What Not to Eat When Breastfeeding: 5 Foods & Drinks to Avoid

You likely spent so much time worrying about the best foods for pregnancy, it’s easy to forget you’re still growing a baby while breastfeeding! Now that your sweet babe is in your arms instead of your belly you can finally indulge in the things you’ve been missing: tuna tartare, a tall Sapporo, Italian cold-cut subs. But there are some things nursing mamas want to steer clear of.

What breastfeeding mothers eat passes into the bloodstream and then onto the breast milk and into your little one. While foods that might make you gassy won’t likely have that effect on your baby, there are certain foods you may want to avoid while nursing so as to avoid any negative developmental effects.

Here’s a short list to help you keep track of what foods and drinks to avoid while breastfeeding

1. Fish with high mercury levels

Fish with high levels of mercury are a big no-no while nursing–so much so that the EPA asks pregnant and nursing moms to avoid those high mercury level fish like some forms of tuna, shark, swordfish, tilefish and king mackerel. Being exposed to too much mercury can have an effect on babies’ tiny, developing brains, impacting their cognitive thinking, memory and fine motor skills. The EPA also suggests limiting canned tuna to six ounces per week while breastfeeding. Instead, try salmon, anchovies, sardines and herring.

2. Cow’s milk

It’s a myth that certain foods in a mother’s diet causes gas in babies—so please don’t avoid broccoli for that reason alone. However, if your child is showing symptoms such as a skin rash or respiratory issues or diarrhea, there may be an underlying food sensitivity or allergy to something in your breast milk. The most common offender is cow’s milk.

Some telltale signs include: reflux, diarrhea, blood in stool, wheezing, and eczema. If you think your baby might have an allergy to cow’s milk, talk to your doctor and try cutting dairy from your diet completely.

It may take as long as one to two weeks without dairy in your diet to see an improvement in your baby’s symptoms. It’s important to realize an allergy to cow’s milk protein is not the same as being lactose intolerant—so taking Lactaid won’t help. It’s also good to note that most infant formulas are based on cow’s milk, so talk to your child’s pediatrician about other options.

3. Caffeine

While yes, you can technically have coffee now, you may still want to temper your caffeine intake while nursing. Babies under 6 months of age tend to be more sensitive, so it may be safer to limit caffeine until your little one is a bit older and they’re better able to metabolize the caffeine content.

Too much caffeine can make your baby fussy and unable to fall asleep. In a newborn, caffeine has a half-life of a shocking 97.5 hours, but in a 6-month-old, the half-life drops significantly to just 2.6 hours, thanks to their improved metabolism.

4. Too much alcohol

First, let’s bust that myth that alcohol stimulates milk production. It doesn’t. But you can still drink it anyway in moderation, and away from breastfeeding.

The American Academy of Pediatrics says it’s OK to drink a small amount (one to two drinks per week) during your breastfeeding career, but you should have your glass of wine or beer right after a nursing or pumping session, not before—and then wait two hours after your drink before your next nursing session.

5. Cannabis and herbal medicines

Using cannabis (marijuana) and some other medicinal herbs when breastfeeding may not be safe for your baby, especially if they’re younger than 6 months, when it may take longer for their tiny livers to metabolize the compounds.

Studies have shown that THC (the psychoactive compound in cannabis) becomes concentrated in human milk, which means it can pass through breast milk to your baby. In other cases, herbal medicines may not have been studied extensively in regards to their effects on infants, so it may be best to avoid them until you’ve stopped breastfeeding. Talk to your doctor before taking any herbal medicines, using cannabis or trying a product with CBD.

A version of this story was originally published on Aug. 30, 2021. It has been updated.