21-Day Immunity Challenge

During a pandemic, we need a healthy immune system more than ever. A healthy immune system defends our body against disease-causing bacteria and viruses. Lately, the world has been focusing on certain measures to decrease our exposure to COVID-19—wearing masks, washing hands and distancing—but why not focus on helping our immune system work its best to decrease our risk of becoming sick or even dying from COVID-19?

The following 21-day challenge from Tereza Hubkova, MD, ABIHM, ABIM, Integrative Medicine Physician at AdventHealth Shawnee Mission, is designed to get your immune system in better working order by addressing the key habits that influence your immune health. Each day will focus on a single topic or habit to help you achieve better health. Notes from Dr. Hubkova provide guidance, insight and tips to help you stay on track with your goals.

By following the 21-day immunity challenge and sticking to its principles long-term, you will not only improve your chance of making it safely through this pandemic, but also lower your risk of diabetes, heart attack, cancer and many other diseases! Each week of the challenge begins on Monday and ends on Sunday, but you can begin the challenge at any time. Use the hashtag #MHKCChallenge and tag @AdventHealthKC on Instagram and Twitter to share your experience. A lifetime of better health starts today!

Week 1: Nutrition

Week 1: Nutrition

Our immune system needs certain nutrients to function well, which is why nutrition plays an important role in our overall immune health. This week’s challenges are designed to get you thinking more about the foods you eat and help you begin a new habit of eating for wellness. Watch the video below to learn more about the week ahead, or feel free to dive right into the first challenge!

MONDAY: Get sugar out of your diet.
WHY: Elevated blood sugar impairs our ability to fight infection. We know this from studying people with diabetes, who are often more prone to infection. Studies on healthy individuals show that consuming sugar makes it harder for white blood cells to attack germs and clean up tissue damage. People with high sugar intake are also more prone to heart attacks (even if they do not get obese). You will be amazed by how good you can feel in a few days if you give up sweets, candy, ice cream and sweetened beverages in addition to processed foods (where sugar often hides as corn syrup). Make sure to notify your physician if you have diabetes, as your medications may need to be adjusted (you may need less of them).
It can take a lot of willpower to get off sugar, but I am almost certain that after several days of avoiding sugar, your taste buds will adjust and they will start appreciating the more subtle, natural sweetness of fruits, vegetables and other real food. It’s nice to be the pilot of your own body.
TUESDAY: Eat more fiber (25–35g/day)
WHY: Fiber is the indigestible carbohydrate in plant foods: whole grains, nuts, seeds, legumes, fruits and vegetables. It goes through our small intestine, slowing down the absorption of sugar, lowering cholesterol and helping us have more regular bowel movements. Fiber also feeds the beneficial bacteria in our large intestine, which creates a healthy microbiome that supports a thriving immune system. A diet rich in fiber is the best way to improve diversity in your gut microbiome and get on the road to better health!
I suggest you start your day with a fiber-rich breakfast that includes some nuts and berries. If you’re an egg eater, have some vegetables, sauerkraut or kimchi on the side. Have a variety of colors through the day—raspberries, blueberries, blackberries, purple beets, red onions, yellow peppers, orange sweet potatoes, leafy greens, green tea and variety of colorful spices. Vegetables should make up at least half of your plate for both lunch and dinner.
WEDNESDAY: Introduce fermented foods into your diet.
WHY: Fermented foods like yogurt, kefir, miso, sauerkraut and kimchi contain probiotics, which are beneficial bacteria that boost the immune system. Good bacteria will protect you against unwelcome germs through a variety of mechanisms: they produce their own anti-microbial compounds (or their own “antibiotics”) and strengthen the mucous barriers of your body, building a stronger wall to protect against harmful microbes.
When I was a child in the Czech Republic, I remember one of my teachers recounting how her family survived two world wars on a barrel of sauerkraut, which kept them from catching the dreadful flu. It wasn’t until decades later that I understood how much immune support the fermented cabbage provided to them, being rich in vitamin C and probiotics as well as fiber. I love to have sauerkraut soup and borsch, especially in the winter months, and pickled vegetables or kimchi on my salad in the summer.
THURSDAY: Learn about the dirty dozen and clean 15.
WHY: The “dirty dozen” refers to the 12 foods most heavily contaminated with pesticides, while the “clean 15” are the 15 foods that seem to be low in pesticides even if they are not organic. Unfortunately, conventional agriculture uses a lot of pesticides, which we ingest when we eat our food. Many pesticides are suspected neurotoxins and carcinogens and have been found to harm our gut microbiome.

