Dairy Restriction During Lactation May Prevent Infantile Eczema

Jirapinyo P, Densupsoontorn N, Kangwanpornsiri C, Limlikhit T. Lower prevalence of atopic dermatitis in breast-fed infants whose allergic mothers restrict dairy products. J Med Assoc Thai. 2013;96(2):192-195.

 

A prospective, randomized, controlled trial.

 

Pregnant women who had a history of allergies, such as allergic rhinitis, asthma, eczema, recurrent urticaria, or food allergy, were recruited for this study. Their infants were followed from 0 to 4 months of age. All infants were exclusively breastfed. There were 32 infants in the control group and 30 in the intervention group.

 

Mothers in the control group ate liberal diets, while those in the intervention group restricted cow’s milk and dairy products from parturition until the end of the 4-month study.

 

Examination for atopic dermatitis in the infants was blindly performed 3 times, when infants were 7 days, 1 month, and 4 months of age.

 

By 4 months of age, 8 infants from the control group (25%) and 2 infants from the intervention group (6.67%) had developed atopic dermatitis. The prevalence of atopic dermatitis in the dairy-restricted group was significantly lower than in the liberal-diet group (P<0.05).

 

The prevalence of milk allergy in infants is difficult to quantify because there is no consensus on the best way to test for reactivity. According to a study reported in the Lancet in 2013, IgE-mediated food allergy affects only 4% of children, and almost all will outgrow their allergy.¹ In a survey conducted in 2009, however, 8% of 38,480 children in the United States were identified as having food allergies; milk accounted for 20% of those.² In a 2013 study of symptomatic infants with no measurable cow’s milk IgE, 32% reacted to an elimination and challenge of cow’s milk.³ These findings suggest that traditional methods to test allergies may underestimate the actual prevalence of cow’s milk reactivity in the infant population.

 

While there is scientific consensus for the protective role of breast milk against atopic disease, not all breast milk is created equal.

 

In the current study, 2 infants drinking dairy-restricted breast milk developed eczema, compared to 8 who were drinking unrestricted breast milk. Dairy restriction during lactation protected 6 out of 8 infants, or 75%. The mothers in this study were atopic, but it was not known whether or not they specifically had a milk allergy. If researchers were to restrict all known food allergens in the mothers, the success rate of a restricted diet during lactation may be even more impressive.

 

The results of this study lend support the benefit of restricting a mother’s diet while breastfeeding as a means to prevent infantile eczema. This may come as no surprise to naturopathic physicians, who often modify maternal diets for the health of the baby. It seems intuitive that the food a pregnant or lactating mother eats may have the potential to cause or prevent disease in her newborn. But the science on this subject is not definitive. In fact the American Academy of Pediatrics (AAP) published recommendations in 2008 in which it concluded that “there is no convincing evidence that maternal manipulation of diet during pregnancy or lactation has any effect on the development of atopic disease.”⁴ This continues to be the position of the AAP and guides the organization's current recommendations to pregnant and lactating mothers. 

 

Less controversial than the role of the maternal diet is simply the role of breastfeeding in the prevention of atopic disease. In the same recommendation paper referenced above, the AAP concludes that in infants at high-risk for atopic disease, there is evidence for the benefit of exclusive breastfeeding for at least 4 months. Exclusive breastfeeding during the first 3 months of life is associated with lower incidence of eczema in children with a family history of atopic disease,⁵ and if continued beyond 4 months it has a protective effect at age 4.⁶ Breastfeeding is protective against wheeze in the first 3 years of life,⁷ and exclusive breastfeeding for at least 4 months is associated with lower risk of cow milk allergy.⁸

 

While there is scientific consensus for the protective role of breast milk against atopic disease, not all breast milk is created equal. Maternal exposures, including environmental pollutants, agricultural chemicals, and food allergens, can influence the components of breast milk. Pertinent to the current discussion, dietary allergens have repeatedly been detected in human breast milk. In mothers with an allergy to cow’s milk, an allergenic milk protein (beta-Lactalbumin) was detected in 75% of breast milk samples within 1–2 hours of drinking milk.⁹ In a group of mothers with no known peanut allergy, breast milk contained 2 major peanut allergens in 48% of samples after eating peanuts.¹⁰ Egg protein was detected in 72% of the breast milk of mothers feeding eczematous infants and 75% of those feeding infants with no atopic symptoms.¹¹ Taken together, these studies show that allergenic proteins are found in breast milk from both allergic and non-allergic moms who are feeding both atopic and non-atopic infants. This tells us that breast milk is clearly a source of allergenic proteins, but their presence does not always result in infant atopy.

 

Other variables in the maternal diet may also impact the risk for atopic disease in an infant. Studies have shown that consumption of probiotic milk products during pregnancy decreases the relative risk of eczema in babies, regardless of allergy status of the mother.¹² Maternal consumption of raw cow’s milk during pregnancy has also been associated with decreased risk of asthma and allergies.^13,14 It is not known whether this protective effect is due to microbial exposure or other heat-labile components of the whey fracture in unpasteurized milk.¹⁵ Numerous variables, both prenatally and during lactation, likely influence immune reactivity in an infant, setting them up to either tolerate or react to allergenic proteins in their mother’s milk.

 

In contrast to the guidelines set forth by the AAP, the current study strongly supports the practice of maternal dietary milk restriction during lactation to prevent infantile atopic dermatitis. In the absence of known allergic status of the mother, a recommendation to restrict dairy products while nursing may help prevent atopic disease in as many as 75% of your at-risk patients.