Establishment of Joint Research Course with Tohoku University on 'Water Metabolism and Total Conditioning' Aiming to Establish Scientific Basis for Personalized Hydration Management and Gain Insights for Health Maintenance

Otsuka Pharmaceutical Co., Ltd. (Headquarters: Tokyo; President and CEO: Shin Inoue; hereinafter "Otsuka Pharmaceutical"), through its Institute of Nutritional Sciences (Saga Research Site), has established the Joint Research Course on "Water Metabolism and Total Conditioning" with Tohoku University, a National University Corporation (hereinafter "Tohoku University"). Starting in August, measurements of water metabolism will begin in approximately 3,000 local residents.

This study will measure "water turnover," an indicator of hydration status, in local residents and investigate its association with various conditioning indicators (health outcomes) reflecting physical condition. Through this research, we aim to establish a scientific foundation for personalized hydration management in the Japanese population and gain insights applicable to preventing dehydration, heatstroke, dryness, and supporting overall health maintenance.

Research Background

Total body water in adults accounts for approximately 60% of body weight. Dehydration has been reported to increase health risks such as cardiovascular events, kidney dysfunction, and cognitive decline1. Furthermore, due to the increasing number of extremely hot days in recent years, heatstroke-related emergency transports, particularly among the elderly, have been on the rise. Therefore, appropriate hydration management tailored to age and environmental changes has become an urgent public health issue.

Water Metabolism Turnover (Conceptual Image)

"Water turnover" refers to the "in-and-out flow of water in the human body," indicating the daily volume of water entering the body through beverages and food (intake) and exiting through urine, sweat, and other means (excretion). It is used as an indicator of human hydration status. Research led by Professor Yosuke Yamada of Tohoku University's Graduate School of Biomedical Engineering has reported that approximately 40% of variation in human water turnover can be explained by internal and external factors such as sex, body weight, physical activity level, temperature, humidity, and altitude2. However, the remaining ~60% of determining factors and direct associations with health outcomes serving as conditioning indicators remain unclear. Therefore, this study will measure water turnover in local residents and investigate its associations with various health outcomes. Furthermore, by constructing a simplified predictive model of water turnover considering characteristics of the Japanese population, we aim to establish a scientific basis for personalized hydration management and gain insights supporting health maintenance.

Overview of the Research

Subjects: Local residents (approximately 3,000 adult men and women aged 18–90 residing in Miyagi Prefecture)

Methods: Water turnover will be measured using the labeled water method with stable isotopes. Concurrently, hydration status markers (e.g., blood and urine components), body composition, lifestyle factors, and other health-related indicators will be evaluated, and their associations with water turnover will be analyzed.

Duration: April 2026 – March 2029 (measurements begin August 2026)

Tohoku University's Research on Water Turnover

A research group led by Professor Yosuke Yamada of Tohoku University's Graduate School of Biomedical Engineering conducted a study on 5,604 individuals (males and females from 8 days after birth to 96 years of age) across 23 countries, and for the first time in the world developed a formula to predict daily water turnover in humans. This was published in the journal Science in November 2022. The group has also conducted extensive research in this field, including work awarded the Japan Society for the Promotion of Science Prize in 2024 titled "Elucidation of Factors Influencing Variations in Water and Energy Metabolism Across the Human Lifespan."

Otsuka Pharmaceutical's Research and Development in Nutraceuticals-Related Business

In its nutraceuticals-related business, Otsuka Pharmaceutical leverages expertise cultivated through its healthcare business to conduct research and development of innovative products based on scientific evidence that contribute to maintaining and improving people's health and societal well-being. Currently, the company conducts R&D related to beverages and foods at the Institute of Nutritional Sciences (Saga and Otsu Research Sites) and the Advanced Science Research Institute.

Going forward, Otsuka Pharmaceutical will continue contributing to the maintenance and improvement of people's health under its corporate philosophy of "Otsuka-people creating new products for better health worldwide."

1 Dmitrieva NI et al., Long-term health outcomes associated with hydration status. Nat Rev Nephrol. 2024; 20(5): 275-294.

2 Yamada Y et al., Variation in human water turnover associated with environmental and lifestyle factors. Science. 2022; 378(6622): 909-915.

About Otsuka Pharmaceutical

Otsuka Pharmaceutical is a total healthcare company committed to the potential of each individual. Under the corporate philosophy of "Otsuka-people creating new products for better health worldwide," the company works toward achieving people's well-being through its healthcare business, which provides new value to meet unmet medical needs, and its nutraceuticals-related business, which supports daily health maintenance and improvement through scientifically backed innovative products and services. For more information, please visit the corporate website at www.otsuka.co.jp.