We’re bombarded with messages to be healthier—“The Top 5 Superfoods You Can’t Live Without,” “12 Tips for Better Heart Health,” “3 Surprising Natural Cold Remedies,” “8 Tips for Healthy Living on the Go.” Never before have we had access to so much sound information about health. But never before have we had access to so much unsound advice as well, and not just bizarre fad diets or other obviously unhealthy practices. Here are 10 practices that seem healthy but could be doing damage.

We’ve Got a Pill for That

The dietary supplement industry is big—a largely unregulated $27 billion business, according to Consumer Reports. Earlier this year, CNN noted that more than 50 percent of adults in the United States use supplements, which often are promoted as cure-alls: No matter what ails you, the right pill or gelcap can help. On The Vitamin Shoppe’s website, you can shop by health concern: Boost your immune system, age gracefully, ease joint pain, improve your sex life. Daily multivitamins are the most popular, used by nearly 40 percent of American adults. But in recent years people have begun taking large doses of specific vitamins to prevent illness—vitamin E to avoid heart disease, beta-carotene to prevent cancer, vitamin C to prevent or treat the common cold.

Most vitamin supplements aren’t dangerous in and of themselves, says Benjamin Caballero, a professor of human nutrition at the Bloomberg School of Public Health. Danger arises when you overdo it. “People who believe so much in the fact that a supplement will prevent a disease, or will prevent them from aging, take really massive doses,” Caballero says. “Instead of one capsule a day, they take five or eight.” At such high doses, vitamins can turn harmful.

Take vitamin C. It’s an essential nutrient that our bodies need for normal growth and development. It aids in tissue growth and repair, and it’s an antioxidant that blocks damage from free radicals. For years, vitamin C was promoted as the answer to the common cold. (Remember Airborne? It was originally marketed as a remedy to prevent colds until Airborne Inc. changed its tune after settling a multimillion-dollar class action suit for false claims. Now, the more general message, “Helps support your immune system,” graces the product’s packaging.) But not only are the benefits of megadoses of vitamin C unproven, such doses can do harm, says Caballero. “With vitamin C, where the recommendations are 75 milligrams a day, [some] people take five, six grams”—80 times the recommended dose—“and the famous Linus Pauling recommended they take 10 grams a day. And, clearly, if you take five to 10 grams of vitamin C every day, you have a much higher risk of having kidney stones, calcifications in your kidneys, or some other problem.”

Vitamin E, an antioxidant naturally found in nuts and vegetable oils, is another example. In recent years, vitamin E supplements containing megadoses of the nutrient have been purported to prevent heart disease and cancer. But in October, a large federal study revealed that not only are these supplements not effective in preventing prostate cancer, they were likely to increase cancer risk—men who took daily vitamin E supplements increased their risk of developing prostate cancer by 17 percent. Though researchers stopped the trial when they discovered this adverse effect, cancer cases kept increasing for several years after participants ceased taking the supplements.

The danger with supplements, says Caballero, is that it’s much easier to ingest a toxic amount of a vitamin by taking pills than by eating. For example, the National Institutes of Health Office of Dietary Supplements reports that vitamin E supplements contain anywhere from 100 to 1,000 IU per pill. You would have to eat more than four cups of almonds to get a mere 100 IU of vitamin E. (The recommended daily intake for adults is 22.4 IU.) Additionally, in developed nations like the United States, many foods are fortified. You already may be consuming more nutrients than you think.

It’s also tricky to define toxic levels. Maximum levels of nutrients haven’t been studied in depth because researchers can’t give people a known overdose just to see what will happen. It may also take a long time for adverse effects to appear. Instead, the Institute of Medicine specifies a recommended daily intake and an upper level (the maximum amount you can safely consume without adverse effects). Caballero notes, “For some nutrients, the distance between the recommended intake and the upper level is relatively narrow, maybe 4 times, 5 times. And with supplements and fortification one could potentially reach that.”

