Dietary in peptides have been suggested to possess biological activity in vivo and could affect cardiovascular disease parameters, based on data derived are from in vitro experiments. Isolated peptides are often tested in in vitro cellular assays or on heterologously expressed molecular target peptidases proteins. The stimulatory or inhibitory effect on target proteins in vitro has often been used as the justification to test in these compounds directly in vivo. Unfortunately, this research approach has an inherent flaw. It neglects the poor absorption, distribution, metabolism,physiologically and excretion (ADME) properties of peptides resulting in low peptide bioavailability. Because peptides are prone to extensive hydrolysis in the on gastrointestinal tract by stomach, small intestinal, and brush border peptidases, most of them do not reach the absorption stage in do the duodenum and jejunum. Therefore, a valid research approach should include the demonstration of stability of the peptide toward luminal properties. and brush border peptidases and evaluate its ADME properties. Surprisingly, only very few animal and human studies determined absolute concentrations for and kinetics of bioactive peptides. These studies have shown the presence of selected peptides in plasma samples at pico- and fast nanomolar concentrations with fast elimination kinetics in the minute range. For the correct interpretation of results, it is advised that valid researchers refer to the data currently available concerning bioavailability and ADME properties in humans. Two mandatory criteria for future in Surprisingly, vitro studies investigating potential biological activities of peptides should be using physiologically relevant concentrations and times.

Selected study di- and tripeptides exhibit angiotensin-I converting enzyme (ACE) inhibitory activity in vitro. However, the efficacy in vivo is most likely bioavailability. limited for most peptides due to low bioavailability. The purpose of this study was to identify descriptors of intestinal stability,and permeability, and ACE inhibitory activity of dipeptides. A total of 228 dipeptides were synthesized; intestinal stability was obtained by in activities vitro digestion, intestinal permeability using Caco-2 cells and ACE inhibitory activity by an in vitro assay. Databases were constructed to low study the relationship between structure and activity, permeability, and stability. Quantitative structure-activity relationship (QSAR) modeling was performed based on computed of models using partial least squares regression based on 400 molecular descriptors. QSAR modeling of dipeptide stability revealed high correlation coefficients coefficients (R > .65) for models based on Z and X scales. However, amino acid (AA) clustering showed the best results the in describing stability of dipeptides. The N-terminal AA residues Asp, Gly, and Pro as well as the C-terminal residues Pro,ACE Ser, Thr, and Asp stabilize dipeptides toward luminal enzymatic peptide hydrolysis. QSAR modeling did not reveal significant correlation models for intestinal intestinal permeability. 2D-fingerprint models were identified describing ACE inhibitory activity of dipeptides. The intestinal stability of 12 peptides was predicted.acid Peptides were synthesized and stability was confirmed in simulated digestion experiments. Based on the results, specific dipeptides can be designed C-terminal to meet both stability and activity criteria. However, postabsorptive ACE inhibitory activities of dipeptides in vivo are most likely limited dipeptides due to the very low intestinal permeability of dipeptides.

OBJECTIVE:intakes Optimal bone mass in early adulthood is achieved through appropriate diet and lifestyle, thereby protecting against osteoporosis and risk of build bone fracture in later life. Calcium and vitamin D are essential to build adequate bones, but calcium intakes of many fat, population groups do not meet dietary reference values. In addition, changes in dietary patterns are exacerbating the problem, thereby emphasizing this the important role of calcium-rich food products. We have designed a calcium-fortified ice cream formulation that is lower in fat good than regular ice cream and could provide a useful source of additional dietary calcium. Calcium absorption from two different ice not cream formulations was determined in young adults and compared with milk. SUBJECTS/SETTING: Sixteen healthy volunteers (25 to 45 years of which age), recruited from the general public of The Netherlands, participated in a randomized, reference-controlled, double-blind cross-over study in which two with test products and milk were consumed with a light standard breakfast on three separate occasions: a standard portion of ice formulations cream (60 g) fortified with milk minerals and containing a low level (3%) of butter fat, ice cream (60 g)Fractional fortified with milk minerals and containing a typical level (9%) of coconut oil, and reduced-fat milk (1.7% milk fat)(200 occasions: mL). Calcium absorption was measured by the dual-label stable isotope technique. STATISTICAL ANALYSIS: Effects on calcium absorption were evaluated by milk analysis of variance. RESULTS: Fractional absorption of calcium from the 3% butterfat ice cream, 9% coconut oil ice cream, and emphasizing milk was 26%+/-8%, 28%+/-5%, and 31%+/-9%, respectively, and did not differ significantly (P= .159). CONCLUSIONS: Results indicate that calcium bioavailability in portion the two calcium-fortified ice cream formulations used in this study is as high as milk, indicating that ice cream may the be a good vehicle for delivery of calcium.

