Free and bound amino acids,minerals and trace elements in matcha (Camellia sinensis L.): A nutritional evaluation

This study provides an overview of free and bound amino acids, minerals and trace elements content in matcha including evaluation of their dietary intakes. The analyses employed IEC and ICP-MS methods. Theanine followed by Glu, GABA, Thr and Me were the most abundant free amino acids. Considering bound amino acids, Glu, Asp, Leu, Lys, Arg and Val were the most frequent. The amino acid score (AAS) for matcha (40.2 %) is comparable to the AAS for wheat and sunflower proteins. Ile and Thr were evaluated as limiting amino acids. Regarding recommended daily allowance (RDA), the contributions of Cys and Met were up to 8%. Matcha is contributor to Adequate Intake (AI) or RDA for males in the following order: Mn (up to 15 %) > Cu > Fe (up to 7%). Similarly, for females, matcha contributes to RDA or AI values in this order: Mn (up to 19 %) > Cu > Zn (up to 5%). It has not been proved that matcha is a significant source of Se and Cr. A daily serving portion of 5 g does not contribute to PTWI (Provisional tolerable weekly intake) and PTMI (Provisional tolerable monthly intake) for Al, Sn, Cd and Hg.     

Whey protein hydrolysate and branched-chain amino acids downregulate inflammation-related genes in vascular endothelial cells

A recent review of clinical studies reports that dairy products may improve inflammation, a key etiologic cardiovascular disease risk factor. Yet the impact of dairy proteins on inflammatory markers is controversial and could be mediated by a differential impact of whey proteins and caseins. In this study, we hypothesized that whey proteins may have a greater anti-inflammatory effect than caseins. A model of human umbilical vein endothelial cells, with or without TNF-α stimulation, was used to investigate the effect of several dairy protein compounds on inflammation. Specifically, the impact of whey proteins either isolate or hydrolysate, caseins, and their amino acids on expression of TNF, VCAM-1, SOD2, and eNOS was examined. After a 24-hour incubation period, whey protein hydrolysate, leucine, isoleucine, and valine attenuated the TNF-α–induced endothelial inflammation by normalizing TNF and eNOS gene expression. This effect was not observed in unstimulated cells. Oppositely, caseins, a whey protein/casein mixture (1:4 w/w), and glutamine aggravated the TNF-α–induced TNF and SOD2 gene expression. Yet caseins and whey protein/casein mixture decreased VCAM-1 expression in both unstimulated and stimulated human umbilical vein endothelial cells. Measurement of TNF-α in cell supernatants by immunoassay substantiates gene expression data without reaching statistical significance. Taken together, this study showed that whey proteins and their major amino acids normalize TNF-α–induced proinflammatory gene expression in endothelial cells.     

Role of selected amino acids on plasma IGF-I concentration in infants

Purpose

Insulin-like growth factor-I (IGF-I) is related to growth and its secretion is modified by protein intake in early infancy. We examined the relationship of dietary protein and circulating amino acids on plasma IGF-I levels and early growth.

Methods

Healthy formula-fed infants (n = 213) were randomly assigned to receive either a protein-reduced infant formula with alpha-lactalbumin-enriched whey and free tryptophan and phenylalanine (IF) or an isocaloric standard formula without free amino acids (CF) for the first 120 days of life. A group of breastfed (BF) infants was studied as a non-randomized reference cohort. Biochemical variables were measured shortly after birth (subpopulation) and at an age of 120 days. A path analysis was used to explore the relationship between IGF-I, insulin and amino acids. Results are derived from secondary analyses of a randomized controlled trial.

Results

Plasma concentrations of IGF-I at 120 days were significantly higher in IF than in CF infants [58.5 (15.0) vs. 53.7 (9.95) ng/mL; p = 0.020]. BF infants showed lower IGF-I concentrations of 41.6 (10.7) ng/mL. All amino acids but Thr and Cit had a more marked effect on insulin than on IGF-I level. Considering weight, sex and feeding group, Trp explained an equal percentage of variance of IGF-I and insulin (total R ² 12.5 % of IGF-I and 12.3 % of insulin), while branched-chain AA explained an up to twofold higher variance of insulin than IGF-I. Compared to CF, IF explained 18.9 % of the IGF-I level (p = 0.03), while for insulin no direct effect was detectable.

