Your Immune System May Not Need a “Boost.”
It may need to be balanced.
Part 1: Understanding What Your Immune System Is Actually Trying to Do
One of my favorite questions to ask a new patient is surprisingly simple.
“When was the last time you were sick?”
Most people expect me to begin with medications, surgeries, or family history. Those questions certainly matter, but the answer to this one often tells me just as much.
Sometimes patients tell me they catch every cold that comes through the office. Others describe sinus infections that seem to linger for months or illnesses that always settle into their chest. Occasionally someone proudly tells me they haven’t been sick in ten years.
That last answer usually catches people off guard because I don’t automatically celebrate it.
Instead, I become curious.
Not concerned. Curious.
You see, one of the biggest misconceptions about health is that the ideal immune system is one that never allows you to get sick. While that certainly sounds desirable, our immune systems were never designed to create a life completely free of illness. They were designed to help us safely interact with the world around us.
Every handshake. Every airplane ride. Every summer barbecue. Every child returning home from camp. Every grocery cart handle. Every weekend spent traveling. Every meal we eat.
Our immune system is continuously deciding what belongs, what doesn’t, what deserves attention, and what can safely be ignored.
The goal isn’t perfection.
The goal is resilience.
As we head into the busiest months of summer travel and begin preparing for another school year, conversations about immune health naturally start becoming more common. Parents begin wondering how to keep their children healthy when classrooms fill back up. Travelers ask what supplements they should pack for vacation. Many people simply want to avoid spending their hard-earned time off in bed with a fever.
Those are reasonable questions.
But before we talk about what supports the immune system, I think it’s important that we first understand what the immune system is actually trying to accomplish.
Because once you understand that, many of the things we’ve been taught about immunity begin to look very different.
The Problem With “Boosting” Your Immune System
Walk through almost any pharmacy or health food store and you’ll quickly find products claiming to “boost,” “supercharge,” or “strengthen” your immune system.
It’s an attractive message.
After all, if the immune system protects us, then more immune activity must be better.
Right?
Not exactly.
If there is one idea I hope every patient takes away from this article, it’s this:
A healthy immune system is not one that is always turned up to maximum volume. It’s one that knows exactly when to respond, how strongly to respond, and when to stop responding.
Think about what happens in allergies.
The immune system reacts aggressively to pollen, pet dander, or foods that pose little actual danger.
In autoimmune disease, the immune system mistakenly identifies the body’s own tissues as foreign and mounts an attack against them.
Chronic inflammatory conditions often involve immune pathways that remain activated long after the original trigger has disappeared.
None of those situations represent a weak immune system.
They’re examples of an immune system that has lost appropriate regulation.
At the other end of the spectrum are people whose immune systems struggle to recognize infections quickly enough or generate an adequate response. They may experience recurrent infections, prolonged recovery, or poor wound healing.
Neither extreme represents optimal health.
The healthiest immune systems are remarkably balanced.
They recognize danger without overreacting.
They eliminate threats efficiently.
Then they return to a resting state, ready for whatever challenge comes next.
As naturopathic physicians, that is what we strive to support.
Not simply more immune activity.
Better immune regulation.
Your Body Is Smarter Than You Think
One of the things I love most about medicine is that our bodies are constantly performing incredibly sophisticated tasks without requiring us to think about them.
You don’t consciously regulate your heart rate every second of the day.
You don’t decide when to release digestive enzymes.
You don’t manually adjust your blood pressure every time you stand up.
Your immune system works the same way.
It operates continuously in the background, making thousands of complex decisions every minute.
When you scrape your knee while hiking.
When you inhale wildfire smoke during a Colorado summer.
When your child comes home from camp with a new virus.
When you pet a dog.
When you board an airplane.
When bacteria enter a small paper cut on your finger.
Your immune system is already working before you’re even aware anything has happened.
It recognizes patterns found on bacteria, viruses, fungi, parasites, damaged cells, and even some cancer cells. Specialized immune cells communicate through an enormous network of chemical messengers called cytokines. Blood vessels become temporarily more permeable so immune cells can leave the circulation and enter affected tissues. Bone marrow increases production of white blood cells when needed. Lymph nodes begin coordinating an adaptive response while the liver produces proteins that assist with defense and tissue repair.¹
None of this happens randomly.
