Cocoa Flavanols Improve Vascular Responses to Acute Mental Stress in Young Healthy Adults.

Mental stress has been shown to induce cardiovascular events, likely due to its negative impact on vascular function. Flavanols, plant-derived polyphenolic compounds, improve endothelial function and blood pressure (BP) in humans, however their effects during stress are not known. This study examined the effects of acute intake of cocoa flavanols on stress-induced changes on vascular function. In a randomised, controlled, double-blind, cross-over intervention study, 30 healthy men ingested a cocoa flavanol beverage (high-flavanol: 150 mg vs. low-flavanol < 4 mg (-)-epicatechin) 1.5 h before an 8-min mental stress task). Forearm blood flow (FBF), BP, and cardiovascular activity were assessed pre- and post-intervention, both at rest and during stress. Endothelial function (brachial flow-mediated dilatation, FMD) and brachial BP were measured before the intervention and 30 and 90 min post-stress. FMD was impaired 30 min post-stress, yet high-flavanol cocoa attenuated this decline and remained significantly higher compared to low-flavanol cocoa at 90 min post-stress. High-flavanol cocoa increased FBF at rest and during stress. Stress-induced cardiovascular and BP responses were similar in both conditions. Flavanols are effective at counteracting mental stress-induced endothelial dysfunction and improving peripheral blood flow during stress. These findings suggest the use of flavanol-rich dietary strategies to protect vascular health during stress.

Substantial Depletion of Vicine, Levodopa, and Tyramine in a Fava Bean Protein-Based Nutritional Product.

A commercial fava bean protein isolate and a liquid nutritional product formulated with it were tested by validated HPLC methods for the favism-associated pyrimidine glycoside vicine, the dopamine precursor levodopa, and the biogenic amine tyramine. The vicine, levodopa, and tyramine concentrations in the protein isolate-306, 13.3, and <0.5 mg/kg, respectively-when expressed on a protein basis-34, 1.5, and <0.06 mg/100 g protein, respectively-were at least 96% lower than the vicine, levodopa, and tyramine (protein-based) concentrations reported for fava beans (≥900, ~200, and ~4 mg/100 g protein, respectively). This was also true for the vicine (13 mg/kg or 22 mg/100 g protein), levodopa (≤0.17 mg/kg or ≤0.3 mg/100 g protein), and tyramine (0.08 mg/kg or 0.14 mg/100 g protein) concentrations in the nutritional product. On the basis of these data, one serving (11 fl. oz.) of the nutritional product would deliver approximately 5 mg of vicine, <1 mg of levodopa, and <0.1 mg of tyramine.

Dietary flavanols improve cerebral cortical oxygenation and cognition in healthy adults.

Cocoa flavanols protect humans against vascular disease, as evidenced by improvements in peripheral endothelial function, likely through nitric oxide signalling. Emerging evidence also suggests that flavanol-rich diets protect against cognitive aging, but mechanisms remain elusive. In a randomized double-blind within-subject acute study in healthy young adults, we link these two lines of research by showing, for the first time, that flavanol intake leads to faster and greater brain oxygenation responses to hypercapnia, as well as higher performance only when cognitive demand is high. Individual difference analyses further show that participants who benefit from flavanols intake during hypercapnia are also those who do so in the cognitive challenge. These data support the hypothesis that similar vascular mechanisms underlie both the peripheral and cerebral effects of flavanols. They further show the importance of studies combining physiological and graded cognitive challenges in young adults to investigate the actions of dietary flavanols on brain function.

Polyphenol-Enriched Plum Extract Enhances Myotubule Formation and Anabolism while Attenuating Colon Cancer-induced Cellular Damage in C2C12 Cells.

