Post-exercise whey protein hydrolysate supplementation induces a greater increase in muscle protein synthesis than its constituent amino acid content.

It is well known that ingestion of a protein source is effective in stimulating muscle protein synthesis after exercise. In addition, there are numerous reports on the impact of leucine and leucine-rich whey protein on muscle protein synthesis and mammalian target of rapamycin (mTOR) signalling. However, there is only limited information on the effects of whey protein hydrolysates (WPH) on muscle protein synthesis and mTOR signalling. The aim of the present study was to compare the effects of WPH and amino acids on muscle protein synthesis and the initiation of translation in skeletal muscle during the post-exercise phase. Male Sprague­Dawley rats swam for 2 h to depress muscle protein synthesis. Immediately after exercise, the animals were administered either carbohydrate (CHO), CHO plus an amino acid mixture (AA) or CHO plus WPH. At 1 h after exercise, the supplements containing whey-based protein (AA and WPH) caused a significant increase in the fractional rate of protein synthesis (FSR) compared with CHO. WPH also caused a significant increase in FSR compared with AA. Post-exercise ingestion of WPH caused a significant increase in the phosphorylation of mTOR levels compared with AA or CHO. In addition, WPH caused greater phosphorylation of ribosomal protein S6 kinase and eukaryotic initiation factor 4E-binding protein 1 than AA and CHO. In contrast, there was no difference in plasma amino acid levels following supplementation with either AA or WPH. These results indicate that WPH may include active components that are superior to amino acids for stimulating muscle protein synthesis and initiating translation.

Dietary whey protein hydrolysates increase skeletal muscle glycogen levels via activation of glycogen synthase in mice.

Previously, we have shown that consuming carbohydrate plus whey protein hydrolysates (WPHs) replenished muscle glycogen after exercise more effectively than consuming intact whey protein or branched-chain amino acids (BCAAs). The mechanism leading to superior glycogen replenishment after consuming WPH is unclear. In this 5 week intervention, ddY mice were fed experimental diets containing WPH, a mixture of whey amino acids (WAAs), or casein (control). After the intervention, gastrocnemius muscle glycogen levels were significantly higher in the WPH group (4.35 mg/g) than in the WAA (3.15 mg/g) or control (2.51 mg/g) groups. In addition, total glycogen synthase (GS) protein levels were significantly higher in the WPH group (153%) than in the WAA (89.2%) or control groups, and phosphorylated GS levels were significantly decreased in the WPH group (51.4%). These results indicate that dietary WPH may increase the muscle glycogen content through increased GS activity.

Comparison of fructooligosaccharide utilization by Lactobacillus and Bacteroides species.

The utilization of 1-kestose (GF(2)) and nystose (GF(3)), the main components of fructooligosaccharides (FOS), by Lactobacillus and Bacteroides species was examined. Of seven Lactobacillus and five Bacteroides strains that utilized FOS, L. salivarius, L. rhamnosus, L. casei, and L. gasseri utilized only GF(2), whereas L. acidophilus and all the Bacteroides strains utilized both GF(2) and GF(3). Only the strains able to utilize both GF(2) and GF(3) had ß-fructosidase activity in the culture supernatants. The culture supernatants of the Lactobacillus strains had higher ß-fructosidase activity for GF(2) than for GF(3), whereas those of the Bacteroides strains had higher activity for GF(3) than for GF(2). Furthermore, ß-fructosidase activity of the culture supernatants of the Lactobacillus cells grown in the GF(3) medium was much higher than that of the cells grown in the GF(2) medium, whereas the activity of the culture supernatants of the Bacteroides cells grown in the GF(3) medium was almost the same as that of the cells grown in the GF(2) medium. These results indicate that Lactobacillus species metabolize FOS in a different way from that of Bacteroides species.

A new glycosylated dihydrophaseic acid from cacao germs (Theobroma cacao L.).