The Dirty Dozen

  • Strawberries
  • Spinach
  • Kale
  • Nectarines
  • Apples
  • Grapes
  • Peaches
  • Cherries
  • Pears
  • Tomatoes
  • Celery
  • Potatoes

The Clean 15

  • Avocados
  • Sweet Corn
  • Pineapple
  • Onions
  • Papaya
  • Sweet Peas (Frozen)
  • Eggplant
  • Asparagus
  • Cauliflower
  • Cantaloupe
  • Broccoli
  • Mushrooms
  • Cabbage
  • Honeydew Melon
  • Kiwi

One of my favorite websites, Environmental Working Group (EWG.org), provides a lot of information about harmful chemicals in our environment. Do your best to avoid pesticides and know how your food was produced. When in doubt, buy organic. A disrupted microbiome makes you more vulnerable to all kinds of diseases, including allergies, autoimmune diseases and inflammatory bowel diseases.
FRIDAY: Learn about the difference between healthy fat and bad fat.
WHY: Fat in our diet has been vilified, but not all fat is bad. In fact, fat is a major building block of every single cell membrane as well as our brain. Certain types of fat, however, can promote inflammation. Stay away from fried foods and the partially hydrogenated fats often found in processed foods. Healthy fats are those in nuts, seeds, olive oil, avocado, coconut oil and in small amounts of organic butter. Omega-3 fatty acids are important for building anti-inflammatory compounds that our body needs to stop inflammation. These types of oils are found mostly in cold water fish and grass-fed animals.
Exposure to high temperatures, such as grilling or frying, can turn healthy omega-3 fats into harmful pro-inflammatory and pro-oxidant compounds. It is better to poach or bake your fish instead. Make sure to avoid any rancid oils (oil will have an odd smell when it has gone rancid). To decrease chances of spoilage, buy oils in dark glass containers and store in a cool, dark place.
SATURDAY: Consider extending your overnight fast to 13-16 hours.
WHY: When we do not eat for more than 13 hours, and we can sleep through most of that time, our body will not only continue burning fat, it will also recycle damaged cells and damaged proteins (a process called autophagy). Think of it as recycling and garbage disposal all in one—it will help you maintain a healthy weight and lower your risk of degenerative diseases including some cancers.

In a study of women with breast cancer, a 13-hour overnight fast lowered the risk of cancer recurrence by as much as 35%, a number that is comparable to some of the cancer prophylactic medications, but without their side effects. When we fast, our insulin levels are very low, creating an anti-inflammatory environment.
Interestingly, the longer we fast, the easier it is to continue to fast thanks to the ketone bodies we produce when we burn fat (which suppress hunger). I experienced this myself when I supported my friend by fasting with him on Yom Kippur many years ago. The first 8 or 10 hours were quite miserable, but I managed to get through by keeping myself busy. When evening came, I realized I was no longer hungry and decided to see how long I could fast out of curiosity. I fasted 4 days, and I felt fantastic— my brain had never been that clear, and I had a surprising amount of energy. I even went downhill skiing on day four of the fast! The only reason I broke it at that point was so that I could enjoy myself at a birthday party. However, despite this personal experience I do not recommend fasting for more than 16 hours, as longer fasts can lead to gallstones. Please do not fast without the approval of your physician because fasting is dangerous for some people.
SUNDAY: Replace alcohol with mocktails.
WHY: Alcoholic beverages suppress the immune system, impair our quality of sleep and can lead to inflammation in the body. People who suffer from sleep apnea may notice that their condition becomes worse after drinking alcohol, and impaired breathing at night is one of the biggest drivers of inflammation. When trying to promote a healthy immune system, it’s best to steer clear of alcohol entirely.
There’s no need to stick to water when going out with friends—a mocktail can be just as enjoyable as a cocktail. Ask for a virgin daiquiri or mojito, or see if the bartender has any recommendations—there may even be non-alcoholic beer available.
Week 2: Stress Management