Preventing muscle wasting in certain chronic diseases including cancer is an ongoing challenge. Studies have shown that polyphenols derived from fruits and vegetables shows promise in reducing muscle loss in cellular and animal models of muscle wasting. We hypothesized that polyphenols derived from plums (Prunus domestica) could have anabolic and anti-catabolic benefits on skeletal muscle. The effects of a polyphenol-enriched plum extract (PE60) were evaluated in vitro on C2C12 and Colon-26 cancer cells. Data were analyzed using a one-way ANOVA and we found that treatment of myocytes with plum extract increased the cell size by ~3-fold (p < 0.05) and stimulated myoblast differentiation by ~2-fold (p < 0.05). Plum extract induced total protein synthesis by ~50% (p < 0.05), reduced serum deprivation-induced total protein degradation by ~30% (p < 0.05), and increased expression of Insulin-Like Growth Factor-1 (IGF-1) by ~2-fold (p < 0.05). Plum extract also reduced tumor necrosis factor α (TNFα)-induced nuclear factor κB (NFκB) activation by 80% (p < 0.05) in A549/NF-κB-luc cells. In addition, plum extract inhibited the growth of Colon-26 cancer cells, and attenuated cytotoxicity in C2C12 myoblasts induced by soluble factors released from Colon-26 cells. In conclusion, our data suggests that plum extract may have pluripotent health benefits on muscle, due to its demonstrated ability to promote myogenesis, stimulate muscle protein synthesis, and inhibit protein degradation. It also appears to protect muscle cell from tumor-induced cytotoxicity.

Iron Bioavailability from Ferric Pyrophosphate in Extruded Rice Cofortified with Zinc Sulfate Is Greater than When Cofortified with Zinc Oxide in a Human Stable Isotope Study.

Background: Extruded rice grains are often cofortified with iron and zinc. However, it is uncertain if the addition of zinc to iron-fortified rice affects iron absorption and whether this is zinc-compound specific.Objective: We investigated whether zinc, added as zinc oxide (ZnO) or zinc sulfate (ZnSO4), affects human iron absorption from extruded rice fortified with ferric pyrophosphate (FePP).Methods: In 19 iron-depleted Swiss women (plasma ferritin ≤16.5 µ/L) aged between 20 and 39 y with a normal body mass index (in kg/m2; 18.7-24.8), we compared iron absorption from 4 meals containing fortified extruded rice with 4 mg Fe and 3 mg Zn. Three of the meals contained extruded rice labeled with FePP (57FePP): 1) 1 meal without added zinc (57FePP-Zn), 2) 1 cofortified with ZnO (57FePP+ZnO), and 3) 1 cofortified with ZnSO4 (57FePP+ZnSO4). The fourth meal contained extruded rice without iron or zinc, extrinsically labeled with ferrous sulfate (58FeSO4) added as a solution after cooking. All 4 meals contained citric acid. Iron bioavailability was measured by isotopic iron ratios in red blood cells. We also measured relative in vitro iron solubility from 57FePP-Zn, 57FePP+ZnO, and 57FePP+ZnSO4 expressed as a fraction of FeSO4 solubility.Results: Geometric mean fractional iron absorption (95% CI) from 57FePP+ZnSO4 was 4.5% (3.4%, 5.8%) and differed from 57FePP+ZnO (2.7%; 1.8%, 4.1%) (P < 0.03); both did not differ from 57FePP-Zn: 4.0% (2.8%, 5.6%). Relative iron bioavailabilities compared with 58FeSO4 were 62%, 57%, and 38% from 57FePP+ZnSO4, 57FePP-Zn, and 57FePP+ZnO, respectively. In vitro solubility from 57FePP+ZnSO4 differed from that of 57FePP-Zn (14.3%; P < 0.02) but not from that of 57FePP+ZnO (10.2% compared with 13.1%; P = 0.08).Conclusions: In iron-depleted women, iron absorption from FePP-fortified extruded rice cofortified with ZnSO4 was 1.6-fold (95% CI: 1.4-, 1.9-fold) that of rice cofortified with ZnO. These findings suggest that ZnSO4 may be the preferable zinc cofortificant for optimal iron bioavailability of iron-fortified extruded rice. This trial was registered at clinicaltrials.gov as NCT02255942.

