Vetra Barley Grass Powder Barley Grass is naturally high in many key nutrients that help to support the immune system such as vitamins minerals amino acids antioxidants and enzymes. It is extremely high in vitamin C which is crucial to the overall health of the body in its efforts to fight off infections â both bacterial and viral. Barley is an excellent source of dietary fiber but also contains other essentialminerals including magnesium manganese and selenium. Compared to whole-grain oats barley has more dietary fiber and is lower in fat and calories