Myths debunked #1

Changing minds is no small feat—especially when it comes to medical myths that have been passed down like family heirlooms. Let’s be honest, it takes more than one article (or even ten) to shift long-held beliefs, and sometimes facts alone aren’t enough to break through. But that’s okay. The goal here isn’t to win arguments; it’s to encourage curiosity, critical thinking, and a little humility. So as you dive into this article, try to stay open-minded—even if it means rethinking something you’ve believed for years. After all, real progress starts with the willingness to question what we think we know.

Myth 1: You must drink eight glasses of water a day.

The Belief: For decades, the "8 glasses per day rule" has been the go-to advice for hydration.

The Scientific Truth: This is a one-size-fits-all recommendation that isn't based on solid scientific evidence. Your body's need for water is highly individual and depends on your age, activity level, climate, and overall health.

The Evidence: The National Academy of Medicine suggests an adequate daily fluid intake of about 3.7 liters (15.5 cups) for men and 2.7 liters (11.5 cups) for women. Crucially, this is total fluid intake—it includes water from all beverages (like coffee, tea, and juice) and even from the food you eat (fruits and vegetables are high in water content). Your body has an excellent built-in indicator: thirst. For most healthy people, drinking when you feel thirsty is a reliable way to stay hydrated.

Myth 2: Cracking your knuckles will give you arthritis.

The Belief: That popping sound must be damaging your joints, leading to arthritis down the line.

The Scientific Truth: The sound is not from bones grinding together. It’s caused by the bursting of nitrogen gas bubbles that form in the synovial fluid, the natural lubricant in your joints.

The Evidence: A landmark study involved a physician who cracked the knuckles on his left hand every day for 60 years but never on his right. X-rays taken at the end of this period showed no signs of arthritis in either hand. Larger observational studies have consistently failed to find any credible link between the habit of knuckle-cracking and the development of osteoarthritis. While it might annoy those around you, it’s not damaging your joints.

Myth 3: We only use 10% of our brains.

The Belief: This popular myth suggests that 90% of our brain lies dormant, holding untapped potential.

The Scientific Truth: This is one of the most persistent myths about the human body. Modern brain imaging technologies, such as functional MRI (fMRI) and Positron Emission Tomography (PET) scans, clearly show that we use virtually every part of our brain, even when we are resting or sleeping.

The Evidence: Neurologists confirm that activity can be seen across the entire brain throughout the day. Different tasks activate different regions more intensely, but there are no unused areas. Even minor brain damage can have severe consequences, which wouldn't be the case if we had 90% of it in reserve.

Myth 4: Getting cold or wet will give you a common cold.

The Belief: Your parents probably told you to wear a jacket so you wouldn't catch a cold.

The Scientific Truth: The common cold is caused by viruses (most commonly rhinoviruses), not by exposure to cold temperatures. You can only get sick if you are exposed to one of these viruses.

The Evidence: The reason infection rates rise in the winter is likely because people spend more time indoors, in closer contact with one another, which facilitates the spread of viruses. Controlled studies have directly tested this theory by exposing volunteers to cold viruses and then placing some in cold environments. The chilled participants were no more likely to develop a cold than those who remained warm.

Myth 5: "Natural" sugars like honey are healthier than regular sugar.

The Belief: Because it comes from nature, honey or maple syrup must be a healthier choice than processed table sugar.

The Scientific Truth: Your body metabolizes the sugar in honey and table sugar in a very similar way. Both are composed of glucose and fructose. While honey contains trace amounts of antioxidants and nutrients, they are not present in significant enough quantities to make it a "health food."

The Evidence: From a chemical standpoint, table sugar (sucrose) is a molecule made of 50% fructose and 50% glucose. Honey is a mixture of the same simple sugars, typically in a ratio of about 40% fructose and 30% glucose. Your body treats them as what they are: added sugars. The American Heart Association advises limiting all forms of added sugar, regardless of their source.

Myth 6: Eating late at night causes weight gain.

The Belief: Calories consumed after a certain time (e.g., 8 PM) are more likely to be stored as fat.

The Scientific Truth: Weight gain is determined by your overall energy balance across 24 hours: TotalCaloriesConsumed−TotalCaloriesBurned. It doesn't matter when you consume the calories, but rather how many you consume in total.

The Evidence: The association between late-night eating and weight gain often exists because evening meals or snacks tend to be higher in calories and are often eaten mindlessly while watching TV. Controlled scientific studies that match total daily calorie intake between groups show no significant difference in weight loss or gain based on meal timing alone.

Myth 7: You need to do a "detox" or "cleanse" to remove toxins.

The Belief: Special diets, juices, or supplements are needed to flush harmful toxins out of your system.

The Scientific Truth: Your body has its own highly efficient, built-in detoxification system. Your liver, kidneys, lungs, skin, and digestive system work around the clock to filter your blood and eliminate waste products and harmful substances.

The Evidence: There is no scientific evidence to support the claim that commercial detox products provide any benefit. In fact, the term "toxin" is often used vaguely in this context. Medical professionals caution that these cleanses can be unnecessary and sometimes harmful, leading to dehydration, electrolyte imbalances, and nutrient deficiencies. The best way to support your body's natural processes is to drink enough water, eat a balanced diet, and limit your intake of alcohol and processed foods.

Myth 8: Healthy adults need a daily multivitamin.

The Belief: A daily multivitamin is a necessary insurance policy for good health.

The Scientific Truth: For the average healthy person who eats a reasonably balanced diet, a multivitamin is likely unnecessary. It is far better to get your nutrients from whole foods.

The Evidence: Major reviews of scientific literature, including findings from the U.S. Preventive Services Task Force, have concluded there is insufficient evidence that taking multivitamins prevents chronic diseases like cancer or heart disease in most healthy adults. Supplements are crucial for people with diagnosed deficiencies or for specific populations (e.g., folic acid for those planning pregnancy, vitamin D for people with limited sun exposure, or vitamin B12 for strict vegans), but they are not a substitute for a healthy diet.