Can eating blueberries every day improve mood?

Not proven yet. In a small three-month pilot trial from Hebrew SeniorLife’s Marcus Institute for Aging Research, inactive adults aged 65 and older with mild depressive symptoms took either 48 grams of blueberry powder a day (about two cups of fresh berries) or a matching placebo. The blueberry group showed a larger and more consistent drop in depressive symptoms, but the difference from the placebo group was not statistically significant.

Only 18 people completed the study (10 on blueberries, 8 on placebo). Overall gut microbe species and short-chain fatty acids did not change, although the blueberry group had significant shifts in genes for certain gut microbial enzymes, including one involved in producing the brain messenger GABA. The researchers say larger studies are needed to know whether these changes lead to real mood benefits. The study was published in The Journal of Nutrition, Health and Aging.

Source: “Eating blueberries every day may have a surprising effect on your mood,” ScienceDaily, from Hebrew SeniorLife Hinda and Arthur Marcus Institute for Aging Research (October 18, 2026).

Image: bowl of blueberries, Brigitte Tohm, CC0, via Wikimedia Commons (Unsplash).

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