21/11/2025
Could the answer to the current allergy epidemic in our children be as simple as feeding them blueberries? A rigorously run infant RCT suggests that adding blueberries as one of the first solids may nudge immune balance in an anti-allergic direction and help allergy-type symptoms settle during the first year—while also shifting the gut microbiome in potentially favourable ways.
The first year of life is a critical window for establishing immune competence and preventing allergic diseases. Dietary exposures during this period can influence the induction of immune tolerance, epigenetic programming, and gut microbial succession.
In a double blind, randomised, placebo-controlled feeding trial in Denver, USA, exclusively breast-fed infants (n=61, start age 5–6 months) received freeze-dried blueberry powder (10 g/day) or an isocaloric, colour/flavour-matched placebo until 12 months of age.
The blueberry group started out with more respiratory/allergy-like symptoms at baseline yet showed a greater resolution over time vs placebo (trajectory p=0.05). Immune biomarkers: IL-13 (pro-allergic/Th2 response) fell significantly with blueberries (p=0.035); IL-10 (anti-inflammatory/regulatory) trended up (p=0.052). However, the changes in these cytokines could not directly explain symptom changes. However, specific gut microbiome changes at 12 months correlated with the cytokine changes, hinting at gut-immune crosstalk.
In a companion paper in the same cohort, blueberry introduction altered gut microbiota composition/diversity (trends toward higher alpha diversity; increases in short-chain fatty acid-associated genera such as Subdoligranulum/Butyricicoccus and reductions in potentially unfavourable organisms such as Escherichia/Streptococcus).
The findings align with broader evidence showing that diverse, fibre- and polyphenol-rich complementary diets plus early allergen introduction help shape the gut-immune axis toward tolerance.
For more information see: https://bit.ly/4i7mr2M
and
https://pubmed.ncbi.nlm.nih.gov/40944184/
