It has been shown that magnesium is essential for formation of immunoglobulin G (IgG), as well as being critical for immune cell function and regulation of inflammatory cytokines. The mineral also controls one of the most important types of cells in the innate immune system: macrophages. For all these reasons, significant magnesium deficiency will impair a person’s immune system, putting them at substantial risk of infection.

A recently described genetic disorder has demonstrated just how important magnesium is to healthy immunity. Scientists named this disorder XMEN disease (X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection, and neoplasia). The condition is associated with a severe chronic viral infection with a high incidence of cancer. Low magnesium impairs the ability of the immune system to combat the virus.

A deficiency in magnesium has also been shown to impair the development of lymphocytes — immune cells that are critical for protecting against viral infections and cancer. People with XMEN disease have very low blood lymphocyte levels.

Asthma sufferers’ condition is also made much worse by magnesium deficiency. On the other hand, supplementing them with magnesium rapidly improves their condition, both by opening their airways and by reducing the immune response that triggered the attack in the first place.

Animals that have been made magnesium-deficient exhibit severe inflammation, heightened stress responses, impaired immunity, and shrinkage of their thymus gland, which produces immune cells.