Letter: 1‐kestose, the smallest fructooligosaccharide component, protection for mild to moderate ulcerative colitis patients—authors’ reply

Abstract

We thank Dr. Chen and Dr. Chen for their comments regarding our study on the efficacy and safety of 1-kestose for patients with mild to moderate ulcerative colitis (UC). 1,2 Regarding the authors' first point, the maltose used as placebo in this study is approximately 20 kcal/5 g. As the authors point out, we agree that long-term administration is undesirable because it leads to obesity and glucose intolerance, but this study was conducted for a short period of 2 months, and hence, we believe that the effect would be limited.Furthermore, in this study, each product was packaged individually as a single dose in an opaque package and the entire product kit was also packaged in such a way that the contents are not revealed.Participants were allocated only one product, either 1-kestose or placebo (maltose). Importantly, they could not compare the weights of the two products. Therefore, participants could not identify the allocated product. Although there are product storage and contamination issues, it would be a useful and interesting idea to use liquid percentage concentrations to adjust doses.Second, as mentioned in the limitation section, the patients in this study had mild to moderate UC and were not administered uniform/similar treatment. Therefore, it is not possible to have a control group that receives similar treatment strategies. Hence, placebo (maltose) is used. Further, we believe that the use of maltose as a placebo is appropriate because polysaccharides such as maltodextrin have been used as placebos in previous clinical trials on prebiotics for UC. 3,4 Furthermore, as noted in the paper, both groups were instructed to continue all therapeutic agents used prior to the study.Third, as the authors point out, 1-kestose is present in foods such as onions and asparagus, but the amount is so small that it is unlikely to affect the results. 5 In addition, the participants were instructed to eat their usual diet during the study, so it is unlikely that 1-kestose in food influenced the results.Fourth, the papers the authors pointed to regarding age-dependent changes in the effect of 1-kestose are for children under 5 years of age. 6 We were unable to identify any reports of differences in the effect of 1-kestose in adults (e.g. younger vs. older). Furthermore, we divided the 1-kestose group into two groups, those younger than 40 years (N = 10) and those older than 40 years (N = 10), and found no significant differences in baseline gut microbiota, disease activity or treatment efficacy (data not shown). However, further validation is needed to determine in which cases 1-kestose is effective.