Zinc is a gatekeeper of immune function. It moves both inside and outside our cells. For example, during an infection, blood levels drop as zinc is siphoned out of the bloodstream into cells that help launch an immune response.
Zinc also appears to be involved in making physical barriers — such as the cells that line our organs — more resistant to invasion, as well as ensuring the proper functioning of macrophages, key white blood cells that gobble up pathogens and send out chemical signals to recruit other cellular soldiers.
Zinc is an antioxidant and has anti-inflammatory actions. Zinc activates antioxidant molecules and proteins and reduces the activity of oxidant-promoting enzymes. Together with Vitamin C, they provide complementary antioxidant protection to high levels of oxidative stress during infection.
Zinc is essential for the process that causes stem cells in the bone marrow to form lymphocytes (for the subsequent differentiation into B- and T-lymphocytes). It is also required for the proper functioning of T-lymphocytes, for the production of antibodies by B-lymphocytes, and for efficient interaction between B- and T-lymphocytes. These cells are responsible for antibody production, direct cell-mediated killing of virus-infected and tumour cells, and regulation of the immune response.
How to get Zinc
Lower bioavailability of Zinc in plant foods
Phytates is a substance that present in whole-grain breads, cereals, legumes. It binds zinc and inhibit its absorption. Thus, the bioavailability of zinc from grains and plant foods is lower than that from animal foods, despite many grain- and plant-based foods are still good sources of zinc.
Supplements contain several forms of zinc, including zinc gluconate, zinc sulfate, zinc picolinate and zinc acetate. The National Institutes of Health considers 40 mg of zinc a day to be the upper limit dose for adults.
All forms of zinc - from supplements and food - can become toxic if you consume more than 40 milligrams daily from all sources, according to the Linus Pauling Institute. So, before you take any zinc supplement, track the amount of zinc consumed through your diet and ensure the dose of your supplement doesn’t add more zinc than you need.