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  • Writer's pictureMoe | Scarlet Plus

5 Common Health Myths Debunked by Your Family Doctor

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Health and wellness advice floods our feeds daily, and while some of it can be invaluable, some can be misleading or outright false. To help set the record straight, we've consulted with a family doctor to debunk five common health myths that might be steering you wrong. Here's what your trusted family physician wants you to know:

On this page:


Myth 1: You Need to Drink Eight Glasses of Water a Day

The Reality: The widespread recommendation to drink eight glasses of water a day is more of a guideline than a strict rule applicable to everyone. Hydration needs can vary greatly depending on individual factors such as age, sex, weight, climate, and level of physical activity. Additionally, people get a significant amount of their daily water intake from other sources besides plain water, including food and other beverages like tea, coffee, and juices.

It’s important to understand that the body’s hydration needs are dynamically regulated by the kidneys, and the sensation of thirst is a sophisticated mechanism designed to prevent dehydration. So, instead of adhering to a rigid rule of eight glasses a day, a more effective approach is to drink when you feel thirsty and to observe the color of your urine — if it’s pale and clear, it generally means you are well-hydrated.

Further Insights:

  • Activity Level and Climate: For those who are active or live in hotter climates, the body will require more fluids to compensate for increased sweat loss. In these cases, maintaining hydration might mean consuming more than the standard eight glasses.

  • Dietary Contributions: Many fruits and vegetables, like watermelon, cucumbers, oranges, and lettuce, are over 90% water by weight. Including these in your diet can significantly contribute to your daily water intake.

  • Health Conditions: Certain health conditions, such as diabetes or heart disease, may require adjustments in fluid intake as prescribed by healthcare professionals. Likewise, medications may alter fluid needs due to their diuretic effects or other side effects impacting hydration.


Myth 2: Cracking Your Knuckles Leads to Arthritis

The Reality: The longstanding belief that cracking your knuckles can lead to arthritis is not supported by scientific research. The sound you hear when you crack your knuckles is caused by the popping of gas bubbles that form in the fluid surrounding the joints, a process known as cavitation. This action does not cause joint damage, inflammation, or increase the risk of arthritis.

Deeper Dive into the Science:

  • Research Findings: Several studies have investigated the relationship between knuckle cracking and arthritis, notably a study published in the Journal of the American Board of Family Medicine which found no significant difference in the incidence of arthritis between habitual knuckle crackers and individuals who do not crack their knuckles.

  • Joint Health: While habitual knuckle cracking has not been shown to cause arthritis, there is some evidence suggesting that it can lead to other forms of joint strain or swelling in some people. However, these effects are generally mild and temporary.

Additional Considerations:

  • Grip Strength: Some research suggests that habitual knuckle cracking may be associated with a decrease in grip strength over time. While these findings are not conclusive, they suggest that there might be some drawbacks to frequent knuckle cracking.

  • Psychological Effects: For some, knuckle cracking is a nervous habit that can be annoying to others around them. In social or professional settings, it might be considered impolite or distracting.

  • Listening to Your Body: If cracking your knuckles causes pain or discomfort, it's a good idea to refrain from doing it. Pain can be an indication of underlying issues that need to be addressed, such as joint misalignment or damage.


Myth 3: Reading in Dim Light Ruins Your Eyesight

The Reality: Contrary to popular belief, reading in dim light does not cause permanent damage to your eyesight. This myth has persisted for generations, likely because reading in poorly lit conditions can lead to eye strain, which might make people think it is harming their vision. However, while it can cause temporary discomfort, there is no scientific evidence to suggest that it can result in lasting eye damage.

Understanding Eye Strain:

  • Symptoms: Eye strain from reading in dim light can include dryness, sore or irritated eyes, and temporary difficulty focusing. These symptoms are usually temporary and should alleviate once proper lighting is restored or after giving your eyes a rest.

  • Mechanism: In dim lighting, the eyes have to work harder to focus, which can tire the muscles in and around the eyes, leading to the symptoms mentioned above.

Additional Insights:

  • Long-Term Effects: Although reading in low light does not cause permanent damage, consistent eye strain over time can lead to general discomfort and might exacerbate existing eye conditions. Therefore, it’s still important to take measures to prevent eye strain.

  • Proper Lighting Solutions: To make reading more comfortable, use a directed reading light. This type of lighting provides direct illumination on the reading material without creating glare, helping to reduce the strain on your eyes.

  • Taking Breaks: The 20-20-20 rule is helpful to reduce eye strain: every 20 minutes, look at something 20 feet away for at least 20 seconds. This practice helps reset your focus and gives your eye muscles a necessary break.

Health and Reading Habits:

  • Adjustable Lighting: Consider adjustable lighting solutions where you can change the brightness to suit different times of the day and various activities. This adaptability can significantly enhance visual comfort.

  • Digital Screens: If you're reading from a screen, use features like "night mode" or blue light filters in the evening to reduce blue light exposure, which can interfere with sleep patterns.

