Strengthen Your Immunity This Winter

True Protein Blog Avatar Fallback reviewed by our Nutrition Team 02 July 2018

Winter-time marks the start of cold and flu season, but luckily we have the strategies for you to strengthen your immunity and protect yourself from falling ill

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Strengthen Your Immunity This Winter

Energy - You might not be eating enough

For many of us, winter is a time where we do a little less exercise and a little more indulging in comfort food whilst snuggled up on the couch, but for some we see it as a time to boost activity and restrict energy intake.


If you're not consuming enough energy to support your training load then over time you will lower your immune defences, which means you’re more likely to fall ill. If this happens over an extended period of time then you may see a decrease in strength, exercise performance and a reduced ability to recover from activity. This could eventually result in poor hormone regulation and compromised bone health.

It is a myth to assume you must reduce your energy or carbohydrate intake during the winter months. Unless you have changed your activity levels then your body will still require the same amount as every other month of the year. So, be sure to fuel your training appropriately.


If you’re looking to lose weight through a reduced energy intake, then do so with a well-balanced and nutrient-dense diet. A drastic restriction below your metabolic needs is unhealthy and unsustainable in the long run. Opt for a small-to-moderate energy deficit specific to you as an individual.

Fluids - For hydration and detoxification


Keeping your fluid levels up when sick is a must. This will assist your body’s natural detoxifying organs (kidneys, skin, liver and gut) to do what they do best, as dehydration can worsen cold and flu symptoms as well as making you feel lethargic.


Water is the best choice, so drink at least two litres per day. Individuals with high sweat rates should be particularly careful about meeting their fluid needs. Taking note of urine colour and volume can be useful for monitoring hydration levels.


If you’re struggling to meet your fluid requirements in winter, try warm water with lemon and ginger slices or herbal teas for a soothing and comforting option.


Vegetables - The hero in every diet


Your mother was right, as usual, you need to eat your vegetables, there’s no question about it! Vegetables are packed with a complex mix of immune-boosting antioxidants, vitamins and minerals. Consuming different vegetable varieties and colours will ensure you get a range of nutrients to support and strengthen your immune defences.


Winter is the perfect time for vegetable-packed bone broths, hearty soups and country-style roast dinners. Adding garlic, in specific, to your winter recipes will incorporate natural compounds that have shown anti-inflammatory and anti-viral properties from studies conducted in vivo1.


Zinc - The ultimate protective mineral


Zinc plays many roles in the body, including assisting the normal development and function of our immune cells and antibodies. Low zinc levels can be a concern for athletes, vegans, vegetarians and those who sweat heavily.




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Zinc can reduce the severity and duration of the common cold if administered within 24 hours of the onset of symptoms2.

Meat, fish, oysters and poultry are major contributors of zinc to the diet, but wholegrain cereals, fortified cereals, nuts and dairy foods also contribute substantial amounts. If you don’t consume enough of these foods then supplementation with a quality product like True ZMA could be an option.


Excessive and long-term zinc supplements is not recommended as it can interfere with the absorption of other nutrients such as iron and copper.


Probiotics - Good health starts in the gut


Probiotics are the ‘good’ bacteria found in cultured, fermented and pickled products, but can also be supplemented in our diet. These friendly microorganisms can improve the health of their host by having a positive impact on the immune system.


Probiotics can prevent upper respiratory tract infections (URTIs) and may reduce the duration of illness according to a systematic review3. Acute URTIs include the common cold and inflammation of the trachea and larynx with symptoms such as fever, cough, pain and headaches. The majority of acute URTIs are caused by viral infections and usually resolve after three to seven days.


Boost your probiotic intake by consuming natural yoghurt with active cultures, kefir, kimchi, kombucha and sauerkraut.


Vitamin D - To fight off the winter blues


Vitamin D is a fat-soluble vitamin that is essential in many bodily function including the absorption of calcium required for healthy muscle contraction. Vitamin D is found in fish, eggs and fortified food. However, 90% of the vitamin D we acquire is synthesised in our skin from direct sunlight exposure, but our body’s ability to carry out this process decreases as we age.


According to a systematic review and meta-analysis, vitamin D supplementation was proven to be a safe and effective measure in protecting against acute respiratory infections. This includes the common cold, pneumonia and various other acute ear, sinus, throat and lung infections4.

Low vitamin D levels have been associated with depression, where supplementation of vitamin D3 has shown improvements in depressive symptoms5. The winter months have been linked to depressive symptoms in cases of seasonal affective disorder (SAD).

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In Australia, vitamin D deficiency is relatively high and associated with obesity, the winter months and low levels of physical activity6. If you’re concerned that you have low vitamin D levels or you are not getting enough sunlight exposure then consult your doctor for a blood test.


Vitamin C - For a speedy recovery


Vitamin C is important for maintaining strong immunity. It is a water-soluble vitamin, which means it can’t be stored by the body. You must consume vitamin C in your diet to ensure adequate levels. Luckily, vitamin C is found in many fruits and vegetables, so if you are consuming the Australian Dietary Guidelines’ recommended two serves of fruit and five to seven serves of vegetables daily, then there’s no need to supplement.

If you find that your appetite is low from illness and you need a nutrient hit, try True’s natural Greens powder for a powerful vitamin C boost.

