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1.
The aim of this study was to determine the pharmacokinetics and urinary excretion patterns of the soy isoflavones daidzein and genistein in humans. Six healthy men with a mean age of 37 y and a mean body mass index (in kg/m2) of 24 consumed a soybean flour-based meal on two occasions approximately 6 d apart. Blood samples and total urine were collected at intervals for the measurement of daidzein and genistein with HPLC. Isoflavone concentrations rose slowly and reached maximum values of 3.14 +/- 0.36 micromol/L at 7.42 +/- 0.74 h for daidzein and 4.09 +/- 0.94 micromol/L at 8.42 +/- 0.69 h for genistein. Elimination half-lives were 4.7 +/- 1.1 and 5.7 +/- 1.3 h for daidzein and genistein, respectively. The slow increase in plasma concentrations is consistent with the facilitation of absorption by hydrolysis in the small and large intestines of the glycosidic forms of the isoflavones present in soybean-containing foods to their corresponding aglycones. The rate of urinary excretion of daidzein was greater than that of genistein throughout the postmeal period, with mean recoveries of 62 +/- 6% and 22 +/- 4% (P < 0.001) for daidzein and genistein, respectively. However, the ratio of the areas under the plasma concentration versus time curves for genistein and daidzein was equal to the ratio of the concentrations of the respective isoflavones in the soy meal. It is concluded that the bioavailabilities of daidzein and genistein are similar, not withstanding the difference in urinary excretion.  相似文献   

2.
The isoflavones daidzein [1] and genistein [2] were fermented with human fecal bacteria under anaerobic conditions. Dihydrodaidzein [3], benzopyran-4,7-diol,3-(4-hydroxyphenyl) [4], and equol [5] were isolated from the fermentation broth of 1. Only one metabolite, dihydrogenistein [6], was isolated and characterized from the fermentation broth of 2. Metabolites 3-6 were identified by spectral methods.  相似文献   

3.
Isoflavones are present in soybeans and its products in concentrations up to 300 mg/100 g, have estrogenic and antiestrogenic properties, and may be protective against hormone-related cancers. The purpose of this cross-sectional study was to investigate the association between urinary isoflavone excretion and self-reported soy intake. A total of 102 women of Caucasian, Native Hawaiian, Chinese, Japanese, and Filipino ancestry completed a dietary questionnaire for soy products consumed during the last year and during the 24-h period before urine collection. Overnight urine samples were analyzed for coumestrol and the soy isoflavones genistein, daidzein, and glycitein and their main human metabolites by reverse-phase high-pressure liquid chromatography. Soy protein and isoflavone intake (predominantly from tofu) were estimated using published nutritional databases. Wilcoxon's rank-sum test scores and Spearman rank correlation coefficients were computed. Japanese women excreted more daidzein, genistein, and glycitein than did Caucasian women, whereas Caucasian women excreted slightly more coumestrol. Soy intake differed significantly among ethnic groups. Dietary soy protein and isoflavone intakes during the previous 24 h were positively related to urinary isoflavone excretion [rs = 0.61 (P < 0.0001) and 0.62 (P < 0.0001), respectively]. Urinary excretion of isoflavones was also related to annual dietary soy protein and isoflavone intake [rs = 0.32 (P < 0.0012) and 0.31 (P < 0.0016), respectively]. The strong correlation between urinary isoflavone excretion and self-reported soy intake validates the dietary history questionnaire that is now used in a study exploring dietary risk factors for breast cancer.  相似文献   

4.
Soy protein, isoflavones and cardiovascular disease risk   总被引:1,自引:0,他引:1  
Since the early 1940s, scientists have examined the effect of soy protein on blood cholesterol concentrations. Although studies in animals have suggested that soy protein lowers blood cholesterol concentrations, similar studies in humans have yielded less consistent results. The presence or absence of the soybean isoflavone fraction may be a confounding factor. This fraction, consisting primarily of genistein, daidzein and glycetein, has been shown to have a hypocholesterolemic effect in animals and humans. Potential mechanisms by which soy protein and/or isoflavones induce lowering of blood cholesterol concentrations include thyroid status, bile acid balance and the estrogenic effects of genistein and daidzein. Some studies have suggested that isoflavones exhibit antioxidant properties and have favorable effects on arterial compliance. In addition to the aforementioned potential beneficial effects, the increased consumption of products containing soy protein may displace foods relatively high in saturated fat and cholesterol from the diet and hence have an indirect blood cholesterol-lowering effect.  相似文献   

