Natural Ingredients for Immune Health

In the last 16 months, the state of health for the people of our nation and the world has been an evolving roller coaster. As this article is being written, the Centers for Disease Control and Prevention (CDC) have reversed the decision to allow vaccinated individuals to not wear masks indoors in certain parts of the country.1 This reversal is based on the uptick in breakthrough COVID-19 cases seen across the country, most of which is of Delta variant origin (78.3 to 86 percent), particularly in hotspots like Arkansas, Florida, Missouri and Louisiana.2

Knowing that the virus is not abating, and with new research showing that the Delta variant of the coronavirus can evade antibodies that target certain parts of the virus, the need for continued positive lifestyle habits to strengthen the immune system to protect us from illness is of necessity.3 While many factors can affect the immune system, generally, making healthy choices related to diet, including good nutritional choices, exercise and sleep, can help preserve optimal immune function, aiding in the combat against illness.

You can support the immune system regularly by:4

• Exercising often
• Getting consistent and adequate sleep (eight hours)
• Drinking plenty of water
• Listening to your body
• Meditating daily
• Learning to recognize early signs of illness
• Eating breakfast
• Eating a variety of healthy foods
• Washing hands frequently
• Limiting alcohol intake
• Quitting smoking

While healthy habits can strengthen immune system function in general, it is important to note that immune cells work best when balanced, and an excessive immune response can have negative effects. Creating new immune cells in the body is not the aim of strengthening the immune system; in fact, too many immune cells cause autoimmune conditions, allergies and excessive inflammatory responses. Keeping the immune system in balance is the key to optimal immune health. Natural ingredients that may support these protective barriers include vitamins, minerals and some select botanicals, which can defend and shield the body from foreign antigens. Here are a few backed by great research:

Vitamin A

• Beta-carotene is converted into vitamin A (retinol) to strengthen the immune system by providing antioxidant protection—helping to maintain healthy skin barriers and mucous membranes. Plus, antioxidants help increase T-cell subset numbers and interleukin-2 production, promote lymphocyte response to mitogen, potentiate natural killer cell activity, and help the body ward off viruses compared to placebo in the elderly.5 Look for beta-carotene in sweet potatoes, carrots, winter squash and even apricots.

Vitamin C

• Human beings are one of the few mammals that cannot synthesize vitamin C, a water-soluble, essential nutrient that is one of 50 essential nutrients that must be obtained from the diet. This antioxidant has been studied for respiratory and lung use since the 1980s (particularly exercise-induced asthma).6 In small studies, vitamin C was helpful in exercise-induced breathlessness in terms of lung function and symptoms; however, there is still a need for strong and large-scale randomized controlled trials.7

Vitamin D

• For many years, doctors have known that people afflicted with tuberculosis respond well to sunlight, and an explanation may now be at hand. Vitamin D, also known as the sunshine vitamin, can modulate the innate and adaptive immune responses.8 This is because the vitamin D receptor is expressed on immune cells (B cells, T cells and antigen-presenting cells).8 Further, in retrospective studies, vitamin D supplementation has been shown to be protective during the COVID-19 pandemic, especially in older, immunocompromised individuals.9


• Zinc is essential for cells of the immune system since it works in tandem with superoxide dismutase (SOD) to elicit an antioxidant effect in the body. Plus, zinc deficiency affects the ability of T cells and other immune cells to function as they should. Studies have observed that even a mild zinc deficiency can elicit changes in immune status, such as defective natural killer (NK) cell function, decreased interleukin-2 production and anergy (i.e., the absence of a normal immune response to a particular antigen or allergen).10 In a clinical trial, 45 mg of zinc was safely given for 12 months without adverse reactions and decreased the risk of infection in the elderly.11 The RDI for zinc is 11 mg/day in adults.12


• In December 2020, Thailand’s government approved a pilot study of andrographis (Andrographis paniculata, Acanthaceae) to treat early symptoms of viral infection and reduce the severity of COVID-19. According to Bloomberg, Andrographis was a safe, effective, less costly treatment alternative for COVID-19 and could reduce inflammation of the respiratory tract.13 Andrographis has a long history supporting immune health; even during the global flu epidemic of 1918, one of the most devastating infectious outbreaks in world history—more virulent even than the Black Death in the 14th century—which killed 50 million people worldwide.14 Andrographis paniculata was credited with stopping the deadly virus spread in India.14

