Impact of Food Additives on Phosphorus Metabolism

September 28, 2015 updated by: Orlando M. Gutierrez, MD, MMSc, University of Alabama at Birmingham
The purpose of the study is to learn more about how phosphorus-based food additives affect phosphorus metabolism in people with normal kidney function.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Phosphorus is a mineral that is found in foods such as dairy products, nuts, and meat, and is important for strengthening the bones. However, too much phosphorus in the blood may be bad for the health of your heart and blood vessels. The kidneys keep the blood levels of phosphorus normal by getting rid of extra phosphorus in the urine. New research has found that common forms of food additives that are high in phosphorus may increase blood phosphorus levels in individuals with kidney disease. In addition, these food additives may increase blood levels of hormones that control phosphorus such as parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23). Like high blood phosphorus levels, high levels of PTH and FGF23 in the blood may also be bad for the health of your heart and blood vessels. In this study, the investigators would like to examine the effects of food additives on blood levels of phosphorus, PTH and FGF23 in individuals with normal kidney function.

Study Type

Interventional

Enrollment (Actual)

54

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35294
        • University of Alabama

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

17 years to 43 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Healthy volunteers, 19 - 45 years of age

Exclusion Criteria:

  • abnormal urinalysis-presence of hematuria, proteinuria, or leukocyturia.
  • pregnancy or breast-feeding
  • Medical conditions impacting phosphate metabolism-primary hyperparathyroidism; gastrointestinal malabsorption disorders such as Crohn's Disease, ulcerative colitis, celiac disease, or liver dysfunction; hyper- or hypothyroidism; irregular menses for female subjects.
  • Body Mass Index (BMI) ≥ 30 g/m2 since obesity is independently associated with impaired phosphorus metabolism.
  • Medications known to affect phosphorus metabolism- current use of phosphorus supplements, high-dose or activated vitamin D compounds, regular antacid or laxative use, anticonvulsants.
  • Hyper- or hypophosphatemia (≥ 4.6 mg/dl or ≤ 2.5 mg/dl respectively), hyper- or hypocalcemia (≥ 10.6 or ≤ 8.5 mg/dl respectively), or severe anemia (hemoglobin < 8 g/dl for women and < 9 g/dl for men).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Subjects with healthy kidney function
Other: Research diet
Participants will be provided specially prepared meals to eat at home for two weeks. During the first week, participants will eat foods that do not have any phosphorus-based food additives in them (this is called the control diet). During the second week, participants will eat foods that all have phosphorus-based food additives in them (called the intervention diet).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
FGF23
Time Frame: 2 weeks
Change in FGF23 levels
2 weeks
PTH
Time Frame: 2 weeks
Change in PTH levels over 2 weeks
2 weeks
Serum phosphate
Time Frame: 2 weeks
Change in serum phosphate over two weeks
2 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Insulin sensitivity as measured by HOMA-IR
Time Frame: 2 weeks
changes in HOMA-IR over two weeks
2 weeks
Brachial flow mediated dilatation measured by ultrasound
Time Frame: 2 weeks
change in flow mediated dilatation over two weeks
2 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Alabama at Birmingham

Investigators

  • Principal Investigator: Orlando M Gutierrez, MD, MMSc, University of Alabama at Birmingham

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

April 1, 2011

Primary Completion (Actual)

June 1, 2014

Study Completion (Actual)

June 1, 2014

Study Registration Dates

First Submitted

July 12, 2011

First Submitted That Met QC Criteria

July 13, 2011

First Posted (Estimate)

July 14, 2011

Study Record Updates

Last Update Posted (Estimate)

September 30, 2015

Last Update Submitted That Met QC Criteria

September 28, 2015

Last Verified

September 1, 2015

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • F110118001

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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