It is one of the most sophisticated communication networks in the human body.
One of my favorite ways to explain it to patients is to imagine a city.
The skin serves as the city walls.
The innate immune system functions like local police officers who respond immediately to almost any disturbance.
The adaptive immune system behaves more like detectives who carefully identify the culprit, remember them for the future, and build a detailed file so they can respond much faster the next time.
Every part of that system communicates with every other part.
Which brings us to something that often surprises people.
Your immune system isn’t just your immune system.
It’s also your nervous system.
Your endocrine system.
Your digestive system.
Your microbiome.
Your sleep.
Your nutrition.
Your stress levels.
Your environment.
Your immune system is less like a single organ and more like an orchestra. Every section has to play together if the music is going to sound the way it was intended.
Symptoms Are Often Evidence That Your Body Is Winning
One of the biggest mindset shifts I try to help patients make is learning to view symptoms differently.
Most of us have been conditioned to think that symptoms automatically mean something has gone wrong.
Sometimes that’s true.
But very often, symptoms are actually evidence that something has gone exactly right.
Let’s take a fever.
Nobody enjoys having one.
Parents understandably become anxious when they see the thermometer climbing.
Yet fever is one of the oldest defense mechanisms in human biology. During many infections, the brain intentionally raises the body’s temperature through signaling molecules called pyrogens. That slightly warmer environment makes it more difficult for many pathogens to reproduce while simultaneously improving several aspects of immune cell function.²
In other words, your body is intentionally making itself a less welcoming place for the invader.
That’s remarkable.
The same concept applies to many of the symptoms we dislike.
Swollen lymph nodes often mean immune cells are rapidly multiplying and organizing their response.
Increased mucus production traps viruses, bacteria, allergens, and environmental particles so they can be removed from the respiratory tract.
Fatigue encourages us to conserve energy so resources can be redirected toward healing.
Inflammation increases blood flow, delivers nutrients, recruits immune cells, and initiates tissue repair.
None of these responses are accidental.
They’re coordinated.
They’re purposeful.
They’re intelligent.
This doesn’t mean every symptom should simply be ignored or celebrated. Excessively high fevers, severe infections, prolonged inflammation, or symptoms that become dangerous absolutely deserve medical evaluation and appropriate treatment.
The point is that symptoms themselves are not the enemy.
They’re often the visible expression of an invisible healing process.
From Dr. Kelsey’s Clinic
One of the things I hear surprisingly often is some version of:
“My immune system failed me.”
Every time, I find myself gently pushing back.
Maybe it didn’t.
Maybe your fever developed because your immune system recognized a virus exactly as it should.
Maybe your swollen glands meant immune cells were multiplying exactly as they should.
Maybe your fatigue was your body’s way of asking for something you’ve been postponing for weeks.
Rest.
Our culture has become incredibly good at viewing symptoms as inconveniences that need to disappear as quickly as possible.
Sometimes that’s appropriate.
Other times, our symptoms are simply evidence that our bodies are fighting on our behalf.
Understanding that distinction often changes the entire conversation.
Why Some People Always Get Sick on Vacation
There is another conversation I seem to have almost every summer.
A patient comes into the office laughing as they say,
“You know what’s funny? I worked sixty-hour weeks for three months, made it through every deadline, got on the airplane for vacation…and woke up sick the very next morning.”
If you’ve experienced this, you’re not alone.
Researchers have been studying the relationship between stress and immune function for decades. We now know that the nervous system, endocrine system, and immune system are in constant communication. Chronic psychological stress alters cortisol production, sympathetic nervous system activity, inflammatory signaling, and immune cell behavior.³
Exactly why people often become ill once a major stressor ends is still being investigated.
My clinical observation is that the body is remarkably good at helping us survive.
It will often keep asking us to slow down through subtle whispers.
You feel a little more tired than usual.
Your workouts don’t feel as easy.
You become a little more irritable.
Your sleep becomes lighter.
Your digestion changes.
You push through.
Because that’s what life requires sometimes.
Then eventually you cross a threshold.
Whether that’s because you’ve accumulated enough physiological stress, your immune system has become temporarily less resilient, or your body finally has permission to express symptoms you’ve been ignoring, something changes.
You get sick.
Patients often apologize for this as though their body has betrayed them.