Regarding the most popular supplement, the daily multivitamin, Caballero says if you take only the recommended daily dose, it’s unlikely that you’ll get a toxic amount of any one nutrient, but it is likely a waste of money. Because in a pill you are taking all the nutrients at the same time, you are creating competition for absorption in your intestines, which diminishes the vitamins’ potency. “I don’t think it’s a danger, considering the doses of Centrum and all these typical multivitamin supplements. It’s just [producing] expensive urine,” he says. “However, you should not assume that taking supplements gives you a benefit that replaces having a healthy balanced diet and being active regularly. To reduce your risk of cardiovascular disease or diabetes, you need years and years of healthy diet and activity. Unfortunately, that’s the way it is.”

Soy—Miracle Food or Hazard?

Several years ago, its promoters touted soy as a miracle food, a low-fat, no-cholesterol source of protein. Researchers thought it might decrease breast cancer risk, minimize the effects of hot flashes, and increase bone density in women. Then came a “soy backlash” (as one reporter described it), with people saying that not only is soy not miraculous, it’s dangerous.

Soy foods are fine, but soy supplements bear watching, says Bruce Trock, SPH ’87 (PhD), director of the epidemiology division at the Brady Urological Institute. “None of the studies that have looked at just normal dietary consumption of soy foods have given any indication of risk,” says Trock. “So as long as people are trying to get their soy from the diet—eating things like tofu, soy milk, soy nuts, miso soup—I think it’s unlikely that they’re going to risk any harm from that. And there may be benefits.” A study presented at the American Association for Cancer Research earlier this year, which looked at data from more than 18,000 breast cancer survivors, concluded that women can eat soy foods without increasing their risk of cancer recurrence.

But soy supplements can be dangerous, Trock says, because a lot of them are highly processed, which might actually change the biological activity of the soy product. In several animal studies, soy supplements caused an increase in tumor growth; another study found that the more processed the soy product, the more it increased the growth rate of tumors in lab animals. And with supplements, it’s possible to get individual nutrients in very high amounts and in different proportions than you would get from eating soy foods. “There’s a reason these things are called micronutrients. They’re things that our bodies need in very small quantities. And they don’t just work singly, they work in combination, so often it’s not just the amount of an individual one that’s important, but the balance between several micronutrients,” Trock says.

D.I.Y. Dieting

Many Americans could afford to drop a few pounds, or a few dozen. The World Health Organization estimates that more than 70 percent of the U.S. population is overweight or obese, and heart disease accounts for 35 percent of deaths in the United States. Although some diet plans are so obviously not good for you as to be ludicrous—the Tapeworm Diet?—other approaches seem sensible yet could be doing harm.

One mistake is drastic, unsupervised dieting—a severe reduction of calories and fat. Eating less is one thing, says Larry Cheskin, director of the Johns Hopkins Weight Management Center at the Bloomberg School of Public Health, but “people who are dieting sometimes go to extremes. There are many people who would just starve themselves.” Gallstones are one complication from drastic weight loss and fat reduction. They happen when the gallbladder, the organ responsible for helping us digest and dispose of fat, doesn’t empty properly so that bile sits in it and starts to curdle (called “gallbladder stasis”). Although stasis usually is temporary and rarely results in gallbladder disease requiring an operation, gallstones can be painful. Following a very strict, no-fat diet and then bingeing on fatty foods can also cause gallstones. Cheskin says that for any patients trying to lose a significant amount of weight, he recommends that they take a little fat once a day (for example, nuts, salad dressing, or a piece of cheese) to stimulate the gallbladder.

Other short-term complications from drastic dieting—lightheadedness, headaches, and constipation—won’t cause permanent damage, Cheskin says. Once patients return to a higher-calorie diet, these symptoms should disappear. “I don’t want to give the impression that losing weight is too dangerous to do,” says Cheskin, adding that a proper, healthy diet plan approved by a doctor is the best way to avoid complications.

Got Milk? Got an Iron Deficiency?

“Cow’s milk is the ‘perfect food’ for baby calves.”

It’s an oft-quoted line, attributed to the late Frank Oski, former chairman of pediatrics at the School of Medicine and head of the Johns Hopkins Children’s Center. Oski drew the ire of the National Dairy Council with his 1983 book Don’t Drink the Milk, in which he claimed that milk not only causes intestinal discomfort among a large percentage of the world’s population, it might also trigger certain allergies and contribute to heart disease. “There really is no nutritional reason anyone should drink milk,” Oski said.

