Herbs and nutrition have been harnessed for their health benefits by people around the world since time began. With the Australian winter nearly upon us, and given the current pandemic, here are some herbs and nutrients that have been widely used to support the immune system, reduce risk of infection and minimise symptoms should an infection occur.

A healthy, varied diet, enough sleep, managing stress, adequate physical activity and not smoking support immunity.
The basics
The cornerstone to good health and to supporting your immune system is enjoying a healthy, varied diet, getting enough sleep, managing stress, getting enough physical activity and not smoking. In addition, several herbs and supplements may also be used to support immunity. Check with your healthcare practitioner before taking supplements and if any symptoms persist.
Because COVID-19 is a novel virus, there are no proven treatments or preventative therapies including supplements, medicines or foods that are known to protect us. Until the virus is better understood, limiting community exposure through social distancing or isolation where appropriate, and practicing good hygiene are vital to limit the spread.
Your immune system
Like other body systems, your immune system is complex. Many cells and tissues make up your defence system from your skin to your gut and even eyelashes and white blood cells. Every area of the body is supported – so you could consider your body as your castle and your immune system as the soldiers that patrol and defend every part of your body.
Keeping your immune system in balance is important at every age and every stage of life. And, traditionally, a number of herbs and nutrients have been used to support the immune system – feeding and supporting your internal soldiers.
1. Astragalus
Native to China, Korea, Mongolia and Russia, the herb Astragalus has been used since the second century AD to support the immune system, and recent study has shown it supports immunity at the cellular level. This herb is an adaptogen which means that it helps to support the body’s reaction to stress. Astragalus root extract is traditionally used to promote a healthy immune system, increase resistance to infection and relieve fatigue.
2. Andrographis
Used widely in Ayurvedic medicine and traditional Chinese medicine for its anti-inflammatory properties, Andrographis contains andrographolide, a terpenoid compound shown to have antiviral effects, including against those that cause respiratory infections. When taken at the first sign of cold symptoms, Andrographis may help to prevent a cold from developing with full force. Andrographis may help to ease the symptoms of upper respiratory tract infections. It might also prevent influenza viruses from binding to cells in the body, although more research is needed to understand its effectiveness in treating the flu. It can be used to relieve symptoms of treat mild fever, the common cold and sore throat.
This herb is not recommended for use in pregnancy and breast feeding. There is a small possibility of developing taste disturbances when using Andrographis products so follow the label instructions.
3. Echinacea
Echinacea is a daisy-like plant and has been used by Native Americans for centuries. There are 2 main species used – Echinacea purpurea and Echinacea angustifolia. Various parts of these different Echinacea species are active in different ways; which is why they are frequently used together.
Echinacea supports a healthy immune response when taken at the onset of symptoms. Studies have suggested that certain species improve immune health and may have antiviral effects against several respiratory viruses, including respiratory syncytial virus and rhinoviruses. The antiviral action may be due to the presence of certain polysaccharides that increase the production of infection-fighting white blood cells.
When taken at the first sign of symptoms, Echinacea can relieve symptoms of colds and mild upper respiratory infections and may reduce the duration of cold-related symptoms such as fatigue, body aches and headache.
4. Vitamin D
The sunshine vitamin, vitamin D, is unusual because the major source is sunshine rather than food sources (it is made when the sunlight interacts with a cholesterol-like substance in your skin). Certain groups, particularly those with restricted access to sunlight may be at risk of vitamin D deficiency, which can be medically diagnosed with a simple blood test. Vitamin D is essential to support the health and functioning of your immune system.
This vitamin works by enhancing the pathogen (disease) fighting effects of white blood cells that are part of your immune defence and decreases inflammation, helping to support the immune response.
Being deficient in vitamin D may be associated with an increased risk of upper respiratory tract infections.
Food sources of vitamin D include some mushrooms, oily fish, fortified foods and egg yolks.
5. Zinc
Zinc deficiency affects around 2 billion people worldwide and is very common in older adults. About 30% of older adults may be deficient in zinc. Low levels can increase the risk of infection because this mineral helps support healthy immune system function.
It’s important not to overdo it though – too much zinc can interfere with copper absorption. Find zinc in whole grains, oysters, baked beans, chickpeas, and nuts.
6. Vitamin C
The best know nutrient when it comes to your immune system is perhaps Vitamin C. Vitamin C is vital for immune health and may reduce the severity and duration of colds. It encourages the production of white blood cells (lymphocytes and phagocytes), which help protect against infection. It also helps these white blood cells function more effectively while protecting them from damage by potentially harmful molecules, such as free radicals. Free radical damage can negatively affect immune health and is linked to numerous diseases.
Because it is water-soluble, you can’t store large amounts so it’s important to consume some every day. Good food sources include vegetables and fruits; however if you cook veggies, cook them until just tender in a small amount of water as vitamin C is destroyed by heat and can leach out into the cooking water.
Last word
Remember that although supplements can make a difference to your immune health, they can’t replace a healthy lifestyle. If you are unwell, stay at home and seek the help of your health professional.
References
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6268577/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4002847
https://www.ncbi.nlm.nih.gov/books/NBK71143/
https://pubmed.ncbi.nlm.nih.gov/25832590/