fat soluble vitamins role in health promotion

Vitamins as a class of essential nutrients in trace quantities are required for normal growth, and reproduction. they are studied in two categories; fat soluble vitamins and water soluble vitamins that are functional in many ways to maintain healthy immune system response for disease prevention, and to improve cognitive functions. the main aims of the present review are on vitamins discovery and classifications, fat soluble vitamins biological functions, conditions of deficiency/toxicity on human health promotion, their possible effect/s regarding covid-19 infection and common neurological and genetic diseases. for this purpose many basic related literatures as well as new advances on fat soluble vitamins were assessed. investigations indicated that malabsorption in fat-soluble vitamins is of particular significance in cystic fibrosis. in addition, in parkinson’s and alzheimer’s patients a diet rich in antioxidant vitamins recommended for their protective role and improvement of the cognitive functions. furthermore, it is recognized that fat soluble vitamins use, especially vitamins a & d supplements during covid-19 days in light of their safe and therapeutic range could be beneficial. however, their possible preventive role and/or supportive therapy against covid-19 are yet controversial. further clinical studies worldwide will hopefully define their role/s in reducing the severity and complications of the infection. in addition, in the absence of specific treatment for covid-19 to date, as well as reducing the risks for other deficiency conditions, looking for alternative approaches like improving the availability, affordability and acceptability of healthy diets for  all,  specifically for the most vulnerable groups are  important.