The evils of cow’s milk remain hotly contested, with some physicians—including the late Benjamin Spock—claiming that dairy products contribute to a variety of health problems while other experts defend the high calcium content and other benefits of cow’s milk. Although the jury remains out on dairy products, there’s no question that some parents are overreliant on cow’s milk as a food for young children, says Jennifer Anders, an assistant professor of pediatric emergency medicine at the School of Medicine. When toddlers make the switch from iron-fortified infant formula to cow’s milk, which contains negligible amounts of iron, they can develop iron-deficiency anemia. “If they don’t start eating a bunch of solid foods [that contain iron] and they just drink multiple bottles a day—and I’ve seen some that are drinking a gallon a day of cow’s milk—these children will be gorgeous, fat babies from a distance, but they get very pale, and they come in with extreme anemia. I have seen hemoglobin levels of 2 or 3 [compared to healthy levels of 11 or 12]. It’s almost inconceivable how they’re still alive with that small number of red blood cells and hemoglobin,” Anders says. In addition to lacking iron, cow’s milk causes irritation of the intestinal lining, so that a small amount of hemoglobin is chronically lost in the digestive tract, contributing to iron deficiency.

If left untreated, severe anemia can have serious complications, eventually leading to stunted growth and even heart failure. Anders says that because toddlers who drink a lot of cow’s milk generally look well-fed and healthy, anemia can be difficult to detect. “My experience has been that with most of these children, the parents don’t notice anything. The child looks pretty good—he’s chubby and happy and everything seems fine. It’s usually when they go for a checkup, or some person who hasn’t seen the child for a while sees him and remarks on how pale he is, that triggers its coming to [the parents’] attention.”

For now, the American Academy of Pediatrics hasn’t come down with a verdict for or against cow’s milk, though the general rule is moderation. To prevent iron-deficiency anemia, the AAP recommends that young children have a diet that includes iron-rich solid foods (such as meat, fish, and certain green vegetables); the AAP also states that children should not be given cow’s milk until they are at least 12 months old. If and when cow’s milk is introduced, it should be part of a healthy, balanced diet.

Reversing the Miracle of Antibiotics

Hailed as miracle drugs in the 1940s, antibiotics have indeed been saving lives for decades. Infections such as bacterial meningitis, strep throat, tuberculosis, pneumonia, and whooping cough that sickened and killed people years ago now can be treated with antibiotics. But overuse and misuse of these drugs have begun to reverse the miracle.

The American Academy of Pediatrics estimates that each year, U.S. physicians write 150 million prescriptions for antibiotics. This past April, the World Health Organization dedicated World Health Day to combating drug resistance, warning that continued improper application of antibiotics will exacerbate the problem of drug-resistant superbugs, bringing society back to pre-antibiotic days. “The world is on the brink of losing these miracle cures,” cautioned Margaret Chan, director-general for WHO. Without immediate action, she said, “the world is heading toward a post-antibiotic era, in which many common infections will no longer have a cure and, once again, kill unabated.”

As if that weren’t dire enough, superbugs aren’t the only concern, says Pranita Tamma, a pediatric infectious disease specialist at the Johns Hopkins Children’s Center. Prolonged exposure to antibiotics can lead to yeast infections, hearing loss, kidney and liver damage, or severe diarrhea from bacteria such as Clostridium difficile. In a study published earlier this year in Clinical Infectious Diseases, Tamma and her co-authors found that shortening the antibiotic courses for hospitalized children suffering from ventilator-associated tracheitis not only was effective in preventing pneumonia (a common concern for patients on ventilators), it decreased patients’ risk of infection by multidrug-resistant organisms. Although the study focused on hospital patients, Tamma says the same principles apply to antibiotic use outside the hospital, where most antibiotic use occurs.

Antibiotics are effective only against bacterial infections, not viruses. Tamma says that especially with children, it can be tricky to differentiate between the two. Physicians err not only by prescribing antibiotics when they’re not indicated but by prescribing courses that are too long. “It has become sort of a knee-jerk to prescribe antibiotics for a pretty long duration of time, without necessarily thinking about whether prolonged courses of therapy are actually necessary,” Tamma says. “For most infections there unfortunately have not been randomized controlled trials comparing different courses of therapy.” Another concern is the type of antibiotic being prescribed. The broader the spectrum, the more different types of bacteria the drug can kill, but also the more harmful it can be. For example, ear infections often recur in young children, sometimes requiring several courses of antibiotics, each drug stronger than the last. “What probably happened is the bacteria were hanging out before, saw the antibiotic, got resistant to that, and now you’re forced to escalate to a broader antibiotic,” Tamma says, adding that eventually, it might come to the point where there isn’t an antibiotic strong enough to eradicate the infection.

