The immune system is incredibly important for protecting our health and defending us against viruses and bacteria. There's certainly a lot that we can all do naturally, through nutrition and lifestyle interventions to strengthen our immune defences, so read on to learn more!
The immune system depends upon certain nutrients to function properly, in particular vitamin A, C, D, zinc and selenium. Certain other botanicals, probiotics, and amino acids can also stimulate the immune system or possess active anti-microbial effects, supporting its activity.
Here’s our A-Z guide of key nutrients to consider to support your immunity.
Vitamin A also supports immune response and protects the epithelium and mucus integrity of the body, such as in the gut and lungs. Deficiency increases the risk of measles and severity of infection.[i] It also helps to regulate inflammation.[ii]
Beta Glucans increase immune response,[iii] including increasing secretory IgA,[iv] and reduce occurrence, symptoms and duration of upper respiratory tract infections.[v]
Everyone knows that vitamin C is important. In fact, prolonged infection depletes the body’s vitamin C levels. Some studies show that vitamin C is effective against some viruses.[vi]It’s also been shown to reduce incidence and severity of pneumonia.[vii]
Vitamin D enhances natural immune response against various infections, including flu and upper respiratory tract infections,[viii] and inhibits chronic inflammation.[ix]
Elderberry - ‘blunts’ the ‘spikes’ on the outside of viruses and stops them entering cells to reproduce.[x] It increases immune system activity against flu, showing 93% more rapid recovery.[xi]
Lysine increases production of immune cells and deficiency may impair immunity and increase susceptibility to infections.[xii]
Probiotics- certain strains or combinations of probiotics such as LAB4 reduce the risk of upper respiratory tract infection.[xiii]Lactobacillus rhamnosus GG has proven effective in decreasing the number, severity and duration of respiratory tract infections in children.[xiv],[xv]
Selenium supports immunity and lung function by aiding the production of our most potent antioxidant – glutathione, and helping with white blood cell and antibody production. It may also reduce viral mutations in the body.[xvi]
Zinc enhances immune cell activity, including natural killer cells.[xvii] It also inhibits viral replication[xviii]and may shorten the duration of colds by 7 days.[xix]
What You Can Do
It goes without saying that a healthy diet is paramount to providing the broad spectrum of nutrients we need to support our immune system - eat a varied dietwith good quality protein and plenty of vegetables, reduce your sugar and alcohol intake and try to choose healthier alternatives, such as dark chocolate, nuts, and non-alcoholic drinks (e.g. kombucha), since both can have a draining impact on our immunity. Another strategy is to use supplementation alongside this, such as;
A good multinutrient containing vitamin A, zinc, selenium etc. Look for at least 15mg of zinc.
Support your levels of gut bacteria with a probiotic product, with at least 30 billion live bacteria.
Optimise your vitamin D level status. Adults and children can start by taking a conservative daily dose of 1000 IU and 400 IU vitamin D3 respectively.
Take extra vitamin C in a gentle buffered form (e.g. magnesium ascorbate), up to 2g per day
Prioritise sleep and relaxation - sleep is the opportunity for our body to ‘rest and repair’ and is just as important as nutrition when looking to strengthen our immune system. Strikingly, research has shown that those with less than 7 hours sleep per night were up to 3x more likely to develop the common cold than those with 8 hours or more.[xx] Therefore, aim for 8 hours or more uninterrupted sleep per night with the help of an eye mask, ear plugs, increased intake of calming nutrients such as magnesium,[xxi] and meditation before bed, to facilitate the protective effect of sleep on our immune defences.[xxii]
If you need nutrition and supplement advice, please contact our Nutrition Team or seek the advice of a Registered Nutritional Therapist or other healthcare practitioner for more tailored advice.
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[i] Katona and Katona-Apte. The interaction between nutrition and infection. Clin Infect Dis. 2008; 46 (10): 1582-
[ii] Iyer N, Vaishnava S. Vitamin A at the interface of host-commensal-pathogen interactions. PLoS Pathog. 2019; 15 (6): e1007750.
