Table 1.

Changes in biochemical blood parameters throughout the oral phenylalanine or serine supplementation period in healthy adults.

Blood Parameter	Trial	Phenylalanine (n = 23)	Serine (n = 30)
Total bilirubin (mg/L) Ref. value: 2–12	Baseline	9.1 ± 0.5	$9.1 \pm$0.6
	3 g/day	9.7 ± 0.6	$9.9 \pm$0.7
	6 g/day	$7.4 \pm$0.5	$8.9 \pm$0.5
	9 g/day	$8.7 \pm$0.7	$9.6 \pm$0.7
	12 g/day	$8.0 \pm$0.5	$9.1 \pm$0.7
Glutamic oxaloacetic transaminase (U/L) Ref. value: 10–40	Baseline	$19.7 \pm$0.8	$21.0 \pm$0.9
	3 g/day	$18.3 \pm$1.0	$19.7 \pm$1.3
	6 g/day	$18.8 \pm$0.7	$19.2 \pm$0.7
	9 g/day	$20.9 \pm$2.1	$20.2 \pm$1.1
	12 g/day	$20.0 \pm$1.2	$20.4 \pm$0.9
Glutamic pyruvic transaminase (U/L) Ref. value: 5–45	Baseline	$18.7 \pm$0.8	$23.2 \pm$2.0
	3 g/day	$17.6 \pm$2.0	$19.8 \pm$1.9
	6 g/day	$17.7 \pm$1.7	$18.2 \pm$1.6
	9 g/day	$18.2 \pm$1.7	$19.3 \pm$1.9
	12 g/day	$18.7 \pm$1.7	$18.6 \pm$1.8
Alkaline phosphatase (U/L) Ref. value: 100–325	Baseline	$191.2 \pm$9.8	$230.1 \pm$11.4
	3 g/day	$185.1 \pm$8.8	$214.8 \pm$0.2
	6 g/day	$191.4 \pm$10.1	$218.4 \pm$10.1
	9 g/day	$186.8 \pm$9.0	$186.8 \pm$9.0
	12 g/day	$191.7 \pm$9.0	$191.7 \pm$9.0
Lactate dehydrogenase (U/L) Ref. value: 120–240	Baseline	$171.4 \pm$4.7	$162.7 \pm$3.4
	3 g/day	$178.1 \pm$4.7	$176.8 \pm$7.0
	6 g/day	$182.2 \pm$4.2	$174.0 \pm$3.7
	9 g/day	$190.1 \pm$8.7	$178.7 \pm$4.1
	12 g/day	$181.3 \pm$4.9	$173.0 \pm$3.1
Gamma-glutamyltransferase (U/L) Ref. value: ≤80	Baseline	$20.9 \pm$2.1	$29.1 \pm$3.6
	3 g/day	$21.6 \pm$2.7	$27.5 \pm$3.0
	6 g/day	$23.2 \pm$2.7	$26.0 \pm$2.0
	9 g/day	$22.8 \pm$2.9	$29.0 \pm$3.8
	12 g/day	$21.5 \pm$2.5	$30.3 \pm$3.8
Creatine kinase (U/L) Ref. value: 60–270	Baseline	$139.8 \pm$12.8	$121.4 \pm$8.2
	3 g/day	$149.4 \pm$18.2	$138.1 \pm$12.9
	6 g/day	$135.8 \pm$13.4	$135.4 \pm$10.9
	9 g/day	$318.8 \pm$169.0	$145.0 \pm$5.9
	12 g/day	$183.7 \pm$33.6	$158.8 \pm$17.6
Total protein (g/L) Ref. value: 67–83	Baseline	$72.8 \pm$0.6	$73.0 \pm$0.7
	3 g/day	$71.1 \pm$0.7	$71.4 \pm 0.6$
	6 g/day	$70.6 \pm$0.6	$71.6 \pm$0.6
	9 g/day	$70.7 \pm$0.6	$71.0 \pm$0.7
	12 g/day	$71.3 \pm$0.8	$71.5 \pm$0.6
Creatine (mg/L) Ref. value: 6.1–10.4	Baseline	$8.6 \pm$0.2	$8.6 \pm$0.2