Week 2: Stress Management

Stress affects our immune system in a major way. Chronic stress leads to measurably higher levels of inflammation, can increase our risk of autoimmune disease and weakens our response to infection as well as vaccines. This week’s challenges are designed to help you manage stress in your daily life, giving you more tools to cope with stress in a healthy way and making you less likely to feel out of control when stressful situations arise.

Watch the video below to learn more about the role of stress management in immune health, or skip ahead to the first challenge!

MONDAY: Connect with a friend.
WHY: We are social beings, and social isolation and loneliness have a profoundly negative effect on our health. In fact, social isolation is comparable to smoking, obesity, lack of exercise and high blood pressure as a risk factor for premature death and disease. It has also been associated with decreased resistance to infections, cognitive decline, depression and dementia.
Connecting with someone doesn’t have to be hard. Call or text a friend whom you haven’t seen or spoken to in a long time, organize a group video chat with family or challenge someone to an online game.
TUESDAY: Practice gratitude.
WHY: Our immune system “listens” to our emotions. Fear, frustration and hostility can actually contribute to inflammation, while positive emotions such as love, gratitude and appreciation help your immune system work better. Gratitude is a positive emotion that can boost not only the immune system of the person who is expressing gratitude, but also that of the receiver. Try sending thank-you notes to the people you are grateful for or give them a call to let them know how much they mean to you. You will boost your immune resilience as well as theirs.
I love writing down 3 things that I am thankful for each day in a gratitude journal. When moving, I discovered a gratitude journal that I kept 30 years ago when I was in medical school, often feeling run down, overwhelmed and stressed. I feel that the gratitude journal saved my sanity back then, and I feel a boost of gratitude every time I re-read it, even now.
WEDNESDAY: Make time to listen to your favorite music.
WHY: Multiple studies show the beneficial effects of music on our immune system. Relaxing music lowers blood pressure and heart rate, shifting us from a stressful “fight or flight” mode into a healing “rest and digest” mode. Whether we’re listening to music, singing or playing an instrument, music can increase levels of immunoglobulin A, a protein that acts as one of the first lines of defense against infections. Some studies even indicate that listening to music may ease allergic reactions.
I come from the Czech Republic, and an old saying goes that every Czech is a musician. Playing music or singing is a part of many Czech family get-togethers or weekend getaways with friends. There is nothing more exhilarating then jamming with friends or singing with your children around a campfire!
THURSDAY: Try a breathing practice.
WHY: Our breath can affect our stress level. When we are anxious and stressed, we breathe fast, which encourages us to feel even more anxious and stressed out. When we consciously slow down our breathing, we are helping to activate the parasympathetic part of our nervous system, which is more conducive to healing. There are many breathing practices used in yoga, meditation or Tai Chi that are designed to help us relax and de-stress.
