Blackcurrants can help people stay alert and reduce mental fatigue, a New Zealand study has found.
The study by New Zealand science company Plant & Food Research showed an extract of blackcurrants enriched with anthocyanins - the compound that gives dark berries their colour - could help people work better under mental stress.
In the study, 35 healthy participants completed 70-minute computer tests designed to be mentally tiring, such as watching a series of numbers and responding when three consecutive odd numbers appeared.
The trial found compared to placebo, those taking the blackcurrant extract pill worked more accurately without slowing down, and felt more alert and less tired after the test.
Study leader Dr Arjan Scheepens said the finding was "really exciting".