Maternal influences on food allergy prevention: A closer look at diet and environment

By Pooja Toshniwal PahariaApr 9 2024Reviewed by Susha Cheriyedath, M.Sc.

In a recent review published in the journal Nutrients, researchers explored the role of maternal factors in preventing food allergies.

Study: Food Allergy Risk: A Comprehensive Review of Maternal Interventions for Food Allergy Prevention. Image Credit: Pixel-Shot / Shutterstock

Background

Food allergies are a serious worldwide health problem, especially among youngsters, resulting in higher healthcare expenses. Common allergies include cow's milk, peanuts, eggs, wheat, tree nuts, fish, soy, and shellfish. Preventive efforts, beginning with pregnancy, have increased; however, avoiding allergens in the prenatal period does not lessen the risk.

International standards advise against exclusion diets due to the possible negative impact on vital dietary intake and general health. Although research on prenatal prebiotic and probiotic consumption is encouraging, there is minimal scientific evidence. Further research is needed to understand the combination of genetics, immune mechanisms, and environmental variables.

About the review

In the present review, researchers evaluated the impact of maternal variables on food allergy prevention, analyzing PubMed MEDLINE records published in English. They included meta-analyses, randomized controlled trials, observational studies, evidence-based recommendations, and reviews.

Maternal influence on infant food allergies

A positive family history increases food allergy risk in the offspring. Filaggrin-encoding gene mutations are related to food sensitivity and play roles in presenting allergens, T-helper 2 (Th2) immunological regulation, and skin permeability. Environmental exposures in utero can cause epigenetic alterations that affect the immune system's ability to tolerate food. Immunomodulation is critical, with maternal Th1 reactions suppressed throughout pregnancy and the fetal immune system producing more Th2 cytokines.

Environmental variables and allergen exposure generate several reactions, each having different allergic propensity effects. Amniotic fluid includes antigens exposed to the mother, which the fetus may swallow, potentially leading to Th2 cell sensitization in small intestinal cells. Maternal immunoglobulin E (IgE) antibodies have high affinities for neonatal IgE receptors, increasing the likelihood of sensitization even at low antigenic concentrations. Environmental elements, such as cigarette smoke, polycyclic aromatic hydrocarbon compounds, traffic smoke particles, and increased 1-hydroxypyrene levels in children's urine, are theorized to impact epigenetic architecture. Studies have linked maternal prenatal stress to higher IgE titers in umbilical cord blood and an increased likelihood of atopic dermatitis, respiratory allergy, and food allergy development. 

Nutrition is critical to the prevention of food allergies in children. A balanced diet promotes a robust immune system, but maternal diets heavy in trans fats and sweets are related to an increased food allergy risk in vulnerable offspring. An iron shortage during pregnancy raises the chance of atopic illnesses in offspring, but increased iron levels protect against allergy development. Recent research suggests that the microbial community in the gut may contribute to food allergies by generating short-chain fatty acids (SCFAs) that reduce Th2-interleukin production and modulate the immune response. Maternal dysbiosis in neonates can cause food allergies, with cow's milk-allergic newborns having higher levels of Lachnospiraceae and Ruminococcaceae.

Guidelines related to maternal factors for food allergy prevention

The European Academy of Allergy and Clinical Immunology (EAACI) recommendations state that avoiding food allergens in the prenatal period may have little or no influence on food allergy symptom development in early infancy. However, the data is ambiguous, and avoiding meals rich in significant allergen substances is not advised. The American College of Allergy, Asthma, and Immunology (ACAAI), the Canadian Society for Allergy and Clinical Immunology (CSACI), and the American Academy of Allergy, Asthma, and Immunology (AAAAI) statements do not suggest maternal exclusion diets.

There is no particular suggestion for prebiotics, probiotics, or symbiotics to help pregnant women avoid FAs. Existing recommendations acknowledge the influence of probiotics on eczema prevention; however, they do not recommend utilizing prebiotic or probiotic supplements to prevent FAs. The World Allergy Organization's (WAO) recommendations do not yet include a particular recommendation for prebiotic supplementation during pregnancy or nursing.

Long-chain polyunsaturated fatty acids (PUFAs) improve FAs and allergy symptoms in children; however, due to scarcity of evidence, maternal omega-3 supplementation is not advised as an FA-preventative treatment. Healthcare professionals advise pregnant women to have a balanced Mediterranean diet and supplement any deficiencies, regardless of food allergy prevention.

The evidence for vitamin supplements is relatively limited, making it hard to prescribe vitamin D supplementation for food allergy avoidance in pregnant women, nursing moms, or healthy newborns. Supplementation is necessary if a pregnant woman is vitamin D deficient. Supplementing with extra antioxidants such as vitamins A, C, and E, β-carotene, zinc, retinol, and copper is not recommended according to current standards.

The review focuses on the influence of maternal features on food allergy prevention. Current clinical trials assess food allergen avoidance during pregnancy, with studies like PrEggNut and SYMBA investigating the benefits of high-fiber/prebiotic supplements on baby allergy risk. Tailored diet attempts to enhance gut colonization in expectant mothers. A pilot study by the National Institute of Allergy and Infectious Diseases is examining the effect of early exposure to the mother's vaginal microbiota on food allergy sensitivity in babies. The theory is that combined maternal treatments, nursing, and early food introduction may lower the likelihood of food allergies.