Each year, as respiratory illness circulates more widely, the same questions consistently arise.
Commons questions that arise are:
“What should I take to support my immune system?”
“Everyone’s getting sick again—what do I need?”
“Is this going to be a bad flu season?”
“Should I get the flu vaccine?”
These concerns are understandable, particularly in the context of seasonal illness patterns and
widespread public messaging. However, immune health is not a single intervention or short
term response. It reflects the integrated function of multiple physiological systems.
Understanding immunity as a system
The immune system operates in close interaction with nutrition, metabolism, and lifestyle
factors. Key influences include:
Nutrient status
Gastrointestinal health
Sleep quality
Psychological stress
Iron status
Systemic inflammation
Disruption in any of these areas can impair immune eAiciency, increasing susceptibility to
infection or aAecting recovery time.
Key nutrients involved in immune function
Vitamin C
Vitamin C contributes to immune defence through support of leukocyte function and
antioxidant activity. It is particularly relevant during periods of increased physiological stress
and infection, where oxidative demand is elevated.
Zinc
Zinc is essential for normal development and function of immune cells. Evidence suggests zinc
supplementation, particularly when initiated early in the course of infection, may reduce the
duration of common cold symptoms in adults (Hemilä & Chalker, 2015).
Vitamin D
Vitamin D functions as an immunomodulatory hormone involved in regulating both innate and
adaptive immune responses. Deficiency is common, including in populations with high sun
exposure such as Australia. Low vitamin D status has been associated with increased
susceptibility to respiratory infections and altered immune regulation (Martineau et al., 2017).
More broadly, vitamin D also supports bone health, muscle function, and metabolic regulation,
making it a key nutrient in overall health resilience (Harvard T.H. Chan School of Public Health, 2004)
Astragalus
Astragalus membranaceus is traditionally used in herbal medicine to support immune
resilience and adaptation to stress. It is generally applied in longer-term immune strategies
rather than acute infection management.
Two primary clinical contexts for immune support
1. Acute immune support
This refers to individuals who are currently unwell or in the early stages of infection.
Clinical focus includes:
Supporting immune response
Reducing symptom duration and severity
Short-term use of nutrients such as vitamin C and zinc
2. Immune resilience and prevention
This focuses on reducing frequency and severity of illness over time.
Key considerations include:
Vitamin D and iron status optimisation
Gut microbiome health
Stress and sleep regulation
Baseline immune system function
This approach prioritises prevention rather than reactive treatment.
Vaccination context and clinical positioning
Influenza vaccination is an important public health measure, particularly for individuals at
increased risk of exposure (e.g. healthcare and aged care workers) or complications (e.g. older
adults and those with chronic conditions).
Individuals may choose to receive the influenza vaccine or not, based on personal and clinical
considerations.
Regardless of this decision, the clinical objective remains consistent: Supporting a well
regulated, resilient immune system.
For those who are vaccinated, support may focus on immune readiness and recovery. For those
who are not, emphasis is placed on strengthening baseline immune defences through nutrition
and lifestyle.
Immune health is not determined by a single intervention but by the coordinated function of
multiple systems over time. A clinically grounded approach prioritises:
Nutrient suAiciency
Gut and metabolic health
Stress and sleep regulation
Evidence-based supplementation where appropriate
EAective immune support is therefore preventative, individualised, and system-based rather
than reactive.
Margaret Leedham works with Go Vita Australia and is the Brand and Training Manager for
NutriVital. She is an experienced naturopath, herbalist, nutritionist, and homeopath with over
27 years in the natural medicine industry. Her background spans product development, TGA
compliance, FSANZ guidelines, marketing, training, retail management, and clinical practice.
An Accredited Member and Fellow of ATMS, Margaret actively consults with clients, specialising
in menopause, gut health, sleep, and stress-related conditions, supporting individuals through
an evidence-based approach.











