Alzheimer􀆶 s disease AD an aging - related neurodegenerative disease and the leading cause of dementia in the elderly represents sharply escalating challenge to public health management. The underlying mechanisms of AD are uncertain which causes the optimal strategies to delay or even prevent the disease progression yet to be established. Over the past two decades clinical trials of single-agent drugs targeting amyloid-beta and tau pathologies have frequently failed to cure AD suggesting that as a complex brain disease with multiple causes and pathological mechanisms AD should be paid attention to multi-dimensional prevention and treatment. In recent years gut-microbiota connecting with the central nervous system through bidirectional communication with aging immune and metabolic pathways has become a hot mechanism for AD. As the most direct and extensive environmental factor affecting gut microbiota dietary nutrition can affect AD related cognitive symptoms through behavioural genetic systemic immune metabolic and vascular factors which provides new insights into comprehensive multi - targeted intervention strategies of AD. Despite accumulating knowledge the understanding of nutrition and AD is still insufficient and current research evidence is mostly limited to preliminary small samples and various dementia types. Whether malnutrition is a risk factor/ cause of AD or the result of AD-related cognitive or psychobehavioral symptoms remain unclear. Thus this review summarizes the evidence in the past decade on the cause of malnutrition in AD patients and malnutrition risking the onset and progression of AD emphasizing knowledge gaps and providing direction for clinical diagnosis and treatment of AD and further exploration.