Introduction and objective:
The latest scientific reports showed that there is a relationship between the state of the gastrointestinal tract and the immune system, and the incidence of COVID-19. Diet can exert an immunomodulatory effect and regulate the immune response of an organism. The aim of the review is to show the effects of immunomodulators contained/supplemented in a diet on the infection SARS-CoV-2 and the course of COVID-19.

Review methods:
The literature review was conducted using PubMed, Google Scholar and the Medline database.

Abbreviated description of the state of knowledge:
Regular vitamin D supplementation significantly reduces the risk of respiratory infection with SARS-CoV-2; vitamin C may inhibit the expression of the ACE2 receptor in human small alveolar epithelial cells and limit the penetration of SARS-CoV-2; reduced iron levels predispose people to severe COVID-19 symptoms; selenium deficiency may be responsible for a decreased level of antibodies and NK cell cytotoxicity. Aloë vera isolated polysaccharides strengthens the immune system; the quercetin and ellagic acid in combination with virus proteins show potential antiviral activity against SARSCoV- 2. Subsequently, adaptogens, ginger, echinacea and curcumin - showed anti-inflammatory effects. Also, the optimal composition of the gut microbiota improved/maintained the integrity of the lymphoid tissue found in the gastrointestinal tract (GALT) and the functioning of the gut-pulmonary axis.

Natural immunomodulators may be a relatively safe therapeutic option in patients during the course of COVID-19, but there are still no official recommendations for their practical use in therapy. It should be emphasized that there is a need for further scientific research into the mechanisms of action and efficacy of phytotherapy in the context of the effectiveness of plant-based immunostimulants in alleviating the course of COVID-19 disease.

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