Health and Economic Impacts of Increased Brown Rice Consumption on Type 2 Diabetes in Japan: A Simulation Study, 2019-2029.

Abstract

Background/objectives: Whole grain consumption is recognized as a key component of healthy diets, offering protection against non-communicable diseases, including type 2 diabetes (T2D). However, in Japan, whole grain intake remains low, with brown rice-a traditional whole grain-underutilized despite its demonstrated health benefits. This study aimed to explore the health and economic impacts of increasing brown rice consumption among Japanese adults aged 40-79 years.

Methods: Using a discrete-time Markov cohort macro-simulation model, we projected the effects of replacing 30% and 80% of mean white rice consumption with brown rice over 10 years. Input parameters were based on published epidemiological data and national healthcare expenditures. Key outcomes included cumulative T2D incidence, all-cause mortality, and associated healthcare costs.

Results: Increasing brown rice consumption could prevent 1.3-3.4% of new T2D cases, avert 0.01-0.02% of all-cause deaths, and save from USD 31.3 million to USD 80.5 million in healthcare costs. Sensitivity analyses revealed that the relative risk of T2D associated with brown rice intake had the greatest influence on variabilities in projected cost savings.

Conclusions: Although the projected reductions in T2D and healthcare costs were modest, the findings highlight the potential of increased brown rice consumption to alleviate the economic and public health burden of T2D in Japan. Incorporating brown rice into dietary patterns may support multidisciplinary lifestyle approaches for T2D prevention. Further research is warranted to explore long-term care costs for the management of complications and the benefits of other whole grains in the Japanese diet.