Busting Myths About Immunity
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Does this sound like something from your childhood: It’s chilly outside, and you’re making a beeline for the front door – without your coat, of course, because you’re a kid who wants to hurry and meet up with your neighborhood pals. A parent spots you and shouts the familiar refrain: “Don’t forget your jacket! You’ll catch a cold!”
If so, you’re not alone. Parents have been passing down this advice for generations. But as it turns out, Mom and Dad weren’t always right. How and why we get sick is a bit more complicated. And at the heart of it is the immune system.
The immune system is a complex network of tissues, cells, and proteins that identify harmful invaders, such as viruses, bad bacteria, and cancerous cells. When it comes across these invaders, it releases antibodies to weaken and destroy them.1,2
In all fairness to Mom and Dad, the immune system and how it functions is not easily understood, so it can be hard to separate fact from fiction. Here are five myths you might have heard about immunity and the truth behind them.
1. You’ll catch a cold from the cold.
Can you catch a cold from cold temperatures? Long story short: No. Viruses make you sick, not the weather.
Not wearing a coat or going outside with wet hair during the winter doesn't make you more attractive to germs. It may seem this way because viruses spread more easily when it's cold outside. However, that's because when it's cold, more people spend time inside in close contact with others, which is perfect for spreading illness. And cold, dry air is the ideal environment for viruses to survive – typically rhinoviruses, which cause the common cold.
Most germs enter through the nose, where the temperature is a few degrees lower than the rest of the body’s usual 98.6 degrees Fahrenheit. This lower temp makes it easier for viruses to reproduce than when they enter through the lungs.3-5
To stave off viruses, wash your hands regularly, don’t share utensils or drinking glasses, and avoid close contact with someone who is ill.4
2. Starve a fever; feed a cold.
Although the rationale behind this adage is a bit murky, the belief might have been that eating when your temperature was high would make it go higher, so fasting was recommended. On the other hand, eating when you had a cold would warm you up.6
When you’re sick, you might not feel like eating. And that’s okay. Staying hydrated is the most important thing to consider. But don’t avoid eating, either. Your body is trying to heal itself and will use the food you eat as energy to do so. Incidentally, there is some truth behind eating chicken noodle soup when you're sick. Sipping on warm liquids such as chicken soup helps thin mucus and eases congestion. Chicken soup might have modest anti-inflammatory properties, too.4,7,8
3. Exercise weakens your immune system.
Regular, moderate physical activity is linked to a lower risk of both contagious and non-contagious diseases, including viral and bacterial infections, heart disease, and cancer. Research suggests exercise improves the immune system’s ability to identify viruses and other invaders. It also increases circulating white blood cells and anti-inflammatory substances that fight pathogens and make the immune system function more effectively.1,9
To ensure you receive the optimal immune benefits from exercise, take enough time between workouts to rest. Although moderate exercise can benefit the immune system, more intense exercise – such as running a marathon – appears to temporarily suppress immunity.9
