Expectant mothers who eat nuts regularly during early pregnancy have more intelligent children, a new study suggests.

Analysis of 2,200 women and their children over eight years found those whose mothers had eaten three or more servings a week during the first 12 weeks performed better in intelligence tests.

Their cognitive function, attention span and working memory were all better than those whose mothers consumed little or no nuts during the first trimester.

The research team at the Barcelona Institute for Global Health believe the beneficial nutrients such as folic acid and essential fatty acids like omega-3 and omega-6 accumulate in the neural tissue of the developing foetus at a crucial early stage of development.

They also searched for associations between intelligence and high nut intake during the final trimester, but found no links.

Nuts are already known to help reduce the risk of hypertension, oxidative stress and diabetes, and it is suspected they confer a protective effect against cognitive decline in old age.

However, this is the first study to explore the link between maternal consumption of nuts during pregnancy and the mental performance of children.

Published in the European Journal of Epidemiology, the research included walnuts, almonds, peanuts, pine nuts and hazelnuts.