Immunonutrition therapy application is varied, ranging from severely ill patients, perioperative immunonutrition, athletic enhancement, and more recently in the COVID- 19 patients. However, the underlying factor of immunonutrition effectiveness is its capacity to downregulate inflammatory responses and improve immune reactions using pharmaconutrients. Furthermore, immunonutrition seeks to counteract, reverse and repair barrier function, reduce inflammation, improve immune response related to COVID-19, and promote protein synthesis. A large number of bioactive compounds used in Functional Medicine are applied in immunonutrition. In COVID-19 pathogenesis, functional foods, vitamins, essential fatty acids, and immunomodulatory compounds can improve outcomes. Also, a better nutritional status supported by these nutritional compounds can reduce the proinflammatory storm and ameliorate respiratory disturbances present in the obese patient diagnosed with COVID-19.

Vitamin A:

Vitamin A functions as a precursor to immune cells, as well as the differentiation of epithelial tissue. Therefore, functions as an intestinal barrier protectant and immune imprinting factor. Furthermore, its carotenoids have a beneficial influence on the membranes as they improve gap-junction communication. In addition, carotenoids are ROS scavengers, which translates to reduced toxic effects due to the immunoregulatory actions.

Vitamin A deficiency has a pivotal impact on immune function. Not only does its deficiency affects barrier permeability, but it impairs the innate immune system. 

NK cells:  Vitamin A modulates the phagocytic and oxidative activity of the macrophage burst. In addition, this vitamin contributes to the maturation and deficiency of macrophages.

Vitamin A also has multiple effects on acquired immunity as it is involved in Th1 and Th2 cell development and differentiation. Vitamin A modulates the balance between Th2 and Th1 cells, reducing Th2 cells response and increasing the latter. This translates to a modulated Th2 response and suppression of the production of Il-12, TNF-a, and IFN-y by Th1 cells. Furthermore, normal ranges of vitamin A suppress the differentiation of Th17, which ensures better control of adverse immune reactions.

Vitamin C:

Vitamin C is a powerful antioxidant that works together with other bioactive compounds to restore epithelial function. For example, collagen interacts with vitamin C to maintain epithelial integrity, which reduces pathogen translocation.

Also, as part of its scavenger functions, vitamin C protects the cell membrane from reactive oxygen species, protecting epithelial barriers. Additionally, this vitamin is crucial for the proliferation, function, and movement of neutrophils, monocytes, and phagocytes. As for leukocytes, vitamin C promotes its migration to the infection site, phagocytosis, and bacterial killing.

Vitamin D:

Most immune cells have vitamin D receptors. Moreover, some of these cells can synthesize the active form of Vitamin D. Indeed, and this suggests that vitamin D has a substantial immunomodulatory impact. 

As well as the previously mentioned vitamins, vitamin D can improve host defense by enhancing the epithelial barrier integrity. Indeed, calcitriol enhances the production of antimicrobial proteins like cathelicidin and β-defensin that favor the growth of healthy intestinal microbiota and supporting gut barrier function. 

 Vitamin D induces the synthesis of an antimicrobial peptide in epithelial cells and macrophages regarding its immune effects. 

Vitamin D potentiates the differentiation of monocytes from macrophages, enhances superoxide production, and facilitates antigen presentation by dendritic cells. In addition, the functional form of vitamin D, calcitriol, promotes pathogenic death by regulating the expression of antimicrobial proteins: cathelicidin and defensin.

The anti-inflammatory effects of vitamin D rely on its capacity to suppress IFN-y. In addition, this compound counteracts inflammation by promoting the synthesis of anti-inflammatory cytokines by macrophages.

Vitamin E:

This vitamin exists in two different forms:

Tocopherols: mainly found in nuts and vegetable oils. 

Tocotrienols: present in high amounts in some seeds and grains.

Not too long ago, it was believed that there was no vitamin E deficiency, or at least no signs and symptoms were linked to it. However, today we know that high levels of vitamin E in serum associate with positive cell-mediated immune responses. The mechanism behind this is vitamin E’s capacity to repair the integrity of epithelial barriers by reversing the damage caused by free radicals.

Vitamin E immune mechanisms are:

  • Vitamin E improves the cytotoxic activity of NK cells.
  • Inhibits the activity of cyclooxygenase-2 (COX-2) by mediating the production of nitric oxide (NO).
  • Increases the percentage of antigen memory, which enhances the immune synapse formation in naïve T cells.
  • Modulates the balance between Th1/Th2 cells 
  • Reduces the chain reaction of free radicals by breaking this process with its antioxidant effects.

Micronutrient testing:

Vitamins are essential co-factors that support metabolic pathways in our body. Despite this critical role, they also support the immune system by modulating its response, promoting immune cell differentiation, synthesizing antimicrobial proteins, and protecting the epithelial barrier against ROS. Also, these effects support the gut’s microbiota diversity and growth which results in a better immune response. Nevertheless, in case of an infection, vitamin depletion is expected due to their endless immune benefits. Therefore, micronutrient deficiency should be assessed and supplemented as part of the COVID-19 treatment. – Ana Paola Rodríguez Arciniega, MS


Di Renzo, Laura et al. “COVID-19: Is there a role for immunonutrition in obese patient?.” Journal of translational medicine vol. 18,1 415. 7 Nov. 2020, doi:10.1186/s12967-020-02594-4

Additional Online Links & Resources (Available 24/7)


Online Appointments or Consultations:


Online Physical Injury / Accident Intake Form: 


Online Functional Medicine Assessment:


Professional Scope of Practice *

The information herein on "Immunonutrition, COVID-19, and Obesity. Part 2" is not intended to replace a one-on-one relationship with a qualified health care professional or licensed physician and is not medical advice. We encourage you to make healthcare decisions based on your research and partnership with a qualified healthcare professional.

Blog Information & Scope Discussions

Our information scope is limited to Chiropractic, musculoskeletal, physical medicines, wellness, contributing etiological viscerosomatic disturbances within clinical presentations, associated somatovisceral reflex clinical dynamics, subluxation complexes, sensitive health issues, and/or functional medicine articles, topics, and discussions.

We provide and present clinical collaboration with specialists from various disciplines. Each specialist is governed by their professional scope of practice and their jurisdiction of licensure. We use functional health & wellness protocols to treat and support care for the injuries or disorders of the musculoskeletal system.

Our videos, posts, topics, subjects, and insights cover clinical matters, issues, and topics that relate to and directly or indirectly support our clinical scope of practice.*

Our office has reasonably attempted to provide supportive citations and has identified the relevant research study or studies supporting our posts. We provide copies of supporting research studies available to regulatory boards and the public upon request.

We understand that we cover matters that require an additional explanation of how it may assist in a particular care plan or treatment protocol; therefore, to further discuss the subject matter above, please feel free to ask Dr. Alex Jimenez, DC, or contact us at 915-850-0900.

We are here to help you and your family.


Dr. Alex Jimenez DC, MSACP, RN*, CCST, IFMCP*, CIFM*, ATN*


Licensed as a Doctor of Chiropractic (DC) in Texas & New Mexico*
Texas DC License # TX5807, New Mexico DC License # NM-DC2182

Licensed as a Registered Nurse (RN*) in Florida
Florida License RN License # RN9617241 (Control No. 3558029)
Compact Status: Multi-State License: Authorized to Practice in 40 States*

Presently Matriculated: ICHS: MSN* FNP (Family Nurse Practitioner Program)

Dr. Alex Jimenez DC, MSACP, RN* CIFM*, IFMCP*, ATN*, CCST
My Digital Business Card

What's your reaction?