Maternal diet index indicates risk for allergic disease among offspring

The maternal diet index appeared superior to other measurements in predicting childhood allergic disease among offspring, according to a study published in The Journal of Allergy and Clinical Immunology: In Practice.

Using the index, physicians may be able to help women adjust their diets during pregnancy to reduce risks for allergic outcomes, the researchers wrote.

“Current allergy prevention guidelines do not offer much information to pregnant women regarding allergy prevention in the infant,” Carina Venter, PhD, RD, associate professor of pediatrics in the section of allergy and immunology at Children’s Hospital Colorado and University of Colorado Denver School of Medicine, told Healio.

Carina Venter

“All international food allergy guidelines only recommend that there is no need to avoid food allergens during pregnancy,” Venter continued.

According to the Global Initiative for Asthma, Venter said, correcting vitamin D deficiency in women who are pregnant or who plan to become pregnant may reduce wheeze in their offspring.

Also, Venter noted, the World Allergy Organization suggests that women who take a probiotic while they are pregnant and breastfeeding may prevent eczema in their offspring, in addition to infants taking probiotics in early life, as well.

Led by Venter, the European Academy of Allergy & Clinical Immunology Immunomodulation and Nutrition Group published three systematic reviews further indicating a lack of data providing dietary information to pregnant women for preventing allergy in their offspring.

“Taking all of the above into account, there is an urgent need to provide nutrition information to pregnant women for offspring allergy prevention,” Venter said.

The researchers then developed the maternal diet index (MDI) to measure components associated with allergy prevention such as yogurt and vegetables and those associated with increased allergy including red meat, rice and grains, fried potatoes, cold cereals and 100% fruit juice. Patients with higher scores have diets that are more allergy-preventive than those with lower scores.

Study design, results

The study investigated 1,218 maternal-child dyads of singleton pregnancies with available diet data attending obstetrics clinics at University of Colorado Hospital between 2009 and 2014 through 4 years after birth.

The researchers assessed these dyads via the MDI as well as the Healthy Eating Index (HEI), total diet diversity (TDD), healthy diet diversity (HDD) and unhealthy diet diversity (UDD) against allergic outcomes among the children including allergic rhinitis, atopic dermatitis, asthma, wheeze and IgE-mediated food allergy.

Overall, 33% of the children had any allergy excluding wheeze, 11% had allergic rhinitis, 26% had AD, 14% had asthma, 18% had wheeze and 3% had IgE-mediated food allergy.

The researchers found significant associations between increases in MDI scores and lower odds for allergic rhinitis (aOR = 0.82; 95% CI, 0.72-0.94), AD (aOR = 0.77; 95% CI, 0.69-0.86), asthma (aOR = 0.84; 95% CI, 0.74-0.96) and wheeze (aOR = 0.8; 95% CI, 0.71-0.9), as well as for any allergy excluding wheeze (adjusted OR = 0.78; 95% CI, 0.7-0.87).

“All outcomes were significant, other than food allergy, due to a lack of power,” Venter said.

Also, increases in maternal HEI scores were associated with significantly lower odds for any allergy excluding wheeze (aOR = 0.98; 95% CI, 0.97-0.99), allergic rhinitis (aOR = 0.98; 95% CI, 0.96-0.99), AD (aOR = 0.98; 95% CI, 0.97-0.995), asthma (aOR = 0.98; 95% CI, 0.97-0.997) and wheeze (aOR = 0.98; 95% CI, 0.97-0.99).

Significant associations continued between increases in maternal HDD scores and lower odds for any allergy excluding wheeze (aOR = 0.91; 95% CI, 0.85-0.98), AD (aOR = 0.93; 95% CI, 0.86-0.997), asthma (aOR = 0.88; 05% CI, 0.81-0.96) and wheeze (aOR = 0.9; 95% CI, 0.83-0.97).

Increases in maternal UDD scores were significantly linked to AD (aOR = 1.1; 95% CI, 1.02-1.19; P = .01) but not to any other allergic outcomes.

Overall, the MDI additionally had greater estimates for its areas under the curve (AUC) for all allergic disease outcomes except for food allergy compared with the other four measures of maternal diet.

According to the researchers, these differences between the MDI’s AUC and the others were statistically significant and the MDI offered the most diagnostic accuracy in predicting allergic outcomes among the children.

Specifically, the MDI had AUC values of 0.68 for any allergy excluding wheeze, 0.68 for allergic rhinitis, 0.66 for AD, 0.65 for asthma, 0.67 for wheeze and 0.56 for food allergy.

Conclusions, next steps

“The most significant aspect of the paper is showing that if a diet index is developed for reduction in a particular disease outcome — in this case, allergic diseases — it performs better than other indices developed for reduction in other diseases, eg, heart disease, such as the Healthy Eating Index,” Venter said.

“Another important finding was that increased healthy diet diversity (variety) was associated with reduced offspring allergies and that increased unhealthy diet diversity was associated with increased disease outcomes,” she continued.

This highlights the importance of a diverse diet, with a focus on healthy foods, Venter added.

“Our index simply states that increased intake of vegetables and yogurt and reduced intake, not no intake, of fried, sugary and low-fiber foods, as well as eating fruit rather than drinking fruit juice, is associated with reduced offspring allergy outcomes,” she said.

These findings were true for asthma, wheeze, AD and allergic rhinitis by age 4 years as shown in this study and for food allergy by age 2 years, which the researchers found elsewhere but not in this study, Venter said.

The researchers also said that including information from other biomarkers such as sensitization status, maternal history of disease, maternal and offspring genetics and possibly maternal and offspring microbiome data could improve the diagnostic accuracy of the MDI scores. Other studies would be welcome as well, Venter said.

“We really need to perform RCTs [randomized controlled trials] to test if our observational findings are supported in an RCT setting,” she said.

As for now, the researchers concluded, the MDI’s superiority in predicting allergy outcomes makes it a potential tool in making appropriate dietary recommendations to women who are pregnant so they can reduce the risks for allergic disease among their children.

References:

• 2022 GINA main report. https://ginasthma.org/gina-reports/. Updated 2022. Accessed Nov. 2, 2022.
• ASCIA guidelines – Infant feeding and allergy prevention. https://www.allergy.org.au/hp/papers/infant-feeding-and-allergy-prevention. Updated November 2022. Accessed Nov. 2, 2022.
• Fiocchi A, et al. World Allergy Organ J. 2015;doi:10.1186/s40413-015-0055-2.
• Fleischer DM, et al. J Allergy Clin Immunol Pract. 2020;doi:10.1016/j.jaip.2020.11.002.
• Greer FR, et al. Pediatrics. 2019;doi:10.1542/peds.2019-0281.
• Halken S, et al. Pediatr Allergy Immunol. 2021;doi:10.1111/pai.13496.
• Venter C, et al. Allergy. 2019;doi:10.1111/all.13764.
• Venter C, et al. Allergy. 2020;doi:10.1111/all.14051.
• Venter C, et al. Pediatr Allergy Immunol. 2020;doi:10.1111/pai.13303.

For more information:

Carina Venter, PhD, RD, can be reached at carina.venter@childrenscolorado.org.