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Ways To Improve Your Immune System

Updated: Apr 19, 2020

Author: Penny Tsai (Student Intern) - reviewed by Claire Ho APD

Even though Australia is now summer, most of the Northern hemisphere is covered in snow. The single-digit temperature can weaken the human immune system as it doesn’t perform as well when the body temperature is lowered by the environment. This year, a new virus, Wuhan coronavirus (or Covid-19), has been a hot topic people focus on recently. While fighting for the masks and hand sanitizers that are out of stock everywhere in many different countries, it’s also important to strengthen the immune system in addition to the external protections. Whilst there is currently no evidence to support that a stronger immune system or eating well could defend against the epidemic - individuals who are immuno-suppressed seem to have higher infection rates (such as elderly and those with medical conditions). One of the ways to improve the immune system is to eat the right food. Here are some eating tips that can make foods more than just a good feeling and happiness. They can strengthen your immune system and help you to decrease the chance of getting sick. (Which is also great way to prepare yourself for the Australian winter).


Protein is what makes up the body, including our cells, organs, tissues, and muscle. Moreover, it plays an important role in the regulatory system that keeps us functioning. Therefore, it’s important to have a sufficient amount of protein to make sure our body is functioning well. But what is protein? We can get protein from animal and plant-based sources. Some good animal sources will be lean meat, poultry, eggs and fish. On the other hand, some plant sources will be legumes, beans, nuts and soy products, such as soymilk and tofu. Nuts and soy products also have a huge amount of Vitamin E that is very important for the defensive cells in the immune system. However, it’s important to have a balanced diet without the excess intake of one certain nutrient. According to Australian Dietary Guidelines, it recommends people to two or three serves of lean meat, poultry, fish, eggs, nuts and seeds, and legumes/beans each day(ADG 2013).


Some people may have misleading thoughts about rice. Even though they contain a lot of starch that may potentially increase body weight, they are essential sources of energy. Even though white rice is commonly consumed by people, it will be a better option if white rice is substituted by brown rice as it has a lot of minerals and Vitamin B left on its bran and germs(bran and germs are removed for white rice). Vitamin B helps in cell growth and antioxidant protection, while some specific vitamin Bs, such as B2, B5, and B6, have really important roles in the immune system to keep it going.

At least one bowl of brown rice a day or even just mixing the brown rice with white rice can be a little thing that improves our immune system.

Check out our post here about increasing nutrition of your rice -


It is well known that we need at least 5 serves of vegetables and 2 serves of fruit a day. But do you know that the colors of the fruits and vegetables make a difference? Different colors of the plants are created by different pigments that have different impacts on human health. Therefore, it will be nice if you can choose vegetables and fruits from different colors to have a more combination of different nutrients.

Red → Lycopene, a strong antioxidant that decreases the risk of cancer

Blue/purple → Anthocyanin, a strong antioxidant that protects cells from damage while decreasing the risk of cancer, cardiovascular disease, and stroke.

Orange/yellow → Carotenoids

  • i.ex// Beta carotene is found in sweet potatoes, pumpkins, and carrots. It is converted to vitamin A which improves eye health.

  • ii.ex// Lutein is stored in the eye and has been found to prevent cataracts and age-related macular degeneration, which can lead to blindness.

Green → carotenoids, indoles, and saponins that can decrease the risk of cancer

Brown/white → phytochemicals such as allicin that has antiviral and antibacterial properties

(Nutrition Australia 2013)

4. Eat Garlic

Garlic is not only known for its strong smell but also known for its super antioxidant property. It’s can strengthen the defensive cells in our immune system to improve the defense against bacteria and viruses. Therefore, it will be good if you can consume 2 to 3 cloves of garlic or half of an onion per day.

5. Avoid Excess Fat Intake

Excess fat intake(including omega-3 and omega-6 fatty acids) can suppress the immune system. It’s found in a study that decreasing the fat intake can effectively increase the activity of defensive cells(natural killer cells)(WHO 1994). It’s recommended that 20% to 35% of the total calorie intake should come from fat. This means that people can eat 44 to 77 g (~3 to 5 tbsp)of fat/oil per day if they eat 2000 calories per day(Cleveland Clinic 2014).

Fats/oil to avoid: corn oil, soybean oil, and sunflower oil

6. Eat Less Sweets

Sugar tends to affect the production and activity of the white blood cells. It’s found in a study that about 18-20 teaspoons of sugar (~100 g) can effectively decrease the defense of white blood cells to foreign matters by at least 40%(Ullah et al 2016). According to WHO, the maximum of sugar intake is recommended to be 5 to 10 teaspoons per day.

Here are some examples of sugar quantities in packaged food and drinks:

  • Dove chocolate bar (37 g): 4.16 teaspoons of sugar

  • Hershey's Milk Chocolate bar (43 g): 4.87 teaspoons of sugar

  • Twix bar (57 g): 5.68 teaspoons of sugar

  • Milk chocolate M&M's packet (42 g): 5.68 teaspoons of sugar

  • Coca-Cola (one can, 330 ml): 7.25 teaspoons of sugar

  • Red Bull (one can): 5.35 teaspoons of sugar

  • Sprite (one can): 7.61 teaspoons of sugar

While being overwhelmed by the coronavirus outbreak, it’s important to strengthen your health from inside by eating the right food!!


  1. National Health and Medical Research Council. Australian Dietary Guidelines. 2013. Canberra: National Health and Medical Research Council. Retrieved from:

  2. Nutrition Australia. 2013. Eat a rainbow. Retrieved from:

  3. World Health Organization & Food and Agriculture Organization of the United Nations. 1994. Retrieved from:

  4. Cleveland Clinic. 2014. Fat: What You Need to Know. Retrieved from:

  5. Ullah, H, Akhtar, M, Hussain, F, Imran, M. 2016. Effects of Sugar, Salt and Distilled Water on White Blood Cells and Platelet Cells. Journal of Tumor, vol. 4, no. 1. Retrieved from:

  6. World Health Organization. 2015. Sugars intake for adults and children. Retrieved from:;jsessionid=DA324376A05B702FB7C0202528E90ABA?sequence=1

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