Proposal for recommended level of dietary fiber intake in Japan

In this report, we attempt to propose a recommended level of dietary fiber (DF) for the Japanese from several epidemiological reports. The authors previously investigated the daily DF intake in 50 patients with colon polyp, 33 patients with colon diverticulosis, 45 patients with colorectal cancer, and two groups 84 and 45 control subjects; the values obtained were 18.2, 17.4, 14.9, and 21.1 and 19.9 g, respectively. In another study, of the 5 regions in Japan, in only one, Aomori, where the rate of the colon diverticulosis detection was the lowest, did the DF intake exceed 20 g. Furthermore, in Japan the incidence of colorectal cancer showed a marked increase after 1955. It was assumed that the period between the diagnosis of colorectal cancer and death was 15 years, and that the DF intakes at this time (before 1940) to had contributed to the development of the disease. However unfortunately daily DF intake before 1940 in Japan were unknown, and we have only data 25.0 g in 1946. Thus, it is proposed that the recommended level for daily DF intake in Japanese be set at about 20–25 g, i.e. 10 g per 1,000 kcal.