Conclusion

Higher IGF-I concentrations and growth velocities in infants receiving protein-reduced IF indicate that the protein concentration of an infant formula alone does not control IGF-I levels and growth. Other components (e.g., selected amino acids) of infant formulae might control directly or indirectly via insulin influence IGF-I.

     

Effect of intravenous amino acids on protein kinetics in preterm infants

PURPOSE OF REVIEW: To summarize recent findings of the effects of intravenous amino acids on protein kinetics in low-birth-weight infants and to describe the potential cellular mechanism for these observations. RECENT FINDINGS: Amino acids administered intravenously for 3-5 h in infants have been shown to suppress whole-body proteolysis. Recent data in low-birth-weight infants show that an increase in the dose of amino acid caused a suppression of proteolysis, and a decrease in the rate of glutamine and urea synthesis. These responses returned to basal state, however, when the amino acid infusion continued for 20-24 h. Supplementation with glutamine sustained the suppression of proteolysis after 3-5 days. Plasma insulin concentration did not change during the amino acid infusion. Data from studies in adults and from in vitro studies suggest that the amino acids impact protein breakdown and synthesis via the mammalian target of rapamycin pathway, stimulating initiation of translation and suppressing autophagic proteolysis. SUMMARY: Intravenous amino acids, by increasing extracellular amino acid concentration, transiently stimulate protein synthesis and suppress protein breakdown. These effects return to basal state when the amino acid infusions are prolonged. The mechanism of this adaptive response remains to be determined.     

Ingestion of protein hydrolysate and amino acid-carbohydrate mixtures increases postexercise plasma insulin responses in men

To optimize the postexercise insulin response and to increase plasma amino acid availability, we studied postexercise insulin levels after the ingestion of carbohydrate and wheat protein hydrolysate with and without free leucine and phenylalanine. After an overnight fast, eight male cyclists visited our laboratory on five occasions, during which a control drink and two different beverage compositions in two different doses were tested. After they performed a glycogen-depletion protocol, subjects received a beverage (3.5 mL. kg(-1)) every 30 min to ensure an intake of 1.2 g. kg(-1). h(-1) carbohydrate and 0, 0.2 or 0.4 g. kg(-1). h(-1) protein hydrolysate (and amino acid) mixture. After the insulin response was expressed as the area under the curve, only the ingestion of the beverages containing wheat protein hydrolysate, leucine and phenylalanine resulted in a marked increase in insulin response (+52 and + 107% for the 0.2 and 0.4 g. kg(-1). h(-1) mixtures, respectively; P: < 0. 05) compared with the carbohydrate-only trial). A dose-related effect existed because doubling the dose (0.2-0.4 g. kg(-1). h(-1)) led to an additional rise in insulin response (P: < 0.05). Plasma leucine, phenylalanine and tyrosine concentrations showed strong correlations with the insulin response (P: < 0.0001). This study provides a practical tool to markedly elevate insulin levels and plasma amino acid availability through dietary manipulation, which may be of great value in clinical nutrition, (recovery) sports drinks and metabolic research.     

Nutritional and technological evaluation of an enzymatically methionine-enriched soy protein for infant enteral formulas

