Alzheimer's disease and other types of dementia are not interfered with such factors as age, gender, race and genetics; they minimizes risk factors such as diabetes, heart disease, high blood pressure and high cholesterol by decreasing the risk of developing the disease. Medical treatment and physical activity have never been adequately effective on these manipulable conditions, unless there is a proper diet. So, how should this diet be, what should we eat, what should we avoid? Naturally, dozens of similar questions come to one's mind. Medical and scientific observations and statistics often point to the same thing; Mediterranean diet and the golden code of this diet, which is olive oil… Before talking about dementia and olive oil, let's talk briefly about a protein that is thought to cause Alzheimer's disease; Tau protein. In a healthy brain, Tau proteins support neurons and strengthen the structure of neurons. However, excessive accumulation (Taupati) of said protein prevents nerve cells from getting nutrients and communicating with other neurons. With this accumulation, inflammation in the brain begins to occur over time. Neurons die at the end of this process. New researches; show that a diet which is rich in extra virgin olive oil (EVOO) prevents toxic accumulation in the tau protein. It also helps to protect the integrity of the connections between neurons and brain and helps brain cells to destroy the toxic waste (autophagy). This effect is attributed to the fact that the olive oil is rich in polyphenols.