We read with the interests letter to the editor titled” promising modality for severe ulcerative colitis: infliximab and plant-based diet as first-line (IPF) therapy”. Whether patients should be restricted or fasted from eating is debatable for hospitalized patients with ulcerative colitis (UC). In our previous retrospective cohort study, the rate of clinical remission (partial Mayo score of ≤ 1and response (partial Mayo of every factor exhibiting a decrease of ≥ 1) at week 4 was 55.3% and 30.6% in hospitalized patients who received corticosteroid [1]. In this study, we also confirmed that clinical efficacy was almost comparable in patients with or without fasting while lichtiger index was comparable between the two groups (data not shown). I believe that unnecessary fasting should be avoided even for hospitalized patients with UC.

Chiba et al. introduced that a plant-based diet was effective for patients with severe ulcerative colitis when infliximab was used. They also introduced that high clinical efficacy was obtained in patients with Crohn’s disease who received plant-based diet [2]. In my recognition, plant-based diet like lacto-ovo-vegetarian food includes taking mainly vegetables, eggs, and dairy products without animal fat/protein. It may be critical to eat with lower fats for severe patients of UC, such as those with frequent diarrhea. However, shouldn't patients be able to decide on the content of their meals based on their preferences, especially for UC with clinical remission? With the exception of overeating and extreme fat intake, it is desirable to minimize dietary restrictions during patients with remission.

We recently demonstrated in multicenter prospective cohort study that advanced therapy as well as corticosteroids was effective as the first-line treatment in hospitalized patients [3, 4], although the influence of dietary restriction was not investigated in our study. While recent guidelines indicated that corticosteroid is the first-line treatment for hospitalized patients with severe disease, we would like to emphasize that use of advanced therapy may be acceptable for patients with acute severe UC. Although there are many advanced therapies, these treatments should be selected according to the clinical background and severity of disease [3, 4]. The effects of dietary therapy on hospitalized patients should be investigated by accumulating a large number of cases.