Do Cell Phones Cause Brain Tumors?

What does the world’s leading authority on carcinogens have to say about mobile phones?

Do cell phones cause cancer? That’s a question billions of people would like to have answered and one I address in my video Cell Phone Brain Tumor Risk?. That’s why we have the World Health Organization’s International Agency for Research on Cancer (IARC), the recognized authority on determining what is and is not carcinogenic. There are five categories: Group 1 carcinogens are agents that we know with the highest level of certainty do cause cancer in human beings, Group 2A probably cause cancer, Group 2B possibly cause cancer, we’re not sure about agents categorized as Group 3, and Group 4 agents probably don’t cause cancer.

In May 2011, 30 scientists from 14 countries met at the IARC to assess the carcinogenicity of the radiation emitted from cell phones and concluded that, given the limited amount of available evidence, cell phones are “‘possibly carcinogenic to humans’ (Group 2B).” So they’re not classified as a Group 1 carcinogen that’s known definitively to be cancer-causing, like plutonium, or processed meat, or as probable carcinogen, like DDT, Monsanto’s Roundup pesticide, or some regular meat, but they are classified as a possible carcinogen, ranked similarly as preserved vegetables like kimchi. 

Now, this classification was made more than five years ago. Evidence continues to mount, and the latest two 2017 systematic reviews found a 33 percent increase in odds of brain tumors with long-term use and showed 46 percent higher odds for tumors on the phone side of your head—and the reviews included the industry-funded studies that have been accused of being biased and flawed, and underestimating the risk, as opposed to independent studies free from “financial conditioning.” How’s that for a euphemism? Given this, some scientists are pushing to have the IARC reclassify cell phones as probable carcinogens or even bump them all the way up into Group 1, at least for brain cancer and acoustic neuroma, a type of inner ear tumor. 

But the IARC classification for cell phones currently remains at possible carcinogen. What does that mean? What do we do with that information? Well, given the uncertainty, we could follow “the precautionary principle” and use simple personal measures to reduce our exposure, like not putting the phone directly up to our head all the time. Indeed, the “main concern about cell phones is that they are usually held close to the head,” which is considered particularly important for children. There’s no evidence of finger cancer, though, so you can keep texting away. 

Other potential personal recommendations include waiting a moment before putting your cell phone to your ear, if you don’t have a headset, because “when the cell phone establishes a connection, the emission is high.” And don’t fall for those anti-radiation gizmos, those “so-called protection covers,” as they may make things worse by forcing the phone to boost the signal.

Not all agree, however, with this precautionary approach. Employees at two cell phone industry trade organizations emphasize “there are many aspects of human activity that are not ‘totally without adverse health effects,’—for example, transport (including aviation) and hot showers,” so they suggest we should just accept the risk as being worth it. Wait. Hot showers? As in we might scald ourselves or something? In any case, they further suggest that we shouldn’t put forth any recommendations because “such judgment should be made by parents on a personal basis for their own children,” and, if we do put out guidelines or something, people might get nervous and we all know “anxiety itself can have deleterious health consequences.” So, basically, the cell phone industry cares so much about your health that it doesn’t want you worrying your pretty little head.

Nevertheless, all of this is openly discussed in the risk analysis literature. “From a public health perspective, it might be reasonable to provide cell phone users with voluntary precautionary recommendations for their cell phone handling in order to enable them to make informed decisions”—but what if the public can’t handle the truth? We don’t want to freak people out. There’s still “scientific uncertainty” and we don’t want to “foster inappropriate fears.” For example, brain cancer is rare to begin with. You only have about a 1 in 15,000 chance a year of getting a brain tumor,  so even if cell phones double your risk, that would only take you up to a 1 in 7,500 chance. You may be more likely to get killed by a cell phone in the hands of a distracted driver than by cancer. So, whether health authorities want to inform the general public about precautionary possibilities really remains more of a political decision.


For more on cell phones and Wi-Fi, see:

What was that about meat and cancer? See my video Carcinogens in Meat. And, to learn more about the IARC’s decision and the industry’s reaction, see:

What about cancer risk of medical diagnostic radiation? See:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Fermented or Unfermented Soy?

As you can see at the start of my video Fermented or Unfermented Soy Foods for Prostate Cancer Prevention?, there is an enormous variation in the rates of prostate cancer around the globe, with among the highest rates in the United States and lowest rates in Asia—though that may be changing. The largest increase in prostate cancer rates in the world in recent decades has been in South Korea, for example: a 13-fold increase in prostate cancer deaths nationwide. Researchers suggested the increase in animal foods may have played a role, since that was the biggest change in their diet over that period, with nearly an 850 percent increase.

This is consistent with what we know in general about foods and the prevention and management of prostate cancer. Tomatoes, cruciferous vegetables like broccoli, and soy foods appear to decrease risk, there’s no clear benefit from fish, but there is an increased risk associated with meat and dairy, as you can see at 0:52 in my video. This may be because a diet based around whole plant foods “may effectively reduce inflammation in the body.”

There is also a genetic factor. If you have a first-degree relative with prostate cancer, you may be at three-fold higher risk, but non-genetic factors may increase your risk 300-fold. How do we know the low rates in Asia aren’t genetic? Because when Asians move to the United States, their rates shoot up, “and by the second generation, the incidence rate [is] already approaching that of average Americans.” This may be because of more Burger Kings and Dairy Queens, but could also be because of eating fewer protective foods, such as soy.

A systematic review of all soy and prostate cancer population studies to date confirmed that soy foods are associated with lower the risk, but that’s a relatively broad category. There are all sorts of soy foods. There are fermented soy foods, like miso and tempeh, and unfermented ones, like tofu and soy milk. Which are more protective? Researchers sifted through the studies, and it turns out that only the unfermented soy seemed to help. Tofu and soy milk consumption was associated with about a 30 percent reduction in risk, whereas there didn’t appear to be any protection linked to fermented soy foods.


What about other healthy plant foods, like broccoli and turmeric? See what they can do in Best Supplements for Prostate Cancer.

Dean Ornish and his colleagues got amazing results, apparently reversing the progression of prostate cancer with a plant-based diet and lifestyle program. Do you think it could be because of the soy? It wasn’t just a vegan diet, but a vegan diet supplemented with a daily serving of tofu and a soy protein isolate powder. Find out in The Role of Soy Foods in Prostate Cancer Prevention and Treatment.

More on the number-one cancer among men:

What about soy and breast cancer? I’m glad you asked!

Who Shouldn’t Eat Soy? Watch the video to find out!

In health, 

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations: