3 Things That Will (And Won’t) Boost Your Immune System This Winter


It’s that time of year.

The person next to you on the bus sniffling all the way in. The colleague with the dry cough that seems to stay all winter. The friend who seems to live on Halls soothers.

The ubiquitous nature of the common cold gives rise to 101 old wives tales about what to do about it – most of them useless.

There are a lot of nutrients that can have a boosting effect on the immune system, and then there are certain things we can do to avoid immunosuppression.

So before you start megadosing vitamin C…

3 Things That Will Boost Your Immune System…

1: Garlic

Garlic is an immune-boosting powerhouse. Garlic directly stimulates the activity of immune system cells (1). It increases the production of antibodies, and the ability of immune cells to ingest and destroy bacteria (1).

Garlic modulates the inflammatory response to immune system activation, promoting an immune response that inhibits inflammation. (1)

The sulphuric compounds in garlic are key components in liver detoxification pathways, and garlic acts as an antioxidant itself, while also enhancing the effect of other antioxidant enzymes. (1)

The great news is you don’t even need a supplement: 3 cloves a day will give you all the immune boosting benefits you need.

If the taste, or aftertaste, is something that you just can’t stand, then 300mg, 3 times per day will cover you. (2)

2: Pelargonium sidoides

Pelargonium is an African herb, commonly used to treat colds and, in particular, respiratory infections in South Africa. It modulates the production of inflammatory immune compounds, and increases the capacity of the immune system to kill infections, both viral and bacterial. (3)

One of the main benefits of Pelargonium is that one its primary sites of actions are tissue boundaries, like the respiratory tract, mounting an immune response at the body’s first line of defence. (3)

Another key effect of the herb is that it stimulates the innate (non-specific) immune system prior to infection, and can act quickly to eliminate incoming bacteria or viruses before they can have an effect. (3)

You’ll likely have to order off Amazon. For use, take 20mg, 3 times per day in divided dose. (2)

3: Zinc

Zinc is another potent immune booster, in particular having the ability to prevent the common cold virus (rhinovirus) from replicating. (4)

The key with zinc appears to be timing: start taking it as soon as you feel symptoms onset (4).

Zinc lozenges are the form that you need, ideally containing zinc gluconate. (2)

You’ll get them in any health food store.

The primary effect of zinc is to reduce duration of the cold, hence the importance of beginning supplementation at the onset. (4)

The dose you need is 75mg per day, for the duration of symptoms. (4)

…And 3 Things That Will Bust Your Immune System

1: Sugar

I hate the “sugar-is-the-root-of-all-evil” oversimplification that gets thrown about. For one, low-carb dogmatists then assume that everything is sugar, from quinoa to Frosties. And while you can make the asinine argument that it’s glucose once digested, the fact is that not all sugar is created equal.

In terms of the immune system, sucrose (table sugar) and fructose (fruit sugar) can have an immediate effect on white blood cells, inhibiting their activity (5). Dietary starch does not have this effect. (5)

The effect inhibits the ability of immune cells to destroy pathogens, weakening the body’s defence against invading bacteria or viruses. (5)

This is where being on the wrong side of the “5-a-Day” advise might really hurt you this winter; eating 3-4 full pieces of fruit, which many people are doing in the belief that they’re fulfilling this sage health advice.

Add in that concentrated orange juice that’s washing down the cereals for breakfast, and it’s no wonder so many people will spend the next three months sniffling and coughing.

Remember that starch doesn’t have this effect, so this winter, shift your attention to some seasonal eating: squash, pumpkin, turnip, and celeriac are all warming root veg that you can sub in for a nutrient boost this autumn/winter.

Ditch the fruit juice. And go easy on the fruit. Remember, oranges don’t grow in Ireland in December.

2: Sleep

Ah, my hobbyhorse.

I’ve written extensively about sleep, why we need it, and the deleterious effects of lack of sleep on the human body and mind.

And if vitamin D was the research vogue of the past 10 years, I’m betting big that melatonin is going to be the next one: we thought it was just a sleep hormone, now, like the vitamin D receptor, melatonin receptors are being identified all over the body. (6)

Messing with your circadian rhythm (i.e. staring at a TV screen until midnight), thus offsetting proper melatonin signalling, interferes with normal physiological function in immune system and antioxidant defences. (6)

If you really want to keep your immune system in top shape this winter, make sure that your sleep hygiene smells like roses. Avoid blue light an hour before bed, don’t light the house like a Christmas tree (yet), and get a full 8 hours in.

3: Stress

Stress is always a funny one to bring up, as it’s a totally subjective experience, but yet it can have objective outcomes for health.

So it’s important to qualify that stress is, primarily, about perception. This is key because if you can change your perception, you can avoid the negative impact that stress can have on your immune system.

How does stress effect the immune system? Primarily through the activation of the “flight or fight” sympathetic nervous system and the secretion of adrenaline and other stress hormones, which can bind to immune cells and inhibit their activity. (7)

If you’ve ever wondered why zebra’s don’t get ulcers, consider this:

“Stress-related disease emerges, predominantly, out of the fact that we so often activate a physiological system that has evolved for responding to acute physical emergencies, but we turn it on for months on end, worrying about mortgages, relationships, and promotions.” (8)

So consider that the immune system can deal with stress. It’s designed to, but only when it’s short-term. Modern life has the system activated in the long-term.

Do what you need to do, what works for you, to de-stress. Meditation, yoga, Pilates, Tai Chi, walking the dog, working out. Whatever.

Find your medium, and keep your immune system, as well as your mental wellbeing, from unecessary suffering.

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  1. Arreola R, Quintero-Fabian S, Lopez-Roa RI, Flores-Guttierrez EO, Reyes-Grajeda JP, Carrera-Quintanar L, Ortuno-Sahagun D. Immunomodulation and anti-inflammatory effects of garlic compounds. J Immunol Res,  2015;2015:401630. doi: 10.1155/2015/401630.
  2. Brewer, S. (2010). The Essential Guide to Vitamins, Minerals and Herbal Supplements. 2nd Edition. London: Constable and Robinson Ltd.
  3. White K, Kock E, Volk HD, Wolk K, Sabat R. The Pelargonium sidoides Extract EPs 7630 Drives the Innate Immune Defense by Activating Selected MAP Kinase Pathways in Human Monocytes. PLoS One. 2015; 10(9): e0138075.
  4. Singh M, Das RR. Zinc for the common cold. Cochrane Database of Systematic Reviews 2013, Issue 6. Art. No.: CD001364. DOI: 10.1002/14651858.CD001364.pub4.
  5. Murray MT, Pizzorno J (2012). The Encyclopedia of Natural Medicine. 3rd Edition. New York: Atria Paperback.
  6. Claustrat B, Leston J. Melatonin: Physiological effects in humans. Neurochirgurie 2015 Apr-Jun;61(2-3):77-84. doi: 10.1016/j.neuchi.2015.03.002
  7. Segerstrom SC, Miller GE. Psychological Stress and the Human Immune System: A Meta-Analytic Study of 30 Years of Inquiry. Psychol Bull. 2004 Jul; 130(4): 601-630. doi: 10.1037/0033-2909.130.4.601
  8. Sapolsky, R. M. (1998). Why zebras don’t get ulcers: An updated guide to stress, stress-related disease, and coping New York: Freeman