大腸癌

Epidemiological studies of intestinal bacteria and colorectal cancer

多人数に対する腸内細菌叢の測定が困難であったため，これまで大規模な疫学研究は少なく，腸内細菌と大腸癌の関係についてははっきりした知見は少なかった．しかし，筆者らは，乳酸菌を用いた無作為割付臨床試験を実施，乳酸菌の投与により大腸癌の前癌病変と考えられる異型の強い腺腫の発生を抑制することを見いだした．本稿ではこれらの成績などを紹介し，その乳酸菌による大腸癌予防の機序を考察した．

Enviromental factors have been consistently associated with colon cancer risk. It has been reported that dietary factors change the proportion of intestinal flora.In this review, I present the clinical studies on the association between intestinal flora and the risk of colorectal cancer that have been carried out to date. The clinical studies of intestinal bacteria related to colorectal cancer risk have not shown consistent results so far, compared with the accomplishments of some basic studies. On the other hand, it was suggested in some clinical studies that lactic acid bacteria reduce the occurrence of colorectal cancer.