Susan A. Roberts

Bioavailability of multiple components following acute ingestion of a polyphenol‐rich juice drink

A healthy diet involves eating fruit and vegetables on a daily basis, the benefits of which are in part linked to the ingestion of bioactive compounds including polyphenols. As a convenient means of delivering additional polyphenols to the diet, a polyphenol-rich (P-R) juice drink was prepared and the bioavailability of its diverse spectrum of constituents investigated. Ten human volunteers followed a low-flavonoid diet for 2 days before drinking 350 mL of the P-R beverage. Plasma and urine were collected for 24 h and analyzed by HPLC-PDA-MS. The plasma pharmacokinetics and recoveries of urinary metabolites of flavan-3-ols, flavanones, dihydrochalcones and 5-O-caffeoylquinic acid, both in terms of their identity and quantity, were, in most instances, not markedly different to those reported in other feeding studies with green tea, orange juice, apple cider and coffee. This indicates that the combination of polyphenolic compounds in the P-R beverage are absorbed and excreted to a similar extent whether fed individually or together in a single beverage. It is concluded that the P-R beverage can deliver the intended blend of bioavailable polyphenols, which would normally require consumption of several different plant-derived foods.

Bioavailability of dietary (poly)phenols: a study with ileostomists to discriminate between absorption in small and large intestine

A feeding study was carried out in which six healthy ileostomists ingested a juice drink containing a diversity of dietary (poly)phenols derived from green tea, apples, grapes and citrus fruit. Ileal fluid and urine collected at intervals over the ensuing 24 h period were then analysed by HPLC-MS. Urinary excretions were compared with results obtained in an earlier study in which the juice drink was ingested by ten healthy control subjects with an intact colon. Some polyphenol components, such as (epi)catechins and (epi)gallocatechin(s), were excreted in urine in similar amounts in ileostomists and subjects with an intact colon, demonstrating that absorption took place principally in the small intestine. In the urine of ileostomists, there were reduced levels of other constituents, including hesperetin-7-O-rutinoside, 5-O-caffeoylquinic acid and dihydrochalcones, indicating their absorption in both the small and large intestine. Ileal fluid analysis revealed that even when absorption occurred in the small intestine, in subjects with a functioning colon a substantial proportion of the ingested components still pass from the small into the large intestine, where they may be either absorbed before or after catabolism by colonic bacteria.

A Pilot Study on the Effect of Short-Term Consumption of a Polyphenol Rich Drink on Biomarkers of Coronary Artery Disease Defined by Urinary Proteomics

Polyphenol rich diets have been associated with a reduced risk of cardiovascular disease. We examined the effect of a polyphenol rich (P-R) drink on biomarkers assessed by urinary proteomics. Thirty nine middle aged and overweight subjects were randomized to P-R drink (n = 20) or placebo (n = 19) in addition to their normal diet. After two weeks urine samples were obtained for assessment of the urinary proteome using capillary electrophoresis coupled to a mass spectrometer. A total of 93 polypeptides were found to be candidates for differential distribution with a nominal p-value <0.05, though these differences did not reach significance when multiple testing was accounted for. Sequences were determined in 19 of these demonstrating that they originate from alpha-1 antitrypsin, collagens, fibrinogen alpha and IgG kappa. Levels of 27 polypeptides were greater than 4-fold different between the two groups. Of these, 7 were previously found to be part of a coronary artery disease (CAD) specific urinary biomarker pattern. Their direction of expression was closer to the healthy state in the P-R drink group and closer to CAD state in the placebo group. Our data suggest that the P-R drink may have beneficial effects on urinary biomarkers of CAD. The data encourage the planning of future prospective studies, aimed at investigating significant effects of polyphenol rich dietary products.

Consumption of mixed fruit-juice drink and vitamin C reduces postprandial stress induced by a high fat meal in healthy overweight subjects.

Postprandial stress induced by acute consumption of meals with a high fat content results in an increase of markers of cardiometabolic risk. Repeated acute dietary stress may induce a persistent low-grade inflammation, playing a role in the pathogenesis of functional gut diseases. This may cause an impairment of the complex immune response of the gastrointestinal mucosa, which results in a breakdown of oral tolerance. We investigated the effect of ingestion of a fruit-juice drink (FJD) composed by multiple fruit juice and extracts, green tea extracts and vitamin C on postprandial stress induced by a High Fat Meal (HFM) in healthy overweight subjects. Following a double blind, placebo controlled, cross-over design, 15 healthy overweight subjects were randomized to a HFM providing 1334 Kcal (55% fat, 30% carbohydrates and 15% proteins) in combination with 500 mL of a placebo drink (HFM-P) or a fruit-juice drink (HFM-FJD). Ingestion of HFM-P led to an increase in circulating levels of cholesterol, triglycerides, glucose, insulin, TNF-α and IL-6. Ingestion of HFM-FJD significantly reduced plasma levels of cholesterol and triglycerides, decreasing inflammatory response mediated by TNF-α and IL-6. Ingestion of a fruit-juice drink reduce markers of postprandial stress induced by a HFM.

Low/No calorie sweetened beverage consumption in the National Weight Control Registry: LNCSB Consumption in the NWCR

The aim of this cross‐sectional study was to evaluate prevalence of and strategies behind low/no calorie sweetened beverage (LNCSB) consumption in successful weight loss maintainers.

Effects of a beverage rich in (poly)phenols on established and novel risk markers for vascular disease in medically uncomplicated overweight or obese subjects: A four week randomized placebo-controlled trial.

OBJECTIVE To determine if (poly)phenols alter cardiovascular risk factors, we assessed the potential of a high (poly)phenol beverage drink, rich in hydroxycinnamates and flavonoids, to modify vascular function in middle aged, overweight or obese subjects without medical co-morbidity in a randomized placebo controlled pilot study. METHODS Randomly assigned active 250 ml beverages containing 361 mg of (poly)phenols and 120 mg of vitamin C or placebo (no polyphenol/vitamin C) were taken twice daily for 4 weeks. Both beverages contained 40 kcals/250 ml. The primary end-points were pulse wave velocity (PWV) and cutaneous microvascular responses to sodium nitroprusside (SNP) and acetyl choline (ACh) laser doppler iontophoresis. A range of established and novel plasma markers were also measured. RESULTS Twenty subjects received active beverage and 19 placebo; all completed the study. There was no difference in cutaneous vascular response to either SNP or ACh with mean group differences (logΔ area under perfusion curve) of 0.30 (-0.65, 1.26) and 0.35 (-0.11, 0.81) respectively. Nor was there evidence of a change in log PWV with a mean group difference of 0.029 m/s (-0.042, 0.10). No significant differences were seen in plasma leptin, apolipoproteins, cystatin C, insulin, adiponectin, CRP, ICAM-1, E-Selectin or t-PA, but IL-6 increased in active versus placebo recipients (0.32 vs - 0.18 pg/ml; p=0.010). CONCLUSION There was no evidence for a short-term beneficial effect of (poly)phenol intervention on microcutaneous vascular response or pulse wave velocity, and no evidence for a benefit on established or novel risk factors in overweight or obese subjects. Our results do not support a short-term benefit of (poly)phenol supplementation on cardiometabolic risk. REGISTRATION Clinical Trials.gov (NCT00795834).