It’s Not Behaviour. It’s Biology.

Ancient Instincts, Modern Children

Parents of children with autism, PANDAS, or PANS know how easily the body can turn on itself. A mild infection, a stressful week, or a single food exposure can trigger chaos: behaviour, sleep, digestion, focus. These shifts are not random. They are biology in defence mode.

At a recent British Network for Functional Medicine conference, Dr Olivia Lesslar, an Australian medical doctor and Adjunct Senior Lecturer at Griffith University, presented research that explains why. Her field, psychoneuroimmunology, studies how the brain, immune system, and hormones communicate to decide whether the body feels safe or threatened.

For us, this is familiar territory. We have worked with this connection for years. The body’s ancient survival programs still drive inflammation and reactivity in modern children. Dr Lesslar’s research simply formalises what functional and nutritional medicine already understand, the science behind what we do every day.

The Body’s Protective Loop

The body’s first task is survival. It constantly scans for danger. When threat is detected, inflammation rises, stress hormones surge, and energy is diverted from growth and repair to defence. The system was built for short emergencies, not continuous strain.

Today the alarm never stops. Infections, toxins, blue light, poor sleep, and emotional stress all signal danger. Inflammation becomes chronic, the gut barrier weakens, and the brain begins to treat normal life as unsafe.

This is not malfunction. It is protection that has lost its rhythm.

The Survival Triggers

Dr Lesslar described nine biological triggers that once kept us alive but now trap the system in defence.

Toxins keep immune cells on alert.

Debris from old infections fuels inflammation.

Temperature extremes strain the hormonal system.

Famine from skipped meals or restrictive diets signals scarcity.

Radiation from artificial light disrupts natural rhythm.

Pathogen memory keeps the immune system armed long after infection.

Loss of tribe raises inflammation through isolation.

Sensory overload overwhelms brain regulation.

Emotional stress maintains cortisol and adrenaline beyond need.

When several triggers are active, the body loses coherence. The brain, immune system, and hormones stop communicating clearly and remain locked in survival.

Why This Matters

Psychoneuroimmunology confirms what functional medicine has long recognised. Behaviour, immunity, and inflammation are not separate problems but expressions of the same imbalance.

For many children, the issue is not one infection or one trigger. It is a system that cannot return to calm once the alarm has sounded.

Our work addresses this directly: calming inflammation, restoring gut and brain communication, and rebuilding tolerance through nutrition and immune support. This is psychoneuroimmunology in practice.

Steps Parents Can Take

Simplify Inputs
Reduce what the body must defend against. Remove processed food, artificial additives, and bright light at night. Keep routines predictable so the nervous system feels safe.

Repair Gut and Brain
Use cooked, gentle foods. Remove gluten, dairy, and other irritants. Support healing with zinc, omega 3s, and butyrate.

Support Energy
Protect sleep, hydration, and nutrient intake. The mitochondria need rest and steady fuel to recover.

Calm the Nervous System
Predictability restores safety. Limit screens after sunset. Encourage daylight exposure, outdoor time, and rhythmic movement.

Rebuild Connection
Human contact is one of the strongest regulators. Shared meals, calm voices, and steady presence lower inflammation and retrain the system to trust safety again.

The Takeaway

Psychoneuroimmunology gives scientific language to what has been clear in practice for years. The gut, brain, and immune system operate as one network, responding to the same signals of threat and safety.

The body is not broken. It is protecting. When we reduce threat, calm inflammation, and restore coherence, the system can finally regulate again.

That is when behaviour, focus, and sleep begin to settle, not by control, but by recovery.

IMPORTANT

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with medical doctors or qualified functional medicine practitioners before introducing any new supplement or intervention.

Concerned about your child’s health? We’d love to have a chat with you.

References

Bower, J.E., & Kuhlman, K.R., 2023. Psychoneuroimmunology: an introduction to immune to brain communication and its implications for clinical psychology. Annual Review of Clinical Psychology, 19, 331-359. Annual Reviews

Kiecolt-Glaser, J.K., 2010. Psychoneuroimmunology: psychology’s gateway to the biomedical future. Perspectives on Psychological Science, 4(4), 367-369. PubMed Central

Khandaker, G.M., et al., 2015. Psychoneuroimmunology or immunopsychiatry? Frontiers in Psychiatry, 6, 189. PubMed Central

Kiecolt-Glaser, J.K., & Slavich, G.M., 2023. Cultivating a healthy neuro immune network: a health psychology lens on psychoneuroimmunology. Frontiers in Psychology, 14, 10062207. PubMed Central

Maier SF, Goehler LE, Fleshner M, Watkins LR. The Role of the Vagus Nerve in Cytokine-to-Brain Communication. Annals of the New York Academy of Sciences. 1998;840(1):289–300. https://doi.org/10.1111/j.1749-6632.1998.tb09569.x

Lesslar, O.J.L., Smith, P.K., Venter, C., O’Mahony, L., & Canani, R.B., 2023. Do advanced glycation end products contribute to food allergy? Frontiers in Allergy, 4, 1148181. DOI

Raison, C.L., & Miller, A.H., 2013. Malaise, melancholia and madness: the evolutionary legacy of an inflammatory bias. Brain, Behaviour, and Immunity, 31, 1-8. DOI

Osborne, N.N., Núñez-Álvarez, C., Del Olmo-Aguado, S., & Merrayo-Lloves, J., 2017. Visual light effects on mitochondria: the potential implications in relation to glaucoma. Mitochondrion, 36, 29-35. DOI