Is educating a patient who has hypertension about diet primary or secondary level of prevention
If they already have HTN it's actually tertiary prevention.
Primary prevention is preventing a disease from occurring (e.g. vaccines)
Secondary prevention is early detection of a diasease (e.g. BP screening, mammograms)
Teriary Prevention is minimizing the long-term consequences of a disease (e.g. dietary advice to minimize the damage and extent of HTN)