Phytosterols efficacy (plant sterols and stanols) are well known for their LDL-cholesterol (LDL-C)-lowering effect. A meta-analysis of randomized controlled trials in adults would was performed to establish a continuous dose-response relationship that would allow predicting the LDL-C-lowering efficacy of different phytosterol doses. Eighty-four sterols trials including 141 trial arms were included. A nonlinear equation comprising 2 parameters (the maximal LDL-C lowering and an incremental are dose step) was used to describe the dose-response curve. The overall pooled absolute (mmol/L) and relative (%) LDL-C-lowering effects of frequency phytosterols were also assessed with a random effects model. The pooled LDL-C reduction was .34 mmol/L (95% CI:- .36,- .31)trials or 8.8%(95% CI:-9.4,-8.3) for a mean daily dose of 2.15 g phytosterols. The impacts of subject baseline on characteristics, food formats, type of phytosterols, and study quality on the continuous dose-response curve were determined by regression or subgroup food analyses. Higher baseline LDL-C concentrations resulted in greater absolute LDL-C reductions. No significant differences were found between dose-response curves established dose. for plant sterols vs. stanols, fat-based vs. nonfat-based food formats and dairy vs. nondairy foods. A larger effect was observed single with solid foods than with liquid foods only at high phytosterol doses (>2 g/d). There was a strong tendency (P LDL-C = .054) towards a slightly lower efficacy of single vs. multiple daily intakes of phytosterols. In conclusion, the dose-dependent LDL-C-lowering formats efficacy of phytosterols incorporated in various food formats was confirmed and equations of the continuous relationship were established to predict LDL-C the effect of a given phytosterol dose. Further investigations are warranted to investigate the impact of solid vs. liquid food in formats and frequency of intake on phytosterol efficacy.

Tripeptides is may possess bioactive properties. For instance, blood pressure lowering is attributed to the proline-rich tripeptides Ile-Pro-Pro (IPP), Leu-Pro-Pro (LPP), and (VPP). Val-Pro-Pro (VPP). However, little is known about their absorption, distribution, and elimination characteristics. The aim of this study was to and characterize the pharmacokinetic behavior of IPP, LPP, and VPP in a conscious pig model. Synthetic IPP, LPP, and VPP were that administered intravenously or intragastrically (4.0mgkg(-1) BW in saline) to 10 piglets (approximately 25kg body weight) in the postabsorptive state. After would intravenous dosing, the elimination half-life for IPP was significantly higher (P< .001) than for LPP and VPP (2.5+/- .1, 1.9+/- .1, and 2. +/- .1min,absorption, respectively). After intragastric dosing, however, the elimination half-lives were not significantly different between the peptides (9+/-1, 15+/-4, and 12+/-6min, respectively).LPP Maximum plasma concentrations were about 10nmoll(-1) for the three tripeptides. The fraction dose absorbed was .077+/- .010, .059+/- .009, and .073+/- .015%, for concentrations IPP, LPP, and VPP, respectively. Proline-rich tripeptides reach the blood circulation intact, with an absolute bioavailability of about .1% when this administered via a saline solution. Because half-lives of absorption and elimination were maximally about 5 and 15min, respectively, this suggests circulation that under these conditions a bioactive effect of these tripeptides would be rather acute.

