New Zealand blackcurrants are good for keeping us mentally young and agile, finds a study.

The berries help in managing the mental decline associated with aging populations and also helps people with brain disorders such as Parkinson's disease or depression.

"This study is the first to look at the effects of berry consumption on the cognitive performance of healthy young adults," said Arjan Scheepens, the plant and food research scientist who led the study.

The juice from a specific New Zealand blackcurrant cultivar, 'Blackadder' also reduced the activity of a family of enzymes called monoamine oxidases which regulate serotonin and dopamine concentrations in the brain.

These chemicals are known to affect mood and cognition and are the focus for treatments of both neuro-degenerative symptoms associated with Parkinson's disease and mood disorders, including stress and anxiety.

"This research has shown that New Zealand-grown blackcurrants not only increase mental performance but also reduce the activity of monoamine oxidases," Scheepens said.

"One of the key trends in the food industry is the development of ingredients and foods that have beneficial effects on human health," said professor Roger Hurst, science group leader food and wellness at plant & food research.

The study was published in the Journal of Functional Foods.