Zinc, Metallothioneins, and Longevity Effect of Zinc Supplementation:Zincage Study

摘要

Aging is an inevitable biological process that is associatedwith gradual and spontaneous biochemical and physiological changesand increased susceptibility to diseases. Because nutritional factors are involved in improving immune functions, metabolic harmony, and antiox-idant defense, some nutritional factors, such as zinc, may modify suscep-tibility to disease and promote healthy aging. In vitro (human lympho-cytes exposed to endotoxins) and in vivo (old or young mice fed with lowzinc dietary intake) studies revealed that zinc is important for immuneefficiency (innate and adaptive), antioxidant activity (supeoxide dismu-tase), and cell differentiation via clusterin/apolipoprotein J. Intracellularzinc homeostasis is regulated by metallothioneins (MT) via ion releasethrough the reduction of thiol groups in the MT molecule. This processis crucial in aging because high MT levels are not able to release zinc,resulting in low intracellular free ion availability for biological functions.Improvement in these functions occurs in the elderly after physiologicalzinc supplementation. In this study, the selection of elderly subjects forzinc supplementation is discussed in relation to the genetic backgroundof MT and pro-inflammatory cytokines, such as interleukin-6, becausethe latter is involved both in MT-gene expression and in intracellular zinchomeostasis.