	3 g/day	$8.5 \pm$0.2	$8.4 \pm$0.2
	6 g/day	$8.4 \pm$0.2	$8.8 \pm$0.2
	9 g/day	$8.3 \pm$0.2	$8.4 \pm$0.2
	12 g/day	$8.5 \pm$0.2	$8.3 \pm$0.2
Blood urea nitrogen (mg/L) Ref. value: 80–200	Baseline	$130.3 \pm$6.0	$144.1 \pm$6.3
	3 g/day	$124.9 \pm$5.5	$139.4 \pm$7.4
	6 g/day	$133.4 \pm$6.5	$144.8 \pm$6.3
	9 g/day	$133.3 \pm$6.9	$143.3 \pm$7.3
	12 g/day	$135.7 \pm$5.2	$143.8 \pm$5.9
Uric acid (mg/L) Ref. value: 38–70	Baseline	$54.2 \pm$2.2	$61.0 \pm$1.9
	3 g/day	$55.7 \pm$2.1	$59.7 \pm$2.0
	6 g/day	$54.6 \pm$1.9	$61.9 \pm$1.9
	9 g/day	$58.6 \pm$2.5	$61.1 \pm$2.0
	12 g/day	$56.7 \pm$1.8	$59.9 \pm$1.9
Total cholesterol (mg/L) Ref. value: 2100–2190	Baseline	$1969 \pm$74	$2023 \pm$47
	3 g/day	$1860 \pm$73	$1913 \pm$53
	6 g/day	$1812 \pm$68	$1885 \pm 54$
	9 g/day	$1837 \pm$71	$1906 \pm$56
	12 g/day	$1900 \pm$59	$1950 \pm$57
Triglycerides (mg/dL) Ref. value: less than 147	Baseline	$86.9 \pm$9.2	$96.7 \pm$8.2
	3 g/day	$75.4 \pm$7.8	$97.0 \pm$9.3
	6 g/day	$93.1 \pm$17.8	$90.4 \pm$6.3
	9 g/day	$79.1 \pm$10.1	$116.1 \pm$12.1
	12 g/day	$78.0 \pm$7.8	$100.9 \pm$11.4
Sodium (mmol/L) Ref. value: 137–147	Baseline	$140.3 \pm$0.3	$140.6 \pm$0.2
	3 g/day	$140.8 \pm$0.3	$140.4 \pm$0.3
	6 g/day	$141.6 \pm$0.3 *	$141.6 \pm$0.4 $
	9 g/day	$141.3 \pm$0.4	$140.7 \pm$0.3
	12 g/day	$140.8 \pm$0.2	$140.6 \pm$0.3
Potassium (mmol/L) Ref. value: 3.5–5.0	Baseline	$4.27 \pm$0.04	$4.17 \pm$0.05
	3 g/day	$4.12 \pm$0.05	$4.06 \pm$0.03
	6 g/day	$4.17 \pm$0.04	$4.10 \pm$0.04
	9 g/day	$4.09 \pm$0.05	$4.02 \pm$0.05
	12 g/day	$4.24 \pm$0.05	$4.08 \pm$0.04
Chloride (mmol/L) Ref. value: 97–107	Baseline	$102.4 \pm$0.3	$102.4 \pm$0.3
	3 g/day	$104.4 \pm$0.3 *	$104.3 \pm$0.4 *
	6 g/day	$104.8 \pm$0.3 *	$104.7 \pm 0.4$ *
	9 g/day	$104.8 \pm$0.4 *	$103.9 \pm$0.3 *
	12 g/day	$103.9 \pm$0.3 *	$103.3 \pm$0.3
Calcium (mEq/L) Ref. value: 8.4–10.4	Baseline	$9.24 \pm$0.07	$9.24 \pm$0.05
	3 g/day	$9.29 \pm$0.07	$9.29 \pm$0.05
	6 g/day	$9.26 \pm$0.05	$9.23 \pm$0.05
	9 g/day	$9.24 \pm$0.04	$9.25 \pm$0.05
	12 g/day	$9.37 \pm$0.06	$9.36 \pm$0.06
HDL cholesterol (mg/dL) Ref. value: 40–85	Baseline	$63.7 \pm$2.3	$61.7 \pm$2.9
	3 g/day	$61.7 \pm$2.0	$57.0 \pm$3.0
	6 g/day	$60.7 \pm$2.1	$58.8 \pm$2.8
