What is the immune system?

The immune system is the body’s main defence against diseases. It is also involved in many aspects of physiological regulation in the body.

The system encompasses a complex network of cells (innate and adaptive cells), and plays a vital role in the defence against various potentially harmful external agents and any internal defects in the body. An immune response, also known as an inflammatory response is triggered when the immune system encounters a pathogen. A pathogen is defined as a microorganism that causes or can cause disease.

The immune system is composed of many different cells that perform a wide variety of functions. One group of these cells is the important natural killer (NK) cells. NK cells are a major player in the body’s response against viruses.

How do I maintain a healthy immune system?

A healthy lifestyle is paramount in giving the immune system its best chance of working effectively. Key components of this healthy lifestyle include:

1. A Good Sleep Routine

Lack of sleep weakens immunity, increases susceptibility to infection as well as the ability of the body to fight incoming infections. Studies show that those who have shorter sleeps at night are much more susceptible of suffering from the common cold.

2. Look After Your Gut

What many people don’t realise, is that a large proportion of the immune system is located in the gut. Therefore, excessive consumption of junk food, heavily processed food, and the typical Western/SAD diet weakens the immune system due to the damage of the gut.

Good nutrition helps promote gut microbiota health and in turn immune health. In contrast, undernourishment (poor diet) as well as an excess consumption of foods loaded with sugars and trans-fats can compromise the immune system, leading to greater susceptibility to infections.

3. Manage Stress

The power of positive thoughts and managing stress must not be underestimated in helping the body’s defences work better.

Psychological stress can induce an acute phase response, which is the body’s rapid attempt to restore homeostasis after tissue injury, infection, or immunological disturbance. It can also increase inflammation and the levels of other unwanted molecules. The combined effect can result in reduced immunity and chaos within the body.

4. Get Regular Exercise

Exercise is a great tool for stress management. Positive mood is achieved through exercise which helps decrease the chance of infections through increased immunity. Our bodies thrive on getting connected with the natural world, therefore it is very important to get daily exposure to sunlight and take walks or runs in nature to further boost immunity.

5. Quit Smoking and Limit Alcohol Intake.

As is now widely known both smoking and the regular use of alcohol alter the function of the immune system and increase inflammation in the body. These should be avoided to give the immune system its best opportunity to be effective.

Can CBD support the immune system?

While the number of completed clinical trials on CBD are still limited when compared with other areas of medicine, a lot of scientific research exists which points to the various therapeutic effects CBD can have on the body, including its immune responses.

Studies have shown that the endocannabinoid system (ECS) plays an important role in regulating immunity, with scientists considering it a “gatekeeper” of the immune system. It is CBD’s interaction with the ECS that may help support a healthy immune system. The beneficial effects may be as a result of the following:

  • Supports the activity of natural killer cells
  • Has been found to support a healthy intestinal inflammatory response in human trials, promoting a healthy gut
  • May support healthy stress responses


This feature is published by Dr. Basma El Homasany of Smile & Age Well, a Galway based clinic that specialises in patient-centred metabolic and nutritional medicine. Follow Dr. Basma El Homasany on Instagram @smile_age_well to learn more about metabolic anti-aging/lifestyle medicine, including her newly launched functional spice mix. 



Immune Responses Regulated by Cannabidiol, James M. Nichols and Barbara L.F. Kaplan, 2019 – GRECC

CBD and the immune system: 4 ways CBD oil provides a virus-season boost, Chris Meletis, www.chiroeco.com

CBD and the Microbiome – KGK Science

The Role of the Endocannabinoid System in the Brain–Gut Axis – Gastroenterology

Cannabidiol (CBD) — what we know and what we don’t – Harvard Health Blog – Harvard Health Publishing