I tend to see it differently.
Sometimes your immune system has simply been fighting to help you survive the season you were in.
Now it’s asking for its turn to recover.
I often tell patients something that usually earns a smile.
If you don’t choose time to slow down, sometimes your immune system chooses it for you.
Our bodies are incredibly adaptable.
They are also incredibly honest.
Eventually they ask us to pay attention.
And the more consistently we listen before they have to shout, the healthier we tend to become.
When the Immune System Loses Its Balance
One of the biggest challenges with talking about the immune system is that people tend to think of it in very simple terms.
It’s either “good” or “bad.”
“Strong” or “weak.”
Working or not working.
The reality is far more interesting.
In medicine, we rarely think about the immune system as simply being stronger or weaker. Instead, we think about how well it is regulated.
Imagine an orchestra preparing to perform a symphony.
If every musician played as loudly as possible, the music would be overwhelming and chaotic. If only half of the musicians showed up, the performance would also fail.
The magic happens because every instrument knows exactly when to join in, how loudly to play, and when to become quiet again.
Your immune system works much the same way.
There are moments when it needs to mount an aggressive defense against a dangerous infection. There are other times when it needs to peacefully tolerate the foods you eat, the pollen you inhale, the bacteria living in your gut, and even the baby growing during pregnancy.
It has to know when to attack.
It has to know when to stand down.
And perhaps most importantly, it has to know the difference.
This process is called immune regulation, and it is one of the most remarkable balancing acts in human physiology.
Not Every Immune Problem Looks the Same
When people tell me they “have a weak immune system,” one of the first things I’m trying to understand is what they actually mean.
Are they developing every viral illness that circulates through their workplace?
Are they taking weeks to recover from relatively minor infections?
Do they have allergies that flare every spring?
Have they developed an autoimmune condition?
Do they constantly feel inflamed without a clear explanation?
Those are all immune-related experiences, but they represent very different biological processes.
Some immune systems struggle to recognize or eliminate infections efficiently.
Others recognize threats perfectly well but have difficulty turning the inflammatory response back off.
Some mistakenly identify harmless substances like pollen, peanuts, or pet dander as dangerous invaders.
Others become confused enough to target the body’s own tissues.
From the outside, all of these people might simply say, “Something is wrong with my immune system.”
From the inside, however, very different conversations are occurring between immune cells.
This is one of the reasons functional and naturopathic medicine place such a strong emphasis on understanding the entire clinical picture instead of simply matching one symptom to one supplement.
The question isn’t simply, “How do we stimulate the immune system?”
The better question is, “Why is this particular immune system behaving this way?”
The answer is rarely simple.
Fortunately, that’s also what makes medicine so fascinating.
Your Gut Is Training Your Immune System Every Single Day
One of the most exciting developments in medicine over the last two decades has been our growing understanding of the gut microbiome.
When I was in school, we certainly appreciated that gut bacteria were important.
Today, we recognize that they are essential partners in human health.
The average adult carries trillions of microorganisms throughout the intestinal tract. Together, they form an incredibly dynamic ecosystem consisting of bacteria, fungi, viruses, and other microbes that constantly communicate with the immune system. Far from being passive passengers, these organisms help educate immune cells, regulate inflammation, produce vitamins and metabolites, strengthen the intestinal barrier, and even influence brain function through the gut-brain axis.⁴
Perhaps even more remarkable is where much of the immune system actually lives.
Approximately seventy percent of immune cells are located within tissues associated with the gastrointestinal tract.⁵
That statistic surprises almost every patient I tell.
Most people imagine their immune system floating around in the bloodstream, waiting for germs to appear.
Instead, one of its busiest headquarters is located exactly where it makes the most sense.
The digestive tract.
Every day, your intestines are exposed to proteins from food, environmental chemicals, beneficial bacteria, occasional pathogens, medications, and countless other foreign substances.
Your immune system has to make an incredible number of decisions.
“This protein came from lunch. Leave it alone.”
“These bacteria belong here. Support them.”
“This virus shouldn’t be here. Activate defenses.”
“This intestinal lining has been injured. Begin repair.”
Those decisions happen thousands of times every single day without us ever realizing it.
I sometimes tell patients that the gut is like customs and border protection at an international airport.