The relative bioavailability of the calcium salt of ß-hydroxy-ß-methylbutyrate is greater than that of the free fatty acid form in rats.

BACKGROUND: ß-Hydroxy-ß-methylbutyrate (HMB) supplementation has been demonstrated to enhance muscle protein synthesis and attenuate loss of muscle mass by multiple pathways. The beneficial effects of HMB have been studied by using either the calcium salt, monohydrate, of HMB (CaHMB) or the free acid form (FAHMB). OBJECTIVE: The present study was designed to compare the pharmacokinetics and relative bioavailability of the 2 forms of HMB administered as a liquid suspension in male Sprague-Dawley rats. METHODS: CaHMB at 30, 100, and 300 mg/kg and equivalent doses of FAHMB at 24.2, 80.8, and 242 mg/kg were administered orally as a liquid suspension to male Sprague-Dawley rats. A single i.v. dose of 5 mg/kg CaHMB, corresponding to an equivalent dose of 4.04 mg/kg FAHMB, was also administered. Plasma concentrations of HMB were analyzed by liquid chromatography tandem mass spectrometry, and pharmacokinetic variables and relative bioavailability of the 2 forms of HMB were determined. RESULTS: After oral administration, the area under the plasma concentration time curve (AUC) from time 0 to time t (0-t) and from time 0 to infinity (0-∞) and the maximum (peak) plasma concentration (Cmax) for CaHMB were significantly greater than for FAHMB, whereas the time to reach Cmax did not differ from that of FAHMB. The relative bioavailability of CaHMB was 49%, 54%, and 27% greater than that of FAHMB for the 3 respective oral doses tested. After i.v. administration, the AUCs 0-t and 0-∞ of the calcium salt were significantly greater than those of FAHMB. The relative bioavailability of CaHMB was 80% greater than that of FAHMB. The higher relative bioavailability of CaHMB may be attributable to its low systemic clearance compared with FAHMB. CONCLUSIONS: This study demonstrates the enhanced relative bioavailability of CaHMB compared with FAHMB. Further studies are warranted to understand the physiologic mechanisms contributing to the differences in systemic clearance.

Direct determination of methionine sulfoxide in milk proteins by enzyme hydrolysis/high-performance liquid chromatography.

A direct and simultaneous HPLC/UV determination of methionine and methionine sulfoxide in enzyme-hydrolyzed milk proteins is described. Protein hydrolysis is accomplished by a three-enzyme (pronase, leucine aminopeptidase, prolidase) 20-h/37 degrees C digestion. A gradient elution reversed-phase HPLC system with UV detection at 214 nm and 280 nm is then used to determine the quantitative releases of methionine sulfoxide, methionine, tyrosine, and tryptophan. The ease of methionine oxidation by a wide variety of oxidants, coupled with the quantitative release of both methionine and its sulfoxide by the three-enzyme hydrolysis, renders the approach valuable for identifying oxidized milk proteins. The relatively simple method proved accurate and precise in its application to commercial milk products, finding methionine sulfoxide levels as high as 74% of the total methionine.

Glutamine in commercial liquid nutritional products.

Total glutamine concentrations in commercial nutritional products have been determined by enzymatic hydrolysis followed by HPLC quantification of free glutamine and free pyroglutamic acid. Hydrolysis was accomplished by a published three-enzyme (Pronase, leucine aminopeptidase, prolidase), 20-h/37 degrees C digestion. Glutamine was determined as its FMOC derivative by reverse phase HPLC-fluorescence, and pyroglutamic acid was determined directly by organic acid HPLC-UV. Approximately 4.11% of the released glutamine is converted to pyroglutamic acid during the 20-h digestion. Experimental ratios of enzyme hydrolysis glutamine to acid hydrolysis glutamic acid + glutamine + pyroglutamic acid (GLX) indicate that the method recovers >90% of the protein-bound glutamine. The nutritional products with casein dominant intact protein systems typically deliver >9 g of glutamine/100 g of protein, or approximately 40 g of glutamine/100 g of GLX.