In the present study, eating rate and eating until full but not skipping breakfast were independently inversely associated with MH among 294 Japanese patients with UC. Eating habits were not associated with clinical remission or partial MH. This is the first study to report the association between eating habits and clinical outcome in patients with UC.
The association between eating habits and the onset of lifestyle-related diseases has previously been examined. Eating quickly was associated with obesity [21-24] and blood pressure [21-23]. Eating until full was associated with obesity and central obesity [25, 26]. Skipping breakfast was positively associated with obesity [27], low-density lipoprotein cholesterol [28], and onset of diabetes [29].
The association between eating habits and digestive diseases has also been reported. Eating dinner late was associated with GERD. In a case-control study of Japanese patients, the dinner-to-bedtime interval was independently inversely associated with GERD [8]. Similar results were reported in Iranian [9], Albanian [10], Korean [11], and a Japanese study [12]. Eating quickly is associated with GERD and FD. Eating quickly was positively associated with GERD in a case-control study of 1518 Chinese subjects [13]. In a cross-sectional Iranian study of 4763 subjects, eating quickly was associated with FD [15]. In a Serbian study, the statistical tendency to eat quickly among patients with FD was high [16]. In a Korean study of 87 patients, the frequency of eating meals within 13 min among patients with FD was higher than that among patients with GERD and the control group [17].
Eating until full and skipping breakfast were positively associated with GERD in the above-mentioned Chinese study [13]. In a cross-sectional Japanese study in which 19,864 subjects underwent medical checkups, skipping breakfast had a positive relationship with GERD severity based on a frequency scale for symptoms of GERD [14]. Skipping meals, including skipping breakfast, was positively associated with FD [15,16, 30]. Skipping breakfast was positively associated with constipation in Japanese university students [18]. In contrast, no association between skipping breakfast and GERD was found in a Turkish study [31] and another Japanese study [32]. Several studies found a positive association between unhealthy eating behaviors and digestive diseases. The association between eating behavior and digestive diseases remains inconsistent, however. The inconsistency might be explained at least in part by sample size, age, BMI, eating behavior definitions, and questionnaire differences. To the best of our knowledge, no studies have investigated the association between eating habits and IBD, including Crohn’s disease. The underlying mechanism linking eating habits and MH among patients with UC remains unclear. Eating rate is inversely associated with numbers of chewing. Chewing was associated with mucosal blood flow via nitric oxide [33]. Eating until full might affect the ghrelin and leptin levels. In IBD model mice, both ghrelin and leptin were associated with intestinal motility and inflammation [34, 35]. Higher ghrelin and lower leptin in patients with UC had been observed compared to healthy controls [36]. Thus, eating quickly might induce mucosal ischemia via low nitric oxide, and eating until full might activate intestinal motility and inflammation via gastrointestinal hormones.
Our study has a few limitations. First, this was a cross-sectional study. Eating habits can, however, undergo intervention. Further research is needed to confirm the association between eating habits and MH in the future. Second, most of the patients were receiving treatment. The long duration of such treatment might have affected eating habits and clinical outcomes. Third, potential confounding factors, such as nutritional information and other unhealthy behaviors, might be missing. Fourth, although self-reported eating rate was validated in a previous study [17, 19], information on eating habits was based on a self-reported questionnaire. Data on frequency of skipping breakfast and eating until full were also based on the responses to a self-reported questionnaire. Finally, the patients of the present study were not likely representative of patients with UC in Japan. Nevertheless, the men: women ratio, median age, and use of biologics, prednisolone, 5-aminosalicylates, and thiopurines were similar between the present study (59.2%, 48.0 years, 6.1%, 20.8%, 91.5%, and 16.0 %, and, respectively) and a Japanese national study based on UC claims data in 2016 (63.9%, 44.0 years, 9.0%, 15.5%, 96.2%, and 13.8%, respectively) [37].