Eating a diet high in vegetables, fish, fruit, nuts and poultry, and low in red meat and butter may reduces the risk of Alzheimer's disease. To assess the association between food combination and Alzheimer’s disease risk, researchers followed 2080 New York residents, aged 65 years and older.

The participants were free from dementia at the start of the study and had their brains scanned using MRI and neuropsychological testing and interviewed them about their dietary habits. Over the course of about four years, 253 developed Alzheimer's disease.

It was found that those whose diet included the most salad dressing, nuts, fish, tomatoes, poultry, cruciferous vegetables (such as cauliflower and broccoli), dark and green leafy vegetables, and the least red meat, high-fat dairy, organ meat and butter had a 38 percent lower risk of developing Alzheimer's than those whose diets included fewer fruits, vegetables and poultry and more red meat and high-fat dairy products. The findings show the protective effect of a healthy diet on the risk of developing Alzheimer's.