“Brain-training” games have not been shown to keep the mind sharp and the middle-aged would be better off learning a language or taking up a new hobby, according to scientists.

Varied activities to keep the mind stimulated are more likely to ward off dementia than apps and games, the Global Council on Brain Health said.

The international scientists and policy advisers said that evidence of the benefits of brain-training games and puzzles was “weak to non-existent”. There is some evidence of a short-term effect for some apps, but no long-term benefits have been shown. Mentally stretching activities, however, have been shown to help people retain memory and thinking skills.

“If you are not engaging in cognitively stimulating activities, seek out a new activity that challenges the way you think,” they said. “If you already engage in some cognitively stimulating activities, continue those you enjoy and try to add one or two new activities.”

People should not wait until they are older to make sure the mind stays tuned up as the younger they start stimulating activities the better. Taking up photography classes, family history or t’ai chi could all help, according to Age UK, which is a member of the council.

“In the same way you need to maintain exercise for physical strength, you need to participate in mentally stimulating activities to support the health of your brain,” James Goodwin, the charity’s head of research, said. “Decline is not inevitable. There are plenty of activities that we can start that provide benefits . . . such as playing with grandchildren, gardening or playing cards.”