Enzymatically modified soy proteins have the amino acid profile and functional properties required for dietary support. The objective of this study was to evaluate the nutritional and technological properties of an enzymatically modified soy protein ultrafiltered fraction with bound methionine (F(1-10)E) to be used as a protein ingredient for infant enteral formulas. F(1-10)E was chemically characterized and biologically evaluated. Thirty-six weaning Wistar rats were fed during 3 weeks with a 4% casein-containing diet. Rats were divided into three groups and recovered for 3 weeks with 18% protein-containing diets based on: (1) F(1-10)E, (2) casein or (3) soy isolate+methionine. Nutritional indicators were weight gain, protein efficiency ratio, plasma proteins, apparent digestibility and protein in the carcass. Additionally, F(1-10)E was added as a protein ingredient of an enteral formula, and its sensory and rheological properties were compared with a hydrolyzed-whey protein commercial formula. F(1-10)E contained 68% protein and 5% sulphur amino acids, with 60% of peptides 0.05) in weight gain (108 g and 118 g, respectively), protein efficiency ratio (2.7), apparent digestibility (93% and 95%), plasma proteins (5.7 mg/100 ml) and carcass protein (61%), and better than soy isolate-based+methionine diet (P<0.05). Viscosity of the commercial formula and our formula was similar during a 24-h period. Sensory acceptability was 8 for our formula and 3.5 for the commercial one, on a scale of 1-10 (P<0.05). Due to its nutritional, sensorial and rheological properties, F(1-10)E could be used as a protein source in infant enteral formulas.     

Free amino acids in preterm and term milk from mothers delivering appropriate- or small-for-gestational-age infants

Free amino acids were quantitated in human milk collected during the first month postpartum from mothers of appropriate preterm (26-32 and 33-36 wk gestation) and term (small or appropriate-for-gestational-age) infants. Glutamic acid and taurine were the most abundant amino acids in all four groups at all stages of lactation. The ratio of essential to nonessential amino acids was higher in colostrum than in mature milk although the total amino acid level of mature milk was double that of the colostrum. Nonprotein amino acids amount to approximately 40% of the free-amino acid pool in colostrum. Differences in the content and changes in free-amino acid levels during lactation among the groups were observed.     

Influences of protein malnutrition on amino acid composition, trace metal elements and tensile strength of rat hairs

We examined hair properties from determinations of diameter, amino acid composition, trace metal elements, and tensile strength of the hairs from protein-malnourished rats. The coarse or medium hair diameters of the experimental protein-malnourished rats had a tendency to decrease more than those of the control. Total contents of amino acids in the hairs had a tendency to decrease in the protein-deficient rats. Cystine content of rat hairs definitely decreased only in 5% wheat- and 5% rice-pattern amino acid mixture diet groups but not in 5% gluten diet and 5% casein diet groups. And many of the low-protein diet groups were significantly lower in methionine content than the control except for the 5% casein diet group. The Mg, Zn, and Fe contents in the hairs considerably increased in protein-deficient rats against the control. Tensile strength of coarse hairs in the experimental protein-malnourished rats was significantly lower than that of the control. The changes in amino acid composition of rat hair proteins are more likely to be influenced by various qualities of dietary protein or different compositions of amino acid mixtures in the diets at a similar dietary protein level. It should seriously be considered from our data whether the reduced cystine content in the hair can be regarded as an indicator of nutritional status.     

Effects of a parenteral nutrition regimen containing dicarboxylic amino acids on plasma, erythrocyte, and urinary amino acid concentrations of young infants

Plasma, erythrocyte, and urinary amino acid concentrations were measured in young infants infused with a solution containing glutamate and aspartate. Eight infants (1.2 to 2.8 kg) were fed parenterally (80 kcal/kg/day) with two regimens containing dextrose (15 g/kg/day), amino acids (2 g/kg/day), and lipid (2 g/kg/day) for successive 3-day periods in a cross-over design. The regimens differed only in the amino acid source. One regimen (I) provided glutamate (1.5 mmol/kg/day) and aspartate (1.0 mmol/kg/day), while the other regimen (II) did not. The mean (+/- SD) plasma glutamate concentration was slightly, but significantly higher (89.9 +/- 28.5 microM) during infusion of regimen I than regimen II (66.5 +/- 19.8 microM), but values did not differ significantly from values observed in normal, orally fed premature infants (107 +/- 36 microM). No significant differences were noted in either plasma or erythrocyte aspartate concentrations, or in erythrocyte glutamate concentration. Since plasma and erythrocyte levels of dicarboxylic amino acids remained within the normal range, the data indicate no hazard to young infants from infusion of dicarboxylic amino acids at this level.     

