Winter is here! Peeling off the cozy covers and getting out of bed is becoming a challenge as the sun becomes more sluggish. With the gloomy winter dark and chill, comes the dreaded season of colds and flu. These healthy eating and immune boosting tips will have your body saying “who?” when the flu comes knocking!


The immune system is an intricate system that needs to be balanced and optimised across all its millions of different functions. As a result of the complexities that create the web of immune cells, there are no specific scientifically proven direct links between food or nutrients and enhanced immune function. But, all is not lost! Research does show that optimising your overall nutritional status and following a healthy lifestyle are the best ways to ensure that your immune system can show the flu, who’s boss.


All of the organs in your body function optimally when protected from environmental damage and stress. This includes your immune defence system. Support for your body is optimised through adoption of these healthy habits:

  1. Avoid cigarette and other tobacco smoking.
  2. Fill your diet with fresh fruit and vegetables – straight out of the earth. Keep these foods in their whole, most natural form in all of the colours of the rainbow. White – potatoes with skin, mushrooms, garlic; Red – tomatoes, red apples, peppers; Green – broccoli, kiwi, spinach; Yellow/Orange – butternut, citrus fruit, patty pans; & Purple – grapes; eggplant; beetroot.
  3. Exercise regularly to improve your energy levels, mood and to keep bones and muscles strong.
  4. Maintain a healthy weight by following a balanced, energy-controlled diet and increasing energy spent through regular exercise, increasing your daily steps taken and incorporate fun activities that get you moving (dancing, skipping, sport, etc.). A diet that consists of vegetables, fruit, whole grains (brown rice, quinoa, oats), mono-unsaturated fats (avo, olives, nuts, nut butters); omega 3 fatty acids (fatty fish such as salmon, pilchards, sardines) and lean proteins which are inclusive of plant based proteins will be optimal for healthy weight maintenance and optimal immune function.
  5. If you drink alcohol, drink only in moderation (1 alcoholic beverage per day for females and 2 for males).
  6. Focus on improving the quality and amount of sleep you get by following a nightly routine that limits stimulation through screen time, alcohol or late-night snacking just before bed. Try to make sure you get 7-9 hour sleep each night.
  7. Managing stress is key to keep your immune function in tip top shape. Try daily meditation; exercise and other self-care strategies that leave you feeling fulfilled and enriched and able to tackle the demands of your day.


A healthy microbiome in the human gut has a direct role in how the immune system functions. The gut contains the largest number of immune cells in the body – almost 60% of the entire immune system! Because of this, it is so important to ensure a balance of the correct bacteria in your gut. The gut microbiota may be compromised by stress, poor diet or past use of antibiotics. To support a healthy gut environment, make sure your diet is rich in fresh fruit and vegetables such as potatoes with their skins, legumes and other whole grain foods (e.g. oats, brown rice, barley). The fibre found in these foods is used as fuel for the bacteria in the gut and helps them to thrive and produce compounds called short-chain fatty acids that protect the cells of the intestines. This strengthens the immune system and ensures optimal functioning of the gut. A healthy gut is also maintained through adequate exercise (guidelines encourage > 150 minutes of physical activity per week for optimal health) and sufficient daily water intake.


There is some evidence that various micronutrient deficiencies — for example, deficiencies of zinc, selenium, iron, copper, folic acid, and vitamins A, B6, C, and E — could negatively affect the immune response. Poor diet, high stress and environmental toxins can lead to a build-up of damaging free radicals. These can cause damage to the cells of the body, which can increase risk of infection and impact negatively on optimum immune function. To support and protect against micronutrient deficiencies and free radical damage, an increase of antioxidants and micronutrients in the diet can be beneficial. These compounds can be found in the colourful fruits and vegetables listed above and must be eaten in abundance to boost your immune system and provide extra support during vulnerable periods, like winter. Whole potatoes contain Vitamin B6 at between 10-19% of daily requirements and also contain potassium, folic acid, copper, iodine, iron, phosphorous, manganese, magnesium, zinc and calcium. The exact amounts do vary across the different varietals and interestingly, the mineral content of the soil can have an influence on the mineral content within the potato. Potatoes contain a varied range of micronutrients that can contribute positively to an improved nutritional status. Remember, there is no added immune-boosting benefit to supplementing certain micronutrients, such as Vitamin C; over and above the required daily amounts. The recommended dietary allowances (RDA) for Vitamin C, for example, is 90mg daily for males and 75mg daily for females older than 19 years of age – just 1 serving of Guava (150g) contains 275mg of vitamin C! A standard serving of potatoes with skin at lunch (90-180g) provides 15-20% of daily Vitamin C requirements. So what’s the verdict? Focus on the diet as a whole and try to eat the colours of the rainbow, focusing on getting as much variety as possible of fresh fruit and vegetables . Remember to select fruit and vegetables in their natural form, for example eating an orange as opposed to having an orange juice. Rather than high-dose supplementation or fixation on specific nutrients, a diet naturally rich in a variety of micronutrients and antioxidants is most beneficial to your immunity.


Phytonutrients assist the immune system by helping the body through anti-oxidant and anti-inflammatory activities and improving the overall nutritional status. Sources of phytonutrients in the diet include all colourful fruits and vegetables, including potatoes with their skin on, as well as other plant based foods i.e. legumes and whole-grains. Diallyl sulphides (a type of phytonutrient) found in garlic, leeks and onions have also been shown to have protective properties that can improve immune function. The number of phytonutrients present in each potato does depend on the variety of potato you eat. Phenolics are secondary compounds produced and found in the flesh and skin of plants and it appears the skin has the highest concentrations of these powerful, health promoting compounds. So, make sure when preparing food, to keep the skin on your potatoes, carrots, butternut and other vegetables to allow these phenolic compounds to help boost your overall nutritional status. This will help to keep your immune system healthy and happy and fend off the colds and flus this winter season. Removing the skin and peeling your potatoes and other vegetables will just mean valuable, health boosting compounds are being tossed onto the compost heap!


1. Adams, C., & Gutierrez, B. (2018). The microbiome has multiple influences on human health. Research and Reviews: Journal of Microbiology and Biotechnology, 7.
2. Clements, S. J., & R. Carding, S. (2018). Diet, the intestinal microbiota, and immune health in aging. Critical reviews in food science and nutrition, 58(4), 651-661.
3. Haller, D. (Ed.). (2018). The Gut Microbiome in Health and Disease. Springer.
4. Makki, K., Deehan, E. C., Walter, J., & Bäckhed, F. (2018). The impact of dietary fiber on gut microbiota in host health and disease. Cell host & microbe, 23(6), 705-715.
5. Probst, Y. & Craddock, J. (2019). Eat your vegetables – studies show plant-based diets are good for immunity. The Conversation, 7 March 1-4.
6. Furrer, A.N., Chegeni, M. and Ferruzzi, M.G. 2018. Impact of potato processing on nutrients, phytochemicals, and human health, Critical Reviews in Food Science and Nutrition, vol.2, no 58, pp. 146-168.
7. Akyol, H., Riciputi, Y., Capanoglu, E., Fiorenza, and Verardo, V. 2016. Phenolic Compounds in the potato and its by-products: An overview, International Journal of Molecular Sciences, vol. 17, no .6, pp. 835-854.

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