19/11/2025
This article is being highlighted just as we come into blueberry season. I love how eating a nutritious diet keeps being proven to be one of the best ways to improve health.
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/