防止

Fruit and vegetables can reduce the chance of heart disease.

Reason is a guard against rash actions.

prevent contamination/pollution

prevent desertification

prevent polarization of society

prevent the abuse of power

forestall/prevent traffic accidents

prevent a disease spreading; prevent the spread of a disease

avert/prevent famine/war

stem the river's outflow

avoid/prevent state-asset drain

protect from infection

guard against corruption/conceit

prevent crime

head off/forestall a conflict

stop/prevent from getting out of shape

prevent violence