Diurnal variations in plasma concentrations of tryptophan, tryosine, and other neutral amino acids: effect of dietary protein intake

The effect of dietary protein content on the diurnal variations in plasma neutral amino acid levels was studied in normal human subjects. For three consecutive 5-day periods, subjects consumed diets containing 0, 75, or 150 g of egg protein per day. Blood samples were drawn at 4-hr intervals on the 4th and 5th days of each period. Consumption of the protein-free diet caused plasma concentrations of all amino acids studied to fall in the late morning and afternoon, while the 150-g protein diet elicited increases in these levels during the daytime. Ingestion of the diet containing 75 g of egg protein tended to diminish the amplitudes of the daily rhythms in plasma amino acid levels, but most amino acids still exhibited small but significant elevations late in the evening. At all times of day, plasma concentrations of the large neutral amino acids studied (i.e., aromatic and branched-chain amino acids, and methionine) varied directly with the protein content of the diet. In contrast, the relationships between dietary protein content and the plasma concentrations of glycine and alanine, two small neutral amino acids, were inverse. The ratios of plasma tryptophan, tyrosine, and phenylalanine levels to the sum of the concentrations of other large neutral amino acids tended to fall as the protein content of the diet was increased. The corresponding ratio for valine increased as protein was added to the diet, while the leucine and isoleucine ratios were not correlated with dietary protein content. Since diet-induced changes in plasma trypotphan and tyrosine ratios in animals are known to cause parallel alterations in brain tryptophan and tyrosine levels, and thus in the rates of brain serotonin and catecholamine synthesis, our data suggest that ingestion of carbohydrates and protein may also normally affected brain monoamine synthesis in humans.     

Nutritional availability of amino acids from protein cross-linked to protect against degradation in the rumen

Casein was labelled with pairs of radioactive amino acids, lysine, tyrosine and leucine, one with 14C and the other with 3H, by jugular infusion into lactating goats followed by isolation of the double-labelled casein from the milk. Total milk protein was similarly labelled by jugular infusion of [35S]cystine. U-14C-labelled fraction-1 leaf protein was isolated from lucerne (Medicago sativa) grown in an atmosphere of 14CO2. The proteins were treated with different levels (333 and 667 mmol/kg protein) of formaldehyde, glutaraldehyde and glyoxal. Absorption from the small intestine was measured in sheep with fistulas in the abomasum and terminal ileum, using Cr-EDTA as the digesta flow marker, by introducing radioactive casein into the abomasum. Lysine, tyrosine and cystine became increasingly unavailable for absorption from the small intestine of sheep with increasing levels of aldehyde. At the lower level (333 mmol/kg) the proportions of the amino acids that were unavailable were 0.192, 0.051 and 0.123 respectively. At the higher level of formaldehyde (667 mmol/kg) the corresponding values were 0.335, 0.201 and 0.432 respectively. Leucine was not made unavailable with formaldehyde. The proportions of lysine, tyrosine and leucine that were unavailable were higher, on a molar basis, after treatment of the proteins with the dialdehydes glutaraldehyde and glyoxal than after treatment with formaldehyde. However, the extent of protein protection provided by the dialdehydes in the rumen, measured using an in vitro procedure, was lower.     

Nutritional modulation of liver regeneration by carbohydrates, lipids, and amino acids: a review.

The survival of patients after a life-threatening hepatic injury of varying etiology depends on the ability of the remaining hepatocytes to regenerate. Thus, the stimulation of hepatic regeneration can have tremendous therapeutic relevance. Experimental studies--performed mostly on a model of regenerating rat liver after partial hepatectomy--indicate that glucose administration inhibits, whereas infusion of a lipid emulsion can enhance, the rate of liver regeneration. However, the inhibitory effect of glucose on liver regeneration is not observed when glucose is administered together with other nutrients. The results further indicate that administration of a standard amino acid mixture without energy substrate has an inhibitory effect and that development of liver regeneration can be favorably influenced by branched-chain amino acids (valine, leucine, and isoleucine) and glutamine.     

