How do I avoid developing dementia?

Reduce risk. There may be ways to reduce the risk of developing dementia such as regular exercise and treating vascular risks such as hypertension, high cholesterol and diabetes. However, there is no way to absolutely prevent dementia (other than dying young, which is not a good option).
Avoiding dementia. Good general health maintenance is essential to delaying or avoiding dementia. Controlling weight, regular aerobic exercise, a good balanced diet and treatment for diabetes or hypertension are all important. Don't smoke or use street drugs and keep alcohol use to a minimum. Evidence about vitamins and mental stimulatio is controversial. All this is easier choosing your parents to avoid dementia.