Early Blueberry Intake May Help Infants Outgrow Allergy Symptoms

Eating blueberries early in life may help resolve allergy symptoms, modulate immune biomarkers, and promote beneficial changes in the gut microbiota during infancy, a study found.1

“The gut microbiota showed dynamic associations with immune development across the first year of life,” wrote study investigator Carina Venter, PhD, RD, from the department of pediatrics at University of Colorado Anschutz, and colleagues.1 “At 12 months, we noticed predominantly negative associations between bacteria and cytokines.”

The complementary feeding period, between 6 to 24 months, is a critical window for shaping infant diet, gut microbiota, and immune development. Some research even shows that the critical window for oral allergen exposure may be between 4 and 6 months, which contradicts recommendations for delaying introductions of complementary foods until after 6 months.2 As of today, the World Health Organization states that complementary feeding should begin around age 6 months, with infants receiving complementary foods 2 – 3 times per day from 6 to 8 months.3

Children can develop allergies early in life, but it is unknown what impact blueberries can have to mitigate an infants’ allergy risk. In this study, investigators sought to assess the daily impact of blueberry consumption during the complementary feeding period on allergy-related symptoms, immune biomarkers, and gut microbiota in breastfed infants.1 The study analyzed 29 cytokines and chemokines: IFN-N3, IL-2, IL-4, IL-4-sens, IL-5, IL-6, IL-7, IL-10, IL-12, IL-12p70, IL-13, IL-13-sens, IL-15, IL-16, IL-17, TNF-N1, TNF-N2, GM-CSF, VEGF, IL-8, Eotaxin, Eotaxin-3, IP-10, MCP-1, MCP-4, MDC, MIP-1N1, MIP-1N2, and TARC.

This double-blind, randomized, placebo-controlled trial included 76 infants aged 5 to 12 months from the Denver metro area, of which 61 completed the study. The team randomized infants to the blueberry arm (n = 30; 31% females), where they received up to 10 grams per day of freeze-dried blueberry powder, or the isocaloric placebo (n = 31; 48% females). Investigators collected stool, blood, and caregiver-reported allergy symptom data at baseline and study end.1

Despite a higher prevalence of allergy-related symptoms at baseline, infants in the blueberry group demonstrated significantly different longitudinal symptom trajectories compared with the placebo group (P = .05) and showed a greater rate of symptom resolution by the end of the trial. Compared to the placebo arm, infants consuming blueberries had significantly reduced pro-inflammatory serum IL-13 levels (P =.035) and increased anti-inflammatory IL-10 levels (P =.052). However, changes in allergy symptoms were not signficantly linked to IL-10 or IL-13.1

“The observed associations between specific bacterial taxa and immune markers such as IL-10 and IL-13 highlight potentially promising targets for further mechanistic investigation,” investigators wrote.1

The analysis found that the relative abundances of Lacticaseibacillus, Blautia, and Peptostreptococcaceae at 12 months were negatively correlated with IL-10. Meanwhile, Lactobacillus, Clostridiaceae, and Megasphaera were positively associated with IL-10. The study also found that IL-13 was positively associated with Citrobacter and negatively associated with anaerostipes and Blautia.

The team noted that these trends align with known polyphenol mechanisms that downregulate IL-13 and enhance IL-10, shifting the immune response toward tolerance and away from allergic inflammation. Although not statistically significant, the pattern indicates that symptom resolution may be linked to increased IL-10 and reduced IL-13 levels.

“Our findings suggest that early-life consumption of blueberries may influence the resolution of allergic symptoms and modulate immune development,” investigators concluded.1 “Future research should…aim to identify the specific components of blueberries that may drive these effects and evaluate whether other foods rich in similar compounds can confer comparable benefits. Expanding sample size, incorporating functional microbial analyses, and including follow-up assessments beyond the first year of life will further clarify the role of diet exposure in shaping the immunity development and gut–immune axis early in life.”

References

1. Prescott SL, Smith P, Tang M, et al. The importance of early complementary feeding in the development of oral tolerance: concerns and controversies. Pediatr Allergy Immunol. 2008;19(5):375-380. doi:10.1111/j.1399-3038.2008.00718.x

2. Complementary feeding - Global. www.who.int. https://www.who.int/health-topics/complementary-feeding#tab=tab_2