Dietary disproportions of amino acids in the rat: effects on food intake, plasma and brain amino acids and brain serotonin.

Food intake, growth, plasma and brain amino acid, and brain serotonin and 5-hydroxyindole-3-acetic acid (5-HIAA) concentrations were measured in rats fed low protein diets containing disproportionate amounts of large neutral amino acids (LNAA) devoid of tryptophan or histidine (tryptophan or histidine imbalance). Five-day food intakes and weight gains of rats fed the imbalanced diets were depressed. The concentration of the limiting amino acid was low in brains of rats fed diets containing LNAA that compete with either tryptophan or histidine for entry into brain. Correlations were observed between the brain concentrations of most individual LNAA and either the ratios of the plasma concentration of that LNAA to the sum of the other LNAA, or the predicted rates of influx of that LNAA. Cumulative food intakes were correlated with brain concentrations of the limiting amino acid, tryptophan or histidine. Food intakes were not consistently correlated with concentrations of serotonin and 5-HIAA because these compounds were altered only in brains of rats in the tryptophan study. Competition among amino acids for uptake into brain appears to be involved in the feeding response of the rat to dietary disproportions of amino acids, but this response is not directly related to changes in brain concentrations of serotonin and 5-HIAA.     

婴幼儿微量元素与体格发育的相关分析

【目的】 了解婴幼儿微量元素与体格发育的相关性和造成营养不良的危险因素,为制定干预措施提供依据。 【方法】 抽取868例0~2岁婴幼儿血锌、铜、钙、铁、镁、铅检测结果与体格发育测量结果进行比较研究。 【结果】 锌、铁、钙缺乏症和高血铅症患儿生长迟缓的发生率均高于正常婴幼儿,发病风险分别为正常儿童的4.04、3.20、2.61、3.00倍(P均<0.05)。锌、铁、钙缺乏症和铅中毒症患儿低体重的发生率均高于正常婴幼儿,发病风险分别为正常儿童的2.49、4.52、2.46、1.63倍(P均<0.05)。锌、铁、钙缺乏症和铅中毒症患儿营养不良的发生率均高于正常婴幼儿,发病风险分别为正常婴幼儿的5.02、3.67、2.29、3.82倍(P均<0.05)。 【结论】 婴幼儿体格发育与微量元素锌、铁、钙、铅水平有密切相关。     

Dose-ranging effects of citrulline administration on plasma amino acids and hormonal patterns in healthy subjects: the Citrudose pharmacokinetic study

Previous experimental studies have highlighted that citrulline (CIT) could be a promising pharmaconutrient. However, its pharmacokinetic characteristics and tolerance to loading have not been studied to date. The objective was to characterise the plasma kinetics of CIT in a multiple-dosing study design and to assess the effect of CIT intake on the concentrations of other plasma amino acids (AA). The effects of CIT loading on anabolic hormones were also determined. Eight fasting healthy males underwent four separate oral loading tests (2, 5, 10 or 15 g CIT) in random order. Blood was drawn ten times over an 8 h period for measurement of plasma AA, insulin and growth hormone (Gh). Urine samples were collected before CIT administration and over the next 24 h. None of the subjects experienced side effects whatever the CIT dose. Concerning AA, only CIT, ornithine (ORN) and arginine (ARG) plasma concentrations were affected (maximum concentration 146 (sem 8) to 303 (sem 11) micromol/l (ARG) and 81 (sem 4) to 179 (sem 10) micromol/l (ORN); time to reach maximum concentration 1.17 (sem 0.26) to 2.29 (sem 0.20) h (ARG) and 1.38 (sem 0.25) to 1.79 (sem 0.11) h (ORN) according to CIT dose). Even at high doses, urinary excretion of CIT remained low ( < 5 %). Plasma insulin and Gh were not affected by CIT administration. Short-term CIT administration is safe and well-tolerated. CIT is a potent precursor of ARG. However, at the highest doses, CIT accumulated in plasma while plasma ARG levels increased less than expected. This may be due to saturation of the renal conversion of CIT into ARG.