Impact of Lowering Phosphate Additive Intake on Metabolism and Cardiovascular Health in Community-Living Adults

NCT ID: NCT02620449

Last Updated: 2021-03-11

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 50 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2015-08-28
• Study Completion Date: 2020-03-30

Brief Summary

The purpose of the study is to learn more about how common food additives can affect phosphorus metabolism in people with normal kidney function and people with chronic kidney disease.

Detailed Description

Disturbances in phosphate homeostasis are strongly associated with cardiovascular morbidity and mortality. High dietary phosphate intake plays a central role in the development of disturbed phosphate metabolism and is common in persons consuming typical American diets rich in processed and fast foods. An important reason for the high phosphate content of these foods is the widespread use of phosphate-based food additives in the food supply. Phosphate additives are heavily utilized by the food manufacturing industry to enhance the appearance, taste and shelf-life of processed foods, accounting for as much as 50% of total phosphate intake per day. Prior work from our group suggest that high phosphate additive intake has serious cardiovascular consequences. We showed that phosphate excess induces heart disease and inflammation in experimental studies, and associates with heart disease and death independently of classic risk factors in epidemiology studies. Further, we showed that high phosphate additive intake stimulates the secretion of fibroblast growth factor 23 (FGF23), a phosphate-regulatory hormone directly implicated in the pathogenesis of cardiovascular disease. Together, these data strongly suggest that high phosphate additive intake promotes cardiovascular disease, with important potential implications for efforts to reduce disparities in cardiovascular disease. This is because individuals with low socioeconomic status have limited means to purchase healthy foods, resulting in excessive consumption of processed foods rich in phosphate additives. Moreover, low income neighborhoods have a disproportionately high prevalence of individuals with chronic kidney disease and black individuals, both groups that have impaired ability to excrete excess phosphate. Together, these data support our overriding hypothesis that high phosphate additive intake is a novel target for reducing socioeconomic and racial disparities in cardiovascular. We will test this hypothesis in detailed feeding studies of 80 individuals fed standardized meals with low phosphate additive content for 6 weeks. We will investigate the impact of reducing phosphate additive intake on changes in FGF23 levels, inflammatory markers and vascular function, and test for effect modification by race and chronic kidney disease (CKD). The results of these studies will help determine whether high phosphate additive intake is a modifiable risk factor for disparities in cardiovascular disease.

Conditions

Healthy; Chronic Kidney Disease

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: OTHER
• Blinding Strategy: NONE

Study Groups

single arm study

Group Type: EXPERIMENTAL

Diet

Intervention Type: OTHER

Participants will be fed a low-additive diet as the primary intervention

Interventions

Diet

Participants will be fed a low-additive diet as the primary intervention

Intervention Type: OTHER

Eligibility Criteria

Exclusion Criteria

• current smoking
• extreme obesity (BMI ≥ 35 kg/m2)
• pregnancy or breastfeeding
• conditions affecting phosphate metabolism (e.g., hyper- or hypothyroidism; irregular menses for menstruating women)
• current intake of medications that impact phosphate metabolism (high-dose vitamin D, chronic antacid use)
• current use of blood pressure medications
• abnormal serum phosphate (≥ 4.6 or < 2.5 mg/dl) or calcium levels (≥ 10.6 or < 8.5 mg/dl)
• severe anemia (hemoglobin < 8 g/dl for women and < 9 g/dl for men).
• Inability to receive weekly shipments of food at home.
• Requirement for any special diet other than a regular diet.

• clinical need for a low potassium, low sodium or low protein diet
• new or recent change (<3 months) in dosage of medications known to impact vascular reactivity
• current smoking
• poorly controlled hypertension (≥160/100 mmHg)
• extreme obesity (BMI ≥ 35 kg/m2)
• pregnancy or breastfeeding
• conditions affecting phosphate metabolism (e.g., hyper- or hypothyroidism)
• current intake of medications that impact phosphate metabolism (e.g., high-dose vitamin D)
• abnormal serum phosphate (≥ 4.6 or < 2.5 mg/dl) or calcium levels (≥ 10.6 or < 8.5 mg/dl)
• severe anemia (hemoglobin < 8 g/dl for women and < 9 g/dl for men).
• Inability to receive weekly shipments of food at home.
• Allergies to any foods in the standardized diets

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of Alabama at Birmingham

OTHER

Sponsor Role: lead

Responsible Party

Orlando M. Gutierrez, MD, MMSc

Principal Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Orlando Gutierrez, MD

Role: PRINCIPAL_INVESTIGATOR

University of Alabama at Birmingham

Locations

University of Alabama

Birmingham, Alabama, United States

Countries

United States

References

Khan MB, Carnethon MR, Isakova T, Wolf M, Gutierrez OM. Effects of Lowering Dietary Phosphorus Additive Intake on Mineral Metabolism in Adults with and without CKD. Clin J Am Soc Nephrol. 2025 May 13;20(7):950-957. doi: 10.2215/CJN.0000000730.

Reference Type: DERIVED

PMID: 40359505 (View on PubMed)

Other Identifiers

F150728005

Identifier Type: -

Identifier Source: org_study_id