Biomarkers of seaweed intake

Abstract

Seaweeds are marine macroalgae, some of which are edible. They are rich in specific dietary fibers and also contain other characteristic biological constituents. Biological activities have been investigated mainly in animal studies, while very few results are available from human studies. Biomarkers of food intake (BFIs) specific to seaweed could play an important role as objective measurements in observational studies and dietary intervention studies. Thus, the health effects of seaweeds can be explored and understood by discovering and applying BFIs. This review summarizes studies to identify candidate BFIs of seaweed intake. These BFIs are evaluated by a structured validation scheme. Hydroxytrifuhalol A, 7-hydroxyeckol, CO -C dimer of phloroglucinol, diphloroethol, fucophloroethol, dioxinodehydroeckol, and/or their glucuronides or sulfate esters which all belong to the phlorotannins are considered candidate biomarkers for brown seaweed. Fucoxanthinol, the main metabolite of fucoxanthin, is also regarded as a candidate biomarker for brown seaweed. Further validation will be needed due to the very limited number of human studies. Further studies are also needed to identify additional candidate biomarkers, relevant specifically for the red and green seaweeds, for which no candidate biomarkers emerged from the literature search. Reliable BFIs should also ideally be found for the whole seaweed food group.

Seaweed Phenolics: From Extraction to Applications

“…Although more research needs to be done, these phlorotannins can be a key for natural biomarkers for various applications [253]. Hydroxytrifuhalol A, 7-hydroxyeckol, diphloroethol, fucophloroethol, and dioxinodehydroeckol can be applied as food biomarkers, because after intake, they can be detected by plasma or urine samples.…”

Urine Metabolites Associated with the Dietary Approaches to Stop Hypertension (DASH) Diet: Results from the DASH‐Sodium Trial

“…[ 42 ] Phloroglucinol sulfate in urine has been most frequently detected in biological samples after seaweed intake, but has also been detected after consuming other foods such as grapes, beans, and lentils. [ 42–44 ] Galactonate is derived from galactose, a monosaccharide that is found in dairy, syrups, and small amounts in pulses and seeds. [ 45 ] Serum concentration of galactonate was positively associated with the DASH diet in the original DASH feeding study and was identified as one of the top 5 important metabolites which distinguished higher versus lower adherence to the DASH diet using food frequency questionnaire data from the Cancer Prevention Study‐II Nutrition Cohort.…”

The potential of marine resources for retinal diseases: a systematic review of the molecular mechanisms

“…Biomarkers enable the evaluation of seaweed intake in dietary intervention studies as well as observational studies. While no marker for red and green seaweed has been suggested, phlorotannins and fucoxanthinol, the main metabolite of fucoxanthin, have been proposed as markers for brown seaweed (Xi and Dragsted 2019). Phlorotannins from seaweed have been demonstrated to be digested and their metabolites in plasma and urine are mainly identified in the samples collected at 8-24 h suggesting colonic metabolism (Corona et al 2016).…”