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).

Findings from an online behavioural weight management programme provided with or without a fortified diet beverage.

The present multi-centre randomised weight-loss trial evaluated the efficacy of a low-intensity 12-week online behavioural modification programme, with or without a fortified diet beverage using a 2 × 2 factorial design. A total of 572 participants were randomised to: (1) an online basic lifestyle information (OBLI) intervention, consisting of one online informational class about tips for weight management; (2) an online behavioural weight management (OBWM) intervention, entailing 12 weekly online classes focused on weight-loss behaviour modification; (3) an OBLI intervention plus a fortified diet cola beverage (BEV) containing green tea extract (total catechin 167 mg), soluble fibre dextrin (10 g) and caffeine (100 mg) (OBLI+BEV); (4) OBWM+BEV. Assessments included height, weight, dual-energy X-ray absorptiometry-derived body composition, and waist circumference (WC). Attrition was 15·7 %. Intention-to-treat (ITT) models demonstrated a main effect for type of Internet programme, with those assigned to the OBWM condition losing significantly more weight (F= 7·174; P= 0·008) and fat mass (F= 4·491; P= 0·035) than those assigned to the OBLI condition. However, there was no significant main effect for the OBWM condition on body fat percentage (F= 2·906; P= 0·089) or WC (F= 3·351; P= 0·068), and no significant main effect for beverage use or significant interactions between factors in ITT models. A 12-week, low-intensity behaviourally based online programme produced a greater weight loss than a basic information website. The addition of a fortified diet beverage had no additional impact.

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.

Identification of metabolites in human plasma and urine after consumption of a polyphenol-rich juice drink.

A polyphenol-rich (P-R) juice drink was developed as a potential approach to increase intake of dietary polyphenols. Analysis of the beverage by HPLC with PDA, fluorescence, and MS detection facilitated the identification/partial identification of 40 flavonoids and related phenolic compounds. The main constituents were (-)-epigallocatechin and other green tea flavan-3-ols, phloretin-2'-O-glucoside, gallic acid, hesperetin-7-O-rutinoside, 5-O-caffeoylquinic acid, and procyanidins, with trace levels of several flavonols and purple grape juice anthocyanins also being present. Healthy human subjects (n = 10) consumed 350 mL of the P-R juice drink, after which plasma and urine samples were collected over a 0-24 h period. HPLC-MS analysis identified 13 metabolites in plasma and a further 20 in urine. Qualitatively, the profiles of the glucuronide, sulfated, and methylated metabolites were very similar to those detected in earlier investigations when the main components in the juice drink were consumed separately in feeding studies with coffee, green tea, orange juice, and apple cider.

A low-calorie beverage supplemented with low-viscosity pectin reduces energy intake at a subsequent meal.

The addition of fiber to foods and beverages has been linked with greater satiety and reduced energy intakes at the next meal. However, measures of satiety can be influenced by the time interval between beverage consumption and the next meal. The objective of this study was to determine how the time interval between consumption and a subsequent test meal impacts the satiating power of a low-calorie beverage supplemented with low-viscosity pectin fiber. Forty-two participants (20 men, 22 women) each participated in 4 study sessions. Study preloads were 2 low-calorie beverages (355 mL, 8 kcal) containing either 0 g fiber (no fiber) or 8 g low-viscosity fiber (added fiber). These preloads were consumed either 90 min before lunch or 15 min before lunch. Every 15 min, participants rated hunger, desire to eat, fullness, and thirst using 100-mm visual analogue scales. A test lunch was served and plate waste was measured. Beverages with added fiber reduced energy intakes at lunch relative to those without fiber. A short delay (15 min) between beverage consumption and a subsequent meal was associated with higher satiety ratings and reduced energy intakes, regardless of fiber content. The addition of low-viscosity pectin to low-calorie beverages reduced energy intakes at the next meal, presenting a possible tool for intake regulation. A short time interval between consumption of a low-calorie beverage and a meal also increased satiety and decreased food intake, reflecting the short-lived effect of volume.

In vivo regulation of phenylalanine hydroxylation to tyrosine, studied using enrichment in apoB-100.

Phenylalanine hydroxylation is necessary for the conversion of phenylalanine to tyrosine and disposal of excess phenylalanine. Studies of in vivo regulation of phenylalanine hydroxylation suffer from the lack of a method to determine intrahepatocyte enrichment of phenylalanine and tyrosine. apoB-100, a hepatic export protein, is synthesized from intrahepatocyte amino acids. We designed an in vivo multi-isotope study, [(15)N]phenylalanine and [2H2]tyrosine to determine rates of phenylalanine hydroxylation from plasma enrichments in free amino acids and apoB-100. For independent verification of apoB-100 as a reflection of enrichment in the intrahepatocyte pool, [1-(13)C]lysine was used as an indicator amino acid (IAA) to measure in vivo changes in protein synthesis in response to tyrosine supplementation. Adult men (n = 6) were fed an amino acid-based diet with low phenylalanine (9 mg.kg(-1).day(-1), 4.54 mumol.kg(-1).,h(-1)) and seven graded intakes of tyrosine from 2.5 (deficient) to 12.5 (excess) mg.kg(-1).day(-1). Gas chromatography-quadrupole mass spectrometry did not detect any tracer in apoB-100 tyrosine. A new and more sensitive method to measure label enrichment in proteins using isotope ratio mass spectrometry demonstrated that phenylalanine hydroxylation measured in apoB-100 decreased linearly in response to increasing tyrosine intake and reached a break point at 6.8 mg.kg(-1).day(-1). IAA oxidation decreased with increased tyrosine intake and reached a break point at 6.0 mg.kg(-1).day(-1). We conclude: apoB-100 is an accurate and useful measure of changes in phenylalanine hydroxylation; the synthesis of tyrosine via phenylalanine hydroxylation is regulated to meet the needs for protein synthesis; and that plasma phenylalanine does not reflect changes in protein synthesis.