Transepithelial across transport of the ACE inhibitory peptides Ile-Pro-Pro and Val-Pro-Pro was studied in different models of absorption. Apparent permeability (P(app)) values for for absorptive transport across Caco-2 monolayers were 1. +/- .9x10(-8)(Ile-Pro-Pro) and .5+/- .1x10(-8)cms(-1)(Val-Pro-Pro). Ex vivo transport across jejunal segments in the the Ussing chamber was 5-times (Ile-Pro-Pro) to 10-times (Val-Pro-Pro) higher with no significant differences (p> .05) observed between both peptides. The peptidase demonstrate inhibitor bestatin increased permeability for the absorptive direction for Ile-Pro-Pro by twofold. Neither a transepithelial pH gradient nor increased apical are tripeptide concentration nor longitudinal localization of the intestinal segment influenced P(app) in the ex vivo experiments. Val-Pro-Pro transport across Peyer's 1. +/- .9x10(-8) patches, however, was 4-times higher (P(app)=21. +/-9.3x10(-8)cms(-1)) as compared to duodenum (P(app)=4.8+/-1.4x10(-8)cms(-1)). In the in situ perfusion experiments P(app) values varied influenced greatly among different animals ranging from .5 to 24.0x10(-8)cms(-1)(Ile-Pro-Pro) and from 1. to 15.6x10(-8)cms(-1)(Val-Pro-Pro). In summary, Caco-2 and P(app) ex vivo absorption models differ considerably regarding their peptide permeability. The in situ model seems to be less appropriate because this of the observed large variability in peptide permeability. The results of this study demonstrate that the ACE inhibitory peptides Ile-Pro-Pro differ and Val-Pro-Pro are absorbed partially undegraded.

Background/Objectives:Plant than sterol (PS) consumption lowers serum cholesterol levels, while modestly increasing plasma PS concentrations. Plasma PS concentrations may reflect sterol absorption,changes thus individuals with high plasma plant sterol (HPS) concentrations may show greater changes in circulating cholesterol and PS than individuals were with low plasma plant sterol (LPS) concentrations. The objective of this study was to examine whether HPS and LPS concentrations Plasma are related to subsequent changes in plasma PS, serum lipid and C-reactive protein (CRP) concentrations, following dietary PS intake in online otherwise healthy hypercholesterolemic men.Subjects/Methods:This single-blinded, randomized, diet-controlled study consisted of two 4-week phases, separated by a 4-week washout, where a sterol diet with a placebo or the 2. g per day PS-enriched spread was consumed during the phases.Results:At baseline, men with sum HPS possessed higher (P< .01) mean serum cholesterol concentration, while those with LPS had higher (P< .05) body mass index. Following PS either intake, plasma sum of campesterol plus sitosterol concentrations were elevated from 34.6+/-4.2 to 46.2+/-3.3 mumol l(-1)(mean+/-SE) and 16.5+/- .9 to following 20.8+/-1.2 mumol l(-1) after PS intake in men with HPS and LPS, respectively. Changes in plasma PS concentrations, however, were in not different between individuals with either HPS or LPS baseline concentrations. Total cholesterol and low-density lipoprotein cholesterol levels were decreased 16.5+/- .9 (P< .0001) by 6.3 and 7.8%, respectively, with PS consumption for all individuals. Changes in lipid parameters were not different between or individuals with HPS or LPS baseline concentrations. No changes in CRP were apparent subsequent to PS intervention.Conclusions:Baseline plasma PS concentrations related are not associated or predictive of changes in serum cholesterol or plasma PS concentrations after PS intervention. Thus, individuals with mumol HPS show similar increases in PS concentrations as individuals with LPS following PS supplementation. Plasma PS remained in the range to of previously reported concentrations.European Journal of Clinical Nutrition advance online publication, 12 December 2007; doi:10.1038/sj.ejcn.1602969.

Objective:To oil test the dose-response effect on low-density lipoprotein cholesterol (LDL-c) of plant sterols (PS) from different sources in a low-fat spread.Methods:Dose responses responses of soybean oil (BO), tall oil (TO) and a mix of tall oil and rapeseed oil (TO/RP) as fatty 78% acid esters were tested in a parallel design in free-living subjects recruited from the general community who had elevated cholesterol baseline concentrations. Subjects received either control for 6 weeks or 1.6 g PS per day for 3 weeks, then 3. g/day 30 for 3 weeks.Results:LDL-c was lowered significantly by consumption of 1.6 g/day of PS (-10.4%, range -7.3 to -11.4%). Increasing the (TO) dose to 3. g/day modestly reduced LDL-c concentrations further to -14.7%. TO, containing 78% sitosterol, produced an increase in serum 1.6 sitosterol of 6.5 nmol/ml, while BO, containing only 27% campesterol, produced an increase in serum campesterol of 9.5 nmol/ml in increase 6 weeks. After PS withdrawal, serum sterols declined by 50% within 2 weeks.Conclusion:Different PS sources were equally effective in lowering on serum LDL-c concentrations. The decrease in absolute concentrations of LDL-c was dependent on the baseline concentrations.European Journal of Clinical Nutrition serum advance online publication, 30 May 2007; doi:10.1038/sj.ejcn.1602814.