Millions of visitors pass through safely.
Most belong there.
Some require closer inspection.
A few absolutely need to be stopped before they enter.
The challenge is identifying the difference quickly and accurately.
The Intestinal Barrier Is More Than Just Digestion
The lining of the small intestine is only one cell thick.
That fact alone is astonishing.
A single layer of epithelial cells separates the outside world from your bloodstream. While we often think of food becoming “inside” our body the moment we swallow it, that’s not actually true.
Food remains technically outside the body until nutrients successfully cross that carefully regulated intestinal barrier.
Healthy intestinal cells are connected by specialized structures called tight junctions, which function like carefully controlled security gates. Nutrients that belong in the bloodstream are allowed to pass through. Larger particles, pathogens, and unwanted substances are generally kept out.⁶
When that barrier functions well, communication between the gut and immune system remains remarkably sophisticated.
When it becomes compromised, the conversation changes.
Researchers continue investigating how alterations in intestinal permeability, changes in microbial diversity, chronic inflammation, medications, dietary patterns, infections, and environmental exposures may contribute to immune dysregulation in susceptible individuals. This remains an active area of research, but there is growing evidence that intestinal barrier function plays an important role in immune homeostasis and inflammatory regulation.⁷
This is one reason naturopathic physicians spend so much time asking questions that initially seem unrelated to your chief complaint.
How is your digestion?
How often are you having bowel movements?
Have you needed antibiotics repeatedly?
Do you experience bloating?
How diverse is your diet?
Those questions aren’t distractions.
They’re often central to understanding what’s happening throughout the rest of the body.
From Dr. Kelsey’s Clinic
One of the most common reactions I hear from new patients is:
“I thought I was coming here because I kept getting sinus infections. I didn’t expect we’d spend twenty minutes talking about my gut.”
I usually smile.
Because by the end of the visit, it makes perfect sense.
Your immune system doesn’t exist in isolation.
Neither does your digestive system.
Neither does your nervous system.
Everything is connected.
That’s one of the biggest differences between treating symptoms and understanding physiology.
Why Lifestyle Matters More Than Most People Realize
Patients often ask me whether there is one supplement that can “keep their immune system strong.”
I understand the appeal.
A single capsule would certainly be easier than improving sleep, reducing stress, eating more vegetables, exercising consistently, and managing blood sugar.
Our physiology, however, doesn’t usually work that way.
The immune system constantly responds to information coming from the rest of the body.
One night of poor sleep has been shown to reduce natural killer cell activity, an important component of our early defense against viruses and abnormal cells.⁸ Chronic sleep deprivation also influences inflammatory cytokines, antibody production, and immune regulation.
Stress has a similarly profound effect.
Acute stress can actually enhance certain aspects of immune function for short periods of time, likely reflecting an evolutionary adaptation that prepared humans to survive immediate danger. Chronic stress tells a very different story. Persistently elevated stress hormones alter communication between the nervous system and immune system, influence inflammatory pathways, impair tissue repair, and may increase susceptibility to infection over time.⁹
Blood sugar is another area that rarely receives enough attention.
When glucose remains chronically elevated, immune cell function changes. Neutrophils become less effective at engulfing pathogens. Oxidative stress increases. Chronic inflammation becomes more likely. This helps explain why individuals with poorly controlled diabetes often experience more frequent infections and slower wound healing.¹⁰
Exercise follows a similar pattern of balance.
Regular moderate physical activity improves immune surveillance, enhances circulation of immune cells, reduces chronic inflammation, and supports long-term health. Excessive training without adequate recovery, however, can temporarily suppress aspects of immune function.¹¹
Notice a pattern?
Almost everything we’ve discussed comes back to the same principle.
The immune system performs best when the rest of the body is adequately resourced.
Which brings me back to something I say almost every day in clinic.
Health isn’t built by doing one extraordinary thing.
It’s built by doing ordinary things consistently enough that your body has the resources it needs when extraordinary challenges eventually arrive.
And they always do.
Why I Sometimes Get Curious When Someone Says, “I Never Get Sick”
Remember the question I mentioned at the beginning of this article?
“When was the last time you were sick?”
By now, you probably understand why I ask it.
