Longitudinal cohort of mushroom intake and cognitive function in the elderly

Project Summary/Abstract: The overall goal of this project is to determine the association of mushroom intake with cognitive function in a middle-aged and elderly cohort conducted in Aichi Prefecture, Japan. Healthy diets are associated with reducing the risk of cognitive decline and there is a need to identify specific foods that delay or reduce cognitive impairment in the elderly. Mushrooms are foods that contain several beneficial ingredients that have shown to reduce cognitive decline in animal studies, possibly through anti-oxidant and anti-inflammatory pathways. Mushrooms are infrequently consumed in the United States and their effects in humans have been understudied. We showed in the National Health and Nutrition Examination survey that in persons over age 60 who participated in a battery of cognitive tests, mushroom consumers evidenced higher scores and better cognitive function. Mushrooms are fungi, and contain unique compounds not found in plants and animals. Mushrooms contain high concentrations of ergothioneine, a thiohistidine betaine amino acid that is a powerful antioxidant. In particular, the ergothioneine transporter OCTN1 gene is a specific transporter for the uptake of ergothioneine to cells and tissues experiencing oxidative stress. Mushrooms also contain high concentrations of glutathione (GSH), the most abundant intracellular antioxidants in humans. The traditional Japanese diet, which includes mushroom consumption, is associated with a lower risk of cognitive decline in the Ohsaki Cohort 2006 Study. We have the opportunity to study the individual effects of mushrooms and their key constituents in the Japanese National Institute for Longevity Sciences-Longitudinal Study of Aging. This is a multi-wave cohort study conducted in men and women ages 40-79 who have been followed for age-related health effects including cognitive measures. The study uses detailed questionnaire, medical records, and nutritional assessments. There are several reasons why the NILS-LSA is the ideal population for our hypothesis. Mushrooms are consumed by a higher percent of the population in Japan and in greater daily amounts than in the U.S. In addition, the ergothioneine content of mushroom species consumed in Japan is higher than the white button mushrooms typically consumed in the U.S. Our specific aims are: 1. Determine the relationship between mushroom intake and a battery of neurocognitive outcomes including cognitive function, dementia, and depression. Based on 24-hr food recall data, mushroom intake at baseline and at success waves will be examined prospectively using generalized equation models in relation to a battery of cognitive measures including medically determined clinical dementia, the Wechsler Adult Intelligent Scale (WAIS-R digit span test), the Mini-Mental State Examination, and clinical depression. 2. Determine the relationship between ergothioneine and GSH levels and risk of neurocognitive measures using baseline blood samples for a subset of 309 participants. Causal mediation analysis will be conducted to determine the direct effects of mushroom and indirect effects attributed to ergothioneine and GSH.