Blueberry Powder Shows No Edge Over Placebo

A small Boston pilot study found older adults with depressive symptoms improved on both blueberry powder and placebo.

Updated on Nov. 7, 2026 in Nutrition

Freeze-dried blueberry powder in an open glass dish beside plain capsules and sealed sample tubes on a lab bench by a window. — Researchers in Boston found daily blueberry powder improved mood in older adults with depressive symptoms no more than a placebo did in a three-month pilot trial. AI Illustration. Upload story photo >

Researchers in Boston tested daily freeze-dried blueberry powder against a placebo in 18 adults aged 65 and older with depressive symptoms over three months. Both groups showed improved mood and fewer symptoms, with no statistical difference between them.

Why it matters

The study suggests a possible link between blueberries and the gut microbiome in depression, but the small, mostly white female sample limits what can be concluded. A larger, more diverse trial would be needed to test whether a real difference exists.

The pilot involved 18 participants aged 65 and older, each consuming 48 grams of freeze-dried blueberry powder or a placebo daily for three months. Five bacterial enzymes rose in the blueberry group, but the study did not show a statistical advantage over placebo for mood.

The players

Boston researchers

Investigators in Boston conducted the pilot study testing blueberry powder against placebo in older adults with depressive symptoms.

The details

Participants were divided into two groups, one receiving freeze-dried blueberry powder and the other a placebo, for three months. Five bacterial enzymes increased among those eating blueberries daily, supporting the researchers' hypothesis about the gut microbiome, though the sample was very small and mostly white women.

Three months: duration of the daily blueberry powder intervention in the study.

Health Landscape

This pilot extends a 2024 study showing anthocyanins inhibit monoamine oxidase, moving that proposed mechanism into a food-based human trial. Early evidence on diet and depression remains preliminary, and the placebo-matched result tempers claims about blueberries as a treatment.

Blueberries are a widely available food, so the study is relevant to people who want to add fruit to their diet. The research does not show that blueberries treat depression, so readers should not substitute them for prescribed care.

The takeaway

Eating blueberries is a low-risk dietary choice, but this small study cannot confirm a mood benefit beyond placebo. Anyone with depressive symptoms should keep working with a clinician while larger trials are awaited.