The answer tells me much more than whether you’ve recently had a cold. It provides insight into how your immune system is interacting with the rest of your physiology and whether your body appears to have the resources it needs to respond appropriately to life’s everyday challenges.
When someone tells me they seem to catch every illness that circulates through the office, we begin asking why. If another patient tells me they’ve had three sinus infections this year or that every cold seems to settle into their chest for weeks, that also gives me important clues. Then there are the patients who proudly tell me they haven’t been sick in fifteen years.
Sometimes that is exactly what I hope to hear.
They’re energetic. They sleep well. They recover quickly from exercise. Their digestion is healthy. Their stress feels manageable. Their laboratory work supports the picture of someone whose body is functioning efficiently.
Wonderful.
Other times, however, the story looks very different.
The patient sitting across from me is profoundly exhausted. They’re surviving on caffeine, sleeping five hours each night, constantly overwhelmed, struggling with digestive symptoms, and telling me they simply push through every day because they have no other choice. Then they proudly add, “But I never get sick.”
That answer doesn’t necessarily reassure me.
Instead, it makes me curious.
Is this an exceptionally resilient immune system? Perhaps.
Or has this person’s body become so depleted that it struggles to generate the kind of robust inflammatory response that would normally create noticeable symptoms? Could their immune system be conserving resources because there simply aren’t enough available to mount a vigorous response?
The truth is that no single answer tells us everything. Medicine almost never works that way. One symptom, or the absence of one, is rarely enough to draw meaningful conclusions. Instead, we begin assembling dozens of small pieces until the larger picture starts to come into focus.
That is one of the reasons medicine remains both humbling and endlessly fascinating.
The Immune System Learns Through Experience
One of my favorite analogies for explaining immune resilience is strength training.
Imagine walking into a gym for the very first time. Your muscles haven’t experienced this particular challenge before, so your first workout feels difficult. Tiny microscopic injuries occur within muscle fibers, inflammatory signals are released, damaged tissue is repaired, and over the following days your muscles adapt. Assuming you recover well, your body becomes stronger and more capable of handling that same challenge in the future.
That adaptation only occurs because two important things happen.
First, the body encounters an appropriate challenge.
Second, it has adequate resources and enough time to recover afterward.
Without challenge there is little reason to adapt. Without recovery there is very little opportunity to rebuild.
The adaptive immune system functions in a surprisingly similar way.
When your body encounters a virus or bacterium for the first time, specialized immune cells begin identifying that organism and coordinating a targeted response. As the infection resolves, populations of memory B cells and memory T cells remain behind, essentially creating a biological record of what the immune system has learned. If that same pathogen appears again months or even years later, those memory cells allow the immune system to recognize it much more quickly and respond far more efficiently.¹²
This process, known as immunological memory, is one of the most elegant features of the human immune system. It allows us to learn from previous exposures while becoming increasingly efficient at recognizing familiar threats.
Of course, this does not mean we should intentionally seek out infections or ignore preventive measures. There are many pathogens capable of causing severe illness, and protecting ourselves through appropriate hygiene, vaccination when indicated, and healthy lifestyle choices remains incredibly important.
What it does mean is that our immune systems evolved expecting interaction with the world around us.
For an otherwise healthy individual, an occasional uncomplicated viral illness is not necessarily evidence that the immune system has failed. Sometimes it is simply evidence that the immune system is doing exactly what it was designed to do.
One of the Most Powerful Concepts in Medicine Is Physiological Reserve
There is another concept that quietly influences almost every decision I make as a physician, even though patients rarely hear it discussed outside of medicine.
It is called physiological reserve.
I often describe physiological reserve as your body’s savings account.
Every night of restorative sleep makes a deposit.
A nourishing meal makes another.
Maintaining muscle mass, spending time outdoors, managing stress effectively, building meaningful relationships, exercising consistently, and allowing yourself adequate recovery all contribute to that account. Over time, those seemingly ordinary habits create a body that is better equipped to handle extraordinary challenges.
Life, of course, also makes withdrawals.
Acute illness makes a withdrawal.
Poor sleep makes a withdrawal.
Pregnancy, caring for a newborn, major surgery, grief, financial stress, chronic inflammation, environmental exposures, and demanding work schedules all require the body to spend from its reserves.
The goal is not to eliminate withdrawals. That would be impossible.
The goal is to consistently replenish what life inevitably asks us to spend.
