Many studies have already shown that a woman's diet during her pregnancy can affect her baby's health, not only during the time it's in the womb, but well into its adulthood. This phenomenon, called fetal programming, posits that the conditions in utero set up the child's risks for certain chronic diseases.

With regards to allergies and asthma, however, the studies are not that conclusive. For peanuts, for example, the current recommendation is to avoid peanuts during pregnancy if you know that your child might be at risk for (food) allergies. There was also a study published last year indicating that apples and fish consumption during pregnancy can help reduce risks of childhood asthma (also reported recently in HealthDay).

The best course? Here's the best recommendation, high-risk or not: "The general consensus is that women should consume a good, well-balanced diet with lots of fruits and vegetables, and not to overindulge in any one food."