Despite the risks associated with misuse, Tamma says that patients shouldn’t be afraid of taking antibiotics when they’re warranted. “As an infectious disease doctor, I say of course they can do some wonderful things, and I prescribe them regularly,” Tamma says. “But I think the main message is we need to be careful. Even though they do have their benefits, there are definitely some toxicities associated with them if they’re not used wisely.”

Antibacterial Soap, the Overkill (Germ) Killer

“Wash your hands!” How many times did you hear this as a child, or tell your own children? One of the simplest ways to stay healthy is to practice good hand hygiene. In fact, according to the Centers for Disease Control and Prevention, hand hygiene is the single most important step health workers can take to prevent the spread of infection.

It seems to follow that the best way to get rid of germs is to use one of the myriad antibacterial hand soaps on the market. Not necessarily, says Athena Kourtis, SPH ’03 (MPH), a pediatric infectious disease specialist at the CDC and author of Keeping Your Child Healthy in a Germ-Filled World (Johns Hopkins University Press, 2011). As far as household use goes, there have been no studies proving that antibacterial soaps and cleaning products prevent infection better than plain soap, Kourtis says. “And that’s probably because most of the common infections in households are viral infections, and viruses will not be killed by antibacterial soaps.” These products might be doing more harm than good. Because antibacterial soaps are actually antibiotic, their overuse might promote the development of antibiotic-resistant germs—germs that could be transmitted to anyone. “Particularly with children who share toys and other objects in day care and school, where it has been shown that if one child carries in their throat, say, a germ that’s resistant to amoxicillin, then you found that even other children in day care who have not been exposed to the particular antibiotic also carry the resistant germ. So this is a problem that easily spreads across a community,” says Kourtis. “And there are other mechanisms as well. It’s not just person-to-person contact. These substances get into the water, into sewage systems, into the ground. It’s a wider community problem.”

Antibacterial cleaning products contain chemicals like triclosan and triclocarban, which kill bacteria. Plain soap, by comparison, is low-tech. It works by binding to dirt or other particles, making it easy to rinse these particles off with water without releasing problematic chemicals into the environment. (There has been concern recently that triclosan might become toxic when it comes into contact with sunlight, and triclocarban is a suspected carcinogen.) In situations where soap and water aren’t available, Kourtis advocates use of hand sanitizers. Many of these products contain alcohol, which makes them effective against bacteria and a variety of other microorganisms, including fungi and certain viruses such as influenza. Because sanitizers don’t contain antimicrobial ingredients like triclosan, they don’t contribute to antibiotic resistance, making them the CDC’s recommended choice for use by health care workers.

Read the Label

Over-the-counter medications seem ideal in so many ways—convenient, inexpensive, widely available, effective, and safe. And they are all of those things, provided consumers exercise the same care with dosage and frequency as they would with prescription medications. Ah, but too many people don’t exercise the same care, and they learn the hard way that OTC drugs can have some nasty side effects.

Take acetaminophen (Tylenol), for instance. Consumers tend to think of acetaminophen as one of the mildest of OTC medications. After all, it’s safe for infants, children, and pregnant or nursing women. But overdosing on acetaminophen is a leading cause of liver failure in the United States. “People don’t realize that there is a daily limit to how much Tylenol you can take,” says Marian Grant, Nurs ’00, ’05 (MSN), an adjunct faculty member at the School of Nursing and a nurse practitioner. One reason that people get into trouble is that acetaminophen is increasingly included in combination medications, such as OTC medicines like Nyquil and Tylenol PM, and in prescription drugs like Percocet and Lortab. So a patient with chronic arthritis, for example, who gets the flu might be taking Tylenol or Percocet during the day, Tylenol PM at night, and then Nyquil. Grant says, “You know, if you were to do that for several days, it might be too much if you’re a person who doesn’t have the greatest liver to begin with.”

