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LMU 155 – Nutrition: Your Immune System’s Shield and Sword


LMU 155 – Nutrition: Your Immune System's Shield and Sword

Source: Multiple Peer-Reviewed Journal Articles

Lifestyle Medicine Update (March 17, 2020)


In the realm of health, few topics have garnered as much attention in recent years as the immune system. Its importance became acutely clear in the face of the global pandemic, highlighting the vital role it plays in safeguarding our well-being. But how does nutrition factor into this intricate biological defence system? In this comprehensive exploration, we’ll delve into the scientific insights that reveal how nutrition and nutritional medicine can fortify and optimize our immune function. As we venture deeper into this fascinating journey, we’ll uncover the keys to preventing viral-induced respiratory infections and maintaining a resilient immune system capable of withstanding the harshest assaults.

Section 1: The Immune System’s Vital Role

At the heart of the matter lies a universal truth: the efficiency of your immune system dictates your susceptibility to respiratory tract infections. Furthermore, should an infection take hold, the robustness of your immune system can be the deciding factor between a mild illness and a severe, life-threatening condition. Age plays a pivotal role, as immune function naturally declines over time. This is a compelling reason why the elderly and those with compromised immune systems are often more susceptible to respiratory infections. However, a multitude of factors can weaken the immune system, making it essential to explore both sides of this crucial equation.

Section 2: Factors That Weaken Our Immune System

  1. Aging – A Natural Decline: The aging process exerts a profound impact on immune function. As individuals reach their mid-50s to 60s, the immune system experiences a decline in effectiveness. Notably, the thymus gland undergoes involution, leading to T-cell lymphocyte dysfunction. Concurrently, free radical damage accumulates, impairing immune cells and contributing to immunosuppression. Fortunately, certain antioxidant supplements can slow or even reverse this process, as we’ll explore later.
  2. Diminished Neutrophil Function: By the age of 60, respiratory bursts of neutrophils decrease, affecting their ability to combat infections. Higher vitamin C intake has been linked to improved neutrophil function, an aspect we’ll investigate further.
  3. The Medication Conundrum: Certain drugs, such as corticosteroids (e.g., Prednisone), TNF-inhibitors (e.g., Humira, Remicade), and anti-rejection drugs for transplant patients (e.g., Cyclosporin), can compromise immune function, rendering individuals more vulnerable to infections.
  4. Compromised Immune States: Conditions like HIV infection, excessive exercise leading to overtraining, and diabetes can weaken the immune system’s defences, increasing the risk of infections.
  5. Depression and Stress: Emotional states, including depression and high cortisol levels resulting from stress, can undermine immune function.
  6. Nutritional Deficiencies: Deficiencies in essential nutrients have a significant impact on the immune system. These deficiencies encompass a range of vitamins and minerals, and we’ll delve into them in detail shortly.

Section 3: Fortifying Your Immune System

In your quest to maintain a robust immune system, several fundamental strategies can help:

  1. Prioritize Sleep: Adequate sleep is essential, as it allows your immune system to recharge and prepare for its daily battles.
  2. Mind Your Exercise: Engaging in light to moderate exercise can strengthen your immune system. However, overexertion and overtraining may have the opposite effect, weakening immunity.

Section 4: The Role of Nutrition and Nutritional Medicine

Now, let’s explore the vital role nutrition plays in optimizing immune function. Several key nutritional factors stand out:

Antioxidants and Other Vitamins and Minerals

Immune cells have a voracious appetite for antioxidants, particularly vitamin C, vitamin E, and beta-carotene. These antioxidants serve a dual purpose: they help immune cells generate free radicals (ROS) that combat viruses and microbes, and they protect immune cells from ROS damage. Research suggests that a daily intake of 250 mg of vitamin C in healthy individuals enhances immune function, with the goal of achieving a vitamin C blood level above 50 umol/L. For individuals over 60, a combination of 1,000 mg of vitamin C and 200 IU of vitamin E may be necessary to bolster immune function. Supplementation with 200 mg of vitamin C per day can reduce the severity and duration of the common cold, particularly when combined with physical stress.

During infections, immune cells rapidly deplete their vitamin C stores, rendering them less effective. This depletion can lead to more severe infections, such as pneumonia. Higher vitamin C intake (1,000 mg per day) has been shown to prevent this decline, keeping immune cells robust and resilient.

Other antioxidants like vitamin E, zinc, beta-carotene, and selenium are equally crucial for immune function. Supplementation with these nutrients can enhance immune parameters in healthy individuals, particularly the elderly. Marginal deficiencies of vitamins and minerals significantly compromise immune function. Vitamin A, vitamin B6, vitamin B12, vitamin C, vitamin E, riboflavin, iron, zinc, and selenium are among the nutrients critical for maintaining a potent immune system. Many people walk around with these marginal deficiencies, underscoring the importance of well-formulated multiple vitamin and mineral supplements.

Herbal Agents

In addition to vitamins and minerals, certain herbal products offer immune-modulating properties:

  1. Astragalus: This herb has shown potential in enhancing immune function. Studies have demonstrated its ability to boost the release of interferon and interleukin-2 from key immune cells, bolstering immune function.
  2. Medicinal Mushrooms: Reishi mushroom extract, along with other medicinal mushrooms like shiitake, maitake, cordyceps, and turkey tail, contain unique ingredients that stimulate immune cells and improve their ability to combat foreign invaders. These mushrooms also interact with immune cell receptors, optimizing their response to threats.
  3. Milk Thistle: Primarily known for supporting liver detoxification, milk thistle has also exhibited immune-modulating properties. It increases lymphocyte proliferation and enhances the secretion of immune-modulating cytokines, crucial when battling infections.
  4. Indole-3-carbinol: Found in cruciferous vegetables, indole-3-carbinol activates immune cell receptors, prompting faster proliferation of T-lymphocytes and improving the ability of other immune cells to combat viruses and bacteria.

Section 5: A Balanced Approach

While these nutritional and herbal strategies offer promising avenues to boost your immune system, caution is essential. Individuals with autoimmune diseases or those on immunosuppressive drugs should be wary of overstimulating their immune systems, as it may exacerbate their conditions. For most healthy adults, however, a high-potency multiple vitamin and mineral supplement enriched with antioxidants is a sound choice. Additionally, considering supplements containing astragalus, reishi mushroom extract, milk thistle, and indole-3-carbinol may further support immune function. Many also find benefits in consuming a blend of medicinal mushrooms daily, along with a probiotic supplement to enhance gut health, another critical aspect of immune support.

Conclusion: Your Immune System’s Best Allies

The intricate dance between nutrition and immune function reveals a world of possibilities for those seeking to fortify their defences. As science uncovers the secrets of these nutritional and herbal allies, the path to robust immunity becomes clearer. By embracing these strategies and nourishing our bodies with the right nutrients, we empower our immune systems to stand strong against the myriad challenges life presents. 


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Eat Smart, Live Well, Look Great,

Dr. Meschino

Dr. James Meschino


Dr. James Meschino, DC, MS, ROHP, is an educator, author, and researcher having lectured to thousands of healthcare professionals across North America. He holds a Master’s Degree in Science with specialties in human nutrition and biology and is recognized as an expert in the field of nutrition, anti-aging, fitness, and wellness as well as the author of numerous books.

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