全谷物和纤维素的摄入量可能会降低结肠癌的风险。宿主基因因素、特定细菌的寄生、短链脂肪酸（SCFA）的生成以及全谷物和纤维素的摄入可能会改变碳水化合物对结肠癌的保护作用。在这里，我们评估了114,217名英国生物库参与者的碳水化合物类型和来源的摄入量，并应用主机多基因评分（PGS）将参与者分类为高或低的肠内微生物SCFA生成者，即丁酸盐和丙酸盐。利用多元Cox比例风险模型确定了碳水化合物和SCFA与结肠癌发生率的关联。在中位随访时间为9.4年的过程中，有1,193名参与者被诊断患有结肠癌。风险与非游离糖和全谷物纤维素的摄入量呈负相关。丁酸盐PGS观察到了异质性证据，摄入更多的全谷物淀粉质仅与高预测SCFA生成者的结肠癌风险降低有关。同样，在使用较少详细饮食评估的更大的英国生物库群体（N = 343,621）进行的其他分析中，只有高基因预测丁酸盐生成的个体每天摄入5克面包和谷物纤维后有较低的结肠癌风险。本研究表明，碳水化合物类型和来源的摄入量会影响结肠癌的风险，并且全谷物的摄入量对SCFA生成的影响可能会发生变化。

Whole grain and fiber intakes may decrease the risk of colorectal cancer. The interplay between host genetic factors, colonization of specific bacteria, production of short-chain fatty acids (SCFA), and intake of whole grains and fiber could alter the protective role of carbohydrates against colorectal cancer. Here, we assessed intakes of types and sources of carbohydrates in 114,217 UK Biobank participants with detailed dietary data (2-5 24-hour dietary assessments), and a host polygenic score (PGS) was applied to categorize participants as high or low for intra-luminal microbial SCFA production, namely butyrate and propionate. Multivariable Cox proportional hazards models were used to determine the associations of carbohydrates and SCFA with colorectal cancer incidence. During a median follow-up of 9.4 years, 1,193 participants were diagnosed with colorectal cancer. Risk was inversely associated with intakes of non-free sugar and whole grain fiber. Evidence of heterogeneity was observed by the butyrate PGS; consuming higher amounts of whole grain starch was only associated with a lower risk of colorectal cancer in those with predicted high SCFA production. Similarly, in additional analyses utilizing the larger UK Biobank cohort (N=343,621) with less detailed dietary assessment, only individuals with a high genetically predicted butyrate production had a lower risk of colorectal cancer per 5 g/day intake of bread and cereal fiber. This study suggests that colorectal cancer risk varies by intake of carbohydrate types and sources, and the impact of whole grain intake may be modified by SCFA production.