Many types of dementia are poorly understood by scientists and have few prevention methods. Vascular dementia is often caused by a stroke, therefore taking action to help protect the body against stroke may be an effective prevention method for this type of dementia. This can be achieved by eating a healthy diet, quitting smoking and controlling high blood pressure. Some studies have shown that controlling systolic blood pressure (the top number of a blood pressure reading) in people older than age 60 can help reduce the risk of dementia by up to 50 percent, according to the National Institute of Neurological Disorders and Stroke (NINDS).

Other potential prevention methods for dementia may include:

• Reducing cholesterol levels. Some studies have linked high cholesterol levels with an increased risk of Alzheimer's disease.
  
  
• Lowering homocysteine. Related to high cholesterol levels, high homocysteine (an amino acid used to produce proteins) has also been linked to an increased risk of both Alzheimer's disease and vascular dementia.
  
  

Scientific studies have also indicated that remaining physically and mentally active throughout life helps to keep the brain healthy, especially in later life. It is not known whether physical and mental activity directly reduces the risk of dementia, but scientists agree that it seems reasonable that keeping the body healthy will also keep the mind healthy.