Effects of a high-prebiotic diet versus probiotic supplements versus synbiotics on adult mental health: The “Gut Feelings” randomised controlled trial

Study answer

What this study found

The high-prebiotic diet was the clearest effective intervention and improved mood disturbance and anxiety, while the probiotic arm showed only limited, non-primary benefits and the synbiotic arm was null. For total mood disturbance, the prebiotic diet beat placebo at week 8 by MD = -6.97 (95% CI -13.6, -0.345; p = 0.039), whereas probiotics (MD = -2.17; p = 0.51) and synbiotics (MD = -0.331; p = 0.92) did not. The prebiotic diet also improved perceived stress (MD = -3.20; p = 0.017) and reduced odds of more severe anxiety (OR 0.290; 95% CI 0.102, 0.801; p = 0.018). The authors concluded that…

Study & population

This was a 4-arm randomized controlled trial in non-clinical adults with moderate psychological distress and low prebiotic intake recruited in Melbourne, Australia.

Intervention

This 8-week randomized trial tested three active regimens against placebo: a high-prebiotic diet targeting at least 7 serves per day of prebiotic-rich foods and at least 5 g/day of prebiotics; a probiotic capsule taken twice daily with food; or the combination of both as a synbiotic.

Key limitation

The trial was small, single-center, and short duration, which limits power and durability of inference.

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Original abstract