Supplements and Strategies for Immune Health

The immune system is the body's first line of defense against infections. Because a functioning immune system is vitally important to overall health, many people search for ways to improve their immunity, with people spending billions of dollars on supplements and other immune-boosting products. 

Yet, it can be challenging to understand the research on what strategies are actually beneficial to help immune function. Healthcare professionals are tasked with interpreting the available research evidence for immunity-boosting products to help patients understand their potential effectiveness, safety considerations, cost/benefit analysis, and the role these supplements may play in wellness. 

This article is intended to help healthcare professionals evaluate the evidence behind immunity supplements so that they can guide their patients and make informed recommendations.

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Basic Principles of the Immune System

The immune system includes a collection of cells, tissues, and organs that work together to protect the body from outside pathogens, like bacteria, viruses, fungi, and parasites. 

• White blood cells (called leukocytes): White blood cells include many different subtypes with different functions, including neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Overall, white blood cells are responsible for identifying pathogens as foreign and mobilizing a team to destroy them.
• Antibodies: These are proteins made by immune cells that are designed to recognize, target, and negate pathogens.
• Lymphatic system: The lymphatic system includes a network of vessels that transport immune cells and clear toxins from the body.
• Immune organs (bone marrow, thymus, and spleen): Within these organs, immune cells are formed, mature, and act.

A healthy functioning immune system requires cooperative, balanced functions across all of the individual components to effectively eliminate pathogens. However, immune functions are not always effective and can be affected by various factors.

Factors Influencing Immune Health

Several factors can impact how well the immune system functions:

• Nutrition: Eating a balanced, nutritious diet that includes the nutrients necessary for proper immune function can help the immune system function at its best.
• Lifestyle: Maintaining a healthy lifestyle, including adequate sleep, regular physical exercise, and appropriate stress management, help promote optimal immune function.
• Age: Increasing age usually weakens the immune system, which makes older adults more susceptible to infections.
• Chronic conditions: Having chronic medical problems, such as diabetes, obesity, and autoimmune diseases, can reduce the immune response.
• Medications: Certain medications, like immunosuppressants, chemotherapy agents, steroids, and antimicrobials, can affect the immune response.

Patients who have risk factors for suppressed immune system activity may benefit from strategies to help prevent infections and support their immune response.

Common Immunity-Boosting Supplements

With an ever-growing array of immune support supplements available, there are some agents that are the most commonly used and the most effective, including vitamins, minerals, herbal supplements, and probiotics. It should be known that these supplements should be utilized only as part of a comprehensive plan to enhance the immune system.

Vitamins

• Vitamin C: Regarded for its role in immune function, vitamin C acts as a potent antioxidant to help protect against oxidative damage and inflammation. Common sources of vitamin C include citrus fruits, berries, bell peppers, and leafy greens. 
• Vitamin D: Vitamin D helps activate T-cells, which are a subtype of white blood cells that have several functions within the overall immune response: signaling to other immune cells, regulating immune cell response, and attacking pathogens. Dietary sources of vitamin D include milk, fortified foods, fatty fish, and egg yolks. 

Minerals

• Zinc: Zinc aids in the development and functioning of immune cells. A zinc deficiency is associated with a lower immune response. Dietary sources of zinc include animal meats (especially red meat), shellfish, nuts, beans, and other legumes. Evidence suggests that while zinc supplementation is unlikely to prevent illness, it may help reduce the duration of colds and upper respiratory tract infections.
  
  
• Selenium: Selenium is a mineral that acts as an antioxidant and helps facilitate the immune response. Food sources of selenium include nuts, seafood, shellfish, and animal meats.

Herbal Supplements

• Echinacea: This is an herb with anti-inflammatory, antioxidant, and potentially antimicrobial properties. It can be purchased over-the-counter, and it may help reduce the occurrences and lessen the duration of colds and upper respiratory infections.
  
  
• Elderberry: Elderberry is thought to potentially reduce the severity and duration of colds and upper respiratory infections, with minimal evidence for illness prevention. Often touted for its ability to reduce cold symptoms and flu-like symptoms. It is sold in various herbal forms over-the-counter, and it is also available in foods and teas.

Probiotics

Probiotics are beneficial microorganisms that help maintain balance within the gut microbiome. As much as 70% of immune function is located within the gut, so maintaining a healthy gut microbiome is important in a healthy immune system. Probiotics may help support a healthy gut microbiome, which plays a role in immune function.

Common food sources of probiotics include yogurt, kombucha, kimchi, sauerkraut, and other fermented foods. Probiotic supplements are also available.

Effectiveness: What Does the Evidence Say?

