Diet plays pivotal role in staying sharp as Alzheimer’s disease linked to nutritional problems

18 Sep 2017 --- Decreased glucose metabolism in medial prefrontal areas of the brain is associated with nutritional status in patients with prodromal and early Alzheimer’s disease (AD), according to results from a Multimodal Neuroimaging for AD Diagnosis (MULNIAD) study. Nutritional problems, especially weight loss, are commonly seen in individuals with Alzheimer’s disease; however, the underlying mechanisms are not well understood.

Findings from the MULNIAD study, which is a prospective one implemented at the National Center for Geriatrics and Gerontology (NCGG), provide that hypometabolism in the medial prefrontal areas is specifically associated with Alzheimer’s disease-related nutritional problems, and a decrease in fat mass may have a key role. This study is published in the Journal of Alzheimer’s Disease.

“This study is a very important study to help understand the underlying mechanism of weight loss in patients with mild cognitive impairment and Alzheimer’s disease,” says Dr. Takashi Sakurai, corresponding author, Head of the Memory Clinic at the NCGG.

This current study is the first to clarify the associations of nutritional status with AD-related brain changes comprehensively by using multi imaging modalities including amyloid beta-positron emission tomography (PET), 18F-fluorodeoxyglucose (FDG)-PET, and structural magnetic resonance imaging, according to the IOS Press news release.

Examined by analysis
Subjects were 34 amyloid beta-positive individuals with mild cognitive impairment or early AD (prodromal/early AD), and 55 amyloid beta-negative cognitively normal (CN) subjects. The associations between nutritional status (body mass index, waist to height ratio, fat mass index, and fat-free mass index) and brain changes were examined by multiple regression analysis using statistical parametric mapping.

In the prodromal/early AD group, nutritional status was significantly positively correlated with regional cerebral glucose metabolism (rCGM) in the medial prefrontal cortices, while different topographical associations were seen in the CN group. Amyloid beta deposition and gray matter volume were not associated with nutritional status. Sub-analysis in the prodromal/early AD group demonstrated that fat mass index, but not fat-free mass index, was positively correlated with rCGM in the medial prefrontal areas.

“These results suggest that hypometabolism in the medial prefrontal areas is specifically associated with AD-related weight loss, and decrease in fat mass may have a key role. However, this cross-sectional study provides preliminary results, so we need further longitudinal investigation considering the fat tissue metabolism including adipokines to deepen our understanding of AD related weight loss,” says Dr. Takashi Sakurai. After adjusting for cognitive function, the significant link between fat-mass index and rCGM was preserved.

The study findings of decreased glucose metabolism in medial prefrontal areas in amyloid beta-positive individuals may explain the underlying mechanism of weight loss in AD, according to the IOS Press news release.

Cognitive health remains a hot topic in the world of nutrition, and a recent advisory from the American Heart Association (AHA) and American Stroke Association has made it clear that a healthy lifestyle may lessen the risk of cognitive decline with age. NutritionInsight’s recent report on healthy aging also included different companies’ thoughts on products to improve cognitive health.