Naka Immune Strength - Immune system support with Quercetin, Zinc Bisglycinate and Vitamin C. Quercetin is a bioflavonoid found in many vegetables, fruits, and herbs. Increased intake helps support cellular health throughout the body by counteracting unstable free radicals, provides seasonal allergy relief, and may support immune health. Zinc is well known for supporting and protecting the immune system, but it is also an essential trace mineral needed for numerous other functions throughout the body. Vitamin C is an essential nutrient that helps in collagen formation, which is needed for the normal development and maintenance of bones, cartilage, teeth, and gums.