The Effects of Sodium and Potassium on Blood Pressure, Vascular Function and Renal Function

Study on the Effects of Sodium and Potassium on Blood Pressure, Vascular Function and Renal Function in Untreated (pre)hypertensive Subjects

To determine the effect of (1) increased sodium intake and (2) increased potassium intake on blood pressure, vascular function and renal function in untreated (pre)hypertensive subjects.

This is a randomized, double-blind, placebo controlled cross-over feeding study.

Inclusion Criteria:

• (Pre)hypertension, defined as office SBP: 130-159 mmHg;

• No use of antihypertensive, lipid-lowering, anticoagulant or other cardiovascular medication;

• Age at start of the ≥ 40 years;

• Apparently healthy:

  • No reported current or previous metabolic diseases
  • No history of cardiovascular diseases
  • No history of renal, liver or thyroid diseases
  • No history of gastrointestinal diseases
  • No diabetes mellitus
  • Fasting laboratory parameters within normal range: renal function (serum creatinine, ureum), liver function (ALAT, ASAT, ɣ-GT) and serum glucose.

Exclusion Criteria:

• Body mass index > 40 kg/m²;
• Smoking
• Secondary hypertension;
• Weight loss or weight gain of 5 kg or more during the last 2 months;
• Usage of non-steroidal anti-inflammatory drugs (aspirin, ibuprofen, naproxen) and not able or willing to stop taking them from at least 4 weeks prior to the study.
• Medical treatment that may affect blood pressure and not able (or willing) to stop taking them;
• Women taking oral contraceptives or estrogen replacement therapy
• Taking nutritional supplements and unwilling to discontinue;
• Women lactating, pregnant or intend to become pregnant during study;
• Reported dietary habits: medically prescribed diet, slimming diet;
• Reported alcohol consumption > 21 units/w (female subjects) or >28 units/w (male subjects);
• Unable or unwilling to consume one meal every workday at the university, or to consume the prescribed study diet for 13 weeks;
• Problems with consuming the supplements or following the study guidelines;
• Unwilling to undergo home or office blood pressure measurements;
• Recent blood donation i.e. 1 month (male subjects) or 2 months (female subjects) prior to the study and planned donation during the study period;
• Reported intense sporting activities > 10 h/w;
• Not agreeing to be informed about unexpected and medically relevant personal test-results
• Participation in another biomedical trial less than 2 months before the start of the study or at the same time;
• No informed consent signed.