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Top 5 Ways to Support Your Immune System in 2020

Immune system function is something that is on everyone’s mind this year. With the cooler weather, more time inside and waning sunlight, your immune system needs some extra support to keep you at your best. These tried and true strategies include essential nutrients for immune system function, herbs that can aid your body’s natural defenses, and foundational lifestyle habits that are unconditionally important to keeping you well.

Vitamin C

Found in citrus fruits as well as many veggies, vitamin C is a favourite in the winter months. Studies show that regular supplementation can reduce both the duration and severity of colds. In adults Vitamin C can reduce cold length by 8% and in children by 18% (for example 4 days instead of 5). The key to getting this benefit is taking a therapeutic dose, as we find many people aren’t taking enough. Vitamin C can also be delivered intravenously for a powerful antiviral effect (1).

Vitamin D

Vitamin D deficiency is extremely common, especially when sunlight is limited in the winter months. It exerts effects on almost every stage of the immune response, so inadequate vitamin D levels leave your defenses impaired. Two small trials show that taking vitamin D supplementation for 4 months in children aged 6-15 years decreases respiratory tract infections associated with asthma or influenza A infection by about 40%. In adults who are deficient in vitamin D, supplementing to adequate levels can decrease the risk of upper respiratory tract infection by 42%. On top of that we know vitamin D is important for other health outcomes including bone strength and cancer prevention. (2)


Astragalus membranaceus is a herb that has been used for hundreds of years in traditional Chinese medicine to support the immune system. It has a balancing and regulatory effect on the immune system, preventing both overactivity and under functioning. When studied, 7 days of astragalus supplementation causes an increase in CD4 and CD8 T cells, the important players in the adaptive immune response. We offer this herb either as a tincture or capsules, and it can be used in both kids and adults (3).


Two important hormonal changes happen when you sleep that are essential to immune system function. Particularly during slow wave sleep, growth hormone surges and cortisol is inhibited, which together create an environment that is beneficial for immune cells. These cells will take up pieces of foreign particles, create memory cells to recognize bugs you’ve seen before, and allow your body to respond quickly upon encounter. Prolonged sleep deprivation wreaks havoc on this response, but even mild sleep deprivation (a reduction from 8 hours per night to 6) for 8 days results in heightened levels of pro-inflammatory molecules, which may impair the normal immune response. (4)


One of your primary stress hormones, cortisol, is powerfully potent at reducing the immune response. We utilize this effect for benefit in situations where the immune system is overactive (think corticosteroid creams for eczema for example), but the effect of chronically elevated cortisol on your systemic immunity may be damaging. This is why stress reduction techniques can be one of the most impactful ways to support your immune system. A meta-analysis of mindfulness based stress reduction techniques found a consistent reduction in pro-inflammatory markers and greater activity of immune cells. Better yet, this effect was found to be dose dependent, with those who participated in these activities more often achieving a more pronounced effect. (5)

If your immune tool-kit needs some updating this fall, talk to one of our NDs. We can give you specific guidance about dosing given your unique needs and health history.

  1. Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2013 Jan 31;(1):CD000980.
  2. Rees JR, Hendricks K, Barry EL, Peacock JL, Mott LA, Sandler RS, et al. Vitamin D3 supplementation and upper respiratory tract infections in a randomized, controlled trial. Clin Infect Dis. 2013 Nov;57(10):1384–92.
  3. Zwickey H, Brush J, Iacullo CM, Connelly E, Gregory WL, Soumyanath A, et al. The effect of Echinacea purpurea, Astragalus membranaceus and Glycyrrhiza glabra on CD25 expression in humans: a pilot study. Phytother Res. 2007 Nov;21(11):1109–12.
  4. Besedovsky L, Lange T, Born J. Sleep and immune function. Pflugers Arch. 2012 Jan;463(1):121–37.
  5. Black DS, Slavich GM. Mindfulness meditation and the immune system: a systematic review of randomized controlled trials. Ann N Y Acad Sci. 2016 Jun;1373(1):13–24.

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