When our immune system is in tip top shape, we take it for granted and rarely give it any love. But, the minute the sniffles start, our eyes begin to water, or we get that raw feeling in the back of our throat, we expect (and hope) that our immune system will pick up the slack. And only then do we reach for the vitamin C, sneak in an extra hour of sleep, or take a precautionary day off of work.
But the immune system is a complicated network of cells, tissues, and organs that work together to protect our bodies on a daily basis, not just on sick days. And since it’s so complex, maintaining immune health can’t be narrowed down to popping one supplement or adding one superfood to a breakfast bowl. Rather, the key to a healthy, well-balanced immune system is an equally healthy and well-balanced lifestyle.
Looking to optimize immune health? Here's our how-to guide for immune responses that work like a well-oiled machine, and a body that feels like one.
Biomarkers Associated with Immune Function:
White Blood Cells (WBC) like lymphocytes, neutrophils, monocytes and basophils, are the primary infection-fighters in the body. However, having WBC levels that are too low or too high can be detrimental to your immune system, so keeping your levels within their optimal range is key to better immune health.
CRP (C-reactive protein) is more of an indirect measure of your immune system. It's produced by the liver during times of physiological stress, so high levels can therefore indicate chronic inflammation. While there are other factors in play for this to be the case, chronic inflammation can be associated with a weakened immune system.
However, immune health is not limited only to these biomarkers. So to give you a more complete picture, we’ve compiled a set of immune-boosting recommendations. Together, these guidelines will help you stifle the sniffles in no time.
Recommendations for boosting your immune system
Plenty of illnesses brought on by the dry and bitter weather of the winter months affect our upper respiratory tract, which includes everything between your nostrils and your voice box. Upper Respiratory Tract Infections, or URTIs, can include more serious illnesses such as laryngitis and sinus infections, but most commonly, they manifest as the common cold. These recommendations come from studies mostly focused on preventing URTI, so follow along for some cold-crushing tips.
Get at least 30 minutes of daily physical activity
Multiple studies have found that moderate levels of physical activity – compared to extremely high or low levels – are associated with a reduced risk of URTI.1 The American College of Sports Medicine recommends that adults should aim for 30 minutes of moderate-intensity physical activity 5 days per week to maintain optimal health. This recommendation is echoed by a study that found a 43% reduction in URTI in those who reported 5 days per week of aerobic activity versus one day per week or less.2
Something as simple as walking your dog, taking a leisurely bike ride or even cleaning your house counts as physical activity. Set a goal for yourself: at least 30 minutes per day will help stop a cold in its tracks!
Aim for 7-8 hours of sleep every night
The more sleep the better, right? Wrong! Both the lack of and the excess of sleep can be detrimental to the immune system. In one study, those who reported sleeping less than five hours per night had a 70% increased risk of URTI, and those who slept more than nine hours per night had an increased risk for both URTI and pneumonia.3,4 Your goal? Shoot for the middle ground and get 7-8 hours of shut eye each night.
Swap your allergy pills or cold meds for a natural supplement
Garlic, ginseng, and probiotics are all great natural immune boosters. Researchers examined the effectiveness of each supplement in combating colds, the flu, URTIs and other related symptoms, and the results were unanimous: taken daily, all were associated with a reduced risk of infection, duration of infection, and severity of symptoms. 5,6,7,8,9,10,11,12
Each supplement offers a unique immune-boosting property:
- Garlic - Allicin, one of the main active nutrients, is thought to have antiviral properties. We recommend taking a 500mg tablet twice-a-day after meals.
- Ginseng - The main extract in ginseng can boost the number of immune cells in the body.8 Look for a 200-400mg supplement to take after breakfast.
- Probiotics - Probiotics are live microorganisms that strengthen the integrity of the gut wall and increase the number of defense cells.13 Look for Lactobacillus and/or Bifidobacterium; they have been shown to stimulate the immune system better than other strains.10
As always, consult your doctor before introducing new supplements into your daily routine.
