Effect of dried-bonito broth intake on peripheral blood flow, mood, and oxidative stress marker in humans

Dried-bonito broth (DBB) has been confirmed to improve various symptoms related to fatigue, but the reasons for this have remained unclear. Hypothesizing that DBB improves peripheral circulation together with mood states, we performed a randomized, double-blind, placebo-controlled crossover study in thirty-one healthy females. The subjects ingested DBB or a placebo for two weeks and changes in mood states after ingestion were investigated using the profile of mood states (POMS) questionnaire. The peripheral blood flow was also measured before and after ingestion of the test diet using a laser Doppler blood flow meter. The six mood factors and total mood disturbance score which reflect the mental states significantly improved, and a significant increase in peripheral blood flow was also found during DBB ingestion. As a result of correlation analysis between changes in each POMS score and changes in blood flow, it was suggested that a change in blood flow correlated with a change in some POMS factors and total mood disturbance. Based on these findings, we considered that blood flow may have increased in subjects whose mood states were markedly improved, suggesting that the improvement in mood states, including fatigue, was related to the increase in blood flow due to the improvement of peripheral circulation. To clarify whether DBB ingestion exhibits antioxidative activity, we investigated the urinary amounts of 8-hydroxy-2′-deoxyguanosine (8-OHdG) known as an oxidative stress marker and found that urinary excretion of the 8-OHdG for 24 h was significantly decreased during DBB ingestion. This study clarified that DBB ingestion improved mood states, increased peripheral blood flow, and decreased the oxidative stress marker.