Onions and Breastfeeding: Effects on Milk + Safety

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Think back to the last time you chopped an onion. Between getting teary-eyed on the first slice to an onion smell wafting from your hands the next day, onions are quite potent.

Most mothers, especially those who are providing their babies with breast milk, are aware of how substances like alcohol and caffeine can affect breast milk. But what about benign foods with strong tastes and smells, like onions?

Onion milk might not sound good to you, but most babies actually don’t mind! When a breastfeeding or pumping mom eats onions, her milk picks up some of the flavors. This isn’t a bad thing, however, as different breast milk flavors can help broaden your baby’s taste preferences from an early age. 

Not all onions are the same- keep reading to find out which types are more likely to flavor your breast milk and how long the taste change is expected to last!

Can I Eat Onions When Breastfeeding? Is it Safe?

There’s no doubt about it, onions have a strong flavor and odor. In many dishes, that’s exactly what we’re looking for and what makes them great for flavoring everything from sauces and soups to garnish on pasta. 

different types of onions in a basket

When you’re breastfeeding (or pumping, if that’s what works for you and your baby), everything you eat contributes to your breast milk. That includes all of the essentials like healthy fats, vitamins and minerals, and also flavor. 

‘Strong’ foods, such as onion, can change the flavor of your breast milk (source: American Journal of Clinical Nutrition).

Most babies have no problems with a variety of flavors of your milk and can actually provide early exposure to new flavors, setting them up to accept a wide variety of foods and tastes once they’re ready to start solids. (source: La Leche League, Mayo Clinic). 

The stronger and more potent onions that you eat, the more likely it is for your milk to have an oniony flavor. Raw onions, red onions, and white onions tend to have the strongest flavors.

Cooked versions, Vidalia (sweet) onions, green onions, and shallots tend to offer a milder flavor and might have a lesser impact on your breast milk. Dishes that rely heavily on onions (think French onion soup) can also affect breast milk taste. 

Whether you personally prefer a strong onion flavor or like it on the mild side, all types of onions can affect your milk. The flavor of breast milk has no impact on its safety, so go ahead and eat as many onions as you’d like. 

Does Onion Cause Gas in Breastfed Babies?

Fussy and gassy babies are the source of many sleepless nights for new parents. Just like during pregnancy, everyone has their own theories about what might be the cause, and the maternal diet is often thought to be the culprit. 

Eating onions can cause gas in some children and adults, but that is due to carbohydrate breakdown in the intestines- something that would affect the mom and not the baby. There is no good evidence to show that when a mom eats certain foods it causes gas in her breast milk fed baby (source: Johns Hopkins). 

Of course, some babies do dislike particular flavors or react to certain foods. If you’ve recently started eating more onions and notice your baby reacting, you can always eliminate onions for up to a week.

If the baby gets better and there is no other reason they weren’t feeling well (like a cold, constipation, or being overtired) then you’ve found a possible link. 

File this one under the breastfeeding myth!

red onion on a wood cutting board

Does Onion Change The Taste of Breastmilk, and For How Long?

As you know, eating onions, especially large amounts of onions, does change the flavor of your breast milk. For most babies, the flavor is not a problem. If you ate onions regularly during pregnancy, then your baby may already be used to the onion flavor from the amniotic fluid (source: La Leche League).

Unlike alcohol, there’s no easy way to estimate how long your milk will be affected or how long the baby will still be able to pick up the taste.

There is evidence to show that babies can taste onion in the breast milk within a couple of hours after mom eats onions. The oniony flavor can even last days if mom eats onions regularly (source: American Journal of Clinical Nutrition). 

Though it might sound odd at first, as long as your baby does not seem bothered by the taste of oniony breast milk, there is absolutely nothing wrong with the change in flavor.

Whether you feed your baby by nursing, giving a bottle, or even if they get your milk through a tube feed hopefully this article has reassured you that oniony milk is perfectly normal and healthy.