Salt and Hypertension: Is arterial function affected by dietary salt intake?

INTERVENTION: Dietary salt restriction followed by dietary salt loading. 2 week dietary salt restriction (sodium 60mmol/day) then randomised sequencial allocation to 4 weeks intervention A (tomato juice no added salt 500ml/day), intervention B (tomato juice plus 90mmol sodium, 500ml/day) intervention C (tomato juice plus 140 mmol sodium 500ml/day). There is a 4 week wash out phase between each intervention (no tomato juice). All participants remaining on the low salt diet for the duration of the study. Dietary compliance was facilitated by weekly dietitic input with advice about low salt foods, fortnightly 4 day diet records. Compliance was measured by urinary sodium/creatinine ratios at baseline, week 1, week 2 and week 4. CONDITION: Hypertension PRIMARY OUTCOME: Changes in arterial function as measured by pulse wave velocity SECONDARY OUTCOME: Markers of Oxidative stress in blood including highly sensitive C reactive protein (hsCRP), lipid peroxides, lipofuscin‐like flurophoes, nitrates and nitrites. Systolic and diastolic blood pressure Vasoactive hormones including renin, aldosterone, insulin, ANP, BNP N terminal CNP, endothelin 1 will be measured from blood samples. INCLUSION CRITERIA: Indviduals with prehypertension or hypertension defined as a systolic blood pressure (SBP) > 130 and/or diastolic blood pressure (DBP) >85 mmHg or on antihypertensive medications