Effect of Dietary Sodium Intake on Blood Pressure in Hypertensive Patients in Primary Care

Inclusion Criteria: * adults, 50 years of age or older with changing blood pressure (bp) with or without drugs and patients with uncontrolled bp despite drugs * An average systolic bp on 2 of the 3 previous visits of 140 mm Hg or more (130 mm Hg for diabetics) and an average diastolic bp of 80 to 100 mm Hg. * Blood analysis (fasting glycaemia, creatinin, total cholesterol, high- density lipoprotein cholesterol) in the last 6 months * At least 3 criteria of the following: * using table salt * 2-3/weeks consumption of prepared meals (butchery, warehouse...) * 2-3/weeks consumption of effervescent tablet * Daily consumption of cheese/cold cuts * Daily consumption of salted butter/margarine * 2-3/weeks consumption of smoked fish/meat * 2-3/weeks consumption of bouillon cube-soup (self-made or preserved) * 2-3/weeks consumption of cookies * 2-3/weeks consumption of vegetables preserved in jars * 2-3/weeks consumption of vegetable juice * 2-3/weeks consumption of snacks (chips, cheese, nuts...) Exclusion Criteria: * heart failure * renal insufficiency * secondary hypertension * isolated systolic/diastolic hypertension * bp difference of more than 10 mm Hg between left and right arm * lactation or pregnancy * active malignancy * an active 'low in salt' diet * changing the use of antihypertensive drugs or other medication that would affect bp for the last 4 weeks * impaired cognitive functioning$ * planning a smoke cessation