5.
6.
We report a novel method for the measurement of urinary daidzein that is suitable for assessment of dietary soya exposure. The method incorporates the following features: (i) a highly specific monoclonal antibody to daidzein (clone 4E4) raised through the 7 position of daidzein and (ii) a europium labeled ovalbumin daidzein conjugate. In the present format, dilute urine samples of subjects who ingested soy milk are hydrolyzed with beta-glucuronidase for 30 min on rabbit anti-mouse coated plates. Afterwards, the specific monoclonal antibody to daidzein, clone 4E4, and europium labeled ovalbumin daidzein conjugate are added. After 1 h incubation, the wall bound fluorescence of europium is measured by time resolved fluorescence and is inversely proportional to the concentration of daidzein over the range 0.1-10 ng daidzein/well. The method demonstrates good sensitivity, precision and comparability with the chemical method GC-FID. Unlike the chemical method, the present immunoassay technique for daidzein is applicable for the measurement of large amounts of samples in epidemiological studies for the assessment and monitoring of human exposure to soya food.  相似文献   

7.
OBJECTIVE: To determine the effect of oral magnesium hydroxide [Mg(OH)2] on iron absorption after simulated iron overdose in human subjects. METHODS: A randomized, controlled crossover study was conducted in healthy adult male human volunteers taking no medications. Subjects received an average of 5.0 mg/kg elemental iron orally followed 1 hour later by either oral administration of 4.5 g of Mg(OH)2 per g ingested elemental iron or no treatment. Serial serum specimens were obtained over the 12 hours following iron ingestion and stored at -60 degrees C until standard serum iron assay was performed. After a 2-week washout period, the subjects were enrolled in the alternative trial arm. Individual baseline diurnal variation in serum iron levels was determined over a 12-hour period on the day prior to each trial. Area under time-concentration curves (AUCs) were calculated, and the AUC due to experimental iron ingestion (deltaAUC) was determined by subtracting the baseline diurnal AUC from the experimental AUC for each subject. RESULTS: Thirteen healthy adult male subjects were enrolled. Mean +/- SEM for deltaAUC due to experimental iron ingestion followed by treatment with Mg(OH)2, 78 +/- 23 micromol(hr)/L, was significantly less than that followed by no treatment, 144 +/- 33 micromol(hr)/L (p = 0.03 by signed rank test). CONCLUSIONS: Magnesium hydroxide, administered 1 hour post-iron ingestion at an oral dose of 4.5 g per g elemental iron ingested, significantly reduced iron absorption during a 12-hour period following simulated mild iron overdose in healthy adult human volunteers.  相似文献   

8.
The soybean has been implicated in diet-induced goiter by many studies. The extensive consumption of soy products in infant formulas and in vegetarian diets makes it essential to define the goitrogenic potential. In this report, it was observed that an acidic methanolic extract of soybeans contains compounds that inhibit thyroid peroxidase- (TPO) catalyzed reactions essential to thyroid hormone synthesis. Analysis of the soybean extract using HPLC, UV-VIS spectrophotometry, and LC-MS led to identification of the isoflavones genistein and daidzein as major components by direct comparison with authentic standard reference isoflavones. HPLC fractionation and enzymatic assay of the soybean extract showed that the components responsible for inhibition of TPO-catalyzed reactions coeluted with daidzein and genistein. In the presence of iodide ion, genistein and daidzein blocked TPO-catalyzed tyrosine iodination by acting as alternate substrates, yielding mono-, di-, and triiodoisoflavones. Genistein also inhibited thyroxine synthesis using iodinated casein or human goiter thyroglobulin as substrates for the coupling reaction. Incubation of either isoflavone with TPO in the presence of H2O2 caused irreversible inactivation of the enzyme; however, the presence of iodide ion in the incubations completely abolished the inactivation. The IC50 values for inhibition of TPO-catalyzed reactions by genistein and daidzein were ca. 1-10 microM, concentrations that approach the total isoflavone levels (ca. 1 microM) previously measured in plasma from humans consuming soy products. Because inhibition of thyroid hormone synthesis can induce goiter and thyroid neoplasia in rodents, delineation of anti-thyroid mechanisms for soy isoflavones may be important for extrapolating goitrogenic hazards identified in chronic rodent bioassays to humans consuming soy products.  相似文献   

