Table 1.

List of studies reporting putative biomarkers for brown seaweed consumption

Dietary factor	Study design	Number and age of subjects	Analytical method	Sample type	Discriminating metabolites	Primary reference(s)
Brown seaweed (food-grade seaweed capsule) 400 mg containing 101.89 mg polyphenol	Single oral dose intervention study with no control group	12 women and 12 men (aged 18–65 years)	Plasma ((RP)-HPLC-DAD), urine (RP-HPLC-DAD and HPLC-MS)	Hydrolyzed urine	Hydroxytrifuhalol A, 7-hydroxyeckol, C-O-C dimer of phloroglucinol	[20]
				Hydrolyzed plasma	Data not shown in the paper
Brown algae (Ascophyllum nodosum) capsule 400 mg containing 107.3 mg phlorotannin	A 24-week randomized, double-blind, placebo-controlled crossover trial	39 men and 41 women (aged 30–65 years)	UHPLC-HR-MS HPLC-DAD	Urine	Pyrogallol/phloroglucinol sulfate, hydroxytrifurahol A-glucuronide, dioxinodehydroeckol glucuronide, C-O-C dimer of phloroglucinol sulfate, diphlorethol sulfate, fucophloroethol glucuronide	[21]
				Plasma	No markers found
10 ml kombu extract containing 31 mg fucoxanthin	Single oral dose intervention study with no control group	10 males and 8 females (aged 22–63 years)	HPLC-UV-VIS	Plasma	Fucoxanthinol	[22]
Stir-fried wakame containing 6.1 mg fucoxanthin	1 week dietary intervention study with no control group	3 women and 2men (aged 30–50 years)	(SPE)-HPLC-DAD	Plasma	Fucoxanthinol	[23]
Astaxanthin from a supercritical CO2 extract of Haematococcus pluvialis (green seaweed) as a softgel capsule (0, 2, 8 mg)	A 8-week double-blind, placebo-controlled study	42 females (aged 20–23 years)	RP-HPLC-DAD	Plasma	Astaxanthin	[24]
Haematococcus pluvialis extract. 12 soft capsules, each containing 4 mg of astaxanthin, total 48 mg	Single oral dose intervention study with no control group. Two females and five non-smoking males received the capsules 2 h in advance of a meal, the others took them right after the meal.	15 males (7 smokers) and 5 females (aged 18–60 years)	HPLC-UV-VIS	Serum	Astaxanthin	[25]
Green alga + lipid to be formulation contained 40 mg astaxanthin	Open parallel design dividing into 4 groups on average for 4 days	32 males (aged 20–46 years)	HPLC-VIS	Plasma	Astaxanthin	[26]
100 mg astaxanthin with olive oil and cereals for 3 days	Single dose intervention study with no control group	3 males (aged 37–43 years)	HPLC-UV-VIS	Plasma	Astaxanthin	[27]
Average 50 sheets of nori (average 200 g β-carotene) for 5 months	Sequential intervention	One 22-year-old female	/	Serum	β-carotene	[28]

Abbreviations: DAD diode array detector, HPLC high-performance liquid chromatography, MS mass spectrometry, RP reverse phase, SPE solid-phase extraction, UHPLC-HR-MS ultra-high-performance liquid chromatography–high-resolution mass spectrometry, UV-VIS ultraviolet-visible spectroscopy