The Gary Null Show - 10-7-26

HEALTH NEWS

Eating walnuts daily may boost mood and shift serotonin-related metabolism

Higher daily step counts linked to fewer mental health problems in early adolescence, study finds

How dementia risk and heart failure is being linked to dreaming

Sardinian village may be a new longevity hotspot

New study shows any healthy eating plan slows aging

Eating walnuts daily may boost mood and shift serotonin-related metabolism

University of Barcelona (Spain), October 2 2026 (News-Medical)

In a recent study published in Food & Function, researchers evaluated whether 8 weeks of walnut consumption affects mood states in young adults and whether these effects are associated with urinary 5-hydroxyindoleacetic acid (5-HIAA), cortisol, and urolithin levels.

Serotonin is a neurotransmitter involved in mood regulation and is produced from the dietary amino acid tryptophan. Its main metabolite, 5-HIAA, can be measured in urine as an indicator of serotonin metabolism. Walnuts are rich in omega-3 fatty acids, tryptophan, fiber, and polyphenols, including ellagitannins that gut microbiota convert into urolithins. These metabolites may indicate walnut intake and biological responses; however, further research is needed to clarify how walnut consumption relates to mood and metabolic pathways.

The study used an 18-week open-label randomized crossover trial involving adults aged 20–35 years.  Participants were randomly assigned to consume 40 g of walnuts per day with dinner or to refrain from nuts and nut products for the next 8 weeks. After a 2-week washout period, participants crossed over to the alternate condition.

During the walnut condition, total mood disturbance was 4.85 points lower than during the control condition. Anger and fatigue also decreased. Two trait food-craving domains showed initial reductions: anticipation of relief from negative states and feelings after eating and guilt associated with cravings or giving in to them.