Written by Kyle Buchanan
Your immune system is a complex, wonderful network of organs, cells and proteins that work together to keep you protected from outside invaders like bacteria and viruses, which don’t have your best interest at heart.
Because the immune system does so much for us, it seems only fair (and frankly, logical) to do the things to help support and strengthen it and avoid the things that weaken it.
So, as I like to keep things as straightforward as possible, what you’ll find below is a list of things that weaken your immune system (some you know, some maybe you don’t), and a list of things that help strengthen this wonderful friend of yours. Let’s start!
Things that HINDER your immune system
Excess sugar: This might seem obvious, but it needs to be said. Sugar has an immune suppressing effect. So, you want to avoid processed sugars (e.g. fruit juices, sodas, sugar in coffee) and excess refined carbohydrates (e.g. white bread, sugary cereals). Sugar also has a negative effect on your gut microbiome, which plays a key role in immunity.
Artificial sweeteners: I know, I always bring the good news. No sugar and no fake stuff? To be clear, when I say artificial sweeteners, I am referring to the traditional artificial sweeteners (like aspartame and Sweet'n Low), not natural sweeteners like stevia and monk fruit. Artificial sweeteners found typically in diet beverages also have a negative effect on your gut bacteria and can hinder your body’s ability to mount a strong immune response.1
Smoking: Smoking helps nothing, and when it comes to immunity, it can compromise the delicate balance of the immune system2, not to mention deplete your body of Vitamin C.3
Excess stress: When it comes to stress, a little bit is okay (short bouts of stress can support your immune response) but a lot of it can have a depressive effect on your immune system.4 So if you find yourself in a daily state of stress, now is the time to develop strategies to find some calm. I know it’s tough, but it is so essential.
Burning the candle at both ends: Not enough sleep is kryptonite for your immune system5 and they’ve found that those who are lacking in both hours of sleep and/or sleep quality are more likely to get sick after being exposed to a virus, compared to those who get a better night’s sleep.
Low vitamin D levels: This is a big one, especially as we get into the colder months without access to strong sunshine. A deficiency in this vitamin (which is more common than we think) leaves you more susceptible to infections.6
Too little time outside: Nature is pretty incredible. Not only does getting outside help reduce stress (which, as we talked about, isn’t great for immunity), but plants themselves produce compounds, like phytoncides, that are inhaled and boost immune cell activity. Those who don’t get outside enough are missing out!
Things that SUPPORT your Immune system
Upping your veggie and fruit intake: including a rainbow of veggies and fruits every day fuels your body with antioxidants, vitamins (like Vitamin C and Vitamin A) and minerals (hello Magnesium!) that help fuel your immune system. Below are some of my favourites to include regularly.
Garlic: Garlic is an immune powerhouse and has been shown to both help prevent colds and flus and shorten the duration of the infection. Whole garlic contains a compound called alliin. When you crush or chew garlic, this compound gets turned into allicin (through the enzyme alliinase), which is responsible for a lot of its immune boosting properties. **To get the most out of your garlic for immunity, chop up the garlic and then let the garlic sit out for fifteen to twenty minutes before you eat or cook it. This helps boost those beneficial compounds!
Mushrooms: Mushrooms are fantastic. They help modulate your immune system or bring balance to it. Shiitakes are one of my favourites - a study showed increased immunity in people who ate 1-2 servings (5-10 grams) of cooked shiitake mushrooms every day for four weeks.7 So including a variety of mushrooms (not only shiitake) is a great way to really support immunity.
Berries like raspberries, blueberries, blackberries: The more colours and variety the better! Rich in plant chemicals called polyphenols, berries help support and protect your immune system. The fibre in berries help improve your gut microbiome, playing a key role in immunity and helping regulate those all-important bowel movements. Berries also contain a decent amount of Vitamin C, which acts as an antioxidant and supports a healthy immune response.
Ginger: Ginger is one of my favourite foods to include in the fall and winter (cooking, teas, etc.). It’s rich in antioxidant and anti-inflammatory properties, both of which support a healthy immune system.
