Dark chocolate has long been recognized for its mood-altering properties; however, the evidence regarding the emotional effects of daily dark chocolate intake is limited. Therefore, we aimed to investigate the effects of dark chocolate intake on mood in everyday life, with special emphasis on the gut-brain axis. Two different dark chocolates (85% and 70% cocoa content) were tested in this study. In a randomized controlled trial, healthy adults (20–30 y) consumed either 30 g/d of 85% cocoa chocolate (DC85, n=18); 70% cocoa chocolate (DC70, n=16); or no chocolate (control group, CON; n=14); for 3 weeks. Mood states were measured using the Positive and Negative Affect Schedule (PANAS). Daily consumption of dark chocolate significantly reduced negative affect in DC85, but not in DC70. To assess the association between the mood-altering effects of dark chocolate and the gut microbiota, we performed fecal 16S rRNA sequencing analysis for the DC85 and CON groups. Gut microbial diversity was significantly higher in DC85 than CON (P<.05). Blautia obeum levels were significantly elevated and Faecalibacterium prausnitzii levels were reduced in DC85 compared to CON (P<.05). Furthermore, we found that the observed changes in negative affect scores were negatively correlated with diversity and relative abundance of Blautia obeum (P<.05). These findings indicate that dark chocolate exerts prebiotic effects, as evidenced by its ability to restructure the diversity and abundance of intestinal bacteria; thus, it may improve negative emotional states via the gut-brain axis.

长期以来，黑巧克力因其改变情绪的特性而得到认可。然而，关于每日黑巧克力摄入量对情绪影响的证据是有限的。因此，我们旨在研究黑巧克力摄入对日常生活情绪的影响，特别强调肠脑轴。在这项研究中测试了两种不同的黑巧克力（85% 和 70% 的可可含量）。在一项随机对照试验中，健康成年人（20-30 岁）每天摄入 30 克 85% 可可巧克力（DC85，n =18）；70% 可可巧克力 (DC70, n= 16); 或不吃巧克力（对照组，CON；n=14); 3周。使用正面和负面影响表 (PANAS) 测量情绪状态。每日食用黑巧克力可显着降低 DC85 中的负面影响，但 DC70 中没有。为了评估黑巧克力的情绪改变作用与肠道微生物群之间的关联，我们对 DC85 和 CON 组进行了粪便 16S rRNA 测序分析。DC85的肠道微生物多样性显着高于CON（P <.05）。与 CON 相比，DC85 的Blautia obeum水平显着升高，而Faecalibacterium prausnitzii水平则降低（P <.05）。此外，我们发现观察到的负面情绪评分的变化与多样性和相对丰度呈负相关。Blautia obeum ( P <.05)。这些发现表明，黑巧克力具有益生元作用，其能够重组肠道细菌的多样性和丰度就证明了这一点；因此，它可以通过肠脑轴改善负面情绪状态。