The Gut Microbiota and Fermented Food: A Nutraceutical Influence on Alzheimer's Disease

Abstract

Alzheimer's disease (AD) is a neurodegenerative disease responsible for most cases of dementia in elderly people. The exact cause of AD is unknown. Many physiological dysfunctions can be related to AD including neuronal decay in the brain, gut dysbiosis, and impaired hormone and oxidation pathways. Of particular interest is the gut dysbiosis experienced by people with AD. People with AD have a decreased abundance of Firmicutes and Actinobacteria, and increased abundance of Bacteroidetes compared to people without AD. On a genus level Bifidobacterium (Acinetobacter) is decreased. Bifidobacterium are commonly found in fermented foods such as natto, kefir, kombucha, sauerkraut, and tempeh. Foods fermented with Bifidobacterium tend to also be populated with lactic acid bacteria (Lactobacillus, Lactococcus, and Leuconostoc). Fermented food has additional benefits beyond being simple probiotics. In addition to their probiotic effects, when consumed for long periods of time, fermented foods possess enzymatic, anti-inflammatory, and antioxidant activities that have been shown to remedy the neurological effects of AD. Since some fermented foods (natto, kimchi, tempeh, etc.) have been shown to be probiotic, they could have similar effects.