Is My Baby Allergic To My Breastmilk?

When people hear you are planning to breastfeed, they are usually full of advice and stories about their own experiences. One topic that always tends to come up is mom’s diet. “You definitely can’t eat cabbage – it will give your baby gas,” you hear. “You need to drink lots of milk whether you like it or not.” “You shouldn’t eat anything spicy – it will upset baby’s tummy.” But how can you truly know what is fact and how much is fiction?

Allergic BabyEvery culture has foods that a breastfeeding mom should or should not eat. For instance, many southeast Asian and African cultures suggest new mothers need to balance their “hot” and “cold” elements in the postpartum period, and they all have culturally specific foods that are prescribed or restricted. Common dishes, for example chicken and shredded ginger stewed in rice wine in China, are thought to reenergize the mother and bring in a strong milk supply. These moms are also taught to avoid raw foods, and are encouraged to eat foods made with garlic, ginger and other spices. So a restriction on eating a garlicky meal is uncommon in these cultures, even though you may hear that from well-meaning friends and family in Western cultures.

In addition, food eaten during pregnancy may have been “tasted” by babies in utero, and may not pose a problem during breastfeeding. Amniotic fluid takes on flavors from mom’s diet, as does breastmilk. One study, for instance, found that infants with prenatal and early postnatal exposure to a flavor enhanced their enjoyment of that flavor when starting solids. So those burritos or spaghetti dinners you had may help your baby enjoy Mexican or Italian foods later in life, and may make baby more accepting of the flavor of breastmilk after eating a strong-tasting dinner yourself.

But my great-aunt Gertrude says I can’t eat broccoli (or cabbage, Brussels sprouts, cauliflower, beans, etc.) …

Aunt Gertie’s argument may be that broccoli will give your baby gas, but the chances of that happening are unlikely. Your digestive system breaks down foods and delivers the nutrients from your diet through your bloodstream to the secretory cells in the breasts. These cells use the nutrients as building blocks to make milk.

When mom gets gas from eating certain foods, it is the byproduct of normal digestion as intestinal bacteria break down undigested carbohydrates such as sugar, starches and soluble fiber. This gas cannot move into mom’s bloodstream, thus it isn’t passed into her breastmilk.

A baby’s fussiness after eating is often attributed to gas, and the thought is that it’s from something the baby ingested. If mom is breastfeeding, her diet is suspect. But gassiness in babies has many underlying factors, and may not mean that he is allergic to something mom has eaten. In fact, only about five percent of babies are allergic to something in mom’s milk. Certain substances, however, can pass into breastmilk and cause problems for baby.

When a baby is allergic to something mom has consumed, fussiness and gassiness are only two symptoms. Look for other indications, such as:

  • skin rashes or eczema
  • vomiting
  • diarrhea, blood or mucous in baby’s stools, green frothy bowel movements
  • congestion, runny nose, wheezing cough
  • difficulty sleeping, and
  • crying during or after feeding, difficulty getting baby to latch and nurse.

If your baby has a number of these symptoms at the same time, look to see what mom has been eating.

So what are the most common allergens?

Breastfeeding Mom

Substances from foods in your diet appear in your milk anywhere from one to 24 hours after eating, with the average being about four to six hours. Your digestion depends on a number of factors, such the type and amount of food, and your individual metabolism. Other factors that may determine how much the foods affect your baby include how old your baby is (and how mature his digestive system), and how many times a day he is nursing.

Before limiting any foods from your diet, think about what else baby is ingesting. Has he already started solids? Is he taking vitamin and mineral supplements or Vitamin D drops? Has he had any juice or formula? It could be that something baby ingested directly is causing the problem, and not necessarily something that go to him through mom’s milk.

The most common substance to cause problems for baby via mom’s milk is cow’s milk protein – found not only in milk but also in other dairy products, including casein and whey. Other protein foods are also common offenders, including eggs, wheat, soy, pork, fish and shellfish, peanuts, nuts, and pork. Additional sources of allergy can be found in corn, tomatoes, onions, cabbage, berries, spices, citrus fruits and juices, and chocolate.

If you or your partner has a family history of food allergies, it might be a good idea to limit the offending foods from the start just as a precaution, though the research on this is contradictory.

How can I figure out if my baby is allergic to something I’m eating?

Determining what baby is allergic to is often a confusing process. Treatments can be as simple as avoiding the offending substance or more complicated like rotation diets and allergy testing.

If you are breastfeeding, you can begin by avoiding a common allergen – one at a time – and see if that makes a difference in your baby’s symptoms. Start with dairy products. Read labels and avoid anything containing milk or milk products like casein and whey. Avoid dairy products like yogurt, cheese, butter, cream, etc. Your baby’s symptoms may resolve in a day or two, but it may take as long as two to three weeks before the protein is completely eliminated from your body and baby’s system before symptoms are completely gone.

If you aren’t sure what in your diet may be causing allergy symptoms in your baby, consider keeping a food diary. Write down everything you and your baby eat, as well as when, and note baby’s symptoms and when they are happening. This way you can easily draw comparisons and identify the source of the problem.

Some mothers whose babies are allergic to multiple foods or who cannot pinpoint a source choose to try an elimination diet. A variety of approaches to this type of dietary change have been proposed. Sometimes the suggestion is to eliminate all known allergenic foods for a period of two to three weeks, then slowly add them back in one at a time every few days to determine which foods or food families cause a problem for your nursing baby. These diets can be very limiting and time consuming, but they tend to be the most complete way of isolating food allergens.

Sometimes moms are able to follow a rotation diet where they can eat known offending foods on a rotating schedule allowing three to seven days to pass before eating the food again. This is a trial and error method that might be used after an elimination diet or if the mother already knows which foods cause problems for her baby.

The good news is that most babies outgrow food allergies. As baby’s digestive system matures, he is better able to handle a variety of foods. During the second half of baby’s life, the gut “closes,” meaning the extracellular spaces present in the intestines early in life become tight junctures that don’t let as many substances through. This limits the amount of offending proteins baby gets into his bloodstream, and limits allergic reactions.

To feel her best, a mom needs to eat a healthy diet – preferably limiting the amount of processed foods she eats. Eating whole foods – those with limited refining or added ingredients, and in as close to their natural state as possible – will help mom stay healthy. Even if her diet is less-than-perfect, though, mom’s body will make just the right milk for her baby, using nutrients she has stored in her tissues. Taking a daily multivitamin – in addition to a healthy diet – is another helpful step to keep mom feeling her best while nursing a baby, especially if she needs to limit her intake due to allergies in her baby.


  1. Mennella JA, Jagnow CP, Beauchamp GK. 2001. Prenatal and postnatal flavor learning by human infants. Pediatrics,107(6):E88.
  2. Mohrbacher, N. 2010. Breastfeeding answers made simple. Amarillo, TX: Hale Publishing. 516-524.
  3. Two comprehensive lists of allergy symptoms can be found here: and
  4. If you aren’t eating dairy, you may worry about your calcium intake. A list on non-dairy sources of calcium can be found here