Healthy Immunity Across the Lifespan

Dr. Olivia Rose, ND

Factors such as diet and lifestyle play an important role, when you are looking to improve immune health. Here are 6 tips to aid in a healthy immune response throughout all stages of adult life. 

Reduce and Manage your Stress.

One of the most powerful steps you can take in creating a healthy immune response is to lower your stress levels. Chronically elevated stress levels cause an increase in the secretion of the stress hormone, cortisol.1 Cortisol has several impacts on the body, one of them includes dampening aspects of the immune system over the short term.1 However, over time, high cortisol levels can lead to an inflammatory cascade which triggers a weaker response from the immune system.1 In a study where researchers looked at the impact of stress on the immune response, it was found that the individuals who were under chronic stress had an increased likelihood of contracting the common cold.1

Decreasing stress is easier said than done. If you are looking to manage stress levels, try activities such as meditation2, deep breathing2, exercise3, and include hobbies that you enjoy more frequently.4 Including a supplement with adaptogen herbs such as Siberian ginseng and mushrooms such as Reishi can also be beneficial for some individuals who are struggling to manage stress.5

Consume a Healthy Diet.

Antioxidants, plant-derived nutrients, vitamins and minerals are essential for proper immune function.6 To obtain enough of these vital immune-supporting nutrients, it’s important to consume a diet that is high in fruits and vegetables.6 Aim to include 5 to 10 servings of fruits and vegetables per day to obtain adequate levels of these compounds.

At the same time, it is important to avoid processed foods such as pastries, white breads, fried foods and sugary cereals when you are looking to optimize your immune health.7 Highly processed foods are higher in trans fats, inflammatory omega-6 fatty acids and simple carbohydrates, all of which has been shown to hinder the immune response.7

Get Enough Sleep.

Sleep is a fundamental component of your health. Without proper sleep, the body cannot mount an effective immune response. Both the innate and adaptive arms of the immune system are negatively impacted by a lack of sleep.8 When you sleep, your body produces immune proteins called cytokines which are used to fight off infection. A lack of sleep is associated with increased risk of infection and a diminished response to vaccination.8

In a study which monitored the impact of sleep on immune function, researchers gave participants nasal drops with the common cold virus.9 Authors found that individuals who slept less than 7 hours were almost three times as likely to develop a cold when compared to those who slept 8 hours.9

Incorporate Moderate Exercise.

Exercise is important for a healthy immune response; however, it is also important to not over-exercise. Studies that look at the impact of exercise on immune health find that there is an exercise ‘sweet-spot’. This means that prolonged periods of intense exercise training can depress immunity, while regular moderate intensity exercise is favourable to support healthy immunity.10 Single sessions of moderate intensity exercise can enhance immune function and even improve vaccine response in some populations.10

Examples of moderate exercise vary depending on your current activity levels. For those who do not regularly exercise, moderate exercise includes taking a brisk walk, a yoga class, jogging, weight lifting, swimming or hiking.

Reduce Alcohol Intake.

Alcohol intake influences both the adaptive and innate immune system. After alcohol consumption, there is a period of immunosuppression which increases the risk for bacterial or viral infection.11 Alcohol is pro-inflammatory and leads to a disruption in the normal cell signalling involved in a proper immune response.11 Chronic alcoholics, therefore, have an increased susceptibility to both bacterial and viral infections.11

Alcohol intake should stay below 30 grams per week for men and below 15 grams per week for women. This translates into no more than one drink per day for women and two drinks for men. Although, if possible, avoiding regular alcohol intake altogether may be best during cold and flu season.

Include Key Vitamins, Minerals and Supplements.

The sunshine vitamin, Vitamin D plays an essential role in proper immune function. Individuals who are deficient in vitamin D have a higher prevalence of bacterial and viral infections.12 The lack of sun exposure in winter months results in a large portion (almost 30%) of Canadians who are deficient in vitamin D.13 Sufficient vitamin D levels can be achieved by eating animal products and fortified foods such as salmon, red meat, liver, cereals, orange juice and milks. However, many Canadians need add in a vitamin D supplement to reach optimal levels.

Vitamin C is important for proper immune function in all age groups.14 A diet rich in fruits and vegetables is needed to maintain proper vitamin C levels.14 Therefore, many populations in North America may need a vitamin C supplement if not including enough of these foods in their everyday diet.

