A study published in the journal Nutrients examined the impact of blueberry intake in early life on allergy-related symptoms, gut microbiota, and immune biomarkers. The complementary feeding period is considered a key stage for shaping immune development, diet, and microbial succession in infants.
Infants began consuming blueberry powder at around five months of age, mixed into purees or breastmilk. Current feeding guidelines recommend introducing plant-based foods from six months, alongside continued breastfeeding. The trial assessed whether blueberry anthocyanins, known to influence the microbiota-inflammation-immunity axis, could alter outcomes in early life.
The randomized, double-blind, placebo-controlled trial recruited term-born infants aged 3 to 4 months who were healthy, exclusively breastfed, and without prior exposure to complementary foods. Participants were assigned to a blueberry group or a placebo group. The blueberry group received 10 g of blueberry powder daily, while the placebo group received a matched isocaloric powder. Caregivers avoided other forms of blackberries or blueberries during the intervention.
Blood and stool samples were collected across multiple time points. Researchers tracked gut microbial profiles using 16S rRNA sequencing and analyzed 29 chemokines and cytokines. Caregivers reported allergy-related symptoms, including respiratory issues, skin problems, and gastrointestinal complaints.
The study enrolled 75 infants, randomizing 38 to the blueberry group and 37 to a placebo. Of these, 29 and 31, respectively, completed the intervention and were included in the final analyses. Baseline characteristics were comparable between groups, though respiratory symptoms were more frequent in the blueberry group at enrolment.
Longitudinal analysis showed differences in trajectories of respiratory (p=0.02) and overall allergic symptoms (p=0.05). Four infants in the blueberry group experienced resolution of respiratory symptoms, and fewer developed new symptoms compared with the placebo group.
Most cytokine levels did not differ significantly. In sensitivity analyses, IL-13 was lower in the blueberry group (p=0.035) and IL-10 was borderline higher (p=0.052). Cytokine data were available for 48 infants, limiting statistical power.
Associations were observed between immune markers and bacterial taxa. IL-10 correlated positively with Megasphaera, Clostridiaceae, and Lactobacillus, and negatively with Peptostreptococcaceae, Blautia, and Lacticaseibacillus. IL-13 correlated positively with Clostridia and Citrobacter, and negatively with Peptostreptococcaceae, Lactobacillus, Blautia, and Anaerostipes. These findings were exploratory and not corrected for multiple comparisons.
The authors conclude that blueberry intake in infancy may influence allergic symptom resolution and immune development, but the results require confirmation in larger trials. The study was not powered to detect clinical endpoints, and additional research is needed to investigate specific blueberry components and their effects.
Source: News Medical