9.
This study compared the physiological responses and performance following the ingestion of a waxy starch (WS), resistant starch (RS), glucose (GL) and an artificially-sweetened placebo (PL) ingested prior to exercise. Ten college-age, male competitive cyclists completed four experimental protocols consisting of a 30 min isokinetic, self-paced performance ride preceded by 90 min of constant load cycling at 66% VO2max. Thirty min prior to exercise, they ingested 1 g.kg-1 body weight of GL, WS, RS, or PL At rest, GL elicited greater (p < 0.05) serum glucose and insulin responses than all other trials. During exercise, however, serum glucose, insulin, blood C-peptide and glucagon responses were similar among trials. The mean total carbohydrate oxidation rates (CHOox) were higher (p < 0.05) during the GL, WS, and RS trials (2.59 +/- 0.13, 2.49 +/- 0.10, and 2.71 +/- 0.15 g.min-1, respectively) compared to PL (2.35 +/- 0.12 g.min-1). Subjects were able to complete more work (p < 0.05) during the performance ride when they ingested GL (434 +/- 25.2 kj) or WS (428 +/- 22.5 kj) compared to PL (403 +/- 35.1 kj). They also tended to produce more work with RS ingestion (418 +/- 31.4 kj), although this did not reach statistical significance (p < 0.09). These results indicate that preexercise CHO ingestion in the form of starch or glucose maintained higher rates of total carbohydrate oxidation during exercise and provided an ergogenic benefit during self-paced cycling.  相似文献   

10.
The aim of this study was to investigate the effect of medium-chain triacylglycerol (MCT) ingestion during exercise on subsequent time-trial cycling performance. Seven well-trained cyclists performed four exercise trials consisting of 2 h at 60% of maximal oxygen uptake followed by a simulated time trial (ie, completion of a preset amount of work as fast as possible) of approximately 15 min duration. During the trials, subjects ingested 1) a 10% carbohydrate solution (CHO; 170 +/- 6 g glucose), 2) a 10% carbohydrate electrolyte with 5% MCT solution (CHO + MCT; 85 +/- 3 g MCT), 3) a 5% MCT solution, or 4) artificially colored and flavored water (placebo). Neither CHO nor CHO + MCT ingestion had any effect on performance compared with placebo ingestion, whereas ingestion of MCT had a negative effect on performance. Average work rates during the time trial were 314 +/- 19, 314 +/- 13, and 312 +/- 18 with CHO, CHO + MCT, and placebo, respectively, and was 17-18% lower in the MCT trial (263 +/- 22 W). In addition, compared with placebo ingestion, MCT ingestion had no effect on total rates of fat or carbohydrate oxidation, nor did it affect exogenous or endogenous carbohydrate utilization. The negative effect of MCT ingestion was associated with increased gastrointestinal complaints (ie, intestinal cramping). These data suggest that large amounts of MCTs (85 g) ingested during prolonged submaximal exercise may provoke gastrointestinal problems leading to decreased exercise performance.  相似文献   

