What a new mom eats during her pregnancy affects her unborn baby’s immunity, especially vis-a-vis allergies, reports new research in The Journal of Physiology. The research found that if a mother’s diet contains a certain group of polyunsaturated fatty acids, such as those found in fish, walnut oil or flaxseed, the baby’s gut develops differently. These substances are thought to improve the way gut immune cells respond to bacteria and foreign substances, making the baby less likely to suffer from allergies.