Effect of dried-bonito broth on mood states: a pooled analysis of four randomized controlled human trials

Dried-bonito broth is commonly employed as a soup and sauce base in Japanese cuisine and is considered to be a nutritional supplement that promotes recovery from fatigue. Previous human trials have indicated that the ingestion of dried-bonito broth improves several mood states including fatigue, however, the effects in these studies have differed. The aim of this study was to clarify the effects of daily ingestion of dried-bonito broth on mood states by a pooled analysis of the randomized placebo-controlled trials. Five comparisons in four trials were selected for the pooled analysis (n = 159). The ingestion of dried-bonito broth significantly decreased the scores for fatigue (P = 0.032) and increased those for vigor (P = 0.027) compared to the placebo ingestion, suggesting that the dried-bonito broth improved fatigue felt in daily life. Furthermore, the ingestion of dried-bonito broth decreased the scores for tension-anxiety (P = 0.004) and confusion (P = 0.008) compared to the placebo ingestion. The ingestion of dried-bonito broth also significantly decreased the scores for total mood disturbance (P = 0.005). These results suggest that the ingestion of dried-bonito broth improves mood states especially fatigue, vigor, tension-anxiety and confusion.