Women who eat nuts in early pregnancy have brainier kids, a study suggests.
Their children developed better memories, higher levels of attention and more thinking skills.
Around three handfuls of nuts a week – 90 grams – in the first three months of pregnancy was best.
Researchers suggest walnuts, almonds, peanuts, pine nuts or hazelnuts for their healthy fatty acids.
The experts, from the Barcelona Institute for Global Health, studied 2,200 mother and child pairs.
The women completed a questionnaire on eating habits and their youngsters completed multiple exams.
These assessed their thinking skills, attention capacity and memory at 18 months and 5 and 8 years.
Those whose mothers ate most nuts in their first trimester scored highest.
Study leader Florence Gignac said: “This is the first study to explore the possible benefits of eating nuts during pregnancy for the child’s neurodevelopment in the long term.
“The brain undergoes a series of complex processes during gestation and this means that maternal nutrition is a determining factor in fetal brain development and can have long-term effects.
“The nuts we took into account in this study were walnuts, almonds, peanuts, pine nuts and hazelnuts.
“We think that the beneficial effects observed might be due to the fact that the nuts provided high levels of folic acid and, in particular, essential fatty acids like omega-3 and omega-6.
“These components tend to accumulate in neural tissue, particularly in the frontal areas of the brain, which influence memory and executive functions.”
The study also examined nut consumption in the last three months of pregnancy but found they had little effect.
Nuts are already known to reduce the risk of high blood pressure and diabetes and may protect against mental decline in old age.
The NHS website says: “Nuts are high in fiber, and unsalted nuts make a good snack. But they do still contain high levels of fat, so eat them in moderation.”