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1.
This study compared plasma and urinary carnitine concentrations in pregnant and non-pregnant Korean women. The subjects were fifty pregnant women and thirty non-pregnant women aged 24-28 years. During the first trimester, dietary carnitine intakes in the pregnant women were much lower than in non-pregnant women (70.00 (SD 29.22) micromol/d), but over the course of pregnancy carnitine intake increased from 44.64 (SD 24.84) micromol/d during the first trimester to 96.11 (SD 36.56) micromol/d during the third trimester. Pregnant women had a significantly lower plasma carnitine concentration than non-pregnant women. Plasma concentrations of non-esterified carnitine, acid-soluble acylcarnitine and total carnitine were significantly lower during the second and third trimesters than the first. Plasma acid-insoluble acylcarnitine levels, which tended to be higher in the non-pregnant women compared with the pregnant women, increased significantly as gestation proceeded. The urinary excretion of non-esterified carnitine, acid-soluble acylcarnitine and total carnitine was significantly higher in the pregnant women during the first and second trimesters than in non-pregnant women and decreased significantly as gestation proceeded. We found that there was a significant decrease in plasma carnitine level even though dietary carnitine intake increased as gestation proceeded. The low urinary excretion of carnitine in late pregnancy may be caused by an increased demand during pregnancy.  相似文献   

2.
The purpose of this investigation was to determine if there was any relationship between dietary carnitine intake and the concentrations of carnitine in skeletal muscle and blood plasma in healthy adult men and women. Subjects (14 men, 14 women, fasted 8 h) reported to the Biodynamics Laboratory where they completed a 24-h diet recall questionnaire. Resting muscle biopsy (vastus lateralis) and blood plasma samples were taken and assayed for free, short-chain, and long-chain acyl carnitine concentrations. Dietary carnitine intake was estimated from data on concentrations in food. There was no significant relationship between either protein or carnitine intake with skeletal muscle carnitine concentrations. There was a significant relationship between both dietary carnitine (r = 0.50) and protein (r = 0.48) intake with blood plasma total acid soluble carnitine concentrations (p less than 0.01) in all subjects.  相似文献   

3.
This investigation determines the effect of two isocaloric diet regimens on plasma carnitine and urinary carnitine excretion in man. Seven healthy men were served a high-carbohydrate, low-fat (C) or a low-carbohydrate, high-fat (F) diet for 2 wk, ie, one diet regimen for 4 d followed by a 3-d break and concluded with 4 d more on the other diet regimen. The two regimens contained the same amount of carnitine-rich food. Plasma free carnitine rose significantly from the initial value on F diet and was significantly higher from day 3 than C diet. Plasma acyl carnitine increased on both diets. Urinary excretion of carnitine increased only on F diet. Renal clearance of both free and acyl carnitine was significantly greater on F diet than on C diet. Results showed that composition of a diet with constant carnitine content influenced carnitine metabolism in man.  相似文献   

4.
The effect of dietary carnitine on urinary excretion of free and total carnitine and on breast-milk secretion of the carnitine fractions in 15 control and 16 lactating women aged 21-40 y was measured. Free and total carnitine excretions, obtained from 24-h urine collections, correlated with carnitine consumed on the collection day (P less than 0.03, P less than 0.01, respectively) but not with the mean intake calculated from 3-d diet records. The immediate responses of the control and lactating groups were not significantly different. Urinary excretion of carnitine (n = 31) was 82 +/- 13 mumol/d for free excretion and 226 +/- 22 mumol/d for total excretion. Milk free, acid-soluble acyl-, acid-insoluble acyl-, or total carnitine did not correlate with dietary carnitine or with the duration of lactation (1-10 mo). Milk total carnitine was 45 +/- 3 mumol/L. With the carnitine content of breast milk remaining stable for greater than or equal to 10 mo, the importance of exogenous carnitine throughout infancy is suggested.  相似文献   

5.
The purpose of this study was to determine the effects of altering the fuel substrate mix of total parenteral nutrition (TPN) on plasma and urinary carnitine in trauma patients. TPN solutions were either 100% carbohydrate (CHO) based or lipid based (70% CHO, 30% lipid). There were statistically significant (p less than 0.05) increases in plasma levels of free carnitine, short-chain acyl carnitine, and total carnitine in trauma patients receiving lipid-based TPN. No significant differences in urinary carnitine excretion were noted between groups. We conclude that the use of lipids in the TPN of trauma patients leads to an alteration in plasma carnitine metabolism.  相似文献   

6.
Low carnitine intake and altered lipid metabolism in infants   总被引:1,自引:0,他引:1  
We examined the effect of dietary carnitine on variables of lipid metabolism in human infants. Normal male full-term infants were fed an isolated soy-protein-based formula with or without added carnitine from age 6-9 d to age 112 d. Growth and food intake were measured throughout the study. At ages 56 and 112 d serum concentrations of carnitine, free fatty acids, and triglycerides and urinary excretion of carnitine and medium-chain dicarboxylic acids were measured. Serum carnitine concentrations were lower in all infants fed unsupplemented formula. There was no difference in growth or food intake between the two groups of infants. Serum free fatty acid concentrations were significantly higher in the infants not receiving dietary carnitine. Moreover, excretion of all three medium-chain dicarboxylic acids was significantly higher in infants not receiving dietary carnitine. We conclude that lack of dietary carnitine affects lipid metabolism of infants during the first 4 mo of life.  相似文献   

