Nutritional Support for Healthy Immune Function: A Proactive Approach to Wellness

The 2024-2025 flu season was classified as one of the most severe in recent history, with hospitalization rates surpassing all seasons since at least 2010, as documented in the 2025 report "Last Flu Season Drove Record U.S. Hospitalizations" published by the CDC's Morbidity and Mortality Weekly Report. The cumulative hospitalization rate reached 127.1 per 100,000 people—nearly double the historical median.

Meanwhile, a 2024 UK study found that respiratory infections cost employers £852 per employee annually, contributing to £44 billion in national economic costs, as documented in the 2024 report "Employer Costs of Respiratory Infections" by the Office of Health Economics.

Understanding how the immune system functions may help individuals make informed decisions about their nutrition and lifestyle choices.

When the immune system detects threats, it releases signaling proteins called cytokines to mobilize defenses. 

Common physiological signals include:

• Disproportionate fatigue that doesn't match activity levels.
• Sleep disruptions despite exhaustion.
• Subtle digestive changes like decreased appetite.
• Heightened stress sensitivity where minor irritations trigger disproportionate responses.
• Cognitive sluggishness or difficulty concentrating.

Paying attention to how your body feels is part of overall wellness awareness.

The relationship between chronic stress and immune function has been extensively documented in recent research. Chronic stress may affect immune function via activation of the HPA axis and subsequent elevation of cortisol levels, which exert substantial immunosuppressive effects on immune cells, particularly lymphocytes and macrophages, as documented in the 2025 study titled "Regulation of Stress-Induced Immunosuppression in the Context of Infection and Sepsis" published in PMC.

A 2024 comprehensive review confirmed that chronic stress significantly reduced immune cell activity and overall immune function, while chronic stress dysregulates or inhibits immune functions through increased cortisol levels, ultimately suppressing the immune response, as documented in the 2024 study titled "Immunology of Stress" published in PMC. 

This research helps us understand the relationship between stress and overall wellness, highlighting the importance of stress management as part of a healthy lifestyle.

A 2024 UK analysis found that employees are impacted by respiratory infections for over an entire working week throughout the year (5.2 days), with 1.1 of these days taken as absence and 4.1 days as presenteeism during which productivity drops by 32%, as documented in the 2024 report "Employer Costs of Respiratory Infections" by the Office of Health Economics. The cost to employers per employee in terms of productivity loss is estimated at £852 per year, contributing to an annual national economic cost of £44 billion in the UK alone.

A 2025 healthcare worker study found that sick leave peaked during the COVID-19 pandemic (8,322 days in 2020) and remained elevated post-pandemic (not returning to pre-pandemic levels of approximately 5,000 days/year), as documented in the 2025 study titled "Dynamics of Absences Due to Respiratory Infections" published in PMC. The research confirmed that preventive actions such as immunization, staff training, and health monitoring are critical in reducing absenteeism.

Maintaining adequate nutrition, managing stress, and being attentive to your body’s signals are all components of a healthy lifestyle that supports overall wellness.

Recent scientific research identifies specific nutrients and compounds that support optimal immune function when maintained at adequate levels.

Micronutrients with the strongest evidence for immune support are vitamins C and D and zinc, as documented in the 2020 review titled "A Review of Micronutrients and the Immune System—Working in Harmony to Reduce the Risk of Infection" published in Nutrients. These nutrients work synergistically—exhibiting greater effectiveness together than individually.

Vitamins C, D, and zinc play synergistic roles in maintaining immune function, working together to maintain physical tissue barriers, support immune cell function, and modulate inflammatory responses, as documented in the 2020 study titled "Zinc, Vitamin D and Vitamin C" published in Frontiers in Nutrition.

Specifically:

• Vitamin C supports immune cell function, enhances phagocytosis, and maintains epithelial barrier integrity.
• Vitamin D enhances innate cellular immunity, maintains epithelial barrier function, and modulates adaptive immune responses.
• Zinc is essential for both innate and adaptive immunity, maintains cellular barrier function in respiratory epithelial tissues, and supports immune cell development.

Beyond micronutrients, certain botanical ingredients have been studied for their potential effects in supporting healthy immune function. Elderberry has been studied for its potential effects on immune function and respiratory health, as documented in the 2021 systematic review titled "Elderberry for prevention and treatment of viral respiratory illnesses: a systematic review" published in BMC Complementary Medicine and Therapies. Some preliminary research has explored elderberry’s potential effects, though ore studies are needed to draw definitive conclusions. 

Medicinal mushrooms including turkey tail, chaga, cordyceps, and shiitake contain beta-glucans and other compounds that modulate immune function. Ginger and turmeric provide anti-inflammatory compounds that support balanced immune responses.

Research suggests these nutrients play important roles in immune function. Maintaining adequate nutrition through diet and, when appropriate, supplementation is part of an overall approach to wellness. Consult with a healthcare provider about your individual nutrition needs.

Supporting your overall wellness involves attention to nutrition, stress management, and lifestyle factors.

Develop awareness of pre-symptomatic changes: disproportionate fatigue, sleep disruptions, subtle digestive changes, heightened stress sensitivity, or cognitive sluggishness. Paying attention to these signals is part of overall wellness awareness.

During the early warning window: prioritize rest by going to bed earlier than usual, reduce unnecessary commitments temporarily, delegate tasks that can wait, and avoid adding new stressors. Given that chronic stress suppresses immunity through HPA axis activation and cortisol elevation, as confirmed by 2024-2025 research, managing stress becomes essential for maintaining immune function.

Focus on whole, nutrient-dense foods including vegetables and fruits for vitamin C and phytonutrients, quality protein sources for amino acids needed for immune cell production, healthy fats for cell membrane integrity, and adequate hydration.

Ensure adequate intake of key immune-supporting nutrients: vitamin C (500-1000mg daily), vitamin D (2000-5000 IU daily, especially during winter months), zinc (15-30mg daily), and evidence-based botanicals like elderberry, echinacea, and medicinal mushrooms. Dietary supplements may help fill nutritional gaps when dietary intake is insufficient. Consult with a healthcare provider about whether supplementation is appropriate for your individual needs and which amounts may be right for you.