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10 Habits That Weaken Your Immune System

Stay healthy during the coronavirus and beyond with this essential advice from a doctor.

Habits are those little things you just can't help doing every day. If we're honest, we all have them. They're things we seem to do without thinking—even though we know some are bad for us. No matter how hard we try—we can't seem to stop.

So which habits might be dangerous in this time of COVID-19? What might we be doing which could weaken our immune system? As a doctor, I've been asked this many times recently. Read on and you might discover a few surprises.

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Virus or No Virus, You Need to Wash Your Hands Consistently

Basic protective measures against new coronavirus. Wash hands, use medical mask and gloves. Avoid touching eyes, nose and mouth. Maintain social distancing. Wash your hands frequently

Although not washing your hands isn't exactly weakening your immune system, if you are not washing your hands frequently, you are constantly challenging your immune system more than is necessary. This is important to mention because, during the COVID-19 pandemic, we should all have firmly grasped the health message about the importance of regular hand washing. 

The Rx: Regularly washing your hands will help preserve your immune function until you really need it. Do it after going outside, doing the laundry, handling your pets, and to stay safe during this time of COVID-19, don't make these Hand-Washing Mistakes That Help Coronavirus Spread.


You Bite Your Nails

impatient girl nail-biting while she waits for a call or an answer to her chat or sms during her breakfast

How can biting your nails weaken your immune system? Besides you potentially getting sick from the grime under your nails? Anxiety, stress and other mental health conditions are often the cause. Those who bite their nails often pull their hair and pick their skin. 30% also bite their toenails! 

Chronic stress results in dysregulation of the immune system. When we are stressed or anxious, the sympathetic nervous system goes into overdrive, with an outpouring of adrenaline. Cortisol levels increase. This then leads to the release of cytokines—these are the cells signaling the immune response—and results in chronic systemic inflammation, also suppressing some aspects of immune function.

The Rx: Try to deal with your anxiety in other ways—exercise, meditation, etc.—and think about how you could stop biting your nails. Now would be an excellent time to get started and give your immune system a boost too!


You Get Less Sleep Than You Need

woman sleeps in bed

Are you an insomniac? If this is you, this will undoubtedly not be helping your immune system. When sleep deprivation becomes chronic, it is associated with metabolic syndrome, a group of conditions that increase the risk of heart disease, stroke, and diabetes, and also harms the cells that make up your immune system.

The Rx: Adults are recommended 7-9 hours of sleep per night. To get your 40 winks, don't miss this special report: 30 Ways to Guarantee a Good Night's Sleep.


You Have Poor Dental Hygiene

man isolated on gray background touching his face and closing eyes with expression of horrible suffer from health problem and aching tooth, showing dissatisfaction

The link between good oral health and general health is now well established. However, it may not seem immediately obvious that by forgetting to clean your teeth you are not doing your immune system any favors.

Not brushing and flossing your teeth regularly is associated with the development of gum disease—gingivitis and periodontal disease. Bacteria grow in little pockets in your gums, around the base of your teeth. This causes an inflammatory reaction, which then becomes longstanding—chronic systemic inflammation. This means your immune system is working overtime when it should be resting, which has many negative consequences. 

The Rx: It's so important to clean your teeth twice a day with fluoride toothpaste and to floss regularly and see the dental hygienist. This will help support not just your teeth—but your immune system too. 


You're Burping a Lot

Woman Feeling Nauseous

Around 20% of Americans suffer from heartburn at least once a week. However, although burping is a common occurrence, many people don't realize that this is an important medical symptom. 

Burping suggests the presence of gastroesophageal reflux (GERD). This happens when acid produced in the stomach passes the wrong way—up into the lower end of your esophagus (throat). You need to think about why this might be happening to you. 

The Rx: Are you eating a poor diet?— junk food, fatty foods, fried foods? Are you lacking fresh foods and essential nutrients in your diet? Could this be due to stress? Or to food sensitivities?

If you suffer from GERD, there are many ways this could be challenging your immune system and damaging your immune response. Go back to basics and think about the possible cause. If you stop drinking, lose weight and eat a healthy diet, this will work wonders to improve your immune system.