Many supplements touted for boosting immunity have been well-studied, whereas evidence for others is lacking. Relying on the available evidence helps outline the potential benefits (and lack thereof) of using supplements to improve immune health.

Vitamins and Minerals

The evidence for the use of vitamin C for immunity demonstrates it may reduce the severity and duration of colds and upper respiratory infections. Evidence that the use of vitamin C helps prevent illness is uncertain. 

Typical dosages, such as 500 to 1,000 mg of vitamin C per day, may be effective for some individuals, but specific needs should be discussed with a healthcare provider.

Some evidence suggests that using vitamin D supplementation to prevent deficiency may support immune function. It is unclear if vitamin D supplementation in the setting of normal vitamin D levels provides improved immunity. 

Sufficient levels of vitamin D (at least 30 ng/mL) are necessary for optimal immune function. Supplement dosages vary based on individual needs, usually in the range of 1,000 to 2,000 IU per day. Always consult with a healthcare provider for individualized dosage recommendations.

Zinc supplementation may also reduce the severity and duration of cold symptoms. Evidence for using zinc to prevent colds and upper respiratory infections is mixed. The usual dosage ranges from 10 to 15 mg per day, although this varies by individual factors.

Selenium supplementation may improve immune function in those who are deficient or who have poor nutrition. However, the available evidence for selenium in improving immunity is conflicting, and selenium overdoses can cause toxicity.

Herbal Supplements

Echinacea has immunomodulatory, anti-inflammatory, and antimicrobial properties, which have been shown to reduce the severity, duration, and recurrence risk of respiratory infections and common colds. The optimal dosing has not been determined, and the overall evidence around echinacea for specific immune functions is limited.

Elderberry may support the body’s natural defense system during viral infections, by potentially reducing the duration and severity of symptoms. Dosages may vary up to 6 g per dose.

Probiotics

There is a large body of evidence supporting the effectiveness of probiotics in reducing the incidence of upper respiratory and gastrointestinal infections by maintaining a healthy gut microbiome. Recommended dosages vary by the strains of microorganisms, usually in the range of 1 to 10 billion CFU (colony-forming units) per day.

Lifestyle Strategies to Promote a Healthy Immune System

In addition to taking supplements, incorporating healthy lifestyle factors is essential to optimize immune function.

• Healthy diet: Prioritize a healthy diet that is rich in anti-inflammatory fruits, vegetables, lean proteins, and healthy fats.
• Regular exercise: Engaging in regular physical exercise may support immune function by promoting healthy circulation and reducing inflammation.
• Hydration: Drinking adequate fluids helps support optimal immune health.
• Lowered stress: Chronic stress leads to immunosuppression. Using stress-reduction techniques, such as mindfulness, yoga, deep breathing, prayer, and hobbies, can help lower stress levels.
• Optimal sleep: Getting adequate sleep is imperative to a well-functioning immune system, as poor sleep increases susceptibility to various illnesses.

Considerations for Choosing Immune Supplements

There are important considerations when selecting immune supplements, which will help ensure safety and efficacy.

• Assess the quality: Look for supplements that feature third-party testing, helpful certifications, and trusted manufacturers.
• Understand the supplement labels: Review all ingredients and supplement facts, including the recommended dosages, potency, and potential allergens.
• Review the evidence: Discuss the use of supplements with a trusted healthcare provider to evaluate for safety and effectiveness.

Healthcare professionals should individualize supplement recommendations for each patient.

• Potential interactions: Many supplements have potential interactions with medications or other supplements. Looking for and recognizing potential interactions helps promote patient safety. Always consult with a healthcare provider before starting any new supplements, especially if you are taking medications or have underlying health conditions.
• Side effects: Some immune supplements carry the risk of possible side effects, and the comparison of potential side effects alongside the possible benefits helps determine what immune supplements may be indicated for each patient. 
• Ongoing monitoring: Emphasizing the need for ongoing monitoring by a knowledgeable healthcare professional puts patient health and safety at the forefront.

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Key Takeaways

• Maintaining a healthy immune system is vital to ensure optimal health and well-being.
• Understanding the basic components of the immune system and how they are affected by specific factors, including nutrition, lifestyle factors, age, chronic medical conditions, and the use of certain medications, helps lay the foundation for understanding how to improve immune function.
• Vitamins, minerals, herbal remedies, and probiotics have been studied for improving immune health, with varying levels of evidence and success in preventing infections, reducing symptoms, and shortening illness courses.
• Lifestyle strategies, like eating a healthy diet, engaging in regular exercise, maintaining hydration, getting adequate sleep, and lowering stress levels, help promote optimal immune function.