11 Controversial Medical Theories That Are Actually True

Updated: Jun. 27, 2018

Find out the truth behind health theories the medical community once claimed were false.

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Adults can grow new brain cells

Most scientists in the 1960s believed the brain peaked in adulthood and stopped making new brain cells, scoffing at a study that suggested otherwise. Once stem cell research took off, though, researchers realized adult brains could keep growing. By the 1990s, adult neurogenesis—producing new brain cells after age 20 or so—was generally accepted. These are 50 myths about the human body that could seriously damage your health.

Magnetic resonance scan of the brain. MRI head scan. Medicine, science

Football can cause brain injury

When a major company like the NFL doesn’t want a story out, it will try its darndest to keep the evidence hush-hush. So when forensic pathologist Bennet Omalu, MD, pinned pro football player Mike Webster’s death on football-related brain damage in 2002, the response was a stubborn “no way.” It took seven years, but the NFL finally acknowledged the link between its players’ concussions and brain damage, earning Dr. Omalu the American Medical Association’s highest honor, not to mention a movie about him: Concussion.

injecting injection vaccine vaccination medicine flu man doctor insulin health drug influenza concept - stock image

Vaccines do not cause autism

Thanks to a researcher who led a couple studies in 1998 and 2002 linking the measles, mumps, and rubella vaccine to autism, parents became concerned that vaccinating their kids could open the door to autism. The problem is, both of those papers have since been shown to be critically flawed, and numerous studies since have discredited the link. The CDC assures those concerned that vaccines are very safe (not to mention protective) and won’t raise risk of autism. Learn the truth behind 15 more health myths that make doctors cringe.

Hand Holds Petri Dish with Bacteria Culture
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Bacteria produce ulcers

Australian physicians Robin Warren, AC, and Barry Marshall, AC, identified the link between Helicobacter pylori and ulcers in 1982, but the medical community maintained that the causes were stress and diet for years. Eventually, Dr. Marshall drank a Petri dish of bacteria (and ended up with an ulcer) to back up their theory. In the mid-1990s, the NIH acknowledged the connection, and Marshall and Warren earned a 2005 Nobel Peace prize for their efforts.

White pills (tablets) background. Medicine objects.

Aspirin lowers heart attack risk

A California physician named Lawrence Craven first published research showing aspirin’s anti-clogging effect back in 1950, but his practice of prescribing an aspirin a day to keep heart disease away wasn’t widely adopted until about 40 years later.

Doctors consider and discuss magnetic resonance image (MRI) of the brain. Back view, selective focus

Radiation can be harmful

Research linking X-rays to leukemia and other cancers was published in 1911, but X-rays, used everywhere from doctors’ offices to shoe stores (yes, really!) were generally considered safe until the National Academy of Sciences issued a report condemning these practices (including use in pregnant women) in 1956. Not that people necessarily know their health better now—here are the 20 worst pieces of health advice on the Internet.

Medical equipment. microscope. Background.test sample under the microscope in laboratory.

A virus causes cervical cancer

In the late 1970s, German virologist Harald zur Hausen published research suggesting that the human papillomavirus causes cervical cancer. Many scientists mocked his claim, but in 2008 he won the Nobel Prize for his research—and children today are routinely vaccinated against HPV.

Close up of Chicken eggs,Close of package with eggs ,Eggs in tray, Pack of hen eggs

Eggs don’t raise cholesterol

For years, doctors believed dietary cholesterol (which eggs are high in) would raise cholesterol levels in the body and increase risk of heart problems. Common sense would agree, but the science doesn’t. In 2013, an American Heart Association report confirmed there’s not enough evidence to claim high-cholesterol diets directly raise “bad” LDL cholesterol. But there is a catch: Saturated and trans fats do raise cholesterol, and those foods tend to be high in cholesterol. A lack of evidence doesn’t necessarily mean we won’t find a link later, though, so anyone concerned about their cholesterol might still want to watch their cholesterol consumption. Don’t believe these other 21 wildly untrue food myths.

Close up shot of human hand holding white transparent tube with some liquid inside.

Some proteins cause disease

Most diseases come from bacteria, viruses, fungi, or parasites, so there was understandable criticism when neurologist Stanley Prusiner, MD, claimed in 1982 that certain proteins called “prions” could make people sick. Over the course of the decade, more evidence emerged, and the tide turned when scientists discovered in 1996 that prions caused mad cow disease. Dr. Prusiner won a Nobel Peace prize the next year. Check out these other 14 health myths even doctors believe.

Medical Stethoscope with pencil and book
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Immunotherapy can treat cancer

In the 1970s, the idea of boosting the body’s own immune system to kick cancer seemed totally outlandish to most doctors, who didn’t think the immune system would respond to cancer. Pharmaceutical companies weren’t interested in pursuing the idea either. Finally in 2010 and 2011, human trials demonstrated that boosting certain white blood cells could stop and even shrink tumors. Now some of the biggest advancements in cancer treatment are related to immunology. Here are 50 more cancer myths people still believe.

The rest of cigarettes in the ashtray. There are many types of cigarette stub on the sand in the ashtray. A cigarette is not good for health. It is not allow to smoking in the public area in Thailand.
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Smoking gives you lung cancer

The first studies connecting smoking to lung cancer came out as early as 1939, but many doctors contended that cancer was largely due to other factors such as air pollution until the early 1960s. Before that, they often actually encouraged smoking in patients for stress-relief purposes. Don’t fall for these 55 health myths that just won’t go away.

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Originally Published in Reader's Digest