How To Strengthen Your Immune System

Science-backed tips for strengthening your immune response effectively

The immune system is the single most essential program in our bodies to defend against foreign pathogens, but its function declines with age in numerous populations. While this is concerning, many tools can be leveraged to optimize the immune system and combat the effects of its decline with age, such as nutrition, exercise, sleep, and supplementation. While building a plan may require working closely with your healthcare providers, many of these proactive habits can be easily incorporated into our daily lives to help maintain healthy immune function into old age and prevent infection and associated disease.

What is the Immune System?

The immune system is a protective program that allows us to interact with our environment while maintaining a healthy balance. It protects us from foreign pathogens such as toxins, bacteria, and viruses by communicating within its vast network of organs, proteins, enzymes, and inflammatory molecules (cytokines and chemokines). Without it, the inflammatory molecules cannot communicate with the immune cells and allow us to stave off sickness and disease continually. Often in medicine and health-related topics, society views inflammation negatively. More accurately, we require a balance of inflammation, a key component of our immune response. A tight level of regulation is required to maintain this balance as too much or too little inflammation in specific cases can be detrimental, especially if persisting over time. The most critical cells in the immune system are the lymphocyte cells. There are two types of lymphocytes: B cells (produce antibodies which are released into the fluid surrounding the body’s cells to destroy the invading viruses and bacteria.) and T cells (if the invader gets inside a cell, T cells lock on to the infected cell, multiply and destroy it).
How does the Immune System decline with age?

In young people, there is a relative abundance of naive immune cells compared to older individuals. Having a larger pool of diverse molecules that can respond to pathogens confers benefits on the immune system. This allows younger individuals to be better equipped to fight infections and respond to foreign antigens successfully. As humans age, there have been numerous clinical observations of reduced numbers of naive B and T cells that recognize foreign invaders. This results in a reduced capacity of the adaptive immune response in the aging population. The remaining naive cells still require an energetic conversion to become active, resulting in increased uptake of nutrients and energy production from the mitochondria via glycolytic metabolism. Another characteristic of aging observed in older populations is lower cellular energetic capacity and output, favoring immune cells to remain inactive (quiescent) rather than activate into killer cells. Especially over the ages of 65-70, there have been observed increases in specific T cells which accumulate and become a source of inflammatory cytokines. If inflammation persists as aging continues, there is an increased risk of inflammatory diseases such as atherosclerosis and coronary artery disease. If circulating immune cells (lymphocytes) are continually exposed to an inflamed environment mediated by cytokines, it can lead to the genetic downregulation of lymphocytes. Cells that become sources of inflammation are deemed to have acquired a senescence-associated secretory phenotype (SASP). SASP accumulation negatively impacts our immune system through sustained inflammation which results in poor trafficking of naive immune cells between organs and impaired function of matured immune cells residing within organs.

How to combat the decline of the immune system with aging

When it comes to the immune system, it may seem as though many factors are working against us, and that decline in the immune system is an inevitable aspect of aging. Fortunately, there are many tools available to help keep our immune system active for protection against foreign pathogens and manage autoimmune function to prevent increased chronic inflammation associated with age, also known as inflamm-aging.
1. Manage psychological stress: Emerging evidence is tracing the pathways of the mind-body interaction. When we’re stressed, the immune system’s ability to fight off antigens is reduced. That is why we are more susceptible to infections. The stress hormone corticosteroid can suppress the effectiveness of the immune system (e.g. lowers the number of lymphocytes). Stress can also have an indirect effect on the immune system as a person may use unhealthy behavioral coping strategies to reduce their stress, such as drinking and smoking.
2. Good sleep habits: Sleep is an essential part of maintaining physical and mental fitness into old age but can also substantially impact immune system function. Sleep deprivation has been shown to negatively affect the immune system, such as a reduction in overall immune response, which is detected as decreased plasma levels of essential immune cells. Partially sleep-deprived individuals have also shown reduced response to vaccination, which can significantly impact our body’s ability to defend against the infection from which the vaccine protects us.
3. Active living: Exercise is another factor that not only improves many aspects of cardiovascular health, mental health, and mobility but has also been shown to have positive impacts on our immune system. Studies have shown that moderate exercise for 1 hour a day five days a week can positively impact the immune system. Frequent moderate exercise has also been shown to be linked to improved response and increased production of antibodies after vaccination. Exercise has also been linked to a reduction in SASP cells, which are responsible for autoimmune-associated chronic inflammation. Although exercise can be very beneficial for immune health, excess intense exercise and overexertion can result in decreased energy availability and mild suppression of immune function and can leave a window of exposure to infection. In this newsletter, Colin Davis, our personal trainer, gives some tips and lists a few exercises you can regularly do for increased blood circulation and reduced inflammation. Moreover, Crystal Bartkowski, our Athletic Therapist, talks about prevention as part of injury rehabilitation and the healing process.
4. Nutrition: An aspect of maintaining good health that can often be overlooked is the importance of a balanced diet rich in essential micronutrients. It likely won’t come as a surprise that nutrition is one of the most important factors that can positively modulate our immune system. In fact, 70% of our immune system is located in the gut. This starts with one of our first lines of defense, which is the microbiome. The good bacteria in our gut feed on fiber and produce short-chain fatty acids as a result. These fatty acids are essential for fortification of the gut barrier but also have an important role in regulating cytokine production and immune cell populations. This includes immune cells that protect against inflammation and the immune cells that keep autoimmunity at bay. Additionally, there are many essential nutrients that we can actively include in our diets or supplementation regime that directly modulate immune function. Some of them are:
Vitamin C helps manage the oxidative stress caused.
Vitamin D has recently been found to play an important role in the modulation of the immune system via regulating the production of inflammatory cytokines and inhibiting the proliferation of pro-inflammatory cells, both of which are crucial for the pathogenesis of inflammatory diseases.
Zinc strongly influences the regeneration of and cytokine production in T-cells, a major aspect of aging-associated decline in immune function. Studies have shown that individuals with more zinc in their diet were almost 50% less likely to get infected with pneumonia. Zinc also inhibits the replication of RNA viruses such as rhinovirus (common cold) and Sars-CoV-2.
Our dietitian, Dan Neuman, dives into the role of nutrition in treatment and prevention in this newsletter. Don’t forget to check his article below to learn more about the specific nutrients that support the immune system.
In summary, replacing bad health habits with good ones can help keep your immune system healthy. If you don’t know what habits are affecting your health and where to start, please reach out to us. We are here for you! Prevention is our passion and we will be happy to provide you with the tools and the information you need to work on strengthening your immune system.

Dr. Rohan Bissoondath,
Medical Director

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