Cacao beans are composed of cacao nibs and germs. Although numerous chemical and physiological studies on cacao nib compounds have been reported, there is little information on cacao germ compounds. We therefore analyzed an extract from the cacao germ, and found two compounds that were specific to the germ. One of these two compounds was identified as the new glycosylated abscisic acid metabolite, dihydrophaseic acid-4'-O-6″-(ß-ribofuranosyl)-ß-glucopyranoside, and the other as the known compound, dihydrophaseic acid-4'-O-ß-D-glucopyranoside.

Dietary whey hydrolysate with exercise alters the plasma protein profile: a comprehensive protein analysis.

OBJECTIVE: It has been shown that dietary whey protein accelerates glucose uptake by altering glycoregulatory enzyme activity in skeletal muscle. In the present study, we investigated the effect of dietary whey protein on endurance and glycogen resynthesis and attempted to identify plasma proteins that reflected the physical condition by a comprehensive proteomics approach. METHODS: Male c57BL/6 mice were divided into four groups: sedentary, sedentary with whey protein hydrolysate, exercise, and exercise with whey protein hydrolysate. The mice in the exercise groups performed treadmill running exercise five times per week for 4 wk. Protein profiling of plasma sample obtained from individuals was performed, as were measurements of endurance performance and the glycogen content of gastrocnemius muscle. RESULTS: After the training period, the endurance of mice fed the whey diet was improved compared with that of mice fed the control diet. Muscle glycogen content was significantly increased after 4 wk of exercise, and intake of whey protein led to a further increase in glycogen. Apolipoproteins A-II and C-I and ß(2)-glycoprotein-1 were found to be altered by training combined with the intake of whey protein, without significant changes induced by exercise or whey protein alone. CONCLUSION: Results of the present study suggest that these three proteins may be potential biomarkers of improved endurance and glycogen resynthesis and part of the mechanism that mediates the benefits of whey protein.

Comparison of different sources and degrees of hydrolysis of dietary protein: effect on plasma amino acids, dipeptides, and insulin responses in human subjects.

The effect of protein fractionation on the bioavailability of amino acids and peptides and insulin response and whether the protein source influences these effects in humans are poorly understood. This study compared the effects of different sources and degrees of hydrolysis of dietary protein, independent of carbohydrate, on plasma amino acid and dipeptide levels and insulin responses in humans. Ten subjects were enrolled in the study, with five subjects participating in trials on either soy or whey protein and their hydrolysates. Protein hydrolysates were absorbed more rapidly as plasma amino acids compared to nonhydrolyzed protein. Whey protein also caused more rapid increases in indispensable amino acid and branched-chain amino acid concentrations than soy protein. In addition, protein hydrolysates caused significant increases in Val-Leu and Ile-Leu concentrations compared to nonhydrolyzed protein. Whey protein hydrolysates also induced significantly greater stimulation of insulin release than the other proteins. Taken together, these results demonstrate whey protein hydrolysates cause significantly greater increases in the plasma concentrations of amino acids, dipeptides, and insulin.

Identification of marker genes for lipid-lowering effect of a short-chain fructooligosaccharide by DNA microarray analysis.

Administration of short-chain fructooligosaccharide (scFOS) is known to lower serum triglyceride levels in rats fed a high-fat diet, but the molecular mechanisms remain unclear. This study aimed to identify marker genes for lipid-lowering effect of scFOS administration. The changes in hepatic gene expressions in rats fed scFOS were investigated using DNA microarray and quantitative RT-PCR analysis. The DNA microarray showed that phytanoyl-CoA 2-hydroxylase 2 (Phyh2), lipoprotein lipase (Lpl) and tyrosine aminotransferase (Tat) were significantly affected by scFOS administration (p < .05). Since Lpl is involved in lipid metabolism, the up-regulation of Lpl in the liver can be a potential marker of the lipid-lowering effect of scFOS.

Cacao procyanidins reduce plasma cholesterol and increase fecal steroid excretion in rats fed a high-cholesterol diet.