Have a glass of red wine at dinner
Too good to be true? Think again! Moderate alcohol consumption has shown a protective effect against the common cold and its symptoms; those who drank two glasses of wine per day were at a lower risk of developing a cold than non-drinkers.14 And compared to non-drinkers and heavy drinkers, those in the middle ground had lower levels of WBC and CRP.15 While these findings were all most strongly associated with red wine consumption, a protective effect was still seen with beer and spirits.
An important note: Moderate alcohol consumption is defined by the Dietary Guidelines for Americans as one drink per day in women and two per day in men. And remember to be careful with portion sizes when pouring; the average 750mL bottle of wine contains 6 glasses.
Maintain a healthy weight
Research has determined that both underweight and overweight people are at an increased risk of infection.16 Underweight individuals may grapple with low nutrient intake, which deprives the immune system of the fuel it needs to fight invaders.17 On the other hand, overweight or obese individuals are prone to low grade inflammation, high WBC and CRP levels, and chronic activation of the immune system, which wears it out over time.18
We get it, weight management is not an easy feat. But, in the long run, it can provide extensive benefits to many aspects of your health – including your immune system!
Optimize your vitamin D
Recently, URTI was found to be inversely associated with serum levels of vitamin D (as your levels go down, your chance of infection goes up), so InsideTracker recommends serum vitamin D levels remain above 32 ng/mL.22 If your bloodwork indicates lower levels, a supplement may be a good option for you; in addition to immune health, vitamin D is linked to increased cognition, bone health, and overall well being.
Plain and simple, increased levels of psychological stress increase your chances of developing the common cold and URTIs.20, 21, 22 To work on reducing stress check out our recommendations here.
So there you have it, a few tips and tricks to arm yourself against winter's worries and woes.
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Some other blog posts we think you'll love:
-  Fondell, E. et al. “Physical Activity, Stress, and Self-Reported Upper Respiratory Tract Infection.” Medicine & Science in Sports & Exercise. 2011 Feb;43(2):272-9.
-  Nieman DC, Henson DA, Austin MD, Sha, W. “Upper respiratory tract infection is reduced in physically fit and active adults.” British Journal of Sports Medicine. 2011;45:987–992.
-  Prather AA, Janicki-Deverts D, Hall MH, Cohen S. Behaviorally Assessed Sleep and Susceptibility to the Common Cold. SLEEP. 2015; 38(9):1353-59.
-  Patel SR, Malhotra A, Gao X, Hu FB, Neuman MI, Fawzi WW. “A Prospective Study of Sleep Duration and Pneumonia Risk in Women.” SLEEP. 2012; 35(1):97-101.
-  Nantz MP, Rowe CA, Muller CE, Creasy RA, Stanilka JM, Percival SS. “Supplementation with aged garlic extract improves both NK and gd-T cell function and reduces the severity of cold and flu symptoms: A randomized, double-blind,placebo-controlled nutrition intervention.” Journal of Clinical Nutrition. 2012 Jun;31(3):337-44
-  Josling,P. “Preventing the Common Cold With a Garlic Supplement:A Double-Blind, Placebo-Controlled Survey.” Advances In Therapy. 2001 Jul-Aug;18(4):189-93.
-  Predy GN, Goel V, Lovlin R, Donner A, Stitt L, Basu TK. “Efficacy of an extract of North American ginseng containing poly-furanosyl-pyranosyl-saccharides for preventing upper respiratory tract infections: a randomized controlled trial.” Canadian Medical Association Journal. 2005 Oct 25;173(9):1043-8.
-  McElahney JE, Goel V, Toane B, Hooten J, Shan J. Efficacy of COLD-fX in the Prevention of Respiratory Symptoms in Community-Dwelling Adults: A Randomized, Double-Blinded, Placebo Controlled Trial.” The Journal of Alternative and Complementary Medicine. 2006 Mar;12(2):153-7.