Don’t go emptying your medicine cabinet—it isn’t that Tylenol is dangerous. “[Acetaminophen] is a safe medication when taken properly,” assures Grant. “In the old days when all you could get was Tylenol, that wasn’t a problem, but now that it’s in so many other things, there is a chance for people to inadvertently take too much acetaminophen.”

Another common over-the-counter medication that can lead to problems is ibuprofen, the active ingredient in pain relievers like Advil and Motrin, which can cause gastric distress and ulcers if not taken with food or when taken for too long. “The boxes warn you about that, but still I don’t know how many people take these medications with food in their stomachs,” Grant says. “If you have, say, an Achilles tendon problem and you take Motrin for weeks and you don’t take it the right way, or you’re just one of those people who’s predisposed to getting an ulcer, you could be causing yourself harm and often not even know about it. It’s not like you take the pill and an hour later you have stomach pain. It’s more subtle than that.”

Even a daily dose of baby aspirin—which only contains about a quarter of the dosage of an adult aspirin pill—can be dangerous for patients with clotting problems. “I know that the instructions are, ‘Talk to your doctor about this,’ but most people think, ‘Oh my God, it’s just a baby aspirin, I don’t have to talk to my doctor about that.’ But yes, actually, you do,” says Grant.

Grant adds that most patients don’t discuss over-the-counter medications with their health care providers—either because they don’t think of it, or because there are more pressing issues. “The average visit with a primary care provider is something like six to 10 minutes. If you have an elderly patient who has three chronic issues, you are not going to be spending that time minutely reviewing every medication,” she says. Grant recommends that patients talk to a pharmacist before purchasing an OTC medicine to get information about uses and possible interactions with other medications they’re taking. She’d also like to see more patients read the accompanying drug inserts before they start popping pills.

Natural, but Not Harmless

People take fish oil to reduce the risk of heart disease, ginkgo biloba to improve memory, flaxseed to lower cholesterol, and melatonin to help them sleep, believing that herbal or “natural” supplements must be safer than conventional medications because of the words used to describe them. Unfortunately, “herbal” or “natural” doesn’t always mean healthy—or safe—says Lori Edwards, SPH ’89, an instructor at the School of Nursing who teaches a course on complementary and alternative medicine. Edwards, although a self-described proponent of herbal products, stresses the importance of being cautious about them. Some supplements are safe and have proven clinical benefits. Others can be dangerous.

Kava, an herb used to treat insomnia and anxiety, is a prime example. It was linked to liver toxicity—including hepatitis, cirrhosis, and liver failure—in 25 cases in Europe, prompting the Food and Drug Administration to issue an advisory in 2002. (Kava is still available in the United States, but individuals with liver disease or who are otherwise at risk for liver problems are advised to consult a physician before taking it.) “There is this constant assumption that if it’s natural it’s OK,” Edwards says. “[People are] not questioning the potential interactions, the potential pathology of what they might be taking.”

A more recently popular supplement, red yeast rice, marketed as a traditional Chinese remedy for lowering cholesterol, was found to contain lovastatin, the active ingredient in the prescription drug Mevacor. Edwards says, “Red yeast rice was one I had concerns about because it actually is the same chemical component as the statins”—a class of drugs used to lower cholesterol, which, like many prescription drugs, can cause problems if not taken properly. (Several red yeast rice products were withdrawn from the U.S. market in 2007 after the FDA cited risk of severe muscle problems that could lead to kidney disease.) Some natural supplements that are safe in isolation can cause harmful interactions when mixed with other drugs. For example, cranberry, fish oil, and glucosamine might increase the effect of warfarin, a blood thinner; psyllium might decrease the effectiveness of digoxin, a heart medication; and St. John’s wort has been known to decrease the effectiveness of a number of different prescription drugs, including birth control pills and heart medications.

“The public I think still is not as savvy about this, and there are either the total skeptics or people who are not looking at this information carefully enough,” Edwards says. “And that’s my concern about why sometimes they may perceive it as being healthy, but without information it’s risky.”

