Blueberries boost your mood? Only 18 people finished the study
- Claim
- BLUEBERRIES BOOST MOOD?
- Catch
- TINY PILOT STUDY
- Verdict
- GREAT SNACK, NOT A MOOD FIX
Headlines claimed blueberries have a "surprising effect on your mood." The study, from the Hinda and Arthur Marcus Institute for Aging Research at Hebrew SeniorLife and published in The Journal of Nutrition, Health and Aging (2026), was a randomized, double-blind, placebo-controlled pilot trial in adults 65 and older who were physically inactive and had mild depressive symptoms. Participants took 48 g a day of blueberry powder (about two cups of fresh berries) or a matching placebo powder for three months. Only 18 people completed the study: 10 in the blueberry group and 8 on placebo. Depressive symptoms fell more consistently in the blueberry group, but the difference from placebo was not statistically significant. Overall gut microbial species, metabolic pathways and short-chain fatty acids did not change; only some microbial enzyme genes shifted within the blueberry group. The catch: this was a tiny pilot study, and the findings do not show that blueberries relieve depression. Larger trials are needed.
SOURCES
- Millar et al. (2026), "A pilot study of daily blueberry intake modulates the gut microbiota enzyme commissions in older, sedentary adults with mild depressive symptoms," The Journal of Nutrition, Health and Aging. DOI: 10.1016/j.jnha.2026.100958
For information only, not medical advice. If you're struggling with low mood, please talk to a doctor or mental health professional.
