Study of Dietary Additive Phosphorus on Proteinuria and Fibroblast Growth Factor-23 (SODA-POP)

Geisinger Health

Status: Completed

Conditions: Albuminuria

Treatments: Other: Higher phosphorus period; Other: Lower phosphorus period

Study type: Interventional

Funder types: Other

Identifiers

NCT02020785

NA_00082089

13CRP16970085 (Other Grant/Funding Number)

Satellite Dialysis (Other Grant/Funding Number)

Details and patient eligibility

About

Phosphorus-based food additives are commonly used by food manufacturers for many applications, such as enhancing flavor, in ready-to-eat foods and beverages. While these additives can significantly increase an individual's daily phosphorus intake, little is known about the effect of dietary phosphorus on kidney health. In this study, the investigators will first lower baseline phosphorus intake to about 1000mg/d by educating participants to avoid foods with phosphorus additives. Then, participants will be randomized to a higher phosphorus period (~2gm/d) and a lower phosphorus period (~1gm/d) by providing unaltered, commercially-available food/beverage products with and without phosphorus additives.

The investigators hypothesize that participants will have higher urine albumin excretion and fibroblast growth factor-23 (FGF-23) during the higher phosphorus period compared to the lower phosphorus period.

Full description

The Study of Dietary Additive Phosphorus on Proteinuria and FGF-23 (SODA-POP) was a single-center, randomized, double-blind, two-period cross-over study that examined the effect of higher vs. lower phosphorus intake for 3 week periods, achieved by addition of commercially available diet beverages and breakfast bars to diet on albuminuria and fibroblast growth factor 23, in adults with presumed early chronic kidney disease (estimated glomerular filtration rate >= 45 ml/min/1.73m2; and urine albumin/creatinine ratio >=17 mg/g for men or >=25 mg/g for women).

Enrollment: 31 patients

Sex: All

Ages: 21+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

Adults at least 21 years of age with at least microalbuminuria

Exclusion criteria

Estimated glomerular filtration rate <45ml/min/1.73m2, poorly controlled diabetes or hypertension, nephrotic syndrome, hyperparathyroidism, Paget's Disease, multiple myeloma, uncontrolled thyroid disease, chronic antacid use, use of phosphorus binders, phosphorus supplements, or high-dose vitamin D, inability to complete feeding study, investigator discretion

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Triple Blind

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31 participants in 2 patient groups, including a placebo group

Higher phosphorus period

Active Comparator group

Description:

Commercially-available unaltered food/beverage products containing phosphorus additives (\~1gm/d of phosphorus) will be given for 3 weeks

Treatment:

Other: Higher phosphorus period

Lower phosphorus period

Placebo Comparator group

Description:

Commercially-available unaltered food/beverage products without phosphorus additives (\<10mg/d of phosphorus) will be given for 3 weeks

Treatment:

Other: Lower phosphorus period