Numerous large-scale epidemiological studies have made it possible to establish a link between the average consumption of table salt (sodium chloride) and blood pressure figures. In France, according to the French Agency for Food, Environmental and Occupational Health \& Safety (ANSES), salt intakes could be estimated from 2 national food consumption surveys INCA 1 and INCA 2. This made it possible to take a photograph of food consumption habits and to show that the average consumption of salt contained in food in France is 8.7g/day for men and 6.7g/day for women. To these contributions must also be added 1 to 2g of salt for the resalting and the cooking water. According to the food consumption survey INCA 3, french plate still contains a large part of processed foods and still a little too much salt (on average 9g/day for men and 7g/day for women at compare with the objectives of the National Health Nutrition Program of 8g/day and 6.5g/day respectively). In addition, the World Health Organization (WHO) recommends consuming less than 5g of salt per day. In this context, sodium intake through mineral water was also questioned. Both in terms of basic and clinical research, the biological effects of dietary sodium chloride intake have been the subject of a great deal of work for several decades. The mechanisms of transmission in the induced or hemodynamic effects related to the absorption of Na multiple debates and their impact on cardiovascular risks remain very uncertain. Work has shown that all subjects do not react homogeneously to sodium chloride intakes, thus determining what are called "NaCl-sensitive" people who in a situation of major sodium intake will show an increase of peripheral vascular resistance and an increase in blood pressure, much more marked than in subjects called " NaCl resistant ". "NaCl-sensitive" people represent 10 to 30% of the population, with notable differences according to ethnic origins, regions and continents. A marked overrepresentation of this phenotype is observed in patients with hypertension or with a family history of hypertension. Furthermore, studies conducted on animals and humans show that sodium intake does not have the same impact on the parameters mentioned above, depending on whether it is in the form of chloride or bicarbonate salt. On the basis of these elements, the investigators developed a clinical study protocol intended to demonstrate a possible differential effect in the biological effects of the same sodium orally intake (2.56g per day), depending on the salt origin.
This single-center, randomized study, aim to determine the difference in absorption between sodium depending on its nature: bicarbonate (NaHCO3) or chloride (NaCl), and the effect of those types of sodium on blood pressure. In order to realize it, 206 volunteers will be include to assess whether or not they are a "NaCl sensitive volunteer" phenotype. The study will be carried out on 34 of NaCl sensitive volunteer which will take the sodium dietary supplements. The 2 dietary supplements are table salt (sachet) or bottled water. They will be test in a cross-over design during 2 periods of 1 week separated from 1 week of a washing-out period. The primary objective will be to compare mean arterial pressure (MAP) resulting from daily supplementation of 2.56 g of sodium (111 mmol), in addition to the food intake of a low-sodium diet from V2 to the end of the study (\<5g of NaCl / day), for 7 days, either as sodium chloride or as sodium bicarbonate in hypertensive subjects. This clinical trial will be separated in 2 phases: 1. Phenotyping (4 visits): to determine if the volunteer is "NaCl sensitive volunteer" or not 1. V1 (day -28/D-28) = inclusion and beginning of phenotyping phase, 2. V2 (day -21/D-21) = start of a low-sodium diet (\<5g of NaCl / day), 3. V3 (day -14/D-14) = daily supplementation of sodium chloride for 7 days (9.78g/day), 4. V4 (day -7/D-7) = "NaCl sensitive volunteer" assessment, end of study for "NaCl non-senstive volunteers". 2. Treatment period for "NaCl sensitive volunteer" with dietary supplement intake in a cross-over design: 1. PC1 (day 0/D0) = beginning of treatment period 1, 2. PC2 (day 3/D3) = volunteer contact to make sure he is all right, 3. V5 (day 7/D7) = end treatment period 1, 4. PC3 (day 14/D14) = beginning of treatment period 2, 5. PC4 (day 17/D17) = volunteer contact to make sure he is all right, 6. V6 (day 21/D21) = end of treatment period 2 and of the study. The protocol includes a total of 6 visits to PIC/CIC Inserm 1405 of the Clermont-Ferrand University Hospital. The maximum duration of the study will be of 7 weeks.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
250
After inclusion in the study, between V1 and V4, patients will be phenotyped among: "NaCl sensitive" patients and "non-NaCl sensitive" patients. they will have a low sodium diet for 2 weeks. The first week without salt supplementation and the second with salt supplementation. At the end of V4, if patient is "NaCl sensitive" he will continue into treatment period and go through randomization, and for patient "non-NaCl sensitive" they will drop out of study.
