Many people think that certain “gassy” foods a nursing mom eats will cause her baby to have gas. But, according to Kelly Bonyata, an International Board Certified Lactation Consultant, this widespread notion is not founded in actual research. There is no definitive list of what breastfeeding moms should eat, because each baby has different food reactions. Breast milk is made from the substances that pass through a mother’s bloodstream, not her gastrointestinal tract or stomach. Foods that are gassy for a mom have no real effects on her baby.
Even though this is true, whatever a mom eats still can affect her baby. Some babies have food sensitivities that can result in gas, rashes, colic and excessive spit-up. Moms can go on an elimination diet to determine which foods bother her baby by forgoing one “fuss food” at a time.
Some babies have gas no matter what their moms do, and there is no need to worry as long as they aren’t in pain or showing other signs of food sensitivities. Babies have immature digestive systems that will improve with time.

Dairy Products

Foreign proteins in breast milk may cause negative reactions in babies. Dairy products are the most common of these problem foods and have been linked to fussiness and gas. Cow’s milk, butter, ice cream, cheese and anything containing whey, casein, lactose or sodium caseinate should be avoided. Don’t assume your baby is lactose intolerant if he’s bothered by dairy in your diet. Intolerance to milk protein is a completely different issue from lactose intolerance and should improve with time.

Other Fuss Foods

Other foods that may cause gas and fussiness include anything with caffeine, soy, fish, peanuts, chocolate, wheat, beef, nuts, eggs, corn, citrus fruits and prenatal vitamins containing iron. Also, anything a baby consumes that isn’t breast milk—juice, solids and medications—can disturb a baby’s delicate digestive system.

Non-food Causes of Gas

Food isn’t the only source of gas. A fast, forceful letdown may cause baby to gulp and take in too much air when nursing, resulting in gas. Excessive crying (gulping too much air) and thrush (yeast infection) may also cause gas. All babies are different, and it’s difficult to determine exactly what it is that’s bothering them.