Setsunan University and Partners Reveal Guar Bean Fiber May Improve Productivity in Office Workers

A research group consisting of Kyoto Prefectural University of Medicine Graduate School of Medicine (Department of Bio-Immuno-Nutrition: Professor Yuji Naito, Department of Gastroenterology: Professor Tomohisa Takagi), Setsunan University (Faculty of Agriculture: Professor Ryo Inoue), International University of Health and Welfare (School of Medicine: Professor Tatsuo Shimosawa), Yoshinoya Holdings Co., Ltd. (President & CEO Tetsuya Naruse), and Taiyo Kagaku Co., Ltd. (Headquarters: Yokkaichi, Mie; President & CEO Nagayoshi Yamazaki) has revealed that the continuous intake of guar bean dietary fiber, known as a prebiotic, can regulate the gut environment of office workers and potentially improve declines in labor productivity (presenteeism) and quality of life (QOL). The findings were presented at the 80th Annual Meeting of the Japanese Society of Nutrition and Food Science in Sunport Takamatsu on Saturday, May 16. Modern office workers are prone to digestive symptoms like constipation and diarrhea due to long hours of desk work, mental stress, and irregular eating habits. These issues lead to presenteeism, where employees are present at work but have reduced efficiency due to health problems, a factor noted for decreasing corporate labor productivity. While guar bean dietary fiber (Partially Hydrolyzed Guar Gum, hereafter PHGG) was previously known for its effects on improving bowel movements and the gut microbiota, this study, from the perspective of 'Health and Productivity Management,' comprehensively verified how PHGG intake affects actual labor productivity, sleep quality, and the gut environment. From February to March 2025, 136 employees of Yoshinoya Holdings Co., Ltd. continuously consumed PHGG (6g/day). Evaluations of their gut microbiota (16S rRNA analysis), digestive symptoms (Izumo Scale), labor productivity (WHO-HPQ: indicators of presenteeism, etc.), and sleep quality (OSA-MA Sleep Questionnaire) were conducted before and after PHGG intake. The results showed a significant increase in beneficial bacteria groups involved in short-chain fatty acid production, such as Bifidobacterium, and also confirmed improvements tailored to individual gut environments (e.g., improvement in types prone to loose stools). Furthermore, a reduction in digestive symptoms such as constipation and heartburn was observed. Significant improvements were recognized in areas related to work performance and quality of life, including improved concentration at work, amelioration of presenteeism, and reduced morning sleepiness. This study indicates that PHGG intake, by regulating the gut environment, may contribute broadly not only to physical discomfort (digestive symptoms) but also to psychological and performance aspects (labor productivity, sleep).