The Effects of Dietary Intervention and Macrophage-Activating Factor Supplementation on Cognitive Function in Elderly Users of Outpatient Rehabilitation

Abstract

Background: Age, genetic, and environmental factors are noted to contribute to dementia risk. Neuroplasticity, protection from degeneration and cell death, and early intervention are desirable for preventing dementia. The linkage between neurons and microglia has been a research focus. In this study, we examined the effects of dietary modification (a reduction in advanced glycation end products [AGEs]) and macrophage-activating factor (MAF; a macrophage regulator) supplementation on cognitive function in elderly participants undergoing rehabilitation. Methods: Participants were older than 60 years of age and had been attending a daycare rehabilitation facility for at least three months without cognitive dysfunction, severe anemia, terminal cancer, or neurodegenerative diseases such as Parkinson’s disease. The exercise protocol at the rehabilitation facility was not changed during the study period. Forty-three participates were randomly divided into three groups: a control group receiving placebo, a group receiving dietary guidance, and a group receiving dietary guidance and MAF supplementation. The amyloid-β40/42 ratio, dietary AGE intake, plasma AGE levels, dietary caloric intake, and mild cognitive impairment (MCI) screen test were evaluated. Results: Four participants withdrew from the study. MCI screening scores significantly improved in the MAF supplementation group, especially after 6 months. Dietary modulation was also more effective than placebo at improving cognitive function after 12 months. Only the control group exhibited significantly increased plasma AGEs while the dietary modulation and MAF supplementation groups showed no change in plasma AGEs after 12 months. Conclusions: MAF supplementation improved cognitive function, especially after 6 months, in elderly people undergoing rehabilitation. Dietary modulation was also effective for improving cognitive function after 12 months compared to that in the control group. It was difficult to supervise meals during dietary guidance at the daycare service. However, simple guidance could show improvements in cognitive function through diet.