One study that analyzed the typical Japanese diet concluded that green tea might enhance life expectancy. This could be attributed to the various ways green tea positively impacts health, all of which compound and help one live longer.
Another American study states that though tea might promote longevity, calcium supplementation is important in those cases – as green tea contains caffeine, and caffeine intake can lead to calcium loss (15). And a Stanford study stated that green tea drinkers usually showed less disability with age. Those who drank green tea are less likely to develop functional disability, which can shorten life expectancy as one ages (16).