A recent study suggests that eating walnuts daily may have an effect on mood among young adults, although researchers say larger and longer-term studies are needed to confirm the findings.
The study examined whether consuming walnuts every day for eight weeks affected participants’ mood and whether any changes were associated with biological changes in the body.
Walnuts contain omega-3 fatty acids, tryptophan, fibre and polyphenols, compounds that may play roles in biological processes associated with brain health and mood.
Researchers specifically examined urinary levels of 5-HIAA, cortisol and urolithins. 5-HIAA is a marker of serotonin metabolism, while urolithins are compounds produced when gut microorganisms break down certain substances found in walnuts.
The study initially assessed 84 people aged 20 to 35, of whom 36 entered the study and 31 completed both study phases.
During the walnut-consumption phase, overall mood disturbance was 4.85 points lower than during the control phase.
Researchers also observed reductions in anger and fatigue, although these differences were no longer statistically significant after adjustment for multiple comparisons.
No significant differences were found in friendliness, energy, perceived stress or overall well-being.
The researchers said the findings provide evidence of a possible relationship between walnut consumption, mood and specific biological changes. However, they stressed that larger and longer-term studies are required to determine whether walnuts directly improve mood.