How much time do you spend talking on your cell phone? (By talking, I mean having a spoken conversation, not texting or surfing the Web or using apps.) If you’re like most people these days, your answer is probably “a lot”…and you probably talk with your phone propped right up against your jaw. But you probably don’t give a second thought to what that phone is doing to your saliva. What? Are you kidding me? you may be saying. But no, I’m not kidding.

Reason: The electromagnetic radiation emanating from cell phones can have some very funky effects on salivary glands and saliva, a new study suggests—effects that reflect increased oxidative stress, which is a risk factor for cancer. Here’s what you should know before you make your next call…


Scientists have been trying to determine whether cell phones’ electromagnetic fields can cause cancer. Though most studies say that the evidence for any such link is weak to nonexistent, there are enough contradictory and inconclusive results to fuel continued concern. Also, cell phones came into widespread use only two decades ago, and many cancers don’t appear until quite a few years after exposure to carcinogenic agents—so it’s still too early to know whether long-term cell-phone use may contribute to cancer risk. In fact, in 2011, the World Health Organization classified cell phones as “possibly carcinogenic to human beings.”

Now back to that saliva. When a cell phone is held up to either side of the face, it’s very close to one of the two parotid glands, the body’s largest salivary glands. These glands sit just millimeters beneath the skin’s surface in front of the lower part of the ears—a prime position for radio energy influence. That’s why researchers in Israel decided to see whether cell-phone use affected saliva.

First, researchers recruited healthy volunteers ages 32 to 63 who had been using cell phones for an average of 12.5 years, whose cell-phone use averaged 30 hours per month (so about an hour a day) and who generally did not use headsets or speakers.

Then, as a basis of comparison, the researchers needed to assemble a control group of people who didn’t use cell phones. Finding such people is no easy feat these days, so the control group consisted primarily of deaf individuals, and they were matched by age and gender to the cell-phone users. Among the control group, cell-phone use (if any) was limited to nonspeaking functions such as texting and Web browsing.

Participants waited 90 minutes after engaging in any sort of “oral stimulus” (eating, drinking, chewing gum, speaking). Next, they allowed their saliva to pool in their mouths, then spat it into test tubes, continuing for 15 minutes.

When the saliva samples were analyzed, researchers found that cell-phone users produced about 20% more saliva than the control group. That was not unexpected, because parotid glands make saliva in response to chewing motions, and the same muscles are used for chewing and for speaking. In the deaf control group members, these muscles naturally would be less developed. Cell-phone users’ saliva also contained lower concentrations of various enzymes, proteins and other substances—also expected, given that the greater amount of saliva would dilute these substances.

The shocker: Various markers of oxidative stress were significantly higher in the saliva of cell-phone users than in that of the control group. For instance, levels of a stress marker called malondialdehyde were more than four times higher, on average…levels of the stress marker carbonyl were nearly twice as high. Research has shown that damage caused by oxidative stress is linked to genetic and cellular mutations that cause tumors to develop.

Safe phoning: This study does not prove that talking on cell phones causes oral cancer or any other kind of cancer…but the findings are worrisome enough that it just makes sense to take some precautions to lower your exposure to cell phones’ electromagnetic fields. Fortunately, that’s not hard to do. You can reduce whatever risk there may be by using a hands-free device, such as a headset, earbuds or a speaker…by text-messaging instead of phoning…and/or by using a regular landline when available.