護理師在社區進行營養衛教，下列哪項飲食調整最能有效降低大腸癌風險？
A nurse is teaching a community group about nutrition. Which dietary change is most effective in reducing the risk of colon cancer?
- ATake daily multivitamin supplements每日服用綜合維生素補充品
- BConsume organic dairy products食用有機乳製品
- CEliminate all red meats完全避免攝取紅肉
- DIncrease intake of dietary fiber✓ 正解增加膳食纖維攝取量
膳食纖維（dietary fiber）能增加糞便體積，並縮短糞便在腸道內的停留時間，從而減少致癌物質（如次級膽汁酸）與腸黏膜的接觸機會。這是國際公認預防大腸直腸癌最有效的營養策略之一。其他選項雖然部分與飲食健康有關，但缺乏強有力的實證支持其能直接顯著降低大腸癌風險，且過度限制紅肉或依賴補充品並非預防癌症的唯一或最關鍵手段。
Dietary fiber increases stool bulk and shortens transit time in the colon, reducing contact between carcinogens (such as secondary bile acids) and the intestinal mucosa. This is one of the most internationally recognized and effective nutrition strategies for preventing colorectal cancer. Other options, while related to general dietary health, lack strong evidence for directly and significantly reducing colon cancer risk, and excessive restriction of red meat or reliance on supplements is not the sole or most important strategy for cancer prevention.
美國飲食指南（USDA Dietary Guidelines）強調「全食物（Whole foods）」而非單一營養補充，對於大腸癌預防，美國癌症協會（ACS）特別強調全穀物與蔬果的攝取。