Combined Dietary Education of Low Sodium and High Potassium Consumption

Inclusion Criteria: 1. Prehypertension: with a systolic pressure from 120 to 139 mm Hg or a diastolic pressure from 80 to 89 mm Hg 2. Stage 1 hypertension: with a systolic pressure from 140 to 159 mm Hg or a diastolic pressure from 90 to 99 mm Hg Exclusion Criteria: 1. Urinary tract disease 2. Secondary hypertension 3. Previous history of unstable angina, heart failure, myocardial infarction, coronary revascularization, cerebrovascular disease within 12 months 4. Ventricular tachycardia, atrial fibrillation and flutter 5. Hypertrophic cardiomyopathy 6. Known chronic kidney disease: serum creatinine = or \> 2.0 mg/dL 7. Hypokalemia (\<3.5 mmol/L) or hyperkalemia (\>5.5 mmol/L) 8. Type 1 diabetes mellitus 9. Poorly controlled diabetes mellitus (HbA1C = or \> 9%) 10. Unable to collect 24 hour urine sample 11. Pregnancy 12. Alcoholics 13. Severe liver disease 14. Night workers 15. Mental retardation