You're Drinking Too Much Alcohol

Man relaxing with bourbon whiskey drink alcoholic beverage in hand and using mobile smartphone

There is now a good deal of medical evidence to support the relationship between excess alcohol intake and various medical conditions, one of which, highly relevant in the midst of the COVID-19 pandemic, is Acute Respiratory Distress Syndrome (ARDS).

Alcohol damages the barrier function of the gut, by creating a "leaky" gut wall, allowing increased numbers of pathogenic bacteria to enter the blood circulation. These micro-organisms pass directly to the liver, causing liver inflammation. Too much alcohol also alters the gut microbiome.

Alcohol affects the lungs too—it damages the cilia in the upper airways, meaning your body is less able to expel any invading organisms. It also damages cells lining the lower airways.

The Rx: The effect of alcohol on the immune function itself is complex. However, to help your immune system, and not hinder it, now is the time to reduce your alcohol intake or stop drinking altogether.


You Eat Too Much Fast Food

Hands holding fresh delicious burgers with french fries, sauce and beer on the wooden table top view.

Did you know when you eat a hamburger your body reacts as if you have swallowed a load of harmful bacteria? The high fat, salt and carbohydrate load, stimulates your immune system to jump into action, and some studies show that poor nutrition does indeed have long term negative consequences on the immune system, and our health.

The Rx: Fast food is dangerous. Ditch it. It's always time to eat for health, but never more so given the pandemic. Why not have a look at for ideas?

RELATED: Registered dietician Ilana Muhlstein lost 100 pounds and shows you how in her new Amazon bestseller, You Can Drop It!—pre-order yours today!


You Drink Sugary Drinks

sugary drinks

Research has confirmed that people who regularly drink sugary drinks have levels of an inflammatory marker. One study, which examined data from the National Health and Nutrition Examination Survey, reported that as sugary drink consumption (soda and fruit juices) has gone down, inflammatory markers have improved—such as a decrease in LDL cholesterol.

The Rx: Drink water or seltzer, tea or coffee, maybe a glass of red wine a day—but skip the soda.


You Eat Too Much Salt

Adding salt. Backlight to salt from salt shaker.

It's a reflex action to reach for the saltshaker and sprinkle salt on just about everything! However, too much salt in your diet results in an increase in blood pressure and an increased risk of heart disease and stroke—and too much salt can also weaken your immune system. Some studies show reducing salt in your diet can give you an extra year of life!

The Rx: Says the FDA: "Americans eat on average about 3,400 mg of sodium per day. However, the Dietary Guidelines for Americans recommends limiting sodium intake to less than 2,300 mg per day—that's equal to about 1 teaspoon of salt." Calculate your intake if you're afraid of going over.


 You Think "Bad Carbs" are Good

African Woman Eating Slice Of Cake Near Open Refrigerator

Why do we crave foods which are bad for us—high sugar, and often nutritionally poor? The sugar burst stimulates areas of the brain which give us pleasure. Too much of these foods can lead to food addiction and food cravings. 

These are foods with a high glycaemic index. The list includes sugary foods and drinks, white bread and white pasta, white rice, cakes, doughnuts, and most packaged breakfast cereals. However, short bursts of high blood sugar can affect a negative effect on the immune response.

The Rx: Time to break the habit! Eat mainly carbs made from whole grains. 


Final Thoughts From the Doctor

Senior woman making choice between healthy and junk food

Changing habits is notoriously difficult. It takes huge determination and incredible staying power. But yes, you can do it. You are the master of your own destiny!

First, you need to understand why you are doing something, and how making the change will have serious benefits. Psychologists acknowledge this isn't easy. For example, in one study, it took an average of 66 days for people just to develop the habit of always eating one piece of fruit at lunchtime!

Right now, during this COVID-19 pandemic, our health has never been more important. Right now—more than ever—is a time to question your habits and try and form new healthy ones.

And to get through this pandemic at your healthiest, don't miss these 100 Things You Should Never Do During the Coronavirus Pandemic.

Dr. Deborah Lee is a medical writer for Dr Fox Online Pharmacy.

Deborah Lee, MD
Dr. Deborah Lee is a health and medical writer with an emphasis on women's health. Read more about Deborah