The Spine-Immune System Connection: What Most People Don't Know

By Dr. Andrew Biggs, DC | Principled Chiropractic | Royal Palm Beach, FL

When most people think about their immune system, they think about vitamin C, hand washing, sleep, and maybe a zinc supplement during cold and flu season. These are all reasonable things to think about. There is a connection between immunity and the health of the human body that almost never comes up in these conversations, one that has been documented in scientific research for decades and that changes the way many of our patients think about their health entirely.

That connection is the relationship between the spine, the nervous system, and the immune system.

It is not a fringe idea. It is not alternative medicine speculation. It is grounded in the basic science of how the nervous system and immune system communicate, and in a growing body of research that points to a clear, measurable link between spinal health and the body's ability to defend itself against illness.

Most people simply don't know this connection exists. Today, we'd like to change that.

Two Systems That Were Never Really Separate

For most of the twentieth century, the nervous system and the immune system were studied largely in isolation from each other. Neuroscientists studied the brain and nerves. Immunologists studied antibodies and white blood cells. The two fields rarely spoke.

That changed dramatically in the 1970s and 1980s, when a new field of research called psychoneuroimmunology emerged; the study of how the nervous system, the endocrine system, and the immune system interact. What researchers discovered was not a loose, indirect relationship between these systems. It was a deeply integrated, two-way communication network in which each system continuously influenced and regulated the other.

The central nervous system, specifically the brain and spinal cord, is constantly sending and receiving signals that affect immune function. Immune cells have receptors for neurotransmitters. The nervous system has direct anatomical connections to immune organs, including the thymus, spleen, and lymph nodes. Stress hormones produced by the nervous system directly alter immune cell behavior. And immune signaling molecules called cytokines feed information back to the brain, influencing mood, behavior, sleep, and pain perception.

In short: the nervous system and the immune system are not two separate departments in the body. They are partners in an ongoing, dynamic conversation. And the spine, as the primary housing and conduit of the nervous system, sits at the center of that conversation.

The Nervous System's Role in Immune Regulation

To understand why spinal health matters for immunity, it helps to understand the specific pathways through which the nervous system regulates immune function.

The Autonomic Nervous System and Immune Organs

The autonomic nervous system, the branch of the nervous system responsible for regulating involuntary functions like heart rate, digestion, and respiratory rate, has direct neural connections to the primary organs of the immune system. Sympathetic nerve fibers innervate the thymus (where T-cells mature), the spleen (where immune responses are coordinated), and the lymph nodes (where immune cells are activated and deployed).

Norepinephrine, a neurotransmitter present in sympathetic nerve fibers that innervate lymphoid organs, plays a significant role in the regulation of the immune system. When the nervous system is under chronic stress, the resulting flood of stress hormones suppresses immune function. When the nervous system is well-regulated and free of interference, immune communication is clear, coordinated, and responsive.

This is not a theoretical mechanism. It is a documented physiological pathway. Stressful conditions (whether physical or emotional) lead to altered measures of immune function and altered susceptibility to a variety of diseases, with the immune system highly impacted by the nervous system through the interconnection between the autonomic nervous system and the endocrine system.

The Vagus Nerve: The Immune System's Primary Regulator

The vagus nerve, the longest cranial nerve in the body, originating in the brainstem and traveling through the neck, chest, and abdomen, is one of the most important regulators of immune function in the entire body.

Research has established what is known as the cholinergic anti-inflammatory pathway: the vagus nerve actively suppresses excessive inflammatory responses by signaling the spleen to reduce the production of inflammatory cytokines. This is a critical function. Chronic inflammation is not just uncomfortable, it is the underlying mechanism of virtually every major chronic disease, from cardiovascular disease and diabetes to autoimmune conditions and cancer.

A vagus nerve that functions well, one whose signal travels freely through a structurally sound upper cervical spine, keeps inflammation in check, supports immune regulation, and contributes to the kind of resilient, well-balanced immune function that keeps the body healthy over the long term.

A vagus nerve whose signal is compromised by a NeuroStructural Shift in the upper cervical spine cannot perform this function as effectively. The resulting reduction in vagal tone contributes to increased inflammatory tone throughout the body, a state of chronic, low-grade immune dysregulation that most people live with for years without recognizing its connection to the health of their spine.