11.
Lactose digestion improves when the energy content of a meal is raised, perhaps due to delayed gastric emptying; however, this has not been demonstrated directly. It is not known whether lactose-intolerant subjects should consume full-fat or high energy milk instead of half-skimmed milk. In this study, breath 13CO2 and hydrogen (H2) measurements were combined to assess simultaneously the effect of increasing milk energy content on gastric emptying, digestion, and tolerance of lactose. On two separate days, 11 adult lactose maldigesters ingested, in the fasting state, a single dose of 710 kJ half-skimmed milk or 1970 kJ high energy milk. Both contained 18 g lactose and were supplemented with 100 mg 13C-glycine for breath 13CO2 measurement. For 6 h after milk ingestion, samples of expired breath were collected, and subjects scored their symptoms on a four-grade questionnaire. Gastric emptying was measured from excretion of breath 13CO2. The mean gastric emptying half-time was significantly longer after ingestion of high energy milk than after half-skimmed milk (84 +/- 4 vs. 64 +/- 4 min, P = 0.004). The mean area under the breath H2 excretion curve measured for 6 h was 330 +/- 61 microL/L after subjects consumed high energy milk vs. 470 +/- 82 microL/L after they consumed half-skimmed milk (P = 0.07). Mean symptom scores did not differ after ingestion of the two milks, but only two subjects experienced disturbing symptoms after high energy milk ingestion compared with five subjects after ingestion of half-skimmed milk (P = 0.56). Although ingestion of high energy milk delayed the gastric emptying of lactose for significantly longer than the ingestion of half-skimmed milk (P < 0.01), it did not lead to significant improvement in symptoms and reflected only a trend toward improved lactose digestion (P = 0.07), as measured by the area under the breath H2 excretion curve. These results indicate that it is not beneficial for most lactose-intolerant subjects to replace consumption of half-skimmed milk by milk with a higher energy content.  相似文献   

12.
Five trained men were studied during 2 h of cycling exercise at 67% peak oxygen uptake at 20-22 degrees C to examine the effect of fluid ingestion on muscle metabolism. On one occasion, the subjects completed this exercise without fluid ingestion (NF) while on the other they ingested a volume of distilled deionized water that prevented loss of body mass (FR). No differences in oxygen uptake during exercise were observed between the two trials. Heart rate was lower (P < 0.01) throughout exercise when fluid was ingested, and rectal temperature after 2 h of exercise was lower (38.0 +/- 0.2 and 38.6 +/- 0.2 degrees C for FR and NF, respectively; P < 0.01), as was muscle (vastus lateralis) temperature (38.5 +/- 0.4 and 39.1 +/- 0.5 degrees C for FR and NF, respectively; P < 0.05). Resting muscle ATP, creatine phosphate, creatine, glycogen, and lactate levels were similar in the two trials, as were the postexercise ATP, creatine phosphate, and creatine levels. In contrast, muscle glycogen was higher (P < 0.05) and muscle lactate was lower (P < 0.05) after 2 h of exercise in FR compared with NF. Net muscle glycogen utilization during exercise was reduced by 16% when fluid was ingested (318 +/- 46 and 380 +/- 53 mmol/kg dry weight for FR and NF, respectively; P < 0.05). These results indicate that fluid ingestion reduces muscle glycogen use during prolonged exercise, which may account, in part, for the improved performance previously observed with fluid ingestion.  相似文献   

13.
OBJECTIVE: To compare the effect of vegetable, fruit, and legume consumption on urinary isoflavonoid phytoestrogen and lignan excretion. DESIGN: After 4 days of data collection, during which subjects consumed their habitual diets, subjects were randomly placed on four 9-day controlled experimental diets with each subject receiving each diet in a random order. SUBJECTS: Seven men and three women, aged 20 to 35 years, were recruited from the University of Minnesota Twin Cities community. INTERVENTIONS: All subjects consumed four experimental diets in an assigned random order: a controlled basal diet, a legume/allium diet (containing garbanzo beans, garlic, and onions), and diets low or high in vegetables and fruits (containing apples, pears, potatoes, and carrots). MAIN OUTCOME MEASURES: Urine samples that were collected while subjects consumed their habitual diets and during the last 3 days of each feeding period were analyzed for isoflavonoid and lignan content using isotope dilution gas chromatography-mass spectrometry. STATISTICAL ANALYSIS PERFORMED: The effect of vegetable and fruit intake on urinary isoflavonoid and lignan excretion was analyzed using the general linear model procedure. Post hoc comparisons were made using Duncan's multiple range test. RESULTS: Subjects excreted more of the lignan enterodiol on the high vegetable/fruit diet compared with the basal and legume/allium diets (P = .03); more of the isoflavonoids O-desmethylangolensin (O-DMA), genistein, and sum of isoflavonoids on the legume/allium diet compared with the other controlled diets (P < .05); and more of the isoflavan equol on the basal and legume/allium diets compared with the high vegetable/fruit diet (P < .01). Subjects who excreted higher levels of equol on the basal and legume/allium diets also consumed more of the milk-based pudding provided as part of the controlled diets. CONCLUSIONS: Urinary lignan and isoflavonoid excretion changed in response to alterations in vegetable, fruit, and legume intake under controlled dietary conditions.  相似文献   

