6 Healthy Habits You May Be Missing for Flu Prevention

Healthy Habits for Flu Prevention

Many of us will enter the upcoming flu season better prepared because we have already been using the COVID-prevention tools, especially careful handwashing, respiratory protection (wearing a mask), and appropriate social distancing.  While these precautions are important for flu prevention, we need to go deeper inside our bodies to learn that real flu virus-prevention is an “inside job.”  I will now take you deep inside your body to introduce you to the main ingredient for overcoming flu viruses:

Empower your immune system warriors (ISW).

Meet Your Immune System Warriors (ISW)

NK cells: what they are, what they do, and how to make them fight better for you.

Your NK cells (natural killer cells) are the rapid-responders of your immune system.  Consider NK cells as the soldiers of your immune system, an important resource for flu prevention.  NK cells are the trillions of troops, your white blood cells, that circulate throughout your body and are constantly on a search-and-destroy mission for viruses that get through your body’s two main checkpoints – the virus-trapping mucus lining of your respiratory tract and intestines.  When NK cells find a virus, they are magnetically drawn to it, attach onto it and shoot biochemical darts (virus-dissolving enzymes, appropriately called perforins – think perforate) into the virus and destroy it.  (More about your NK cells later.)

Other warriors in your immune system (B-cells from your bone marrow and T-cells from your thymus) are a back-up system, the memory cells of your immune system.  They also search out the virus and biochemically barcode the virus so that if a similar virus tries to get into your body the checkpoints in your immune system have already been notified: “This is a foreign virus, we won’t let you into the body,” and your other soldiers (called antibodies) destroy it.  This is similar to how vaccines work.

woman holding thermometer

6 Missing Steps for Flu Prevention

1. Practice Your Belief Effect

The better you believe your ISW will fight for you the more likely they will during flu season, and beyond.  Believe in your ISW: “It’s my ISW, I’m in control of it.  I believe you will fight for me.  Now go get those viruses!”  Over my fifty years as a parent and physician I have witnessed one simple immune-health fact:

Positivity promotes immunity.

Science agrees: optimists stay healthier and heal quicker than do pessimists, for two main reasons: 1) they have higher levels of NK cells and other immune-system troops; and 2) they heal quicker than do pessimists.  Also, they don’t stress out their ISW.

Let’s go deeper.  Your NK cells have “stress receptors,” doors on their cell membranes, that are easily opened (aka bothered or weakened) by prolonged, unmanaged stress. If your ISW immune cells could talk (they do but we don’t listen), they would shout: “Don’t stress me out!”

Dr. Bill notes: Preparing for the flu season is an opportunity for those with a family to shine.  This is a window of opportunity for you to teach your children the concept of resilience, the ability to bounce-back quickly from life’s setbacks.  Spend time doing arts and crafts, watching movies and playing games together.  Social interaction smartens the immune system; excessive and unwarranted social isolation depresses both the mind and the immune system.

Say goodnight to bad news. Inaccurate news can promote faulty ISW.  Welcome good news!  One of the main stress-management tools we teach our children and our patients is: “You can’t always control situations (virus epidemics), but you can control your reaction to them.” Text your friends: “Good friends, text me good news only.”  If there’s news that’s true and you need to know about it, you eventually will.

Remember, your brain is the commanding chief of your immune system warriors.  The better your brain, the better your immune system. Read more about better brain health and stress management.

2. Eat Immune-Boosting Foods for Flu Prevention

It makes sense that the better you feed your troops the better they will fight for you.  If your immune system could talk it would tell you: “Feed me the real-food diet.”  Translation: processed food contributes to depressed ISW.  Before eating, ask yourself: “Will this food or drink help or harm my ISW?”

3. Movement Mobilizes Your Immune System

The main place in your body you want to keep viruses out of is your bloodstream. As a tribute to the greatest machine ever made, the human body, many of your NK cells are stationed like troops along the lining of your blood vessels, your inner natural ISW pharmacy called your endothelium.

Follow your blood flow.  You walk briskly.  Blood flows faster over the lining of your endothelium and sends biochemical text messages and what is called a “shear force” to help many of the ready-and-waiting NK cells to join the flow – your bloodstream – and circulate throughout your body to search-and-destroy the virus invaders.  Your NK cells, the top white blood cell in your immune system warriors, are in two compartments: one that is circulating in your bloodstream and the other is what immunologists call “marginated WBCs,” white blood cells that adhere to your vascular endothelium.

Another perk is the blood vessels in your lungs (probably the number one checkpoint for viruses entering your body and the largest reservoir of NK cells in the vascular lining) have one of the largest ISW’s of the NK cells that can be mobilized by exercise.  Imagine you are walking with a group of friends and you’re talking about how you can prepare yourself for the coming viral season.  You say: “Right now, just by walking fast, I’m mobilizing my immune system warriors inside to equip them to keep the viruses from harming me.”

family outside being activeGet outside.  Fascinating studies from Nippon University in Tokyo, Japan, showed that persons who exercised outdoors, especially in a forest setting, had higher levels of NK cells and lower levels of stress hormones – a double “like!” for your immune system.  This is why one of my favorite authors, Harvard neurologist Dr. Eva Selhub, in her book Your Brain on Nature, calls movement outdoors “exercise squared.”

