21.膳食纤维保护肠道，预防肠癌

Dietary fiber, including soluble and insoluble types, plays a crucial role in maintaining gut health, preventing constipation, obesity, and certain cancers. It stimulates bowel movement, balances the gut microbiome, and aids in controlling blood sugar levels. The Chinese dietary guidelines recommend daily intake of around 30g fiber, primarily from fruits, vegetables, whole grains, and legumes.