NAC (N-acetyl-L-cysteine)

• NAC’s primary role in the body is producing glutathione peroxidase, an important antioxidant enzyme that functions in various redox reactions, including scavenging free radicals, detoxifying harmful compounds and working as a cofactor in enzymatic reactions.15 NAC has been in clinical use for more than 70 years to prevent permanent harm caused by acetaminophen poisoning and as a mucolytic drug.15 It has also been used and advocated for respiratory support and to protect against oxidative stress induced by viral infections.15

Knowing that the vaccine for the coronavirus is not foolproof and with many not able or hesitant to take additional precautions to ensure the health and wellness of those around them, there is a need for continued healthy habits to strengthen our immune systems, to protect us and those we care for from illness. By taking a proactive approach to health by washing hands, staying active, being stress-free and using our pantries as medicinal cabinets, healthy days are on their way. Stay well! VR


1 When You’ve Been Fully Vaccinated. Centers for Disease Control and Prevention website. (Link to site). Updated July 27, 2021. Accessed July 27, 2021.

2 Variant Proportions. Centers for Disease Control and Prevention website. (Links to site). Updated July 28, 2021. Accessed July, 2021.

3 Planas D, Veyer D, Baidaliuk A, et al. Reduced sensitivity of SARS-CoV-2 variant Delta to antibody neutralization. Nature. 2021. doi:10.1038/s41586-021-03777-9. 4 Harvard Health Publishing. (2021, February 15). How to boost your immune system. Retrieved April 12, 2021, from

5 Chandra RK. Effect of vitamin and trace-element supplementation on immune responses and infection in elderly subjects. Lancet. 1992;340:1124–7.

6 Anah CO, Jarike LN, Baig HA. High dose ascorbic acid in Nigerian asthmatics. Trop Geogr Med. 1980; 32(2):132-137.

7 Wilkinson M, Hart a, Sj M, Sugumar K. Vitamins C and E for asthma and exercise-induced bronchoconstriction (Review) SUMMARY OF FINDINGS FOR THE MAIN COMPARISON. 2014;(6). doi:10.1002/

8 Maruotti N, Cantatore FP. Vitamin D and the immune system. J Rheumatol. 2010;37(3):491-495. doi:10.3899/jrheum.090797.

9 Bao L, Deng W, Huang B., et al. The pathogenicity of SARS-CoV-2 in hACE2 transgenic mice. Nature. 2020; 583, 830–833. (links to external site).

10 Black RE. Zinc deficiency, infectious disease and mortality in the developing world. J Nutr 2003;133:1485S-9S. [PubMed abstract].

11 Prasad AS, Beck FW, Bao B, et al. Zinc supplementation decreases incidence of infections in the elderly: effect of zinc on generation of cytokines and oxidative stress. Am J Clin Nutr. 2007;85(3):837-844. doi:10.1093/ajcn/85.3.837.

12 Zinc.National Institue of Health website. to external site). Updated on March 26, 2021. Accessed on July 28, 2021.

13 Yuvejwattana S. Thailand clears use of herbal medicine for COVID-19 treatment. Bloomberg website. December 30, 2020. Available at: Accessed January 14, 2021.

14 Sun W, Leng L, Yin Q, et al. The genome of the medicinal plant Andrographis paniculata provides insight into the biosynthesis of the bioactive diterpenoid neoandrographolide [published correction appears in Plant J. 2019 Mar;97(5):996]. Plant J. 2019;97(5):841-857. doi:10.1111/tpj.14162.

15 De Flora S, Balansky R, La Maestra S. Rationale for the use of N-acetylcysteine in both prevention and adjuvant therapy of COVID-19. FASEB J. 2020;34(10):13185-13193. doi:10.1096/fj.202001807.

16 Patra JK, Das G, Bose S, et al. Star anise (Illicium verum): Chemical compounds, antiviral properties, and clinical relevance. Phytother Res. 2020;34(6):1248-1267. doi:10.1002/ptr.6614.