Dr. Bill quips:

 The more you move, the more your NK cells move.

The more you sit, the more your NK cells sit.

4. Laugh

Humor heals, fear harms.  Laughter is the best medicine is especially true for your immune system when focusing on flu prevention.  Also, enjoy funny movies with your family.  During the COVID epidemic one of my favorite stories is a take-off on the word “quarantine.”  Enjoying more couples time may give us a minor baby boom in nine months.  As a result, thirteen years from now teenagers in the year 2033 will be dubbed “quaranteens.”

5. Help Others Heals

The more you help someone else heal, the better you are likely to heal.  This is a perfect time to think about how you can brighten someone else’s day through a kind or funny text, even a phone call.  The immune system “likes” what I call the “helper’s high,” but viruses don’t.  Also, remember that social distancing does not mean social isolation.  Those labeled “most vulnerable” (persons in nursing homes or assisted living residences) are “vulnerable” in some ways because their immune system suffers from social isolation.  Again, the brain is the commanding chief of your immune system.  The GRANT Study, the largest study to date on the top contributors to dementia, showed that social isolation was the number one contributor and excessive alcohol (also more common during virus epidemics) was number two.

6. Get a Good Night’s Sleep

During quality sleep is when your immune system warriors report for nightshift duty and can better prepare for flu prevention.  Melatonin, the natural sleep medicine you make, triggers the immune system to produce more NK cells.  The better your quality of sleep, the greater the quantity and quality of the NK cells you produce.

Concerned about differentiating between COVID or the flu? Find out what the CDC has to say.

woman sleeping to prevent flu

[Download the “6 Healthy Habits you May be Missing for Flu Prevention” printable infographic]


Nutrition Resources to Naturally Boost Your Immune System

Use these helpful nutrition resources to naturally boost your immunity by choosing healthy, whole foods.


  • Asparagus
  • Beets
  • Berries
  • Broccoli
  • Curcumin
  • Garlic
  • Ginger
  • Green tea
  • Mushrooms
  • Nuts
  • Olive oil
  • Onions
  • Pomegranate*
  • Rosemary
  • Turmeric partnered with black pepper
  • Wild pacific salmon: omega-s


*Pomegranates are in season during flu season – smart!


Select choices from each of the five food categories below. Start with a few ingredients that you already know you like. Gradually add more ingredients. Be sure to add protein and healthy fats to each smoothie, which will taste better and keep you fuller longer than a carb-only drink. Our basic recipes have the percentage of nutrients as: 20-25 percent proteins, 25-30 percent healthy fats, and 45-50 percent healthy carbs.

1. Healthy Fluids

  • Kefir, organic, plain
  • Coconut milk/water, unsweetened
  • Almond or cashew milk, unsweetened
  • Goat milk, Meyenberg
  • Green tea
  • Organic juices: green vegetable, pomegranate
  • Milk, whole, organic


2. Healthy Fats

  • Avocado
  • Nutbutters
  • Coconut oil, virgin
  • MCT oil, organic
  • Coconut chunks
  • Ground flaxseeds, hemp, or chia seeds
3. Healthy Proteins

  • Greek yogurt, organic, full fat, plain
  • Nutbutters
  • Tofu
  • A healthy protein powder, multi-nutrient mix; or your choice of a plant-based protein powder.
4. Healthy Fruits and Greens

  • Blueberries
  • Kiwi
  • Strawberries
  • Acai berries
  • Pomegranates
  • Papaya
  • Kiwi
  • Banana
  • Greens: kale, spinach, chard celery
5. Special Additions: Flavor and Nutrients

  • Cinnamon
  • Hawaiian spirulina
  • Wheat germ
  • Cacao powder
  • Grated, organic orange peel
  • Shredded coconut
  • Mint
  • Lemon rind, organic
  • Ginger



The most motivated recipe designers are those fighting for their lives, or better said, eating for their lives.  During my personal beat-cancer crusade, this is the science-based salad I came up with and continue to eat nearly nightly to this day.  Here are the five “food groups” to choose from as you design your personal salad.  You don’t have to pick from all five to begin with, but eventually as you shape your tastes and your gut feel you’ll choose the ones that work for you:


  • Kale
  • Spinach
  • Arugula
  • Red  and jalapeno peppers
  • Leeks
  • Onions
  • Beet greens and roots
  • Broccoli
  • Red cabbage
  • Chard
  • Collard greens
  • Asparagus
  • Mushrooms


  • Black beans (no added salt)
  • Lentils (my favorite legume)
  • Pinto beans
  • Hummus
  • Edamame (raw soybeans)

  • Turmeric, with black pepper
  • Pumpkin seeds
  • Garlic
  • Rosemary, thyme, oregano



  • Olive oil
  • Balsamic vinegar



  • Cauliflower
  • Brussel sprouts
  • Berries
  • Nuts
  • A 4-ounce fillet of wild salmon



*If you suffer from leaky gut syndrome (LPS), to help protect your immune system, your doctor may advise you to avoid these foods.

Remember Dr. Mom’s keep-well wisdom? “Eat more fruits, veggies, and seafood; and get outside!”

Dr. Bill Sears