Effect of Milk on the Urinary Excretion of Microbial Phenolic Acids after Cocoa Powder Consumption in Humans

6 páginas, 1 figura, 1 tabla.Health effects of cocoa flavonols depend on their bioavailability, which is strongly influenced by the food matrix and the degree of flavanol polymerization. The effect of milk on the bioavailability of cocoa flavanoids considering phase II metabolites of epicatechin has been the subject of considerable debate. This work studies the effect of milk at the colonic microbial metabolism level of the nonabsorbed flavanol fraction that reaches the colon and is metabolized by the colonic microbiota into various phenolic acids. Twenty-one human volunteers followed a diet low in polyphenols for at least 48 h before taking, in a random order, 40 g of cocoa powder dissolved either in 250 mL of whole milk or in 250 mL of water. Urine samples were collected before the intake and during three different periods (0−6, 6−12, and 12−24 h). Phenolic acids were analyzed by LC-MS/MS after solid-phase extraction. Of the 15 metabolites assessed, the excretion of 9 phenolic acids was affected by the intake of milk. The urinary concentration of 3,4-dihydroxyphenylacetic, protocatechuic, 4-hydroxybenzoic, 4-hydroxyhippuric, hippuric, caffeic, and ferulic acids diminished after the intake of cocoa with milk, whereas urinary concentrations of vanillic and phenylacetic acids increased. In conclusion, milk partially affects the formation of microbial phenolic acids derived from the colonic degradation of procyanidins and other compounds present in cocoa powder.This research was supported by national grants CICYT (AGL: 2004-08378-C02-01/02 and 2006- 14228-C03-02/01); CIBER 06/03 Fisiopatologı´ a de la Obesidad y la Nutrici on is an initiative of the Instituto de Salud Carlos III, Spain; Centro Nacional de Investigaciones Cardiovasculares (CNIC-06) and Ingenio-CONSOLIDER program, Fun-c-food (CSD2007-063).M.U.-S. and N.K. thank the FPI and FPU fellowship programs, respectively, and M.M. and R.Ll., the postdoctoral programs Juan de la Cierva and Fondo de Investigaci on Sanitaria (FIS CD06/00161), respectively, all from the Ministry of Science and Innovation.M.R.-R. thanks the APIF fellowship from the University of Barcelona. R.E. is recipient of a grant from F.I.S., Madrid, Spain.Peer reviewe

Quantifying the human diet in the crosstalk between nutrition and health by multi-targeted metabolomics of food and microbiota-derived metabolites

Background Metabolomics is a powerful tool for investigating the association between nutrition and health status. Although urine is commonly employed for studying the metabolism and transformation of food components, the use of blood samples could be preferable to gain new insights into the bioavailability of diet-derived compounds and their involvement in health. However, the chemical complexity of blood samples hinders the analysis of this biological fluid considerably, which makes the development of novel and comprehensive analytical methods mandatory. Methods In this work, we optimized a multi-targeted metabolomics platform for the quantitative and simultaneous analysis of 450 food-derived metabolites by ultra-high performance liquid chromatography coupled to tandem mass spectrometry. To handle the chemical complexity of blood samples, three complementary extraction methods were assayed and compared in terms of recovery, sensitivity, precision and matrix effects with the aim of maximizing metabolomics coverage: protein precipitation, reversed solid-phase extraction, and hybrid protein precipitation with solid-phase extraction-mediated phospholipid removal. Results After careful optimization of the extraction conditions, protein precipitation enabled the most efficient and high-throughput extraction of the food metabolome in plasma, although solid-phase extraction-based protocols provided complementary performance for the analysis of specific polyphenol classes. The developed method yielded accurate recovery rates with negligible matrix effects, and good linearity, as well as high sensitivity and precision for most of the analyzed metabolites. Conclusions The multi-targeted metabolomics platform optimized in this work enables the simultaneous detection and quantitation of 450 dietary metabolites in short-run times using small volumes of biological sample, which facilitates its application to epidemiological studies

Total polyphenol excretion and blood pressure in subjects at high cardiovascular risk

Background and aims Dietary factors are critical for the prevention and treatment of hypertension, but data on the effects of specific nutrients on blood pressure (BP) are scarce. The aim of this study was to assess the relationship between total polyphenol excretion (TPE) in urine, as an objective measurement of total polyphenol intake and BP in an elderly population at high cardiovascular risk. Methods and results Cross-sectional substudy of 589 high-risk participants entering in the PREDIMED trial. BP was measured and TPE was determined in urine by Folin–Ciocalteu assay. A significant positive association was observed between TPE in urine and daily intake of fruit and vegetables (F&V), coffee or wine after adjusting for potential confounders. The intake of 100 g of F&V (Beta = 0.150;P < 0.001) had a greater contribution to TPE than 100 mL of coffee (Beta = 0.141;P = 0.001), and the latter two foods contributed more than the consumption of 100 mL of wine (Beta = 0.120;P = 0.019). An inverse association was observed between urinary TPE and the prevalence of hypertension. Participants in the highest quartile of urinary TPE had a reduced prevalence of hypertension compared to those in the lowest quartile (Odds Ratio = 0.64; 95% confidence interval 0.45 to 0.92; P = 0.015). Systolic and diastolic BP were inversely associated with urinary TPE after adjustment for potential confounders (P = 0.024 and P = 0.003, respectively). Conclusions Polyphenol intake, assessed via TPE in urine, was negatively associated with BP levels and prevalence of hypertension in an elderly Mediterranean population at high cardiovascular risk. Participants with the highest intake of polyphenol-rich foods showed the lowest BP measurements.This work has received financial support from AGL2005-05597; AGL2006-14228-C03-02, AGL2007-66638-C02-01, RETICS RD06/0045/0003, and in part by the CONSOLIDER INGENIO 2010 Programme, FUN-C-FOOD CSD2007-063 all from the Spanish Ministry of Science and Innovation (MICINN) and grant PI070240 from Instituto de Salud Carlos III, Spain.Peer Reviewe

Dietary biomarkers: advances, limitations and future directions

<p>Abstract</p> <p>The subjective nature of self-reported dietary intake assessment methods presents numerous challenges to obtaining accurate dietary intake and nutritional status. This limitation can be overcome by the use of dietary biomarkers, which are able to objectively assess dietary consumption (or exposure) without the bias of self-reported dietary intake errors. The need for dietary biomarkers was addressed by the Institute of Medicine, who recognized the lack of nutritional biomarkers as a knowledge gap requiring future research. The purpose of this article is to review existing literature on currently available dietary biomarkers, including novel biomarkers of specific foods and dietary components, and assess the validity, reliability and sensitivity of the markers. This review revealed several biomarkers in need of additional validation research; research is also needed to produce sensitive, specific, cost-effective and noninvasive dietary biomarkers. The emerging field of metabolomics may help to advance the development of food/nutrient biomarkers, yet advances in food metabolome databases are needed. The availability of biomarkers that estimate intake of specific foods and dietary components could greatly enhance nutritional research targeting compliance to national recommendations as well as direct associations with disease outcomes. More research is necessary to refine existing biomarkers by accounting for confounding factors, to establish new indicators of specific food intake, and to develop techniques that are cost-effective, noninvasive, rapid and accurate measures of nutritional status.</p