agency for Toxic Substances and Disease Registry. There’s also, of course, no evidence that bleach has a positive effect on the symptoms of autism because no one would entertain the idea of giving such a toxic substance to people in a research study. But there is also absolutely no conceivable theoretical reason to believe in this notion. So we had no trouble debunking this one.

Bleach doesn’t cure autism but doesn’t seem to cause cancer (source: Shutterstock)

Does Bleach Cause Cancer?

Harder was the claim that any exposure to household bleach, like Clorox, can increase the risk for cancer. Whenever something is accused of causing cancer, we always take a deep breath. As we have noted before, almost any substance can be dangerous if taken in too large a quantity. So first, we ask if the claim is based on doses that humans are actually likely to encounter.

         Then, we ask if the source of the claim seems to be one that “shoots from the hip” or cites actual evidence from reputable scientific journals. We also look at those studies to make sure they were actually done in humans; many things cause cancer in mice and rats but not in people. Finally, we ask how large the effect is; smoking cigarettes increases the risk for lung cancer hundreds of times compared to not smoking. In other cases, something claimed to cause cancer turns out to increase the risk by extremely small amounts and it is questionable whether avoiding the putative carcinogen is worth it. A very good guide to evaluating a cancer claim is available online from the American Cancer Society.

          In the case of bleach, we just couldn’t find any convincing evidence that it has a link to cancer. None of the regulatory agencies charged with warning us about the carcinogenicity of commonly encountered products, like the International Agency for Research on Cancer (IARC), Environmental Protection Agency, or CDC, lists bleach as a compound that increases the risk for cancer. There are animal studies, but nothing in the human scientific literature that looks like bleach is a cancer risk.

That is not to imply that everyone will want to use bleach; it can irritate the eyes, nose, and throat, for example. Our conclusion here is that you should not drink bleach or feed it to your children, and you shouldn’t mix it with formaldehyde or ammonia. But it probably won’t cause cancer if you are just cleaning with it.

Dandelions Said to Kill Cancer Cells

Turning to the opposite sort of claim, we have first the seemingly great news that “Dandelion ‘weeds’ kill cancer cells, leave healthy cells intact”. So what’s the evidence for this one? Some scientists apparently “inserted dandelion root extract into Petri dishes with blood drawn from leukemia patients and lab rats…To their delight, the dandelion root induced apoptosis or ‘cell suicide’ in cancer cells, while leaving healthy cells alone.” The article, published last September, says that human tests of dandelion extract will occur next. It also claims that researchers at the Canadian University of Windsor have seen patients “who chose dandelion tea over chemotherapy” have a good result.

         If only things were so simple. A good way to bring one down to earth after reading one of these cancer cure claims is to see if the very trustworthy Snopes online site has anything to say about it. Snopes (which is undergoing its own woes now because of legal battles involving its divorced founders) does do  a good job in this case of hunting down the facts.  Their verdict on the dandelion claim: “Mostly False”. Snopes explains that “We were not able to locate any published research indicating dandelion root affirmatively demonstrated an anti-cancer effect in humans.” Indeed, experiments in petri dishes and laboratory animals sometimes show very encouraging results that when tried in humans prove disappointing. Without any real human data to support the claim, it would be dangerous, to put it mildly, for patients with leukemia to substitute dandelion tea for chemotherapy.

Don’t we wish dandelions could kill cancer cells? (source: Shutterstock)

         Finally, we have the seemingly bizarre claim that an enzyme called i3c found in brussels sprouts, broccoli, and other cruciferous vegetables might be capable of curing several cancers, including prostate and breast cancer, in people with a rare genetic mutation. The fact that this one was reported on last May in the New York Times is not by itself all that reassuring. The Times has not been immune to inaccurate health claims, both positive and negative. But there are a few things on the face of this story that increase the likelihood that there is something valid about it.

         The first thing is that the word “rare” appears in the headline. That isn’t a word we frequently see when people are making exaggerated health claims. Those stories usually give the impression that the touted cure is good for almost everyone and everything. But in this case, the Times story starts right off telling us that the mutation-which occurs in a gene called PTEN—is rare.

         Second, although we would have rather seen this in the first paragraph, there is a statement in the eighth paragraph that that “The new study was done only in mice and in human cancer cells grown in Petri dishes.” Human studies, the story explains, are needed before i3c can be called a legitimate treatment for cancer.

         Third, the study the Times story is referencing was published in the journal Science, one of the two most prestigious scientific journals in the world. Although not everything published in Science turns out to be true, articles that appear there are extensively peer-reviewed and usually represent highly sophisticated and rigorous research.

         Finally, this story does no more than whet our appetite for what future research might show. Unlike exaggerated claims for cancer cures that tells us the cure is a simply matter of changing one’s diet, this one acknowledges that no one with the rare mutation who has cancer could possibly eat the amount of brussels sprouts needed to get an anti-cancer effect—six pounds a day, raw.

         The facts or lack of facts behind the four claims we have discussed here took us several hours to hunt down, and we could have spent even more time searching through the scientific literature and reading through thousands of papers about sodium chlorite, chlorine dioxide, bleach, dandelions, i3c, and PTEN. We think, on balance, that we came to reasonable conclusions by doing a reasonable amount of research. Most important, we hope that our little adventures here help our readers formulate a plan every time they confront a new claim that something causes or prevents cancer. If you don’t have the time or inclination to do that, just ask us and we will be happy to do it for you. 


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