Owing to rapid increase in aging population, Alzheimer's dementia (AD) is one of the leading problems all over the world. Over the past few years, a number of clinical trials have been conducted to assess various potential treatments, which have put emphasis on the modification of vascular contribution to AD's pathophysiology, especially on the subjects of modifiable lifestyle and diet pattern. Recent studies showed the possibility of lowering risk of cognitive decline by following a Mediterranean diet which has high intake of vegetables, fruits, nuts, cereals, fish and monounsaturated fatty acid from olive oil. High fish consumption is associated with better cognitive function in late life. A small amount of red wine may be associated with reduced incident dementia, while overuse of alcohol could cause brain damage and increase risk of addiction. Treatment with vitamin B6, B12 and folic acid can lower serum homocysteine, but has no significant beneficial effect on cognitive function in patients with dementia. Strategies for feeding the patients with dementia should be modified according to individual factors, including cognitive and physical function, psychological status, and environmental factors. In patients with advanced dementia, oral feeding may be one of the most troublesome problems. Quality of life and nutritional necessaries are the most concerns in making the decision to use oral or tube feeding.