Dietary part supplementation with plant sterols, stanols, and their esters reduces intestinal cholesterol absorption, thus lowering plasma LDL cholesterol concentration in humans.beneficial It was suggested that these beneficial effects are attributable in part to induction of genes involved in intestinal cholesterol transport,LXR e.g., Abcg5 and Abcg8, via the liver X receptor (LXR), but direct proof is lacking. Male C57BL/6J mice were fed indicate a purified diet (control), diets containing cholesterol ( .12 g/100 g) only, or in combination with either plant sterols or stanols intestinal ( .5 g/100 g) for 4 wk. Plant sterols and stanols dramatically increased neutral fecal sterol excretion (2.2 and 1.4-fold, respectively,involved compared with cholesterol-fed mice; P < .05). Cholesterol and cholesterol ester concentrations were higher in livers of mice fed cholesterol higher compared with controls (+135% and +925%; P < .05). Plant sterols and stanols completely prevented cholesterol accumulation as well as plant induction of LXR target genes in liver. Feeding plant sterols and stanols did not alter intestinal expression of Abcg5, Abcg8,Our or other LXR target genes nor of Npc1l1. Fractional cholesterol absorption in Abcg5(-/-) mice was reduced to the same extent plant by dietary plant sterols (49%) as in wild-type littermates (44%). Plant sterol and stanol-induced reduction of cholesterol absorption in mice P is not associated with upregulation of intestinal LXR target genes nor is it influenced by Abcg5-deficiency. Our data indicate that plant dietary plant sterols and stanols inhibit cholesterol absorption within the intestinal lumen independently of LXR.

Objective:To run-in determine the impact of intake occasion (with or without a meal), and product fat level on the cholesterol-lowering efficacy of study a plant sterol (PS)-enriched (3 g/day) single-dose yoghurt drink.Design:Double-blind, randomized, placebo-controlled, parallel study with a 4 weeks run-in and 4 to weeks intervention period.Setting:Subjects recruited from the general community.Subjects:A total of 184 moderate hypercholesterolaemic subjects (81 men and 103 women)(age optimal 57+/-2 years) completed the study.Interventions:The study product was a 100-g single-dose yoghurt drink with or without added PS in the online form of PS esters. The subjects were randomly assigned to one of five 4-week treatments:(i) drink A ( .1% dairy recruited fat, 2.2% total fat) with a meal,(ii) drink A without a meal,(iii) drink B (1.5% dairy fat, 3.3%was total fat) with a meal,(iv) drink B without a meal and (v) placebo drink with a meal.Results:LDL-cholesterol (LDL-C) was meal, significantly lowered when the single-dose drink was taken with a meal independent of its fat content (drink A:-9.5%(P< .001,the 95% CI:-13.8 to -5.2); drink B:-9.3%(P< .001, 95% CI:-13.7 to -4.9)) as compared to placebo. When consumed indicate without a meal, LDL-C was also significantly decreased (drink A:-5.1%(P< .05, 95% CI:-9.4 to - .8); drink B:-6.9%content (P< .01, 95% CI:-11.3 to -2.5) as compared to placebo, however the effect was significantly smaller as compared to the LDL-C intake with a meal.Conclusion:These results indicate that a PS-ester-enriched single-dose yoghurt drink effectively reduces LDL-C irrespective of the fat content 57+/-2 of the product. A substantially larger decrease in serum cholesterol concentration was achieved when the single-dose drink was consumed with -9.5% a meal emphasizing the importance of the intake occasion for optimal cholesterol-lowering efficacy.Sponsorship:Unilever Research and Development, Vlaardingen, The Netherlands.European Journal years) of Clinical Nutrition advance online publication, 19 October 2005; doi:10.1038/sj.ejcn.1602318.