Forgot to add folate. :)
Nutrients needed for a healthy immune system: vitamin A, vitamin B6, folate (vitamin B9), vitamin B12, vitamins C, vitamin D, vitamin E, copper, iron, selenium, and zinc.
Lower immunity causes an increased susceptibility to infection. Commonly due to nutrient deficiency but may indicate low or deficient levels of immunglobulins. Deficiency states that list muscle twitches include magnesium deficiency, vitamin D, vitamin B12 deficiency. Vitamin A is also needed for good eye health.
Nutrients needed for a healthy immune system: vitamin A, vitamin B6, vitamin B12, vitamins C, vitamin D, vitamin E, copper, iron, selenium, and zinc. Magnesium is needed for vitamin D absorption. Vitamin D deficiency is correlated with a higher susceptibility to infections.