The Stress-Immunity Axis

The relationship between the nervous system's stress response and immune function is one of the most extensively documented areas of modern medicine. Cortisol, the primary stress hormone produced by the adrenal glands in response to nervous system activation, directly suppresses multiple aspects of immune function, including the activity of natural killer cells, the production of antibodies, and the inflammatory response.

High levels of stress hormones like cortisol can weaken the immune system, making it harder for your body to fight infections and stay healthy.

When NeuroStructural Shifts are present in the spine, the nervous system tends to operate in a state of chronic sympathetic dominance, the fight-or-flight state we discussed in our post on ADHD and the nervous system. In this state, the body is continuously producing elevated stress hormones, continuously suppressing immune function, and continuously diverting resources away from the repair and regulation processes that keep the immune system healthy.

This is not an acute stress response. It is a chronic, low-level state of neurological dysregulation, one that most people never connect to their recurring colds, slow recovery from illness, allergy flare-ups, or persistent fatigue. But the connection is direct, physiologically documented, and profoundly relevant to anyone who wants to understand what is actually driving their immune health.

What the Research Shows

The theoretical framework connecting spinal health to immune function is compelling. But the research makes it concrete.

Dr. Ronald Pero's Landmark Study

In 1975, Dr. Ronald Pero, Ph.D., chief of cancer prevention research at New York's Preventive Medical Institute and Professor of Medicine in Environmental Health at New York University, began developing scientifically valid ways to estimate individual susceptibility to various chronic diseases.

In 1986, Pero collaborated with Joseph Flesia, D.C., Chairman of the Board of Directors for the Chiropractic Basic Science Research Foundation, and began a research project at the University of Lund in Sweden. They hypothesized that people receiving long-term chiropractic care would show enhanced immune competence compared to those who had not received care.

What they found exceeded their expectations.

Chiropractic patients were found to have a 200% greater immune competence than those people who had not received chiropractic care, and 400% greater immune competence than those people with cancer and other serious diseases.

Crucially, this immune superiority did not appear to diminish with age, suggesting that the benefit of regular chiropractic care on immune function compounds over time rather than fading.

Dr. Pero's own words are worth noting: "When applied in a clinical framework, I have never seen a group other than this chiropractic group to experience a 200% increase over the normal patients. This is why it is so dramatically important. We have never seen such a positive improvement in a group."

The Interleukin-2 Study

A groundbreaking study by Teodorczyk-Injeyan and colleagues examined chiropractic's effect on the production of interleukin-2 (IL-2), an immunoregulatory molecule that is instrumental in the body's response to microbial infection and for the body's ability to discriminate between foreign and self tissue. IL-2 is pivotal in T-cell-dependent immune responses and plays a major role in the development, maintenance, and survival of regulatory T cells.

The study followed 67 patients who had blood samples taken before and 20 minutes and 2 hours after receiving an adjustment, finding measurable increases in immune-regulating molecules following spinal correction. These changes occurred rapidly, within minutes, suggesting a direct neurological mechanism rather than a slow, indirect effect.

White Blood Cell Activity

A study from the National College of Chiropractic in Lombard, Illinois found that disease-fighting white blood cell counts were higher just 15 minutes after a chiropractic adjustment was applied to the spine.

A study published in the Journal of Chiropractic Medicine found that upper cervical adjustments significantly increased white blood cell counts, which are essential for immune defense.

White blood cells are the soldiers of the immune system. They identify, attack, and neutralize pathogens, foreign invaders, and abnormal cells. An increase in white blood cell activity following spinal correction is a direct, measurable indicator of enhanced immune readiness.

Historical Evidence: The 1918 Influenza Pandemic

Perhaps the most striking historical data on chiropractic and immune function comes from the 1918 influenza pandemic, one of the deadliest infectious disease events in recorded history, which killed an estimated 50 to 100 million people worldwide.

During the 1918 influenza epidemic, patients under chiropractic care showed remarkably better outcomes, with only 25 deaths per 10,000 cases compared to 950 deaths under conventional medical care.

This is a staggering difference. It cannot be dismissed as coincidence, and it was not lost on the chiropractic profession or on the patients who experienced it. In the years following the 1918 pandemic, chiropractic care saw a dramatic increase in public adoption, in large part because so many families had witnessed firsthand the difference in outcomes between those who were under chiropractic care and those who were not.