Try sitting or lying down in a comfortable position, put one hand on your belly and the other on your chest, take a deep breath in through your nose and let your belly rise. Then, breathe out and feel your hand on the belly go back down. Imagine healing light entering your body when you breathe in, and let any tension and stress leave your body as you breathe out. Repeat three times. Notice how relaxed you feel!
FRIDAY: Try guided meditation.
WHY: Even listening to guided meditation for 15 to 20 minutes has shown to suppress inflammatory genes. The physical benefits of meditation have also been shown and increase the enzyme telomerase, slowing down the aging of your chromosomes. It is possible to look and feel physically younger than our biological age when we’re at the peak of health. This is just one more reason to work on decreasing stress in our lives!
If sitting still while meditating isn’t your cup of tea, try Tai Chi—a form of meditation that incorporates physical movement—or a walking meditation.
SATURDAY: Spend time outside enjoying nature.
WHY: Nature heals our soul and, as it turns out, also helps our immune system work better. Try to spend at least 30-60 minutes outside every day (weather permitting). In addition to relieving stress, the vitamin D and light we get from the sun is crucial for our immune system to function. People with low vitamin D levels are more likely to become ill and experience complications from illnesses. Forest bathing (Shinrin-Yoku), a meditative walk through a forest, has become a very popular activity in Japan to improve lung health and blood pressure, boost the immune system and is now rightfully gaining traction in the U.S. as well.
If you are unable to go outside, try to create a nature corner in your home with live plants, stones, a water fountain and other natural items. While it won’t help with vitamin D, it will help you deal with stress. One of my favorite weekend activities in the summer is camping—being outdoors, breathing in the fresh smell of pine trees, sitting by a campfire. Being outdoors nurtures the soul, aligns the circadian rhythm with the cycle of nature and contributes to a healthier microbiome.
SUNDAY: Get at least 30 minutes of exercise.
WHY: A daily habit of exercising for at least 30 minutes can help make your immune system work better. People who exercise regularly are less likely to catch a cold, be obese, have high blood pressure or develop diabetes. Find an activity you enjoy, whether that’s taking a class at the gym or simply going for a brisk walk. If you are short on time and can’t commit to 30 minutes, studies indicate that high-intensity interval training (HIIT) may have similar benefits, but make sure to check with your physician first, especially if you have any cardiovascular risk factors. Studies in women with polycystic ovaries and prediabetes showed that 30 minutes of exercise improved their glucose metabolism by 40% for 48 hours!
I love to walk with my dog for half an hour twice a day, which turns into my walking meditation as well. I also enjoy going for a bike ride or a swim with my daughter and husband. Besides keeping us healthy and active, this time together is a great opportunity for us to bond as a family.
Week 3: Sleep

