Abstract

Dewaxed brown rice (DBR), which was prepared by excluding only the wax layer existing in the outermost layer of brown rice using the new rice milling technique, has improved water absorbency, digestibility, and taste than regular brown rice. DBR has a nutritional value close to that of brown rice and contains a large amount of lipopolysaccharides (LPS), which are known to improve the cognitive function of mice. In this study, we examined the effect of continuous DBR ingestion on the cognitive function of elderly people. A crossover comparison test was performed in which elderly people who move into an elderly welfare facility were divided into two groups and ingested DBR or polished white rice for three meals a day for 6 months, followed by a change in test meals for the next 6 months. Cognitive function was assessed using Revised Hasegawa’s Dementia Scale (HDS-R) before starting the test and 6 months after ingesting each test meal. No subjects dropped out or discontinued DBR intake during the study period, and all subjects continued the test for 6 months. In subjects with low cognitive function, (defined as subjects with HDS-R total score of ≥ 1 but <10 at the start of the study), there was a significant association between continuous DBR ingestion and cognitive function improvement (increase in total HDS-R score). Our findings suggest that the long-term ingestion of DBR as a staple food could be useful for the prevention of disorientation disorder or memory impairment, which is the core symptom of dementia.

Keywords: Brown rice; Cognitive function; Lipopolysaccharides; Elderly