Postprandial Response of Individuals to Dietary Inorganic Phosphate

Study Overview
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Brief Summary
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The study aims to compare the postprandial response of plasma phosphate and cardiometabolic relevant factors to phosphate intake in defined diet(s).

Detailed Description
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It is a monocentric, controlled intervention trial. The study will be carried out in cross-over design. This design was chosen because of a moderately strong individual metabolic response to the test meal. Two interventions are planned in which the subjects will receive a test meal with phosphate supplement or with placebo in random order on 2 days. Subjects will be randomized to one of the 2 treatment arms. On the two intervention days (T1 and T2), the subjects are placed a venous indwelling cannula. Immediately after the first blood sample the subjects take the fat and carbohydrate-rich test meal along with 700 mg of phosphorus or a placebo, both in the form of capsules. Phosphorus is administered as sodium phosphate . The placebo used is sodium chloride with equivalent amounts of sodium. The filler should be silica and mannitol. The capsules are made of hard gelatin and dissolve in about 10 minutes. The capsules are taken with 300 ml of water. The verum and placebo capsules are produced by the central pharmacy of the University Hospital. The test meal consists of a pasta dish with oily tomato sauce. It is freshly prepared by the study staff and packaged airtight in individual portions before being handed out to the subjects. The test meal should be consumed within 10 - 12 minutes. The time is documented by the study staff. The next blood sample is taken immediately after the end of consumption (time 0), all other 15, 30, 45, 60, 90, 120, 180, 240, 300, 360, 420 and 480 minutes thereafter. All blood samples are taken in a lying position. The first 3 hours after eating the test meal the subjects should spend reclining. In the following 5 hours subjects are free to move in the study center with each patient taking a recumbent position 10 minutes before the next blood draw. Immediately before all blood samples are taken the measurement of blood pressure and pulse is provided for which the opposite arm is to be used. Furthermore the collection of urine samples is provided every hour. Subjects are encouraged to take 200 ml of water every hour on the intervention day. At the end of the intervention, a snack will be provided.

Official Title
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Postprandial Response of Individuals to Dietary Inorganic Phosphate- a Randomized Trial

Conditions
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Cardiovascular Risk Factor

Intervention / Treatment
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* Dietary Supplement: inorganic phosphate
* Dietary Supplement: placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy men and women age between 18 and 60 years informed consent body mass index between 18,5 up to 29,9 kg/m2 anamnesis without diagnostic findings Exclusion Criteria: Participants with epidermal growth factor receptor (eGFR) < 90 ml/min and chronic kidney disease Subjects suffering from vitamin D-deficiency (plasma 25(OH)D < 30 nmol/l) Pregnancy or lactation Subjects with any acute or chronic diseases (infection, tumor, cardiovascular diseases, respiratory diseases, inflammatory diseases), gastrointestinal diseases, diabetes mellitus type 1 and 2, bone diseases, diseases of the parathyroid gland Use of medication Use of dietary supplements (minerals) Relevant food allergies (wheat protein, tomatoes) Weight reduction Smokers Blood donor in the last 3 months Participation in another intervention study

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: inorganic phosphate<br>Experimental intervention: Single dose of orally administered 700 mg inorganic phosphate as sodium phosphate in combination with a standardized meal and blood sampling | Dietary Supplement: inorganic phosphate<br>* Sodium phosphate<br>|
| Placebo Comparator: Placebo<br>Single dose of Sodium chloride in combination with a standardized meal and blood sampling | Dietary Supplement: placebo<br>* Sodium chlorid<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postprandial change of plasma phosphate concentration from baseline (0 minute) until 480 minutes | Impact of inorganic phosphate on the postprandial levels of plasma phosphate concentration | 0,15,30,45,60,90,120,180,240,300, 360, 420 and 480 minutes after ingestion of testmeal rich in carbohydrates and fat | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postprandial course of the plasma concentration of: electrolytes (calcium, sodium, potassium, magnesium) | Impact of inorganic phosphate on the postprandial levels | 0,15,30,45,60,90,120,180,240,300, 360, 420 and 480 minutes after ingestion of testmeal rich in carbohydrates and fat | 
| Postprandial course of the plasma concentration of: phosphate status markers (c-terminal and intact FGF23, parathormone, soluble Klotho (sKlotho), calcitriol) | Impact of inorganic phosphate on the postprandial levels | 0,15,30,45,60,90,120,180,240,300, 360, 420 and 480 minutes after ingestion of testmeal rich in carbohydrates and fat | 
| Postprandial course of plasma concentration of: cardiovascular risk marker glucose | Impact of inorganic phosphate on the postprandial levels | 0,15,30,45,60,90,120,180,240,300, 360, 420 and 480 minutes after ingestion of testmeal rich in carbohydrates and fat | 
| Postprandial course of plasma concentration of: cardiovascular risk marker insulin | Impact of inorganic phosphate on the postprandial levels | 0,15,30,45,60,90,120,180,240,300, 360, 420 and 480 minutes after ingestion of testmeal rich in carbohydrates and fat | 
| Postprandial course of plasma concentration of: cardiovascular risk marker triglycerides | Impact of inorganic phosphate on the postprandial levels | 0,15,30,45,60,90,120,180,240,300, 360, 420 and 480 minutes after ingestion of testmeal rich in carbohydrates and fat | 
| Postprandial course of plasma concentration of: cardiovascular risk marker cholesterol | Impact of inorganic phosphate on the postprandial levels | 0,15,30,45,60,90,120,180,240,300, 360, 420 and 480 minutes after ingestion of testmeal rich in carbohydrates and fat | 
| Postprandial course of concentration of: calcification markers dephosphorylated, noncarboxylated matrix Gla protein (dp-ucMGP), fetuin A, osteocalcin, osteoprotegerin) Inflammatory markers (hsCRP and inflammatory cytokines, especially interleukin (IL-1β) | Impact of inorganic phosphate on the postprandial levels | 0,15,30,45,60,90,120,180,240,300, 360, 420 and 480 minutes after ingestion of testmeal rich in carbohydrates and fat | 
| Activation of NLRP3-inflammasome components (ASC, caspase-1) in isolated peripheral blood monocytes (PBMC) and granulocytes under basal conditions and after stimulation | Impact of inorganic phosphate on the postprandial levels | 0,15,30,45,60,90,120,180,240,300, 360, 420 and 480 minutes after ingestion of testmeal rich in carbohydrates and fat | 
| systolic and diastolic blood pressures | time course: measurement of blood pressure in mm Hg | 0,15,30,45,60,90,120,180,240,300, 360, 420 and 480 minutes after ingestion of testmeal rich in carbohydrates and fat | 
| heart rate | time course: measurement of heart rate in beats per minute | 0,15,30,45,60,90,120,180,240,300, 360, 420 and 480 minutes after ingestion of testmeal rich in carbohydrates and fat | 
| Postprandial course of urine concentrations of electrolytes (phosphate, sodium, potassium, calcium, magnesium) and creatinine | Impact of inorganic phosphate on the postprandial levels | 0,15,30,45,60,90,120,180,240,300, 360, 420 and 480 minutes after ingestion of testmeal rich in carbohydrates and fat | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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inorganic phosphate, postprandial response, fibroblast growth factor-23, health individuals