卡路里限制（CR）和间歇性禁食（IF）在没有营养不良的情况下可减少癌症发展的风险。另外，CR和IF也可以导致肠道微生物组重塑。但是，肠道微生物组在与CR或IF相关的抗肿瘤作用中是否起作用仍不清楚。我们在这里展示，CR但不是IF，通过与雌性小鼠的肠道微生物组有关的机制，保护免受皮下MC38肿瘤形成的风险。在CR后，我们通过肠道微生物组的16S rRNA测序鉴定了双歧杆菌的富集。此外，Bifidobacterium bifidum的投与足以挽救肠道微生物组缺乏的小鼠中CR的抗肿瘤效果。从机械上讲，B. bifidum通过产醋酸介导CR诱导的抗肿瘤效应，而这种效应也依赖于肿瘤微环境中干扰素-γ + CD8 + T细胞的积累。我们的研究结果表明，CR可以调节肠道分类组成，在肿瘤生长动力学和癌症免疫监察方面具有癌症学意义。©2023。作者（们）独家使用Springer Nature Limted的许可证。

Calorie restriction (CR) and intermittent fasting (IF) without malnutrition reduce the risk of cancer development. Separately, CR and IF can also lead to gut microbiota remodelling. However, whether the gut microbiota has a role in the antitumour effect related to CR or IF is still unknown. Here we show that CR, but not IF, protects against subcutaneous MC38 tumour formation through a mechanism that is dependent on the gut microbiota in female mice. After CR, we identify enrichment of Bifidobacterium through 16S rRNA sequencing of the gut microbiome. Moreover, Bifidobacterium bifidum administration is sufficient to rescue the antitumour effect of CR in microbiota-depleted mice. Mechanistically, B. bifidum mediates the CR-induced antitumour effect through acetate production and this effect is also dependent on the accumulation of interferon-γ+CD8+ T cells in the tumour microenvironment. Our results demonstrate that CR can modulate the gut taxonomic composition, which should be of oncological significance in tumour growth kinetics and cancer immunosurveillance.© 2023. The Author(s), under exclusive licence to Springer Nature Limited.