Generally when breastfeeding, you can eat whatever you like, whenever you like, in the amounts that you like and continue to do this unless you notice an obvious reaction in your baby. Most infant fussiness is normal for a young baby, and is not related to foods in mom’s diet. However a small percentage of breastfeeding mothers notice an obvious difference in their baby’s behaviour and/or health when they eat certain foods.
If your baby is sensitive to something you are eating, you will most likely notice other symptoms in addition to fussiness, such as irritability, colic or discomfort, excessive spitting or vomiting, a rash or hives, eczema, sore bottom, dry skin; wheezing or asthma; nasal congestion; red, itchy eyes; ear infections, constipation and/or diarrhoea, or green stools with mucus or blood.
The severity of the reaction is related to the degree of your baby’s sensitivity and to the amount of the problem food that you ate—the more food eaten and the greater baby’s sensitivity, the more severe the reaction. Symptoms in breastfed babies more commonly show up 4-24 hours after exposure. If baby is sensitive to a food that mom eats frequently, symptoms may be ongoing.
Cow’s milk products are the most common problem foods and the only foods conclusively linked by research to fussiness/gassiness in babies, but some babies do react to other foods through breastmilk such as soya, wheat, eggs, and peanuts. If you are unsure what is triggering a reaction in your baby, keeping a food diary with a record of foods eaten and your baby’s symptoms, with time of day for each, may be helpful when trying to pinpoint a problem food.
If you think your baby is reacting to a particular food, then eliminate that food from your diet for 2-4 weeks to see if baby’s symptoms improve. You should hopefully see an improvement within 7 days of eliminating a problem food. To confirm that a particular food is the problem for your baby, reintroduce the food again to see whether baby has the same reaction (although most moms are understandably reluctant to do this if their baby is better on the exclusion). The more severe your baby’s original symptoms, the longer you will need to wait before reintroducing it into your diet and for a very severe reaction you may not reintroduce the food at all. If you reintroduce a food and your baby does not have the same reaction as before, then baby is probably not sensitive to that food. If he does react in the same way, you will want to limit or avoid this food until baby is older and in most cases exclude the food when introducing solids.
Sensitivity to cow’s milk proteins
Breastfed babies who are sensitive to dairy in mom’s diet are sensitive to specific cow’s milk proteins (not the lactose), which pass into the mother’s milk. Therefore if your baby is sensitive to dairy in your diet, it will not help to switch to lactose-free dairy products which still contain the protein component. Cooking dairy products may reduce but will not eliminate the allergens. A few babies with cow’s milk protein allergy will also react to soya and most dairy-allergic babies will also react to goat’s milk or sheep’s milk.
If you think that your baby may be sensitive to dairy products in your diet, remember that it can take between 7 days to 3 weeks to eliminate cow’s milk protein from your system—allow a full 2-4 weeks of dairy elimination before evaluating the results.
If your baby is only a little sensitive to dairy proteins, you may be able to relieve baby’s symptoms by eliminating only the obvious sources of dairy (milk, cream, yogurt, butter, cheese, sour cream, ice cream, cottage cheese, etc.); you may even be able to eat small amounts of dairy without it affecting baby.
If your baby is highly allergic, it will be necessary to eliminate all sources of dairy proteins, which requires a careful reading of food labels. If you’ve cut out dairy because your breastfed baby is sensitive to cow’s milk proteins, you may be able to phase it back in after a few months. Many dairy-sensitive babies outgrow their sensitivity by 12-18 months, and most outgrow it by 5 years.
Bear in mind, when excluding dairy from your or your baby’s diet, you will need to use an appropriate calcium fortified milk substitute and calcium and vitamin D supplement to ensure adequate intake for your baby’s bone growth. Whenever excluding foods from your or your baby’s diet it is best to speak with your dietitian to ensure you aren’t missing out on vital nutrients. Your dietitian can also give you ideas on non-dairy sources of calcium.