Grandchildren of women who consume milk, egg in pregnancy experience fewer reactions

Children whose grandmothers consumed diets rich in egg and milk in the third trimesters of their pregnancies experienced the lowest prevalence of egg and milk reactions compared with other groups, according to a letter published in Allergy.

Diets that exclude allergens may then have an impact on later generations, Ida Mogensen, MD, physician and postdoctoral fellow in the department of clinical science and education, Södersjukhuset, Karolinska Institute in Stockholm, Sweden, and colleagues wrote.

“The origins of allergic disease are, to a large extent, still unknown,” Mogensen told Healio.

Ida Mogensen

“In this cohort, with data from three generations after a diet intervention with either elimination or a high intake of egg and milk during pregnancy, we wanted to investigate whether the prevalence of reactions to egg and/or milk was affected in the third generation,” she continued.

Conducted between 1983 and 1985, the Diet During Pregnancy study investigated whether excluding egg and milk from diets during the third trimester could prevent allergic disease among offspring. These women included 27 who avoided milk and egg and 19 who consumed one egg and 0.5 L of milk each day during their third trimester.

More than 30 years later, researchers examined 78 of the grandchildren of these women, including 52 (48% boys; median age, 43 months) from the avoidance group and 26 (64% boys; median age, 25 months) from the exposure group. They measured IgE against egg and milk and assessed parental-reported ever-reactions to egg and milk among these grandchildren.

Eight (15%) of the grandchildren of women who avoided egg and milk reported reactions to egg, but none of the grandchildren of women who consumed egg and milk reported egg reactions (P = .047). Reactions to milk also were numerically higher among grandchildren of the avoidance group (19% vs. 3.9%).

In total, 16 (31%) of the grandchildren of the avoidance group and one (3.9%) of the grandchildren of the consuming group reported reactions to egg and/or milk (P = .008).

“Despite the small group size, we found a higher prevalence of egg and/or milk reactions in the group whose grandmothers avoided egg and milk during the end of pregnancy compared to the group whose grandmothers had had a high intake,” Mogensen said. “This difference was unexpected.”

Also, seven grandchildren had reactions to egg or milk and had simultaneously elevated IgE, all of whom were among the grandchildren of the avoidance group. The finding that not all the children who had ever-reported reactions had IgE against egg or milk may possibly be due to the wide age range as some children outgrow the allergy, IgE only being tested in a subgroup or other unidentified mechanisms, according to the researchers.

Additionally, 24% of the grandchildren of the avoidance group and 8% of those in the consumption group had atopic dermatitis. The researchers did not consider this a significant difference, but they suggested that it could indicate a higher risk factor for food reactions.

Stratified analyses revealed that reactions to egg or milk associated with avoidance occurred only for the grandchildren of maternal grandmothers but not those of paternal grandmothers, suggesting epigenetic mechanisms attributed to changes in fetal oocytes.

At age 5 years, none of the grandchildren in the consumption group had any reported reactions to egg or milk, compared with three reporting reaction to egg and/or milk in the avoidance group, although this was not a significant difference.

With the lowest prevalence of egg and milk reactions among children whose grandmothers had diets rich in egg and milk in their third trimesters, the researchers concluded that exclusion diets, particularly those that exclude allergens, are potentially associated with food reactions in subsequent generations.

“Our study is small, and the results need to be confirmed in other studies. The results, however, suggest avoidance of specific aliments during pregnancy, at least of allergens such as egg and milk, could potentially increase the risk of reactions to this food in later generations and support the beneficial effect of a diversified diet during pregnancy,” Mogensen said.

The researchers plan on continuing their work with additional grandchildren and by following the participants in the cohort as they age.

“The results need to be confirmed in larger cohorts and the potential mechanisms, such as epigenetic changes, need to be explored,” Mogensen said. “Further, it would be of interest to analyze the associations between intake during pregnancy and food reactions in later generations including other allergens.”

For more information:

Ida Mogensen, MD, can be reached at ida.mogensen@ki.se.