Vitamins and minerals are utilized by a wide array of enzymes that protect cells and DNA from damage. Zinc, in particular, is essential for maintaining DNA integrity and adequate antioxidant defenses. A new paper reviewing the work of Dr. Bruce Ames and others highlights the importance of zinc in promoting longevity and preventing chronic diseases.
Zinc is a metallic mineral that is consumed in the diet from foods such as meat, shellfish, legumes, and fortified foods. Severe zinc deficiency results in growth retardation, hair loss, skin sores, and depressed immunity and is uncommon in developed nations. However, marginal deficiency, which is asymptomatic and dangerous over long periods of time, is likely very common. Children, older adults, and people with altered gastrointestinal function are particularly susceptible to zinc deficiency.
Zinc is concentrated in the nuclei of cells where it functions to stabilize chromatin (large structures of spooled DNA) and catalyze chemical reactions for DNA repair, replication, and transcription. Along with other metals such as copper, iron, and magnesium, zinc is essential for balancing oxidative and reductive reactions in the cellular environment. One enzyme, copper-zinc superoxide dismutase, neutralizes hydrogen peroxide radicals by accepting an electron at its copper site. By absorbing reactive oxygen species, antioxidant compounds prevent damage to structures such as lipid membranes, enzymes, and DNA.
The immune system is a major producer of hydrogen peroxide and other oxygen radicals, which attack pathogens and recycle damaged host cells. Adequate zinc intake is essential for moderating the inflammatory response. In particular, zinc inhibits activation of the NF-kappaB pathway, driving the production of inflammatory cytokines such as tumor necrosis factor-alpha. Zinc deficiency increases the risk of developing neurodegenerative and autoimmune diseases through mechanisms that involve over-activation of inflammatory pathways.
Zinc deficiency further increases one’s risk of disease by reducing the number of pathogen-fighting cells such as antibody-producing B cells, natural killer cells, and monocytes. Reduced pathogenic immunity and increased chronic inflammation are common in old age, but they begin in middle-adulthood and progress over time in parallel, with decreasing zinc absorption and retention. Zinc supplementation in older adults reduces inflammation while increasing production of new immune cells and strengthening the body’s response to vaccines.
Overall, zinc deficiency accelerates the aging process by impairing antioxidant production and cellular repair mechanisms, over-activating inflammatory pathways, and reducing pathogen defenses. The authors conclude there is good evidence to suggest that supplementing with at least 20 milligrams of zinc per day may be an effective strategy for reducing the adverse effects of aging on the immune system.
