Mothers should eat more fish. Eating fish during pregnancy and breastfeeding appears to prevent post-natal depression.

Countries where women eat the most fish have the lowest rates of baby blues. Those where they eat the least fish have the highest rates.

In Singapore, where the average person consumes 81.1 pounds of fish per year, only one in 200 mothers gets the baby blues.

In South Africa, where women eat only 8.6 pounds, an incredible one in four women suffers post-partum depression.

In the US, in the middle with an average consumption of 48 pounds of fish per year, about one in 10 new mothers gets the baby blues.

The breast milk of women who eat a lot of fish contains high levels of DHA (docosahexaenoic acid), an omega-3 fatty acid that is now being added to some infant formulas. However, pregnant and nursing women need to be careful about what type of fish they eat. Shark and swordfish, for instance, may be high in mercury.

Kholmquist@irish-times.ie