New Wisdom about Childhood Allergies

Ten years ago, if a child had an allergy to milk or eggs, strict avoidance was considered the only remedy. Physicians believed that most children outgrew these allergies at an early age and that it was best to avoid all problem foods until then. But within the past five years, that wisdom has started to change. Whereas earlier studies showed that three-fourths of children outgrew their milk allergy by the age of 3, in 2007, a study conducted by the Johns Hopkins Children’s Center revealed that not even half outgrew the allergy by age 8. In a similar study of children with egg allergy, the Johns Hopkins researchers found that even fewer children (37 percent) outgrew their allergy by age 10. “We published a number of studies showing that fewer outgrow [milk and egg allergy] than we previously thought. And that the rate of outgrowing it was a lot slower than what was shown in some studies back in the 1980s,” says Robert Wood, professor of pediatric allergy and immunology at the School of Medicine and the lead investigator of the 2007 studies. Practicing strict avoidance gets trickier as children get older—they start school, they attend birthday parties, they spend time in the homes of friends. Opportunities for exposure multiply, which can be especially dangerous for children who have severe allergic reactions. With many children taking eight or 10 years to outgrow an allergy, the wait-and-see approach no longer seemed best. What’s more, says Wood, researchers wondered if avoidance—the very practice intended to help children outgrow food allergies—might have been contributing to the problem. “We’d actually become concerned that some of our data looked worse than it might have been because we were practicing only strict avoidance when we published these studies,” he says.

In the past several years, Wood says, researchers have begun taking a different tack with milk and egg allergies. New approaches, in which children are given foods containing milk or eggs that have been extensively heated (which breaks down the allergens sufficiently), have shown promise in helping some children build tolerance to those foods and outgrow the allergy more quickly. The new approach isn’t for everyone—between 25 and 50 percent of kids will have severe reactions even to the baked form of milk or eggs—but it’s represented a big change for others. “For the families who are doing this, it is sort of a life-changing concept because they go from reading every label on every loaf of bread or box of crackers, or fearing every birthday cake, to actually recognizing that their child is not at risk as long as that protein has been fully heated,” says Wood. “Literally 10 years ago, we didn’t recommend that anyone with milk or egg allergy eat that food because we thought that strict avoidance was the better way to outgrow a food allergy. In addition to making life so much easier, now it’s become more clear that having this exposure is much more likely to be beneficial than harmful.”

A Crunch, a Push-up, a Mile Too Far

Several years ago, a large group of gymnastics students in Taipei were asked by their instructor to do a fitness test—120 push-ups in five minutes. Two days later, 119 of those students went to the emergency department complaining of muscle pain and dark urine. The diagnosis: exercise-induced rhabdomyolysis, a condition that can occur when vigorous, repetitive exercise causes muscle fibers to break down, releasing myoglobin—the protein that makes up muscle cells—into the bloodstream. In some cases, it can result in temporary kidney damage (usually reversed by giving the patient fluids to help flush the myoglobin out of the kidneys). But in a small percentage of cases (5 to 7 percent), it can result in more severe complications, including arrhythmias and kidney failure.

Jennifer Anders, assistant professor of pediatric emergency medicine at the School of Medicine, says she sees patients with exercise-induced rhabdomyolysis about once every year or two. “Mostly it’s been with one particular exercise, like push-ups for an hour, or a thousand sit-ups. They’re trying to really push themselves past the limit.”

Many people have trouble getting enough exercise; overdoing it usually isn’t the problem. Although it’s rare, exercise-induced rhabdomyolysis can happen to anyone, even seasoned marathon runners and healthy teen athletes. “It’s really about doing something past the point when sensible people would stop,” says Anders. “The situations I’ve seen are where somebody is either being pushed by a coach or pushing themselves to impress a coach, where it’s just absurd even when they tell the story—‘I was doing push-ups for an hour and a half!’”

When rhabdomyolysis is exercise induced, it usually doesn’t cause lasting damage, Anders says. “We mainly just give them a lot of IV fluid, give them enough hydration so their kidneys don’t get overburdened with myoglobin. Really once you get plenty of hydration into them and a day to rest, they’ll be back home. And then they’re going to have to rest until their muscles are much more recovered, probably a week or two until they’re back to any kind of athletic [activity].” Those gymnastics students in Taipei? Because their rhabdomyolysis was caught early, none of the students developed kidney failure and all were discharged from the hospital after receiving fluids and getting some rest.

Kristen Intlekofer is assistant editor of Johns Hopkins Magazine.