1. Honda M, Yamada H, Nozawa Y, Ishizaki T, Kuroda M, Noguchi T. Consumption of bonito extract suppresses the decrease in cerebral blood flow in stroke-prone spontaneously hypertensive rats. Biomed Res. 2010 Aug; 31(4):251-8.
*Quick Summary: This animal model experiment study the effect of Bonito Extract on stroke-prone spontaneously hypertensive (SHRSP) rats. The SHRSP rats were divided into two groups, one that was feed Bonito Extract and the control group that was not feed any Bonito Extract. After 12 weeks several parameters were measured such as cerebral blood flow, cerebral blood vessel width, blood pressure and expression of the enzyme nitrogen oxide synthese, which is responsible for blood vessel dilation through the production of nitric oxide. All rats in the Bonito Extract group survived and significantly better results than the control group which had two deaths from strokes.
"The effect of consuming bonito extract (BE) on cerebral blood flow was evaluated in stroke-prone spontaneously hypertensive rats (SHRSP), a cerebrovascular disease model. BE dissolved in drinking water was given to 5-week-old male SHRSP for 7 weeks. Tap water was given to the control group. At the age of 12 weeks, blood flow and vascular diameter were measured in the middle cerebral artery. Both cerebral blood flow and cerebral vessel width were greater in the BE group than in the control group. Also, stroke occurred in 7 (with death in 2) of the 8 animals in the control group but in none of the 6 animals in the BE group. To clarify its mechanism, the expressions of nitrogen oxide synthase (NOS) and the superoxide dismutase activity (SOD) in the brain were evaluated. NOS mRNA expression and SOD activity in the cerebrum were higher in the BE group. These results suggest that the consumption of BE suppresses the decrease of cerebral blood flow and reduces the risk of stroke to maintain vasorelaxation through the production of nitrogen oxide and suppression of active oxygen generation."
2. Umeki Y, Hayabuchi H, Hisano M, Kuroda M, Honda M, Ando B, Ohta M, Ikeda M. The Effect of the Dried-Bonito Broth on Blood Pressure, 8-Hydroxydeoxyguanosine (8-OHdG), an Oxidative Stress Marker, and Emotional States in Elderly Subjects. J Clin Biochem Nutr. 2008 Nov; 43(3):175-84.
*Quick Summary: This research article examines the positives effects of Bonito Extract on blood pressure and various emotional states in a human clinical trial involving elderly individuals.
"Dried-bonito broth (DBB, katsuo-bushi dashi) is commonly used in Japanese cuisine, and is also used as a traditional remedy for recovery from fatigue and improvement of blood circulation. To clarify the effect of DBB on blood pressure, oxidative stress and emotional states, a randomized crossover human trial was performed. Twenty-seven elderly Japanese subjects ingested DBB or water for one month. Measurement of blood pressure and urinary 8-hydroxydeoxyguanosine (8-OHdG) and evaluation of emotional states were performed before and after the ingestion periods. The changes in systolic blood pressure (SBP) during DBB ingestion was significantly lower than that during water ingestion (p = 0.037). Urinary 8-OHdG significantly decreased during DBB ingestion (p = 0.0002). Evaluation of emotional states indicated that composure significantly improved during DBB ingestion (p = 0.034). These results suggest that the daily ingestion of DBB lower SBP, reduce urinary 8-OHdG and might improve emotional states in elderly subjects."
3. Nozawa Y, Ishizaki T, Kuroda M, Noguchi T. Effect of dried-bonito broth intake on peripheral blood flow, mood, and oxidative stress marker in humans. Physiol Behav. 2008 Jan 28; 93(1-2):267-73.
*Quick Summary: This study aimed to investigate the correlation between peripheral blood flow and mood disturbances. Individuals were randomly separated into two groups, one that was given Bonito Broth and the control group which was administered a placebo. Dried bonito broth has the ability to increase peripheral blood flow through the process of increase nitric oxide production. The group administered the dried bonito broth showed increased blood flow and subsequently improved mood states.
"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."