Introduction:
Most of the patients treated with COVID-19 belong to vulnerable groups, resulting in many cases of malnutrition and dysphagia due to persistent cough. It can also cause nausea, vomiting, and diarrhea, which may increase the risk of dehydration and muscle catabolism. Therefore, patients with COVID-19 are at high risk of malnutrition, making the need for nutritional management one of the basic needs for their care. It seems, therefore, that good nutritional status is an advantage for those who suffer from this disease.

Methods:
Studying and analyzing a variety of articles published in English, a systematic literature review was performed, using the PubMed and Scopus databases.

Results:
Dietary protocols for patients suffering from COVID-19 infection should be straightforward because the urgent and massive arrivals of patients in need of emergent respiratory care often make nutritional evaluation and care of lower priority. The Mediterranean diet has been rendered as one of the healthiest nutritional standards in the world, due to the inclusion of a great variety of nutrients mainly of plant origin - namely fruits, vegetables, legumes, fish, and olive oil, - which in addition to essential vitamins and antioxidants, bioactive polyphenols, especially flavonoids, provides a shield against the highly inflammatory and pro-thrombotic environment caused by COVID-19.

Conclusions:
Due to the elevated need for vitamins and antioxidants of seriously ill patients, in order to strengthen their immune system, the hypothesis of the protective effect of the Mediterranean Diet against COVID-19 should be considered in parallel with the currently available epidemiological data. However, there are not yet enough studies in seriously ill patients fed in hospitals and merely hypotheses about the beneficial properties of the micronutrients provided by this diet model could currently be stated.