Week 3: Sleep

As adults, getting 7–8 hours of good quality sleep each night can be a challenge, but prioritizing sleep in our lives is a key component of maintaining a healthy immune system. Lack of sleep increases our susceptibility to infections and even makes us less likely to respond to a vaccine. This week is all about prioritizing sleep, so get ready to rest up! Watch the video below to learn more about how the quality of our sleep affects our immune health, or skip ahead to view the first challenge.

MONDAY: Establish a reasonable bedtime.
WHY: It is much easier to sleep well when you go to bed at the same time each night because you’re training your body to expect sleep. To find your ideal bedtime, figure out when you need to get up in the morning and count backwards 7 or 8 hours. Make it a goal to stick to this bedtime every night this week.
The reason I had to give up being a hospitalist (working as a physician in the hospital) was that I could not tolerate switching between day and night shifts. I constantly felt jet lagged. Indeed, people who work shifts often pay a price for it with their own health—they are more susceptible to insulin resistance and diabetes, hypertension, obesity and even breast cancer.
TUESDAY: Assess your use of sleep disruptors.
WHY: Substances such as caffeine, alcohol, sugar or stimulating medications disrupt sleep. Your body’s ability to handle caffeine is based on your genetic capacity for its metabolism. People with slow caffeine metabolism may have difficulty falling asleep even if they had just one cup of coffee early in the day. Start by cutting out stimulating substances a few hours before bedtime. If you are continually having trouble falling asleep, talk to your doctor about possible root causes.
I am a fast coffee metabolizer and never have trouble falling asleep after drinking coffee. On the flip side, coffee does not really do much to give me energy or help me focus. I prefer even a brief opportunity to exercise or to use adaptogenic herbs like Rhodiola rosea to keep my mind sharp.
WEDNESDAY: Create a blue light-free zone two hours before bedtime.
WHY: Blue light, the light emanating from electronic devices like phones, computers and TV screens, tricks our brains into thinking we need to stay awake and alert. While it might be tempting to scroll through social media in bed, this habit can make it harder for you to fall and stay asleep. Try to keep electronics out of the bedroom altogether and reserve that room as a sacred space for sleep.
Try playing board games with your family or reading a book instead of watching TV before bed. You might have even more fun!
THURSDAY: Set up ideal sleep conditions.
WHY: It is much easier to fall asleep when your bedroom is comfortable, around 65–68 degrees F and dark. Even small amounts of light can disrupt our circadian rhythm and the production of melatonin, a hormone that helps us sleep. Lack of melatonin may contribute to inflammation, inhibiting our immune system from fighting infection.
Make sure you have good curtains to keep your bedroom dark, and if you get up in the middle of the night to go to the bathroom, use red light to minimize inhibition of melatonin production. When my daughter was little, she was afraid to sleep without lights on in her bedroom, so we used red night lights to ease her fears without inhibiting her ability to produce melatonin.
FRIDAY: Avoid eating for at least three hours before bedtime.
WHY: Digesting food elevates your body temperature, making it harder to sleep. Digesting while lying down could also cause gastroesophageal reflux or heartburn, which can actually prevent you from falling or staying asleep in addition to making you uncomfortable. If you eat an evening snack due to diabetes or low blood sugar, then skip this challenge or talk to your physician first.
If you’re in the habit of making dinner the largest meal of the day, consider increasing your food intake earlier in the day and eating a smaller meal in the evening—especially if you tend to eat dinner after 7 p.m.
SATURDAY: Take time to unwind in the evening.
WHY: Stress and sleep do not go well together. You may have a hard time falling asleep if your cortisol (the stress hormone) is elevated. Prepare your body for sleep by developing a ritual that helps you unwind in the evening, such as practicing restorative yoga, taking a relaxing bath, reading or meditating. If you are in the habit of exercising in the evening, try moving your workout to the morning or afternoon hours.
Try putting a few drops of lavender essential oil in your bath to further promote relaxation before sleep. I know it can be challenging to give yourself permission to relax when you’re feeling overwhelmed and stressed, but you deserve this nightly ritual of self-care!
SUNDAY: Commit to using your bedtime only for sleep.
WHY: When we get used to being awake in our bedroom, watching TV, working or using the computer, our bodies have a harder time adjusting to the concept of going to sleep in the same area. Reserving our bed and bedroom for sleep creates a trigger for our bodies to more easily fall and stay asleep.
Waking up in the middle of the night and struggling to go back to sleep? Get out of bed and go to another room. Read or meditate until you are tired again, then go back to sleep in your bed. Do not stay in bed if you are struggling to sleep. You don’t want to associate your bed with struggling to sleep!


Whether or not you were able to complete each challenge, you’ve been thinking about your immune health for 21 days, and that deserves a pat on the back! Immune health is an ongoing challenge in our lives and simply educating yourself on healthy habits to boost your immunity is the first step in achieving a lifetime of wellness. From here, I challenge you to continue the healthy habits you’ve begun these last three weeks—continue to be mindful of how your nutrition is impacting your body’s ability to fight infection, continue practicing self-care to reduce your stress levels and continue making healthy sleep a priority in your life.


Dr. Hubkova and her team at AdventHealth South Overland Park offer individual consultations as well as lectures and group visits on building a resilient immune system, losing weight, improving sleep and gut health and other topics pertinent to improving our chances of staying well. Laboratory assessment of your nutritional status, metabolic health and microbiome diversity is also available on demand. To schedule an appointment, call (913) 632-3550.