Mass Spectrometry-based Metabolomics for the Discovery of Biomarkers of Fruit and Vegetable Intake: Citrus Fruit as a Case Study

Abstract

Elucidation of the relationships between genotype, diet, and health requires accurate dietary assessment. In intervention and epidemiological studies, dietary assessment usually relies on questionnaires, which are susceptible to recall bias. An alternative approach is to quantify biomarkers of intake in biofluids, but few such markers have been validated so far. Here we describe the use of metabolomics for the discovery of nutritional biomarkers, using citrus fruits as a case study. Three study designs were compared. Urinary metabolomes were profiled for volunteers that had (a) consumed an acute dose of orange or grapefruit juice, (b) consumed orange juice regularly for one month, and (c) reported high or low consumption of citrus products for a large cohort study. Some signals were found to reflect citrus consumption in all three studies. Proline betaine and flavanone glucuronides were identified as known biomarkers, but various other biomarkers were revealed. Further, many signals that increased after citrus intake in the acute study were not sensitive enough to discriminate high and low citrus consumers in the cohort study. We propose that urine profiling of cohort subjects stratified by consumption is an effective strategy for discovery of sensitive biomarkers of consumption for a wide range of foods.

Nutrimetabolomics fingerprinting to identify biomarkers of bread exposure in a free-living population from the PREDIMED study cohort

“…Partial least squares discriminant analysis with orthogonal signal correction (OSC-PLS-DA) was used to explore the differences in metabolomes among the three bread consumer groups (Llorach-Asuncion et al 2010). OSC filtration was used to reduce the variability not associated with dietary classification, as has been done in other recently published nutrimetabolomic studies (Pujos-Guillot et al 2013). The quality of the models was evaluated by R 2 Y(cum) and Q 2 (cum) parameters (Llorach-Asuncion et al 2010).…”

The role of metabolomics in determination of new dietary biomarkers

“…This approach has resulted in the identification of a number of putative biomarkers of specific foods and drinks such as citrus fruit (49,51,52) , cruciferous vegetables (53,54) , red meat (55,56) , coffee (57,58) , tea (59,60) , sugar-sweetened beverages (61) and wine (62) . A good example of a robust biomarker of citrus fruit is proline betaine, which was identified initially by Atkinson et al (52) and subsequently validated by independent research groups (49,51,63) . The biofluid used in all of these studies was urine; however, different metabolomic analytical strategies were applied to measure proline betaine, which included NMR and MS. One such study was performed by Heinzmann et al (49) , which involved eight volunteers consuming standardised meals over a 3 d period.…”

Urinary metabolomic fingerprinting after consumption of a probiotic strain in women with mastitis

“…The data set was Pareto-scaled (each variable weighted according to 1/√SD), and then pre-processed using Orthogonal Signal Correction (OSC) filtration before PLS-DA analysis to reduce the variability not associated with the intervention effect [21,22]. The application of this filter was by a corresponding tool provided by SIMCA-P+13.0 software.…”