Impact of Food Additives on Phosphorus Metabolism

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.

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).