This perspective helps explain why two people can be exposed to the same virus and experience very different outcomes. One person may recover with little more than a runny nose while another spends two weeks feeling completely exhausted. Genetics certainly contribute, but so do nutritional status, sleep quality, metabolic health, stress levels, age, microbiome diversity, previous immune experiences, and countless other variables that collectively determine how much physiological reserve someone has available at that moment.¹³
When patients tell me they feel like they have “no gas left in the tank,” they’re often describing physiological reserve without realizing it.
Their body is telling them the account has been overdrawn.
Why Naturopathic Medicine Thinks About Immunity Differently
People sometimes ask what makes a naturopathic approach to immune health different from a conventional approach.
While there are certainly differences in therapies, I think the biggest distinction begins much earlier.
It starts with the questions we ask.
Rather than asking only, “What can we give this immune system?” we also ask, “What has been preventing this immune system from functioning the way it was designed to?”
That shift in perspective changes everything.
Instead of immediately reaching for another supplement, we begin looking for obstacles that may be interfering with normal physiology.
Has chronic stress fundamentally altered communication between the nervous system and immune system?
Has poor sleep reduced the body’s ability to regulate inflammation?
Has repeated antibiotic use changed the composition of the gut microbiome?
Are blood sugar fluctuations contributing to chronic inflammatory signaling?
Is vitamin D insufficient?
Has the patient been living or working in an environment that continually activates the immune system?
Have years of overwork simply left this person with very little physiological reserve?
Those questions often lead to very different treatment plans because they recognize an important truth.
The immune system does not exist independently of the rest of the body.
It is constantly responding to the information it receives from every other physiological system.
This philosophy is deeply rooted in naturopathic medicine. Rather than trying to force the body into health, we aim to remove obstacles, restore missing resources, and create the conditions that allow normal physiology to function more effectively.
Sometimes that includes targeted supplementation.
Sometimes it includes nutritional therapy.
Sometimes it means improving sleep, rebuilding the gut microbiome, addressing environmental exposures, managing stress more effectively, or simply giving the body permission to recover after years of running on empty.
The treatment recommendations may differ from patient to patient, but the philosophy remains remarkably consistent.
Support the body’s innate ability to heal.
Looking Ahead
Over the past several weeks, we’ve explored how our environment influences health and how the immune system works tirelessly to protect us every day. One of the themes that has continued to emerge is that no body system functions in isolation. The lungs influence the immune system. The nervous system influences the immune system. Hormones influence the immune system.
Perhaps no relationship is more fascinating than the one between the immune system and the gut.
As you’ll remember, nearly seventy percent of immune cells reside within tissues associated with the gastrointestinal tract, making the digestive system one of the body’s most active immune training grounds. The conversations occurring between your microbiome, intestinal lining, immune cells, and nervous system are shaping your health every single day.
That relationship is so important that we’re dedicating next month’s educational series entirely to gastrointestinal health. We’ll explore digestion, the gut microbiome, intestinal permeability, nutrient absorption, and why supporting digestive health can influence everything from immune resilience and inflammation to mood, hormones, and energy.
It is one of my favorite topics to teach because once patients understand the gut, so many seemingly unrelated symptoms begin to make sense.
A Final Thought
One of the greatest privileges of being a naturopathic doctor is watching patients begin to trust their bodies again.
Somewhere along the way, many people were taught that every symptom meant their body was broken, every fever should be feared, and every illness meant they had somehow failed.
I don’t see it that way.
I see bodies working incredibly hard to protect the people who live inside them.
Sometimes they need guidance.
Sometimes they need resources.
Sometimes they need rest.
Almost always, they deserve our curiosity before our criticism.
The more I learn about medicine, the more respect I have for the extraordinary intelligence of the human body. It is constantly adapting, communicating, repairing, learning, and striving to maintain balance in a world that asks a great deal of it. Our role as physicians is not simply to fight disease. It is to understand the barriers preventing health and help remove them whenever we can.
Your body is far wiser than we often give it credit for. Our job is not to overpower it. Our job is to understand it, support it, and give it every opportunity to do what it was beautifully designed to do.
Because in the end, your immune system doesn’t need to win every battle. It needs a body that’s healthy enough to keep showing up for the next one.
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