Cocoa powder is rich in polyphenols, such as catechins and oligomeric procyanidins, and has a hypocholesterolemic effect in humans. This study evaluated the principal active components and potential mechanism(s) for the hypocholesterolemic effect of polyphenolic substances from cocoa powder in rats. Male Wistar rats were fed a 1% high-cholesterol diet (HC) or a high-cholesterol diet containing 1% polyphenol extract from cocoa powder (PE) or a mixture of 0.024% catechin and 0.058% epicatechin (CE) for 4 weeks. We also examined the effects of these polyphenolic substances on micellar cholesterol solubility in vitro. The PE group had significantly lower plasma cholesterol concentrations, and had significantly greater fecal cholesterol and total bile acids excretion than the HC group. The CE group diet did not influence plasma cholesterol concentrations, or fecal cholesterol or total bile acids excretion. Micellar solubility of cholesterol in vitro was significantly lower for procyanidin B2 (dimer), B5 (dimer), C1 (trimer) and A2 (tetramer), which are the main components of polyphenol extract from cocoa powder, compared to catechin and epicatechin. These results suggest that oligomeric procyanidins from cocoa powder are the principal active components responsible for the hypocholesterolemic effect, and inhibit the intestinal absorption of cholesterol and bile acids through the decrease in micellar cholesterol solubility.

Plasma LDL and HDL cholesterol and oxidized LDL concentrations are altered in normo- and hypercholesterolemic humans after intake of different levels of cocoa powder.

Cocoa powder is rich in polyphenols, such as catechins and procyanidins, and has been shown in a variety of subject models to inhibit oxidized LDL and atherogenesis. Our study evaluated plasma LDL cholesterol and oxidized LDL concentrations following the intake of different levels of cocoa powder (13, 19.5, and 26 g/d) in normocholesterolemic and mildly hypercholesterolemic humans. In this comparative, double-blind study, we examined 160 subjects who ingested either cocoa powder containing low-polyphenolic compounds (placebo-cocoa group) or 3 levels of cocoa powder containing high-polyphenolic compounds (13, 19.5, and 26 g/d for low-, middle-, and high-cocoa groups, respectively) for 4 wk. The test powders were consumed as a beverage after the addition of hot water, twice each day. Blood samples were collected at baseline and 4 wk after intake of the test beverages for the measurement of plasma lipids. Plasma oxidized LDL concentrations decreased in the low-, middle-, and high-cocoa groups compared with baseline. A stratified analysis was performed on 131 subjects who had a LDL cholesterol concentrations of > or =3.23 mmol/L at baseline. In these subjects, plasma LDL cholesterol, oxidized LDL, and apo B concentrations decreased, and the plasma HDL cholesterol concentration increased, relative to baseline in the low-, middle-, and high-cocoa groups. The results suggest that polyphenolic substances derived from cocoa powder may contribute to a reduction in LDL cholesterol, an elevation in HDL cholesterol, and the suppression of oxidized LDL.

Identification of marker genes for intestinal immunomodulating effect of a fructooligosaccharide by DNA microarray analysis.

Prebiotic fructooligosaccharides are noted for their intestinal immunodulating effects, and the identification of markers for the effects is a matter of great concern. This study aimed to identify marker genes for physiological effects of a particular fructooligosaccharide (FOS) on a host animal and also to define the target of its function in the small intestine. DNA microarray technology was used to screen candidate marker genes, and comprehensive changes in gene expressions in the ileum of mice fed with FOS were investigated. One of the major physiological effects of FOS was intestinal immunomodulation. Marker genes were then identified for major histocompatibility complex classes I and II, interferon, and phosphatidylinositol metabolites. Also, the ileum was segmented into Peyer's patch (PP) and the other ileal organ (DeltaPP), and these were analyzed by quantitative RT-PCR method, with the result that the site for recognizing the FOS function was the DeltaPP rather than the PP. This is the first paper showing the markers for the physiological effects of FOS in the small intestine at gene expression level. Applying these marker genes would make it possible to clarify the mechanisms of how the administration of dietary FOS and associated changes in the intestinal environment are recognized by host organisms as well as how its immunomodulating effects are expressed in the body.