Amino Acid Medical Foods Provide a High Dietary Acid Load and Increase Urinary Excretion of Renal Net Acid, Calcium, and Magnesium Compared with Glycomacropeptide Medical Foods in Phenylketonuria

Table 3

Bone-related blood and urine biomarkers with AA-MF or GMP-MF¹.

Test		AA-MF	GMP-MF	p
Blood Biomarkers^2
Vitamin D, 1,25(OH)2D, pg/mL	19	65.4 ± 3.39	71.9 ± 4.10	0.079
Vitamin D, 25(OH)D, ng/mL	28	33.6 ± 1.53	33.8 ± 1.70	0.797
Calcium, mg/dL	30	9.07 ± 0.07	9.10 ± 0.07	0.706
BSAP, µg/L	26	17.0 ± 2.20	17.0 ± 2.08	0.966
BSAP (females), µg/L	18	12.9 ± 1.08	13.6 ± 1.37	0.455
BSAP (males), µg/L	9	25.2 ± 5.42	23.8 ± 5.05	0.416
NTX, nmol/L BCE	27	17.1 ± 0.65	17.5 ± 0.66	0.629
NTX (females), nmol/L BCE	18	14.7 ± 1.94	15.0 ± 1.48	0.345
NTX (males), nmol/L BCE	9	21.1 ± 1.98	18.4 ± 2.56	0.370
Urinary biomarkers^3
Basic
Volume, L/d	8	1.74 ± 0.22	1.66 ± 0.16	0.88
Creatinine, mg/d	8	2921 ± 497	1987 ± 417	0.02
Total protein, mg/d	8	129 ± 21	151 ± 32	0.47
Specific gravity	8	1.016 ± 0.002	1.018 ± 0.002	0.38
Titration
Renal net acid excretion, mEq/d	8	47 ± 11	−20 ± 12	0.002
Ammonium (), mmol/d	8	44 ± 6	16 ± 5	0.0007
Titratable acid, mmol/d	8	3 ± 7	−36 ± 8	0.005
Mineral excretion
Chloride, mEq/d	8	295 ± 50	212 ± 51	0.052
Calcium, mg/d	8	350 ± 81	217 ± 59	0.01
Magnesium, mg/d	8	260 ± 32	178 ± 35	0.03
Phosphorus, mg/d	8	1478 ± 281	1293 ± 366	0.08
Potassium, mEq/d	8	126 ± 20	112 ± 20	0.49
Sodium, mEq/d	8	266 ± 44	210 ± 33	0.22
Sulfate, mEq/d	8	34 ± 3	12 ± 3	0.0008

Values are means ± SE. The p values included in this table represent the treatment comparisons.
Results are based on fasting venipunctures obtained during the clinical trial with AA-MF or GMP-MF [17]. Vitamin D and bone turnover markers were measured in serum and calcium was measured in plasma. Statistical analysis included ANOVA with effects for treatment, baseline, sequence, and treatment-sequence interaction. NTX was analyzed by ANCOVA with baseline levels as a covariate. For all other tests, baseline was not significantly different.
Results are based on 24-hr urine collections with AA-MF or GMP-MF. Statistical analysis included ANOVA with effects for treatment, genotype, and treatment-genotype interaction. There were no significant genotype effects for urinary biomarker excretion comparisons. AA-MF, amino acid medical foods; GMP-MF, glycomacropeptide medical foods; BSAP, bone-specific alkaline phosphatase; NTX, N-terminal telopeptide.