  • Regular Eye Exams: Regular check-ups with an eye care professional are essential, especially if you frequently experience eye strain. They can provide personalized recommendations based on the health of your eyes and your visual needs.


Myth 4: Eating Carrots Improves Your Vision

The Reality: The idea that eating carrots improves your vision, especially in dim light, is rooted in truth but often misunderstood. Carrots are rich in beta-carotene, a type of vitamin A, which is crucial for maintaining healthy eyesight. Vitamin A helps the retina function smoothly and is essential for night vision. However, eating carrots in excess will not grant you superhuman eyesight or correct vision impairments like nearsightedness or astigmatism.

The Origin of the Myth:

  • Historical Context: This myth was popularized during World War II. The British government propagated the idea that their pilots had superior night vision because of their high-carrot diet. This was actually a cover story to conceal their use of radar technologies from the enemy.

Expanding on the Benefits of Vitamin A:

  • Preventing Deficiency: Vitamin A deficiency is a major cause of preventable blindness in children worldwide. Ensuring an adequate intake of vitamin A can prevent night blindness and preserve eyesight, but it doesn't improve vision beyond normal levels.

  • Overall Eye Health: While carrots contribute to overall eye health by providing vitamin A, other nutrients also play a crucial role. For instance, lutein and zeaxanthin, found in leafy greens and eggs, can protect against cataract and age-related macular degeneration.

Additional Insights:

  • Balanced Diet for Eye Health: To truly support eye health, a well-rounded diet is necessary. This includes not only carrots but also other fruits and vegetables that are rich in antioxidants and vitamins. Foods like blueberries, sweet potatoes, and fish rich in omega-3 fatty acids are also excellent for maintaining eye health.

  • Limitations of Diet Alone: While a healthy diet can prevent or delay the onset of certain eye conditions, it cannot correct optical issues such as myopia or astigmatism. These conditions are typically genetic and require optical correction (glasses, contact lenses) or surgical treatment.

  • Nutritional Supplements: If dietary intake is not sufficient, or if you're at risk for macular degeneration, nutritional supplements specifically formulated for eye health may be beneficial. These often contain a mix of vitamins C and E, zinc, lutein, and omega-3 fatty acids.

Practical Advice:

  • Regular Eye Exams: Along with maintaining a balanced diet, regular eye exams are crucial to monitor eye health, detect issues early, and manage any existing conditions effectively.

  • Awareness of Symptoms: Pay attention to any changes in your vision, such as difficulty seeing at night or blurry vision, and consult an eye care professional if these occur. Early detection is key in managing and treating eye health issues.


Myth 5: You Must Wait an Hour After Eating to Swim

The Reality: The old advice that you should wait an hour after eating before swimming is based on the assumption that digestive processes could divert blood from the muscles to the stomach, potentially leading to muscle cramps or drowning. However, medical evidence does not support this caution. There is no direct link between eating and experiencing cramps while swimming, making this more of a cautionary tale than a medical necessity.

Breaking Down the Myth:

  • Digestion and Blood Flow: While it's true that digestion increases blood flow to the stomach, the human body is capable of supplying enough blood to both the digestive system and muscle tissues during swimming. For most people, swimming after eating does not pose a significant risk of cramps or discomfort.

  • Actual Risks: The real risk of swimming too soon after eating is more about comfort than safety. Some people might experience indigestion, bloating, or mild discomfort if they engage in vigorous swimming right after a large meal.

Additional Insights:

  • Listen to Your Body: It's important to be attentive to how your body feels. If you generally feel fine swimming after eating, it's likely safe for you to do so. However, if you notice discomfort when swimming post-meal, giving yourself more time to digest might be beneficial.

  • Type of Activity: The intensity of the activity should also be considered. Leisurely swimming might not require as much caution as competitive swimming or diving, where intense exertion is more likely to cause discomfort if done soon after eating.

  • Age and Health Factors: Young children and individuals with certain health conditions might have different sensitivities or digestive capacities. Parents and caregivers should monitor how swimming after eating affects their child or dependent and use discretion based on individual responses.

Practical Advice:

  • Moderation in Meals: If you plan to swim and it coincides with meal times, opt for a lighter meal or a snack that is easier to digest. Foods high in carbohydrates and low in fat and protein can be digested more easily and are less likely to cause discomfort.

  • Hydration: Ensure you're well-hydrated before going swimming, as dehydration is more likely to cause cramps than eating.

  • Observing Effects: Keep an eye on how different foods affect your comfort and performance in the water, and adjust your eating habits accordingly before swimming.



When it comes to health advice, it’s essential to check the facts rather than simply following common beliefs. Always consider advice from healthcare professionals over folklore or anecdotal evidence. If you have concerns about your health or habits, discussing them with your family doctor is the best course of action. This way, you ensure that the health decisions you make are informed and tailored to your personal needs.


Looking for a family doctor?

At Charis Medical Center, we believe in providing personalized, compassionate care for every member of your family. Our dedicated team is here to support your health journey with comprehensive services tailored to meet the holistic needs of your loved ones.



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