	9 g/day	$60.8 \pm$1.9	$58.0 \pm$3.0
	12 g/day	$61.0 \pm$1.7	$61.3 \pm$3.4
LDL cholesterol (mg/dL) Ref. value: 65–139	Baseline	$116.2 \pm$6.1	$123.5 \pm$4.8
	3 g/day	$106.3 \pm$5.8	$112.9 \pm$4.6
	6 g/day	$101.4 \pm$5.5	$110.0 \pm$4.9
	9 g/day	$107.6 \pm$5.9	$111.6 \pm$5.1
	12 g/day	$112.2 \pm$5.1	$116.3 \pm$5.0
Albumin (g/L) Ref. value: 38–52	Baseline	$46.3 \pm$0.7	$46.5 \pm$0.4
	3 g/day	$45.4 \pm$0.5	$45.4 \pm$0.4
	6 g/day	$44.8 \pm$0.6	$45.7 \pm$0.4
	9 g/day	$45.0 \pm$0.6	$45.2 \pm$0.3
	12 g/day	$45.7 \pm$0.7	$45.9 \pm$0.4
White blood cells (/mL) Ref. value: 3300–9900	Baseline	$5287 \pm$201	$5400 \pm$223
	3 g/day	$5465 \pm 244$	$5603 \pm$221
	6 g/day	$5961 \pm$274	$5490 \pm$208
	9 g/day	$5661 \pm$241	$5573 \pm$255
	12 g/day	$5813 \pm$386	$5493 \pm$196
Red blood cells (×104/mL) Ref. value: 430–580	Baseline	$509.2 \pm$5.4	$507.2 \pm$5.6
	3 g/day	$502.6 \pm$5.3	$492.0 \pm$5.1
	6 g/day	$497.3 \pm$6.5	$494.4 \pm$5.3
	9 g/day	$493.5 \pm$5.2	$493.2 \pm$5.2
	12 g/day	$503.0 \pm$6.9	$497.4 \pm$5.1
Hemoglobin (g/dL) Ref. value: 13.5–17.5	Baseline	$15.86 \pm$0.21	$15.55 \pm$0.21
	3 g/day	$15.65 \pm$0.21	$15.07 \pm$0.17
	6 g/day	$15.47 \pm$0.23	$15.18 \pm$0.20
	9 g/day	$15.35 \pm$0.22	$15.10 \pm$0.20
	12 g/day	$15.66 \pm$0.26	$15.23 \pm$0.16
Hematocrit (%) Ref. value: 39.7–52.4	Baseline	$47.54 \pm$0.50	$46.78 \pm$0.50
	3 g/day	$48.17 \pm$0.52	$46.64 \pm$0.45
	6 g/day	$48.23 \pm$0.69	$47.14 \pm$0.54
	9 g/day	$47.80 \pm$0.55	$47.05 \pm$0.53
	12 g/day	$48.17 \pm$0.58	$46.86 \pm$0.41
Platelet (×104/mL) Ref. value: 14–34	Baseline	$27.02 \pm$0.84	$26.09 \pm$0.75
	3 g/day	$26.30 \pm$0.85	$26.01 \pm$0.81
	6 g/day	$26.12 \pm$0.79	$25.37 \pm$0.86
	9 g/day	$26.14 \pm$0.78	$25.52 \pm$0.77
	12 g/day	$26.60 \pm$0.87	$25.10 \pm$0.70
Glucose (mg/dL) Ref. value: 70–109	Baseline	$88.2 \pm$1.5	$87.1 \pm$1.4
	3 g/day	$90.0 \pm$1.5	$87.5 \pm$1.0
	6 g/day	$90.1 \pm$1.5	$92.2 \pm$1.9
	9 g/day	$87.1 \pm$1.6	$91.7 \pm$1.4
	12 g/day	$87.1 \pm$1.3	$89.7 \pm$2.0

Values represent mean ± SEM. One-way ANOVA was followed with Tukey’s multiple comparisons test between each amino acid intake: * p < 0.05 from baseline, ^$ p < 0.05 from dosage of 3 g/kg.