-  Seida JK, Durec T, Kuhel S. “North American (Panax quinquefolius) and Asian Ginseng (Panax ginseng) Preparations for Prevention of the Common Cold in Healthy Adults: A Systematic Review.” Evidence-Based Complementary and Alternative Medicine. 2011;2011:282151.
-  Berggren A, Ahren IL, Larsson N, Onning G. Randomised, double-blind and placebo-controlled study using new probiotic lactobacilli for strengthening the body immune defence against viral infections.” European Journal of Nutrition. 2011;50:203–210
-  de Vrese M, Winkler P, Rautenberg P, Harder T, Noah C, Laue C, Ott S, Hampe J, Schreibere S, Heller K, Schrezenmeir J. “Effect of Lactobacillus gasseri PA 16/8, Bifidobacterium longum SP 07/3, B. bifidum M 20/5 on common cold episodes: A double blind,randomized, controlled trial.” Clinical Nutrition. 2005;24, 481–491
-  Smith TJ, Radler DR, Denmark T, Haley T, Touger-Decker R. “Effect of Lactobacillus rhamnosus LGGw and Bifidobacterium animalis ssp.lactis BB-12w on health-related quality of life in college students affected by upper respiratory infections.” British Journal of Nutrition. 2013; 109, 1999–2007
-  Hao Q, Dong BR, Wu T. “Probiotics for preventing acute upper respiratory tract infections.” Cochrane Database of Systematic Reviews. 2015, Issue 2. Art. No.: CD006895.
-  Takkouche B, Regueira-Méndez C, García-Closas R, Figueiras A, Gestal-Otero JJ, Hernán MA. “Intake of Wine, Beer, and Spirits and the Risk of Clinical Common Cold.” American Journal of Epidemiology. 2002 May 1;155(9):853-8.
-  Imhof A, Woodward M, Doering A, Helbecque N, Loewel H, Amouyel P, Lowe GDO, Koenig W. “Overall alcohol intake, beer, wine, and systemic markers of inflammation in western Europe: results from three MONICA samples (Augsburg, Glasgow, Lille).” European Heart Journal (2004) 25, 2092–2100
-  Harpsøe MC, Nielsen NM, Friis-Møller N, Andersson M, Wohlfahrt J, Linneberg A, Nohr EA, Jess T. “Body Mass Index and Risk of Infections Among Women in the Danish National Birth Cohort.” American Journal of Epidemiology. 2016 Jun 1;183(11):1008-17
-  Campitelli MA, Rosella LC, Kwong JC. “The association between obesity and outpatient visits for acute respiratory infections in Ontario, Canada.” Int J Obes (Lond). 2014 January ; 38(1): 113–119.
-  Vuong J, Qui Y, La M, Clarke G, Swinkels DW, Cembrowski G. “Reference intervals of complete blood count constituents are highly correlated to waist circumference: Should obese patients have their own “normal values?” American Journal Hematology. 2014 Jul;89(7):671-7.
-  Ginde AA, Mansbach JM, Camargo CA. “Association Between Serum 25-Hydroxyvitamin D Level and Upper Respiratory Tract Infection in the Third National Health and Nutrition Examination Survey.” Arch Intern Med. 2009 February 23; 169(4): 384–390.
-  Takkouche B, Regueira C, Gestal-Otero JJ. “A Cohort Study of Stress and the Common Cold.” Epidemiology. 2001 May;12(3):345-9.
-  Cohen S, Tyrrell DAJ, Smith AP. “Physiological Stress and Susceptibility to the Common Cold.” New England Journal of Medicine.1991 Aug 29;325(9):606-12.
-  Pedersen A, Zachariae R, Bovbjerg DH. “Influence of Psychological Stress on Upper Respiratory Infection—A Meta-Analysis of Prospective Studies.” Psychosom Med. 2010 Oct;72(8):823-32.