Immunonutrition and COVID-19 Some of the main findings from the scientific literature search by the researchers were:
A healthy immune system requires vitamins A, D, C, E, B6, B12, folate, copper, iron, zinc, and selenium. There is an interplay of these nutrients in a healthy immune system Immunonutrients of considerable importance are vitamin C, D, and zinc. Vitamin C helps in the development of the epithelial barrier functions of the respiratory system that prevents invasion by pathogens. It can help prevent pneumonia. Vitamin D is a powerful immunoregulator. B and T lymphocytes, macrophages, and monocytes are some of the immune cells that have vitamin D receptors on their surface. Vitamin D has a protective role in respiratory infections Authors write, “Zinc is regarded as a ‘gatekeeper’ of immune function.” Recommendations The researchers wrote, “The general public and indeed the aging population should be encouraged to follow guidance from Public Health England and continue taking supplements containing 10 μg of vitamin D daily...”. They recommend foods rich in vitamin C (broccoli (60 mg/100 g), blackcurrants (130 mg/100 g), fortified breakfast cereals (up to 134 mg/100 g) and oranges (37–52 mg/100 g). They recommend foods rich in natural zinc such as “canned crab (5.7 mg/100 g), canned shrimps (3.7 mg/100 g), canned adzuki beans (≈2.3 mg/100 g) and boiled eggs (1.3 mg/100 g)”. The recommendations are for vitamin D supplementation with an upper limit of 50 µg/day and an upper limit of daily zinc at 25 mg/day.
