How Diet During Pregnancy Can Cause Allergies

Dietary Habits During Pregnancy and the Development of Childhood Allergies

Allergies and asthma are becoming more common, with up to 40% of the population suffering from allergic rhinitis, 10% of the population has asthma, and 5% of the population has food allergies. Since the rate of allergies is on the rise, there is interest in trying to prevent the onset of allergic disease in children by focusing on the prenatal period – during a mother’s pregnancy before a child is born.

For many years, it was recommended that children at high risk for allergic disease – meaning when one or both parents had allergies -- that highly allergenic foods, such as milk, egg, nuts and seafood, should not be fed to children until a certain age in an attempt to decrease the chance of food allergies or other allergic disease from developing. However, newer studies have not shown that this delayed introduction of highly allergenic foods is effective at reducing or preventing the onset of any allergic disease, including food allergies. Currently, there is no recommendation to delay the introduction of any food in young children, beyond exclusive breastfeeding for 4-6 months.

In addition, studies haven’t proven that dietary restrictions during pregnancy are effective at reducing the chance that the baby will develop allergic diseases. However, many of these studies were performed during the second and third trimesters of pregnancy – a time that this probably too late to influence the immune system in terms of allergic disease.

A recent study published in 2014 by researchers in New York, Boston and Virginia sought to determine if dietary habits during early pregnancy would influence the development of allergic disease during childhood.

Can Dietary Habits During Pregnancy Affect Childhood Allergies?

A large group of pregnant women were followed regularly during pregnancy, and the children from these pregnancies were followed after birth until they were approximately 8 years old.

Food questionnaires were given to the pregnant women to ask about dietary habits, particularly in terms of consuming foods that are considered common food allergens, such as peanut, milk, wheat, egg and soy. The children were followed to determine the onset of allergic diseases, including atopic dermatitis, allergic rhinitis, asthma, and food allergies.

Children of women who ate more than the average amount of peanuts during the first trimester of pregnancy were shown to have approximately 50% less of a chance of having an allergic reaction to peanuts during childhood. Peanut consumption during other times of pregnancy did not appear to influence peanut allergy, and any in general did not influence other allergic diseases.

Children of women who drank more than the average amount of milk during the first trimester of pregnancy were about 15-20% less likely to develop asthma or allergic rhinitis during childhood. Milk consumption later in pregnancy had no effect on the development of allergic diseases.

Women who ate more wheat containing foods during the second trimester of pregnancy were nearly 40% less likely to have a child develop atopic dermatitis.

Dietary Habits During Pregnancy and Childhood Allergies: The Bottom Line

It appears that the consumption of various foods during early pregnancy – mostly during the first trimester – seems to influence the development of various allergic diseases during childhood. The first trimester of pregnancy is an important time for the development of immune tolerance – that is, when the immune system decides what to “react” to and what to “ignore”. The presence of various food proteins in the blood stream of a fetus, absorbed from the mother via the placenta, may cause the fetus’ immune system to ignore these food proteins and reduce the chance that allergies will develop.

Learn more about the prevention of allergic disease.


Bunyavanich S, et al. Peanut, Milk, and Wheat Intake During Pregnancy is Associated with Reduced Allergy and Asthma in Children. J Allergy Clin Immunol. 2014;133:1373-82.

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