A year of matcha left its main thinking tests flat, nudging two others
In one trial, 99 older adults with mild cognitive decline took 2g of matcha a day for a year: slightly better at reading faces, a hint of better sleep, nothing on the main thinking tests.
What the study found
A year of matcha missed every one of its main cognitive targets
The main tests came back flat. In one trial, 99 older adults with mild cognitive decline drank 2g of matcha a day for a year and ended up slightly better at reading facial expressions, with a hint of better sleep, while the cognitive tests the trial was built around showed nothing.
The caveat · Whole matcha, not theanine alone
This was whole matcha, theanine and catechins and caffeine together, so no result here belongs to theanine specifically. The two results that moved were secondary outcomes, which carry less weight than the ones the trial was built to test. And everyone in it already had cognitive decline, which is not a healthy adult drinking green tea.