Besides being Madonna's chef, Mayumi Nishimura is the author of a macrobiotic cookbook called “Mayumi's Kitchen,” which details how to prepare whole grains, vegetables, and beans, as well as seafood, fruit, pickles, and nuts.

That's great news for expecting Madonnas, because new research has shown that for pregnant women, eating a nut-rich diet in the first trimester is linked to a child's improved cognitive function — including attention capacity and long-term working memory.

Spanish researchers had 2,208 expecting mothers fill out a questionnaire during their first and third trimesters. After the mothers gave birth, researchers tested their children for cognitive function at 18 months, and at 5 and 8 years old.

The researchers found that moms who had eaten the most nuts in their first trimester had kids with the highest cognitive scores.

The nuts the researchers asked about — walnuts, almonds, peanuts (which are actually legumes), pine nuts, and hazelnuts — all contain high levels of folic acid, essential in every aspect of fetal development.

They also contain the fatty acids omega-3 and omega-6, which are great for all-round neural and cognitive development, because they tend to accumulate in the frontal areas of the brain that are responsible for memory and attention span.

The researchers concluded, “Nut intake during early pregnancy is associated with long-term child neuropsychological development.”

In addition, while the researchers found that just over 3 ounces a week is enough to make noticeable improvements, once a day is the smarter move.