[iii] Goodridge et al. β-glucan recognition by the innate immune system. Immunological Reviews. 2009; 230: 38-50.
[iv] McFarlin BK et al. “Baker's Yeast Beta Glucan Supplementation Increases Salivary IgA and Decreases Cold/Flu Symptomatic Days After Intense Exercise” 1Applied Physiology Laboratory, College of Education, University of North Texas , Denton, Texas , USA. Journal of Dietary Supplements 08/2013; 10(3). DOI: 10.3109/19390211.2013.820248
[v] Jesenak M, et al. Immunomodulatory effect of pleuran (β-glucan from Pleurotus ostreatus) in children with recurrent respiratory tract infections. Int Immunopharmacol. 2013 ;15(2):395-9.
[vi] Hemilä H. Vitamin C and SARS coronavirus. Journal of Antimicrobial Chemotherapy. 2003; 52 (6): 1049-1050.
[vii] Hemilä H, Chalker E. Vitamin C Can Shorten the Length of Stay in the ICU: A Meta-Analysis. Nutrients. 2019 Mar 27;11(4).
[viii] Yamshchikov et al. Vitamin D for treatment and prevention of infectious diseases: a systematic review of randomized controlled trials. Endocrine Practice. 2009; 15 (5): 438-49.
[ix] Griffin et al. Vitamin D and its analogs as regulators of immune activation and antigen presentation. Annual Review of Nutrition. 2003; 23: 117-45.
[x] Mumcuoglu. 1995. Sambucus nigra (L), Black Elderberry Extract: A breakthrough in the treatment of influenza. RSS Publishing.
[xi] Kong. Pilot Clinical Study on a Proprietary Elderberry Extract: Efficacy in Addressing Influenza Symptoms. J Pharmacol Pharmacokin. 2009; 5: 32-43.
[xii] Iseri and Klasing. Changes in the amount of lysine in protective proteins and immune cells after a systemic response to dead Escherichia coli: implications for the nutritional costs of immunity. Integr Comp Biol. 2014; 54 (5): 922-30.
[xiii] Garaiova I et al. Probiotics and vitamin C for the prevention of respiratory tract infections in children attending preschool: a randomised controlled pilot study. European Journal of Clinical Nutrition. 2015; 69: 373-379.
[xiv] Hojsak I et al. Lactobacillus GG in the prevention of gastrointestinal and respiratory tract infections in children who attend day care centres: A randomised, double-blind, placebo controlled trial. Clinical Nutrition 2010; 29:310.
[xv] Kumpu M, et al. The use of the probiotic Lactobacillus rhamnosus GG and viral findings in the nasopharynx of children attending day care. J. Med. Virol. 85:1632-1638, 2013.
[xvi] Harthill M. Review: Micronutrient Selenium Deficiency Influences Evolution of Some Viral Infectious Diseases. Biological Trace Element Research . 2011;143:1325–1336.
[xvii] Encyclopedia of Human Nutrition. Caballero B, Allen L, Prentice A (eds.). Academic Press, San Diego, 447-454
[xviii] Turner. The treatment of rhinovirus infections: progress and potential. Antiviral Res. 2001; 49:1-14.
[xix] Eby et al. Reduction in duration of common colds by zinc gluconate lozenges in a double-blind study, Antimicrobial Agents and Chemotherapy (1984) 25:20-24
[xx] Cohen S et al. Sleep habits and susceptibility to the common cold. Arch Intern Med. 2009; 169 (1): 62-7.
[xxi] Nielsen et al. Magnesiumsupplementation improves indicators of lowmagnesiumstatus and inflammatorystressin adults older than 51 years with poor quality sleep. Magnes Res. 2010 Dec; 23 (4): 158-68
[xxii] Besedovsky L et al. Sleep and immune function. Pflugers Arch. 2012; 463 (1): 121-137.
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