Prebiotic veggies: Think asparagus, onions, dandelion greens, and leeks. These veggies contain decent amounts of prebiotic fiber to support the gut microbiome and feed our good bacteria. These bacteria then produce short chain fatty acids like butyrate that also support our body’s immune response.
Zinc-rich foods: like poultry, oysters, eggs, sprouted legumes and pumpkin seeds. Zinc supports the immune system but also keeps it in check, making sure it doesn’t spin out of control.
Getting enough protein: Your immune system relies on protein for its building blocks, and not getting enough protein in your day puts your immunity at a disadvantage. So, ensure each meal has a source of protein like eggs, poultry, tempeh, fish, legumes, etc. And consider adding in a protein powder if you know your diet is lacking in this important macronutrient.
Getting a good night’s sleep: One of the best things you can do for a healthy immune system is to prioritize sleep. Resist the urge to binge the latest show, and get to bed. Aim for roughly 7 to 9 hours per night (ideal sleep time is different for everyone).
Calming down: As I mentioned before, chronic stress is terrible for immunity. Really make an effort to find calm: say “No!” more often, practice breathing exercises daily and try meditation. Check out our Instagram for more tips in this area!
Exercise: I couldn’t finish this list without mentioning this one. Exercise does help support your immune system, and it’s important to maintain regular physical activity even if the gyms in your area are closed. If you’re looking for a number, aim for 2.5 hours a week of exercise, including aerobic exercise like walking, jogging or spinning, and resistance exercise like weights, band work and calisthenics!
Your immune system is arguably your biggest supporter. It wants to protect you, and keep you living a long and happy life. Try as best you can to avoid the things that can weaken it and include more things that help provide it with the strength it needs to be your inner-superhero!
- Rahiman F, Pool EJ. The in vitro effects of artificial and natural sweeteners on the immune system using whole blood culture assays. J Immunoassay Immunochem. 2014;35(1):26-36. doi: 10.1080/15321819.2013.784197. PMID: 24063614. https://pubmed.ncbi.nlm.nih.gov/24063614/
- Smoking and Overall Health. Centers for Disease Control and Prevention. Office on Smoking and Health. Retrieved from https://www.cdc.gov/tobacco/data_statistics/sgr/50th-anniversary/pdfs/fs_smoking_overall_health_508.pdf
- Jens Lykkesfeldt, Stephan Christen, Lynn M Wallock, Harry H Chang, Robert A Jacob, Bruce N Ames, Ascorbate is depleted by smoking and repleted by moderate supplementation: a study in male smokers and nonsmokers with matched dietary antioxidant intakes, The American Journal of Clinical Nutrition, Volume 71, Issue 2, February 2000, Pages 530–536, https://doi.org/10.1093/ajcn/71.2.530 https://academic.oup.com/ajcn/article/71/2/530/4729195
- Segerstrom, S. C., & Miller, G. E. (2004). Psychological stress and the human immune system: a meta-analytic study of 30 years of inquiry. Psychological bulletin, 130(4), 601–630. https://doi.org/10.1037/0033-2909.130.4.601 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1361287/
- University of Washington Health Sciences/UW Medicine. (2017, January 27). Chronic sleep deprivation suppresses immune system: Study one of first conducted outside of sleep lab. ScienceDaily. Retrieved October 30, 2020 from sciencedaily.com/releases/2017/01/170127113010.htm
- Aranow C. (2011). Vitamin D and the immune system. Journal of investigative medicine : the official publication of the American Federation for Clinical Research, 59(6), 881–886. https://doi.org/10.2310/JIM.0b013e31821b8755 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/
- Xiaoshuang Dai, Joy M. Stanilka, Cheryl A. Rowe, Elizabethe A. Esteves, Carmelo Nieves Jr., Samuel J. Spaiser, Mary C. Christman, Bobbi LangkampHenken & Susan S. Percival (2015). Consuming Lentinula edodes (Shiitake) Mushrooms Daily Improves Human Immunity: A Randomized Dietary Intervention in Healthy Young Adults, Journal of the American College of Nutrition, 34:6, 478-487, DOI: 10.1080/07315724.2014.950391