14.
OBJECTIVE: The hypothesis was tested that the rate of postmenopausal bone loss is inversely associated with long-term urinary excretion of phyto-oestrogens, as a marker of habitual dietary intake. DESIGN: Secondary analysis of a 10-year follow-up study (1979 1989) among postmenopausal women in the Netherlands. SUBJECTS: From the original population of 154 women, 32 women were selected with an annual rate of radial bone loss of < or = 0.5% over the first 5 years of the study and 35 women with a rate of > or = 2.5% per year. METHODS: The isoflavonoids genistein, daidzein and equol, and the lignan enterolactone were determined by gas chromatography mass spectrometry in aggregate samples from annually collected urine samples. Cortical bone density of the radius had previously been measured annually by single-photon absorptiometry. RESULTS: Excretion of isoflavonoids did not differ between both groups, although in multivariate analysis equol excretion was weakly positively associated with rate of bone loss in the 5 years after the menopause. Enterolactone excretion was significantly higher in the group with high rate of bone loss. This positive association remained in multivariate linear regression analysis after adjustment for age, years since menopause, body mass index and intake of calcium, vegetable protein and dietary fibre. CONCLUSIONS: Enterolactone excretion is likely to be an indicator of consumption of grains and legumes; it is not clear whether the observed positive association with rate of bone loss is a causal one. Our results do not support a preventive effect of low, unsupplemented dietary intake of phyto-oestrogens on postmenopausal cortical bone loss. However, no conclusions can be drawn about effects of higher doses of phyto-oestrogens.  相似文献   

15.
16.
Poppy seeds from seven different origins (Dutch, Australian, Hungarian, Spanish, Czech, and two Turkish) were analyzed for the amount of opiates present. Four grams of each kind of seeds, equivalent to the amount of seeds on two bagels, were ingested by volunteers. One volunteer also ingested four times the same amount of poppy seeds from the same origin (Spanish). During 24 hours urine samples were obtained and screened for the presence of morphine and codeine using the FPIA technique (cut-off = 200 ng/mL) and a GC/MS confirmation with a limit of detection (LOD) of 25 ng/mL for codeine and morphine. Poppy seeds from different origins contain a wide variation of morphine (2-251 micro g/g) and codeine (0.4-57.1 micro g/g) content. No other opiate could be detected. After ingestion a large interindividual variation of excretion of opiates exists. The testing results from the same kind of seeds ingested four times with a one week interval by the same volunteer also show a poor reproduceability. Several kinds of poppy seeds can give positive testing results (Australian, Hungarian, Spanish and one kind of Turkish seeds). Within 24 hours all testing results became negative.  相似文献   

17.
BACKGROUND: The urinary isoflavonoid equol inhibits membrane Na-K-Cl cotransporters at similar concentrations to those at which furosemide inhibits them, but the significance of this action is not known. OBJECTIVE: To investigate the potential salidiuretic and vascular actions of equol in the rat. METHODS: Renal functioning was assessed in vitro in the isolated perfused kidney and in vivo in conscious rats. The vascular contractility of isolated aorta was assessed. RESULTS: In the isolated perfused kidney equol was concentrated 50- to 70-fold in the urinary fluid, it was 3-4 times less potent than furosemide at increasing diuresis, natriuresis and kaliuresis (the difference was due to its higher protein-binding affinity), and it induced a modest but significant increase in glomerular filtration rate. In vivo, orally administered equol was a modest natriuretic agent, about 8-fold less potent than orally administered furosemide (in molar terms). In isolated aortic rings precontracted by administration of phenylephrine, administration of equol relaxed the contracted aorta at 10-fold lower concentrations (concentration for half-maximal activity 58.9 +/- 16 micromol/l, n = 3) than did furosemide (concentration for half-maximal activity 633 +/- 145 micromol/l, n = 3). CONCLUSIONS: Equol is a modest natriuretic and vasorelaxant agent in the rat. Further studies are required in order to investigate the potential natriuretic and perhaps hypotensive actions of dietary equol precursors (daidzein).  相似文献   

