Is a baby easily effected by what the mother eats eg. cabbage?

No: Not really. Nutrients are absorbed via bloodstream. Things not good include things that can also concentrate in blood such as nicotine, alcohol, street drugs

Breast Feeding: Sometimes babies are indeed affected buy things momma eats. Usually this readily becomes apparent as baby will become more fussy and seems to have an upset tummy after nursing. You will notice a cause and effect based on foods you recently ate a meal or two before baby has problems. It is a matter of elimination in your diet to determine the foods that cause problems.