Dear Doctor: Are those wireless earbuds everyone seems to be wearing nowadays safe? I heard that some international researchers are petitioning the World Health Organization about them because the signals that they emit may be hurting our brains. Should we be concerned?

Dear Reader: When it comes to wireless devices, which have been swiftly and near-universally adopted over the last two decades, advances have far outpaced our ability to monitor or even understand the potential health effects and consequences.

Wi-Fi, which first became commercially available in 1997, is one of the fastest-growing technologies in history. Cellphones quickly moved from a pricey niche product to the ubiquitous pocket computers of today, their telephone functions now barely an afterthought. (Fun fact -- the first truly wireless phone call was made in 1973 on a "mobile" phone that weighed 2.5 pounds.) And now, with the advent of wireless earbuds, phone manufacturers are bringing wireless tech into even closer and more sustained contact with the body.

At issue are EMFs, or electric and magnetic fields. These fall into two categories -- ionizing and non-ionizing. Ionizing EMFs are high-level radiation with the potential to cause damage to cells and DNA. Non-ionizing EMFs, which are low-level radiation, are the ones generated by wireless devices. Non-ionizing EMFs haven’t been proven to be harmful to humans. But they haven’t been shown to be harmless, either, and so the debate rages on.

As you point out in your letter, some scientists and researchers are raising an alarm. In 2015, a group of 250 doctors and scientists who specialize in EMF research signed a petition directed at the WHO and the United Nations. In it, they state their belief that the non-ionizing EMFs released by wireless devices pose a range of health hazards. These include cancer, memory problems and reproductive and genetic disorders. The U.S. Food and Drug Administration, meanwhile, does not consider the low-level EMFs released by cellphones and wireless devices to be a health hazard.

The debate about non-ionizing EMFs doesn’t hinge on the power of the energy fields generated by our wireless devices, which everyone agrees are on the low end of the non-ionizing EMF spectrum. Instead, it focuses on the effects of sustained exposure from the growing number of wireless devices we’re letting into our lives. Now, with wireless earbuds being placed into the ear canal, the concern is that we have moved from being bathed in non-ionizing EMFs from a distance to directing them into our bodies and close to our brains.

As we mentioned earlier, the results of ongoing research into the health effects of low-level EMFs remain mixed at this time. Scientists point out that Bluetooth devices, which include wireless earbuds, give off less than 10% of the radiation of cellphones. But if you’re at all worried, skip the wireless earbuds and stick with the old-school wired ones. Yes, it’s true that a number of cellphone manufacturers have ditched the headphone jack in their devices in recent years, but you can get an adapter that lets you used wired earbuds or headphones.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Could energy drinks really lead to stimulant use? How can that be? No one’s ever linked coffee or cola consumption to an increased risk of drug abuse. This sounds like some kind of urban legend.

Dear Reader: Considering the centuries-long history of coffee drinking, and the estimated 2.5 billion (!) cups of the stuff consumed each day worldwide, your skepticism is understandable. However, a 2009 study by researchers at the University of Maryland indeed suggested a link between the sustained use of energy drinks by young adults and the chance of future abuse of certain types of drugs.

The study began with 1,060 first-year college students with an average age of 18. Over the course of the following three years, the students completed three annual interviews regarding their use of energy drinks, any other sources of caffeine, and alcohol and tobacco use. The students also reported the use of prescription drugs, and any illegal drugs. In a series of post-college interviews, which took place when the participants were between the ages of 21 and 25, the researchers assessed their drug use.

Over the course of the first three years of the study, about half of the students either diminished or stopped using energy drinks. The other half continued to consume them in the same large quantities. When they followed up several years later, researchers found that students who continued robust energy drink use went on to have a markedly higher risk of using cocaine or illicit stimulants after the age of 25 than did the group of occasional or nonusers. The high-use group was also found to have an increased risk of alcohol abuse.

Whether the energy drinks themselves set the stage for the future drug abuse, or whether the individuals who were naturally susceptible to drug or alcohol abuse were also drawn to the effects of the energy drinks, is not known. However, the researchers concluded that the implied connection between sustained energy drink usage among young adults and the potential for future illicit stimulant use deserves further study. With an estimated one-third of teens between the ages of 12 and 17 now regularly downing several energy drinks per day, we heartily agree.

Addiction aside, ongoing studies continue to identify a range of health risks associated with energy drinks. These include increased blood pressure, heart arrhythmias, sleep disturbance, damage to the heart and blood vessels, kidney damage and weight gain. This last may seem counterintuitive for a product engineered to rev you up, but many varieties of energy drinks contain excessive amounts of sugar, up to 2 or more tablespoons per 8-ounce can. That means just one energy drink will put you over the recommended allotment of sugar for the day.

In addition to caffeine and sugar, energy drinks contain a range of herbs, enzymes, vitamins and other additives. And because the products are not regulated, you can’t always know exactly what you’re ingesting. Bottom line -- research repeatedly shows that energy drinks can have serious health effects, particularly in children, teenagers and young adults.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Hello again, dear readers, and welcome to our monthly column devoted to your thoughts, notes and suggestions. We’re deep into spring, so here’s our annual reminder to be on high alert for ticks. Dress defensively, use repellents and do thorough and regular tick checks. Always seek medical care if a tick bite is followed by a rash, fever or other flulike symptoms. Be sure to also protect any four-footed companions with access to the outdoors. And now, to the inbox.

-- Many of you wrote in response to a column about the health benefits of nuts, asking if roasted and salted nuts are OK. Although roasting doesn’t affect protein, fiber or carbohydrate content, it may chemically alter the healthy fats that nuts contain. Roasting can also cause the formation of acrylamide, a compound that has been studied as a potential carcinogen. Roasted nuts have less acrylamide than potato chips or french fries, and the American Cancer Society says the effect on cancer risk in humans remains unclear. Regarding salted nuts, the main caution is to include the added sodium in calculating your total daily intake. This shouldn’t exceed 2,300 milligrams, and is hopefully closer to the American Heart Association’s goal of 1,500 milligrams per day.

-- Regarding a column about sexually transmitted diseases, a reader asked whether washing or douching after sex will protect against sexually transmitted diseases. The answer to both of those is NO. The best protection against STDs is the correct and consistent use of latex condoms, which can prevent transmission of both bacterial and viral STDs.

Although topical microbicides, which are substances like gels, films or suppositories, can kill or neutralize viruses and bacteria, it is recommended they be used along with condoms. Since some STDs can be transmitted via oral sex, it’s important to have a frank conversation about sexual history and potential health risks with your partner before sex.

-- We heard from a lot of parents in response to the column about the potential problems caused by the heavy school backpacks our kids are now toting. One reader wishes we had gone into more detail about how to lighten the load.

“This is a good time to teach children how to plan and decide what to keep in their backpack all the time versus what they need at certain periods of the day,” she wrote. “Many keep everything just because they might need it. Teaching them planning, time management and simple solutions like rotating books and binders during their day, or sharing binders for several morning or afternoon classes, can lighten the load.”

-- When we write about dogs, we get a ton of mail. In response to a recent column about a grandfather’s plans to adopt a dog, a reader from Oklahoma pointed out that pets aren’t for everyone: “If the person has balance problems or vision problems, there could be a high likelihood of tripping over the pet,” he wrote. “That could result in some serious injury.”

Thank you, as always, for your interest and engagement with this column. We love hearing from you and look forward to your letters.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)