Table 2.

Recent progress in vitamin E metabolomic studies.

Study	Study Parameters a	Metabolites 13′-COOH [nm/L]	M1 + M2	Σ b	13′-OH [nmol/L]	M3	Σ	TOH [µmol/L]
Bartolini_2021	300 µL plasma endogenous (n = 17)	3.5 ± 1.8	35.1 ± 20.4 + 11.5 ± 6.3	50	2.6 ± 2.1	3.0 ± 0.9	5.6	23.5 ± 3.5
	after supplementation (n = 17)	5.8 ± 1.4	549.2 ± 329.6 + 102.3 ± 76.8	657	18.8 ± 8.7	5.9 ± 2.8	24.7	53.2 ± 10.5
Guisepponi_2019	300 µL plasma endogenous (n = 13)	1.8 ± 1.0	47.8 ± 36.6 + 7.4 ± 7.5	57.0 ± 33.6	3.0 ± 1.6	1.8 ± 1.5	4.8 ± 1.3	31± 6
	NIST plasma (SRM 1950)	1.2 ± 0.4	-	-	3.2 ± 0.5	-	-	16.9 ± 0.2
Guisepponi_2017	500 µL plasma or serum endogenous (n = 2)	1.1–1.3	21–24 + 3.7–4.8	27–29	0.7–1.0	1.1–0.7	1.7–2.8	22.2–23.7
	after supplementation (n = 2)	2.4–2.9	228–295 + 33–43	273–331	4.0–12.0	3.6–10	14–16	38.9–54.2
	endogenous (n = 6)	1.8 ± 0.9	68 ± 40 + 5.3 ± 2.9	75 ± 41				29.6 ± 5.9
Ciffolilli_2015	1000 µL serum endogenous (n = 2)	n.d.	-	-	n.d.			24.2–31.5
	after supplementation (n = 2)	-	-	-	26.5–42.9	-	-	51.6–98.5
this study	700 µL serum endogenous (n = 1) c	-	-	6.7 ± 0.6 (9%) d	-	-	9.2 ± 3.53 (38.4%)	15.7 ± 3.6 (23%)
	after supplementation (n = 1)	-	-	184.5 ± 21.4 (11.6%)	-	-	104.9 ± 47.6 (45.4%)	32.2 ± 10.3 (32%)

^a Amount of plasma/serum (µL) for determination of metabolites; endogenous levels of metabolites or after supplementation with α-TOH; number of participants (n). ^b Sum of α-13′-COOH + M1 + M2 and α-13′-OH + M3, respectively (Σ). ^c Subject of this study is identical to subject 1 in Guisepponi_2017. ^d variation coefficient in %.