Immunity through Nutrition and Natural Product

Nature provides plenty of antioxidants available to the common man in the form of phytoconstituents present in various fruits, vegetables, herbs and other dietary substitutes. Antioxidants are compounds that neutralize and destroy the excess free radicals formed during, exposure to environmental pollutants and others. These free radicals cause damage to membranes, enzymes and DNA and in the long run, lead to weak immunity in a person. Hence to enhance and boost the immunity of people, during this ongoing COVID-19 pandemic, it is very essential to include antioxidants in our daily dietary routine, Antioxidants may be included in the form of fresh fruits, vegetables containing antioxidants or in the form of health drinks containing sufficient amount of antioxidants.^1,2

When the antioxidant levels in the body reduce oxidative stress arises it may cause damage to the cells or kill cells. Our defense mechanism is the immunity system. It may be the innate immune system and the adaptive immune system. Various environmental factors may expose the immune system to oxidative stress.²

Antioxidant vitamins play a major role in reducing and controlling oxidative stress and infectious diseases. Antioxidants may include enzymes such as superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, minerals such as Se, Mn, Cu, and Zn and vitamins such as A, C, E, phytoconstituents such as carotenoids, curcumin, Mangiferin, quercetin etc present in natural fruits like turmeric, Centella, orange, mango, amla are also a rich source of antioxidants.³

Vitamin A is an important antioxidant that plays an essential role in the development and functioning of T and B lymphocytes, regulating bone marrow homeostasis. Beta-carotene converts to vitamin A in the body. Other carotenoids exhibit anti-inflammatory functions and help in boosting immune function. An animal study showed increased pulmonary regeneration when using Vitamin A and Simvastatin were used. ⁴

Vitamin C is one of the biggest immune system enhancers and acts as an antioxidant agent against oxidative stress and plays a crucial role in neutralizing free radicals throughout the body.⁵ It acts by donating electrons to various enzymatic and non-enzymatic reactions, making it very effective in biological systems.² It promotes the proliferation of lymphocytes and is rapidly consumed during infections, suggesting a prominent role in the regulation of the immune system⁶. It has been reported that a high dose intravenous vitamin C can be a safe and beneficial option for early-stage COVID-19 treatment, along with anti-inflammatory treatments⁷. Vitamin C acts as a potent antioxidant and helps to maintain the redox homeostasis inside the cell prevents lipid peroxidation, and protein alkylation and prevent damage of cells due to ROS or RNS during the oxidative burst. Studies also have revealed that administration of VC in combination with quercetin provides synergistic antiviral, antioxidant and immunomodulatory effects.^8,9

Vitamin E, as an antioxidant, and prevents the lipid peroxidation and formation of free radicals, and singlet oxygen hence, considered to be the most important antioxidant found within lipid membranes in the body 10. Vitamin E enhances humoral and cell-mediated immunity and provides protection of low-density lipoprotein (LDL) from oxidation¹¹.

Turmeric has been shown to exhibit anti-inflammatory property which helps the body’s immune system with healing and repair and also acts as an antioxidant by reducing oxidative stress.¹²

Curcumin exhibited the potential to inhibit ACE2, modulates characteristics of the lipid bilayer, inhibits the viral S protein inhibiting the entry of the virus into cells, inhibits the viral protease, stimulates host interferon production to activate the host innate immunity, etc.¹³

Studies have shown that zinc, glutathione, and polyphenols act as Antioxidants and helps in reducing hyperactivation of cytokines such as TNF alpha, IL-1β, IL-6, and IL-8 for the treatment of COVID-19 and other viral infection.¹⁴ 

Thus we see that antioxidants play a major role in protecting cells from damage. Antioxidants such as vitamins C, E, and A along with different minerals affect the immune system, strengthens the immune system and enhance the protection against infections such as bacteria, viruses, parasites and pandemics like COVID-19.

References:

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3. Mulmina, Scientific updates, Update-1, 1-64.
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5. Sebastian J Padayatty, A. K., Peter EckPeter Eck. Vitamin C as an Antioxidant: Evaluation of Its Role in Disease Prevention, Journal of the American College of Nutrition, 2003, 22(1):, 18-35.
6. Guy A. Richards , A. J. T., Constance E. J. van Rensburg , Audrey J. van Rensburg , Carel A. van der Merwe , Johan M. Kuyl , and Ronald Anderson. Investigation of the Effects of Oral Administration of Vitamin E and Beta-Carotene on the Chemiluminescence Responses and the Frequency of Sister Chromatid Exchanges in Circulating Leukocytes from Cigarette Smokers. American Review of Respiratory Disease 1990, Volume 142, Issue 3, 648–654.
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8. Olabinjo1, O. O.; , A. S. O.; , O. O. A.; , A. P. O. Analysis of Physical and Chemical Compositionof Sweet Orange (Citrus sinensis) Peels. International Journal of Environment, Agriculture and Biotechnology (IJEAB) 2017, 2 (4) 2201-2206.
9. https://www.webmd.com/food-recipes/health-benefits-oranges
10. H K Biesalski , J. F. Antioxidants in nutrition and their importance in the anti-/oxidative balance in the immune system. Immun Infekt, 1995, 23(5):, 166-173.
11. A. A. Hamid, O. O. A., L. A. Usman, O. M. Ameen and A. Lawal. Antioxidants: Its medicinal and pharmacological applications. Africal Journla of Pure and Applied Chemistry 2010, Vol.4(8),, 142-151.
12. Christopher D Lao, M. T. R., Daniel Normolle, Dennis D Heath, Sandra I Murray, Joanne M Bailey, Martha E Boggs, James Crowell, Cheryl L Rock, and Dean E Brenner. Dose escalation of a curcuminoid formulation. BMC Complement Altern Med; 2006, 6, 1-4.
13. M. Mrityunjaya, V. P., R. Neelam1, P. Janhavi, P. M. Halami and P. V. Ravindra. Immune-Boosting, Antioxidant and Anti-inflammatory Food Supplements Targeting Pathogenesis of COVID-19. Front. Immunol. 2020, 11:570122. , 1-12.
14. José Manuel Pérez de la Lastra , C. A.-J., Francisco J. Plou and Eduardo Pérez-Lebeña Impact of Zinc, Glutathione, and Polyphenols as Antioxidants in the Immune Response against SARS-CoV-2. Processes , 2021, 9(3), 1-16.