We cite this historical data not to overclaim, as the world of 1918 was very different from today, and this observation predates modern clinical trial methodology, but because the pattern it describes is entirely consistent with what the subsequent century of research has documented: that a nervous system operating with structural integrity supports a more capable, more resilient immune response.

How NeuroStructural Shifts Compromise Immunity

With this research context established, the mechanism becomes clear.

When a NeuroStructural Shift is present in the spine, particularly in the upper cervical region where the brainstem, vagus nerve, and the primary autonomic regulatory centers are housed, it creates neurological interference in the precise pathways responsible for immune regulation.

The result is a nervous system that:

• Operates in a state of chronic sympathetic dominance, producing elevated stress hormones that directly suppress immune function

• Delivers compromised vagal tone, reducing the body's ability to regulate inflammation through the cholinergic anti-inflammatory pathway

• Sends disrupted signals to immune organs (the thymus, spleen, and lymph nodes) that depend on clear neural communication to coordinate immune responses

• Diminishes the production and activity of immune-regulating molecules like interleukin-2 and the natural killer cells that patrol the body for pathogens and abnormal cells

None of this produces a dramatic, immediately obvious symptom. You don't feel your vagal tone drop. You don't notice when your white blood cell activity decreases. You don't sense the subtle shift in your inflammatory baseline.

What you do notice, eventually, is that you seem to catch every cold that goes around the office. That your recovery from illness takes longer than it used to. That your allergies are getting worse each year. That you're tired in a way that sleep doesn't fully resolve. That your body just doesn't seem to bounce back the way it once did.

These are the downstream expressions of a nervous system that has been operating under structural interference, often for years, without anyone identifying or addressing the underlying cause.

Immunity Across the Lifespan

The spine-immune connection is relevant at every stage of life, but it takes on particular significance at the extremes of the age spectrum.

In Infants and Children

The immune system of a newborn is immature and highly dependent on the nervous system for its development and regulation. An infant whose upper cervical spine has been stressed by the birth process, as we discuss in our post on birth trauma, may have compromised neurological signaling to the immune system from the very first days of life.

This may help explain why some children seem to get every illness that circulates through daycare or school while others remain relatively healthy under the same conditions. It may also contribute to the high rates of recurrent ear infections in children, a condition with well-documented associations with upper cervical dysfunction, and to the susceptibility to respiratory illness that many parents observe in their infants and toddlers.

Early evaluation and correction of upper cervical dysfunction in infants can support healthy immune development during the most critical window of neurological growth; the first several years of life, when the nervous system is developing faster than it ever will again.

In Aging Adults

Dr. Pero's finding that the immune superiority of chiropractic patients does not diminish with age is particularly significant for adults in their middle and later years.

Immunosenescence, the gradual decline of immune function with aging, is a well-documented phenomenon. The immune system becomes slower to respond, less accurate in distinguishing self from non-self, and more prone to chronic low-grade inflammation. This decline is considered a major contributor to the increased susceptibility to infection, cancer, and autoimmune disease that characterizes aging.

If regular chiropractic care supports immune function in a way that does not weaken with age, it represents a profoundly important tool for maintaining immune health through the decades, not by replacing the natural aging process, but by ensuring that the nervous system continues to support immune function as effectively as the body's age allows.

What This Means for Your Family

We want to be clear about what we are and are not claiming here.

We are not claiming that chiropractic care cures infections, prevents all illness, or replaces any aspect of medical care. We are not suggesting that patients discontinue appropriate medical treatment in favor of chiropractic adjustments.

What we are saying is this: the nervous system regulates the immune system. The spine houses and protects the nervous system. When the spine is structurally compromised, the nervous system cannot regulate the immune system as effectively. And when that structural interference is corrected through NeuroStructural chiropractic care, the research consistently shows measurable improvements in immune function.

If you are looking for every legitimate, evidence-informed way to support your family's health, including the health of your immune system, the structural integrity of your spine deserves to be part of that conversation.

Take the First Step

Principled Chiropractic has been serving Royal Palm Beach, Wellington, West Palm Beach, Loxahatchee, Lake Worth, and the surrounding Palm Beach County communities since 2008. We offer complimentary consultations for new patients, a conversation, not a commitment, so that you can learn whether NeuroStructural chiropractic care is the right fit for your family's health goals.