TLDR
Seasonal weather changes can place additional stress on the immune system. Nutrients such as vitamin D, zinc, vitamin C and B vitamins are commonly used to support normal immune function.
In Australia, vitamin D levels can decline during cooler months due to reduced sunlight exposure. Combined with generally low dietary intake of vitamin D-rich foods, this may influence overall vitamin D status. Vitamin D plays an important role in immune regulation, supporting the body’s natural defence systems.
Choosing supplements from reputable Australian companies that follow Therapeutic Goods Administration (TGA) standards can help ensure quality and safety.
Why Do Seasonal Weather Changes Affect Our Immune System?
Many Australians report feeling more fatigued when the weather shifts between seasons.
Changes in temperature, daylight hours, and daily routines can influence immune function.
Several factors may explain why seasonal transitions often coincide with increased coughs, colds or fatigue.
Reduced Sunlight Exposure
Sunlight is the main source of vitamin D production in the skin.
During winter, shorter days and increased indoor activity can reduce exposure to sunlight. This may influence vitamin D levels in some individuals.
Vitamin D is involved in immune signalling and helps regulate certain immune cells.
More Time Indoors
Cooler weather often means people spend more time indoors.
Indoor environments may increase close contact with others and reduce airflow, which can influence how easily common respiratory viruses circulate.
Routine Changes
Seasonal shifts can influence everyday habits such as:
- Sleep patterns
- Physical activity levels
- Diet quality
- Stress levels
All of these factors contribute to overall immune health.
Dry Air and Mucosal Barriers
Cold or dry air may affect the body's natural protective barriers, such as the nasal passages and throat.
These barriers play a role in the body's first line of defence against environmental irritants and pathogens.
What Are the Best Vitamin Supplements for Immune Support in Australia?
A balanced diet remains the foundation of immune health. However, vitamin and mineral supplements are commonly used to help support nutritional intake when dietary gaps occur.
Below are several nutrients widely used to support normal immune function.
Vitamin D
Vitamin D plays a key role in immune system regulation.
It interacts with immune cells that help coordinate immune responses throughout the body.
Despite Australia being known for its sunshine, vitamin D insufficiency can still occur due to:
- Indoor lifestyles/office jobs
- Sun protection practices
- Seasonal daylight changes
- Lack of Vitamin D rich foods
Some people choose vitamin D supplements to help maintain adequate levels during cooler months.
Approximately 1 in 4 Australian adults are vitamin D deficient, with rates rising / higher in winter, especially in southern states.
Zinc
Zinc is an essential mineral that is important for the communication between immune cells, helping them to work together more efficiently. Adequate zinc intake ensures efficient immune response, reducing infections.
It is commonly used to support:
- Normal immune system function
- Skin health
- Nutrient metabolism
Dietary sources include meat, seafood, nuts and seeds.
Vitamin C
Vitamin C contributes to immune system function and provides antioxidant support.
It also supports collagen production and helps protect cells from oxidative damage.
Foods rich in vitamin C include:
- Citrus fruits
- Capsicum
- Berries
- Broccoli
Some people use vitamin C supplements during times of increased stress or seasonal change.
B Vitamins
B vitamins support energy metabolism and nervous system health.
When people feel fatigued during seasonal transitions, B vitamins may help support energy production and overall well-being.
|
Nutrient |
Role in the Body |
Food Sources |
Why People Supplement |
|
Vitamin D |
Supports immune regulation and bone health |
Sunlight, fatty fish |
Lower sun exposure |
|
Zinc |
Supports immune cell function |
Meat, seeds, shellfish |
Dietary gaps, frequent flu/ colds |
|
Vitamin C |
Antioxidant and immune support |
Citrus fruits, vegetables |
Low intake of fruit and vegetables, frequent flu/ colds |
|
B Vitamins |
Energy metabolism and nervous system support |
Whole grains, legumes, and meat |
Fatigue or stress |
Trusted, Australian Companies That Manufacture Vitamin Supplements
Australia has one of the most regulated supplement markets in the world through the Therapeutic Goods Administration (TGA).
When selecting supplements, consumers may wish to look for products listed on the Australian Register of Therapeutic Goods (ARTG).
At Vitable, we operate to TGA standards, with products listed on the ARTG where applicable, and a strong focus on quality and transparency. Our formulas use carefully selected ingredients with clear labelling, designed to support everyday health alongside good nutrition, sleep, movement and stress management.
Take our 2-minute quiz to find your personalised vitamin plan.
Frequently Asked Questions
Do vitamin supplements prevent colds?
Certain vitamins and minerals, such as vitamin C, vitamin D and zinc, can support immune cell activity and help the body respond to infections. In some cases, they may help reduce the duration or severity of cold symptoms, particularly if a person has a nutrient deficiency.
Rather than preventing illness outright, vitamins primarily support the normal functioning of the immune system, which can make it easier for the body to fight off pathogens and recover from infections.
Is vitamin D deficiency common in Australia?
Some Australians may have lower vitamin D levels, particularly during the cooler months when sunlight exposure is reduced. Vitamin D is primarily produced in the skin after exposure to sunlight, so levels can vary depending on season, location, lifestyle and time spent outdoors.
It can also be difficult to obtain sufficient vitamin D from food alone, as relatively few foods naturally contain meaningful amounts. Oily fish such as salmon, sardines and mackerel are among the richest dietary sources, and Australian dietary guidelines generally recommend two serves of fish per week as part of a healthy diet.
Because sunlight exposure and dietary intake vary, some people may choose vitamin D supplements to help maintain adequate levels, particularly when sun exposure is limited.
Can I take multiple immune-support supplements together?
Some nutrients are often combined in supplement formulas. Speaking with a healthcare professional may help determine what is appropriate for individual needs.
When should Australians consider vitamin D supplements?
Some people review vitamin D intake during winter when sunlight exposure decreases.
References
- Dunlop, E., Boorman, J. L., Hambridge, T. L., McNeill, J., James, A. P., Kiely, M., Nowson, C. A., Rangan, A., Cunningham, J., Atyeo, P., Adorno, P., & Black, L. J. (2023). Evidence of low vitamin D intakes in the Australian population points to a need for data-driven nutrition policy for improving population vitamin D status. Journal of Human Nutrition and Dietetics, 36(1), 203–215. https://doi.org/10.1111/jhn.13002
- Mitra S, Paul S, Roy S, Sutradhar H, Bin Emran T, Nainu F, Khandaker MU, Almalki M, Wilairatana P, Mubarak MS. Exploring the Immune-Boosting Functions of Vitamins and Minerals as Nutritional Food Bioactive Compounds: A Comprehensive Review. Molecules. 2022 Jan 16;27(2):555
https://pmc.ncbi.nlm.nih.gov/articles/PMC8779769/pdf/molecules-27-00555.pdf