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Vitamin C supplementation is commonly suggested for preventing the common cold. However, a systematic review showed it’s more useful in helping you recover from a cold by reducing the severity and duration7. If you’re training heavily, it has also been shown to reduce the incidence of colds. But high doses are not recommended as excessive supplementation can have a negative effect on exercise adaptations8. Another prime example of when too much of a good thing can be bad!

Handwashing - Simple and extremely effective


Possibly the most simple practice, yet often overlooked. Washing your hands with plain soap is a proven method to reduce the spread of respiratory viruses9.


Centers for Disease Control and Prevention (CDC) recommends to wash your hands for at least 20 seconds:

  • Before, during and after preparing food

  • Before eating food

  • Before and after caring for someone who is sick

  • Before and after treating a cut or wound

  • After using the toilet

  • After changing diapers or cleaning up a child who has used the toilet

  • After blowing your nose, coughing or sneezing

  • After touching an animal, animal feed or animal waste

  • After handling pet food or pet treats

  • After touching garbage


Some of these occasions are clearly obvious times you would wash your hands, but I’m the first to admit that in the past I have sneezed and didn’t dash off to the sink for a thorough 20-second hand wash! Alas, I will keep this in mind now I’ve realised I have somewhat contributed to the spread of illness.

Final thoughts...


Winter time marks the start of cold and flu season, but luckily there are numerous strategies you can adopt to strengthen your immunity and protect yourself from falling ill.


Strategies to help prevent catching a cold or flu:

  • Eat a nutrient-dense diet that provides you with enough energy to support your lifestyle, exercise demands and a healthy immune system.

  • Consume lots of colourful vegetables of different varieties every day. For a micronutrient top-up try True Greens.

  • Keep hydrated by drinking plenty of water.

  • Consume probiotic-rich foods like natural yoghurt with active cultures, kefir, kimchi, kombucha and sauerkraut.

  • Be mindful of washing your hands and coming into contact with others who are unwell.

  • Keep on top of stress. Take the time to go outside and soak up the sunshine for essential vitamin D.

  • True ZMA contains zinc, which is protective against many illnesses and the unique formulation promotes healthy sleep.


Strategies to help recover from a cold or flu:

  • Drink plenty of water to prevent dehydration, which can worsen symptoms of a cold and flu.

  • Try to eat a healthy nutrient-dense diet with lots of colourful vegetables and fruit, probiotic and zinc-containing foods to support your immune defenses in fighting off illness. If your appetite is low, try nourishing and comforting foods like herbal/lemon tea, vegetable and chicken bone broths or True Greens for a micronutrient top-up.

  • Rest and sleep so your body can recover properly and your immune system can do what it does best, naturally.

  • Wash your hands frequently and be mindful of others as the cold and flu virus is highly contagious.





  1. Arreola R, Quintero-Fabián S, López-Roa RI, et al. Immunomodulation and Anti-Inflammatory Effects of Garlic Compounds. Journal of Immunology Research. 2015;2015:401630. doi:10.1155/2015/401630.
  2. Singh M, Das RR. Zinc for the common cold. Cochrane Database of Systematic Reviews 2011, Issue 2. Art. No.: CD001364. DOI: 10.1002/14651858.CD001364.pub3.
  3. Hao Q, Dong BR, Wu T. Probiotics for preventing acute upper respiratory tract infections. Cochrane Database of Systematic Reviews 2015, Issue 2. Art. No.: CD006895. DOI: 10.1002/14651858.CD006895.pub3.
  4. Martineau AR, Jolliffe DA, Hooper RL, et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. The BMJ. 2017;356:i6583. doi:10.1136/bmj.i6583.
  5. Zahra Sepehrmanesh, Fariba Kolahdooz, Fatemeh Abedi, Navid Mazroii, Amin Assarian, Zatollah Asemi, Ahmad Esmaillzadeh; Vitamin D Supplementation Affects the Beck Depression Inventory, Insulin Resistance, and Biomarkers of Oxidative Stress in Patients with Major Depressive Disorder: A Randomized, Controlled Clinical Trial, The Journal of Nutrition, Volume 146, Issue 2, 1 February 2016, Pages 243–248,
  6. Gill TK, Hill CL, Shanahan EM, et al. Vitamin D levels in an Australian population. BMC Public Health. 2014;14:1001. doi:10.1186/1471-2458-14-1001.
  7. Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database of Systematic Reviews 2013, Issue 1. Art. No.: CD000980. DOI: 10.1002/14651858.CD000980.pub4
  8. Mari-Carmen Gomez-Cabrera, Elena Domenech, Marco Romagnoli, Alessandro Arduini, Consuelo Borras, Federico V Pallardo, Juan Sastre, Jose Viña; Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance, The American Journal of Clinical Nutrition, Volume 87, Issue 1, 1 January 2008, Pages 142–149,
  9. Jefferson T, Del Mar CB, Dooley L, Ferroni E, Al-Ansary LA, Bawazeer GA, van Driel ML, Nair S, Jones MA, Thorning S, Conly JM. Physical interventions to interrupt or reduce the spread of respiratory viruses. Cochrane Database of Systematic Reviews 2011, Issue 7. Art. No.: CD006207. DOI: 10.1002/14651858.CD006207.pub4

IMPORTANT INFORMATION: all content provided here is of a general nature only and is not a substitute for individualised professional medical advice, diagnosis or treatment and reliance should not be placed on it. For personalised medical or nutrition advice, please make an appointment with your doctor, dietitian or qualified health careprofessional.