4. Handwashing kills viruses.
Handwashing helps keep viruses from making you sick. But it doesn’t kill them. Lathering up with soap and water for 20 seconds forms pockets called micelles, which trap and remove germs. When you rinse your hands, you’re washing away dirt, viruses, and other substances that cause illness or infection.10,11
Experts say washing with soap and water is more effective than using hand sanitizers, particularly when removing common illness-causing germs. To be most effective, it’s important to wash your hands for 20 seconds first to remove dirt and grime. Then a hand sanitizer can complete the job by inactivating any remaining germs, keeping them from spreading and making you ill. However, they don't protect against all viruses and are only effective when used correctly. A hand sanitizer is often used too sparingly or wiped off before it has had time to dry.10-12
If soap and water aren't available, then properly applied hand sanitizer containing between 60 and 95 percent alcohol is a reasonable alternative. And in case you were wondering about another myth, hand sanitizers do not contribute to antibiotic resistance.10,11
5. Bacteria are bad for your immune system
There are, of course, harmful bacteria. Many disease-causing bacteria produce toxins – powerful chemicals that damage cells and make you ill. Other bacteria can directly invade and damage tissues. Some infections caused by bacteria include strep throat, tuberculosis, and urinary tract infections.13
But not all bacteria are harmful, and some bacteria that live in your body are helpful. For instance, Lactobacillus acidophilus – a harmless bacterium that resides in your intestines – helps you digest food, destroys some disease-causing organisms, and provides nutrients. In fact, many of the body’s beneficial bacteria reside in the digestive system – an environment called the gut microbiome.13
A crucial component of helping your gut bacteria support your immune system is to keep the gut microbiome balanced with prebiotics and probiotics. Prebiotics help the microbes already in your microbiome by giving them the foods they like. Prebiotics are found in many fruits and vegetables containing complex carbohydrates, such as fiber.14
Probiotics add living microbes directly to your microbiome to support the balance of beneficial microorganisms. The most common type of probiotic food is yogurt. Certain cheeses, kombucha, kimchi, pickles, and sauerkraut are other bacteria-fermented foods containing probiotics.14
Now that you know what doesn’t impact your immune system, you can focus on ways to support it. Eating well, getting adequate sleep – at least seven hours for adults – exercising, and working on healthy coping mechanisms for stress can all help keep your immune system in tip-top shape.3
A word from Thorne
In addition to adequate sleep, a healthy diet, and moderate exercise, there are several nutritional supplements that can support immune function, including zinc, vitamins C and D, quercetin, and pre- and probiotics.*
References
- Understanding immune system health. Mayo Clinic Health Letter. https://www.mayoclinic.org/~/media/80569BAD2DF84A7394895F041D2726C5.pdf. [Accessed July 1, 2023]
- Vaccines protect you. U.S. Department of Health and Human Services. https://www.hhs.gov/immunization/basics/work/prevention/index.html. [Accessed July 1, 2023]
- Can the cold really make you sick? American Heart Association. https://www.heart.org/en/news/2021/12/17/can-the-cold-really-make-you-sick. [Accessed July 1, 2023]
- Mayo Clinic Q&A: Myths about catching a cold. Mayo Clinic. https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-q-and-a-myths-about-catching-a-cold. [Accessed July 1, 2023]
- Foxman EF, Storer JA, Fitzgerald ME, et al. Temperature-dependent innate defense against the common cold virus limits viral replication at warm temperature in mouse airway cells. Proc Natl Acad Sci USA 2015;20;112(3):827-832.
- Fact or fiction? Feed a cold, starve a fever. Scientific American. https://www.scientificamerican.com/article/fact-or-fiction-feed-a-cold/. [Accessed July 1, 2023]
- Cold remedies: What works, what doesn’t, what can’t hurt. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/common-cold/in-depth/cold-remedies/art-20046403. [Accessed July 1, 2023]
- Home remedies: a case of the common cold. Mayo Clinic. https://newsnetwork.mayoclinic.org/discussion/home-remedies-a-case-of-the-common-cold/. [Accessed July 1, 2023]
- Nieman DC, Wentz LM. The compelling link between physical activity and the body's defense system. J Sport Health Sci 2019;8(3):201-217.
- Frequent questions about hand hygiene. Centers for Disease Control and Prevention. https://www.cdc.gov/handwashing/faqs.html. [Accessed July 1, 2023]
- Show me the science – when and how to use hand sanitizer in community settings. https://www.cdc.gov/handwashing/show-me-the-science-hand-sanitizer.html. [Accessed July 1, 2023]
- Coronavirus disease (COVID-19) advice for the public: Mythbusters. https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public/myth-busters. [Accessed July 1, 2023]
- Germs: Understand and protect against bacteria, viruses and infections. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/infectious-diseases/in-depth/germs/art-20045289. [Accessed July 1, 2023]
- Good bacteria for your gut. Mayo Clinic. https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/good-bacteria-for-your-gut. [Accessed July 1, 2023]