After being phenotyped, "NaCl sensitive" patients will continue the study in one of the 2 treatments arms : royal water (bottle) or salt sachet.
Platform of Clinical Investigation / Clinical Investigation Center French Institute of Health and Medical Research-1405 University Hospital
Clermont-Ferrand, Auvergne, France
Change from mean blood pressure (MBP) at Day 21
Comparison between blood pressure data recorded by the volunteer between the 2 weeks of treatment (measurement during 2 days before Day 7 and 2 days before Day 21). Recording of systolic and diastolic blood pressure will be made by the patient at home with the Microlife BP A200 device, in the morning and evening. Comparison of the data collected from these 2 weeks of treatment will allow us to meet the main objective of the study.
Time frame: Day 21
Change from mean blood pressure (MBP) at Day -7
Comparison between blood pressure data recorded by the volunteer for the last 2 days before Day -14 and the last 2 days before Day -7. Recording of systolic and diastolic blood pressure will be made by the patient at home with the Microlife BP A200 device, in the morning and evening to determine if the subject is "NaCl sensitive" or not.
Time frame: Day -7
Weight
Measure of patient weight (in kilograms) using a weighing machine.
Time frame: Day -28, Day -21, Day -14, Day -7, Day 7 and Day 21
Body composition analysis
Measurement of water quantities in the body, fat and muscle, will be analyzed using an non-invasive device by impedance measurement. Patient will be comfortably installed in a quiet room, lying down on a bed where two electrodes will be applied, one at the level of the hand, the other at the level of the foot.
Time frame: Day -21, Day -14, Day -7, Day 7 and Day 21
Optional genotyping
With patient agreement: 1 tube of blood (9mL) used for genetics analysis: genotyping
Time frame: One time at Day -28
Plasma renin dosage on fasted state
Concentration of renin in plasma (ng/mL/h) will be measured on fasted state.
Time frame: Day -28, Day -14, Day -7, Day 7 and Day 21
Plasma Angiotensin II dosage on fasted state
Concentration of angiotensin II (µg/L) in plasma will be measured on fasted state.
Time frame: Day -28, Day -14, Day -7, Day 7 and Day 21
Plasma Aldosterone dosage on fasted state
Concentration of aldosterone (pg/mL) in plasma will be measured on fasted state.
Time frame: Day -28, Day -14, Day -7, Day 7 and Day 21
Plasma potassium dosage on fasted state
Concentration of potassium (mmol/L) in plasma will be measured on fasted state.
Time frame: Day -28, Day -14, Day -7, Day 7 and Day 21
Plasma sodium dosage on fasted state
Concentration of sodium (mmol/L) in plasma will be measured on fasted state.
Time frame: Day -28, Day -14, Day -7, Day 7 and Day 21
Plasma calcium dosage on fasted state
Concentration of calcium (mmol/L) in plasma will be measured on fasted state.
Time frame: Day -28, Day -14, Day -7, Day 7 and Day 21
Plasma chlorine dosage on fasted state
Concentration of chlorine (mmol/L) in plasma will be measured on fasted state.
Time frame: Day -28, Day -14, Day -7, Day 7 and Day 21
Plasma protein dosage on fasted state
Concentration of protein (mmol/L) in plasma will be measured on fasted state.
Time frame: Day -28, Day -14, Day -7, Day 7 and Day 21
Serum creatinine dosage on fasted state
Concentration of creatinine (mmol/L) in serum will be measured on fasted state.
Time frame: Day -28, Day -14, Day -7, Day 7 and Day 21
Serum urea dosage on fasted state
Concentration of urea (mmol/L) in serum will be measured on fasted state.
Time frame: Day -28, Day -14, Day -7, Day 7 and Day 21
Sodium concentration in 24h urine
Concentration of sodium in urine (mmol/24h) will be measured.
Time frame: Day -28, Day -14, Day -7, Day 7 and Day 21
Potassium concentration in 24h urine
Concentration of potassium in urine (mmol/24h) will be measured.
Time frame: Day -28, Day -14, Day -7, Day 7 and Day 21
Creatinine concentration in 24h urine
Concentration of creatinine in urine (mmol/24h) will be measured.
Time frame: Day -28, Day -14, Day -7, Day 7 and Day 21
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