A healthy microbiome is also important for proper immune function.15 Supplementation with probiotics in both food and supplement form has shown to have positive impacts on the immune response in healthy adults.15 In a 2017 study, individuals infected with the common cold were separated into two groups; one that received a probiotic supplement of the bacteria Bifidobacterium animalis and the other a placebo.16 The group which received the probiotic had a stronger immune response and decreased shedding of the virus.16 Therefore, adding in a probiotic supplement may be beneficial when fighting off a cold or flu.

Although we cannot always control our exposure to infection, we can control lifestyle factors such as sleep, diet, exercise, and alcohol intake. Having a healthy immune system may help decrease both the frequency and severity of colds and flus as well as more severe illness throughout the lifespan.


1.Cohen S, Janicki-Deverts D, Doyle WJ, Miller GE, Frank E, Rabin BS, Turner RB. Chronic stress, glucocorticoid receptor resistance, inflammation, and disease risk. Proceedings of the National Academy of Sciences. 2012 Apr 17;109(16):5995-9.

2.Kim SH, Schneider SM, Bevans M, Kravitz L, Mermier C, Qualls C, Burge MR. PTSD symptom reduction with mindfulness-based stretching and deep breathing exercise: randomized controlled clinical trial of efficacy. The Journal of Clinical Endocrinology & Metabolism. 2013 Jul 1;98(7):2984-92.

3.Beserra AH, Kameda P, Deslandes AC, Schuch FB, Laks J, Moraes HS. Can physical exercise modulate cortisol level in subjects with depression? A systematic review and meta-analysis. Trends in psychiatry and psychotherapy. 2018 Dec;40(4):360-8.

4.Detweiler MB, Lane S, Spencer L, Lutgens B, Halling MH, Rudder TF, Lehmann L. Horticultural therapy: A pilot study on modulating cortisol levels and indices of substance craving, posttraumatic stress disorder, depression, and quality of life in veterans. Alternative Therapies in Health and Medicine. 2015 Jul 1;21(4):36.

5.Chandrasekhar K, Kapoor J, Anishetty S. A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults. Indian journal of psychological medicine. 2012 Jul;34(3):255.

6.Serafini M, Peluso I. Functional foods for health: the interrelated antioxidant and anti-inflammatory role of fruits, vegetables, herbs, spices and cocoa in humans. Current Pharmaceutical Design. 2016 Dec 1;22(44):6701-15.

7.Myles IA. Fast food fever: reviewing the impacts of the Western diet on immunity. Nutrition journal. 2014 Dec;13(1):1-7.

8.Besedovsky L, Lange T, Haack M. The sleep-immune crosstalk in health and disease. Physiological reviews. 2019 Jul 1;99(3):1325-80.

9.Cohen S, Doyle WJ, Alper CM, Janicki-Deverts D, Turner RB. Sleep habits and susceptibility to the common cold. Archives of internal medicine. 2009 Jan 12;169(1):62-

10.Simpson RJ, Kunz H, Agha N, Graff R. Exercise and the regulation of immune functions. InProgress in molecular biology and translational science 2015 Jan 1 (Vol. 135, pp. 355-380). Academic Press.

11.Szabo G, Saha B. Alcohol’s effect on host defense. Alcohol research: current reviews. 2015;37(2):159.

12.Vanherwegen AS, Gysemans C, Mathieu C. Regulation of immune function by vitamin D and its use in diseases of immunity. Endocrinology and Metabolism Clinics. 2017 Dec 1;46(4):1061-94.

13.Statistics Canada by Teresa Janz and Caryn Pearson. Vitamin D blood levels in Canadians.

14.Bucher A, White N. Vitamin C in the prevention and treatment of the common cold. American journal of lifestyle medicine. 2016 May;10(3):181-3.

15.Galdeano CM, Cazorla SI, Dumit JM, Vélez E, Perdigón G. Beneficial effects of probiotic consumption on the immune system. Annals of Nutrition and Metabolism. 2019;74(2):115-24.

16.Turner RB, Woodfolk JA, Borish L, Steinke JW, Patrie JT, Muehling LM, Lahtinen S, Lehtinen MJ. Effect of probiotic on innate inflammatory response and viral shedding in experimental rhinovirus infection–a randomised controlled trial. Beneficial microbes. 2017 Apr 26;8(2):207.

Leave A Reply

Your email address will not be published. Required fields are marked *