It has been shown that severe COVID-19 could manifest as a hyperinflammatory syndrome (secondary haemophagocitic lymphohistiocytosis), which is characterized by an important hypercytokinaemia (cytokine storm) with multiorgan failure and ARDS in approximately 50% of patients [220]. Several studies have been conducted to determinate if omega-3 fatty acids DHA and EPA could modulate systemic inflammatory response and affect plasma cytokine production. Thienprasert et al., in a randomized controlled trial, demonstrated that consumption of omega-3 PUFAs was associated with fewer episodes and shorter duration of illness (mainly upper respiratory tract) and with a significantly lower concentration of TGF-beta1 concentration compared with the placebo group [221]. Two randomized controlled trials, aimed to determinate if omega-3 fatty acids could modulate the systemic inflammatory response, improving the outcomes in patients with acute lung injury, have shown that in the intervention groups there was not a reduction of the biomarkers of systemic inflammation and pulmonary outcomes did not improve [222,223]. In a recent systematic review, Dushianthan et al. have reported a significant improvement in blood oxygenation and in the duration of ventilator days and ICU length of stay in patients with ARDS who received nutrition containing antioxidants and rich in EPA and DHA, although there was a low quality of evidence [224].