18.
We administered 3 g of taurine orally for four weeks to 35 patients suffering from liver cirrhosis with repeated muscle cramp (MC). Improvement of MC was noted in 22 cases (62.9%). We also determined the plasma taurine concentration in eight cases of liver cirrhosis with MC. The plasma taurine concentration before ingestion was 54.1 +/- 20.7 nmol/ml, whereas that of four weeks after ingestion was 125.1 +/- 59.1 nmol/ml, which was significantly elevated by 2.3 fold. As the concentration increased, the frequency of MC decreased, suggesting the good correlation between ingestion and the decrease in frequency of MC. In liver cirrhosis without MC the plasma taurine concentration was 81.0 +/- 16.7 nmol/ml, which was significantly higher than in liver cirrhosis with MC. In a few cases with taurine ingestion, serial plasma taurine concentrations were detected. Plasma taurine reached the peak value during the first week of ingestion and plasma taurine levels were maintained 2-5 fold higher during ingestion.  相似文献   

19.
The aim of this study is to examine the effect of carbohydrate (CHO) ingestion during the first hour of treadmill running on endurance capacity. Eleven male subjects ran at 70% VO2max to exhaustion on three occasions one week apart. On two occasions two CHO-electrolyte solutions (a 5.5% (E) and a 6.9% (L) were ingested for the first hour of exercise; water was ingested until exhaustion. On the third occasion water (W) was ingested throughout the run. The order testing was randomly assigned. Exhaustion times for the W, E, and L trials were 109.6 +/- 9.6 min, 124.5 +/- 8.4 min, and 121.4 +/- 9.4 min, respectively. There was no difference between the two CHO trials, but time to exhaustion was longer only for the E trial (P < 0.05), compared with the W trial. Nevertheless the average performance times for the combined results of the two CHO trials were longer than the water trial. Carbohydrate ingestion resulted in higher blood glucose concentration (P < 0.01) at 20 min in the E trail only and lower (P < 0.05) serum growth hormone and plasma FFA and glycerol concentrations at 60 min but not at exhaustion in both E and L trials compared with the W trial. Blood lactate, plasma ammonia, electrolytes, catecholamines, and serum insulin and cortisol concentrations were not different in the three trials. In conclusion, CHO ingestion during the first hour of exercise improves endurance capacity go a greater extent compared with water alone.  相似文献   

20.
The aim of our study was to test the hypothesis that the better absorption of sorbitol when ingested with glucose could be related to a delayed gastric emptying. We tested the effect of the ingestion of glucose and lipids on the gastric emptying and intestinal absorption of sorbitol in six healthy volunteers, using gastric scintigraphy and hydrogen breath test. After an overnight fast, subjects ingested in random order, on 48-h test periods separated by at least one week, the following solutions: (a) 20 g sorbitol alone; (b) 20 g sorbitol and 20 g glucose; (c) 20 g sorbitol and 9 g lipids. Isotopic acquisitions were taken for 3 h following the ingestion of sorbitol labelled with 111Indium. Hydrogen concentration was measured in end-expiratory samples during 5 h, and the areas under the breath hydrogen curve, reflecting the amounts of sorbitol unabsorbed in the small bowel, were compared between periods. Mean area under the curve was 397 +/- 159 when sorbitol was ingested alone, and this was significantly lower when ingested with glucose or lipids (313 +/- 181 and 337 +/- 135, respectively; P < 0.05). The three curves of sorbitol gastric emptying differed significantly from each other, the gastric emptying being the slowest for sorbitol plus lipids, and the fastest for sorbitol taken alone. We found a positive correlation between the half-emptying time and the hydrogen areas under the curve (r = 0.46, P = 0.05). In conclusion, our study demonstrates that adding glucose or lipids to a solution of sorbitol slows the gastric emptying of sorbitol, resulting in a better intestinal absorption of sorbitol.  相似文献   

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