Yes, you may not be able to change how old you are or what genes you have but there are still things you can do to help prevent Dementia. Physical exercise is good for you in a number of ways, but increasing the blood and oxygen flow to the brain is said to help prevent Dementia. Also, what you eat plays a big role in preventing dementia. It is said that eating heart healthy foods will lower your risk of Dementia because of its direct relationship the brain.