7.
《Nutrition Research》2001,21(1-2):31-39
Healthy men receiving adequate intakes of energy and fat without protein and carnitine for 14 days had significantly higher mean 24-h urinary free, acyl, and total carnitine excretions than the control subjects. Hen egg was the sole source of protein in this study and constained 7.77 μmol of carnitine/100 g. The stress stimuli due to the lack of protein and carnitine intakes were alleviated with the protein intakes of 0.35, 0.50, 0.55, 0.65, 0.70, and 0.85 g/kg/d, evidenced by the significant decreases in the 3 forms of 24-h urinary carnitine excretions. Their significantly lower in the 3 forms of 24-h urinary carnitine excretions than the control subjects with carnitine intake of 176 μmol/d were due to their limited intakes of carnitine: 12–30 μmol/d. Their significant increases in urinary acylcarnitine/total carnitine ratios indicated the utilization of carnitine in fatty acid oxidation.  相似文献   

8.
Erythrocyte and plasma total, free, and acyl carnitine concentrations in 13 low birthweight, preterm infants were determined between birth and 21 days of age. Although erythrocytes contributed 73.6 +/- 4% (mean +/- SD) of total blood carnitine at birth, the contribution by day 14 declined to 42.2 +/- 14.1. Linear regression analysis showed no significant correlation between plasma and erythrocyte concentrations. At 3 wk erythrocyte total carnitine concentrations were similar to adult values, but erythrocyte acyl carnitine concentrations were markedly lower. Although a significant (p less than 0.05) positive correlation between plasma carnitine concentrations and mean daily intake from birth was found at 7, 14, and 21 days of age (r = 0.66, 0.87, and 0.88, respectively), no significant relationships between erythrocyte carnitine concentrations and carnitine intake could be demonstrated by linear regression analysis. It appears that the carnitine present in plasma and erythrocytes represents two separate pools which are influenced by different factors in preterm infants.  相似文献   

9.
The purpose of this study was to examine whether caffeine (CAF), carnitine (CAR), or CAF+CAR mixture administration affects exercise endurance time via carnitine metabolism. Water (CON), CAF, CAR, or CAF+CAR mixture was administered to five male rugby athletes participating in this study by a randomized double-blind fashion who were made to ride a cycle ergometer for exercise. The CAF effect on exercise endurance time was small, but the CAR trial significantly increased the exercise endurance time compared with CON trial; a further CAF+CAR mixture trial had greater effects on the exercise endurance time than those of a CON, CAF, or CAR trial. A CAR or CAF+CAR mixed trial increased urinary nonesterified carnitine (NEC) and total carnitine (TCAR), but no changes were observed in acid-soluble acylcarnitine (ASAC) and acid-insoluble acylcarnitine (AIAC) excretion. A CAR or CAF+CAR mixed trial resulted in higher levels of plasma NEC, ASAC, and TCAR fractions than the CON and CAF trials did on exhaustion time. Total cholesterol, triglyceride, and free fatty acid in blood were significantly increased at exhaustion time, but they were not affected in the CAF or the CAR trial. These results suggest that carnitine ingestion could promote fat oxidation, resulting in higher endurance performance in athletes, and especially these ergogenic effects of carnitine coingested with caffeine may be greater than those of carnitine alone.  相似文献   

10.
The effect of feeding different amounts of a standard laboratory pellet diet on tissue carnitine concentration was studied in four groups of rats. Group I was fed ad libitum, whereas food intake was restricted to 25, 20, and 15g protein/kg body weight/day in group II, III, and IV, respectively. The intake of food, protein, energy and carnitine was constant and adjusted to actual body weight in groups 2-4. Six weeks food restriction had no effect on muscle carnitine. Restricted diet caused lowered concentrations of carnitine in serum (group I, fed ad libitum, total 95.0 +/- 13.8, free 80.2 +/- 2.7; group II total 78.4 +/- 8.4, free 56.9 +/- 4.7; group III total 81.7 +/- 8.8, free 66.0 +/- 8.8; and group IV total 73.8 +/- 8.7, free 59.5 +/- 7.6 mumol/l) and urinary carnitine excretion (group I, total 7.1 +/- 3.3, free 6.3 +/- 3.1; group II, total 2.5 +/- 0.7, free 2.2 +/- 0.7; group III, total 1.9 +/- 0.8, free 1.6 +/- 0.8; and group IV, total 1.3 +/- 0.4 free 1.1 +/- 0.3 mumol/day). In contrast, the liver carnitine tended to increase when dietary intake was reduced (group I total 1.1 +/- 0.1, free 1.0 +/- 0.1; group II total 1.5 +/- 0.2, free 1.4 +/- 0.2; group III total 1.3 +/- 0.1, free 1.1 +/- 0.1; and group IV total 1.5 +/- 0.2, free 1.4 +/- 0.2 mumol/g dry wt). The highest liver carnitine concentrations were observed during the lowest dietary intake when also the serum and urine carnitine were lowest. We conclude that the amount of food intake has a direct impact on carnitine concentrations in the liver, serum, and urine while muscle carnitine concentration remains relatively stable despite wide variations in food intake.  相似文献   

11.
OBJECTIVE: The purpose of this study was to examine the association between dietary intake of phytoestrogens estimated by a food frequency questionnaire (FFQ) with urinary metabolites. METHODS: Participants were 26 premenopausal, Caucasian women aged 25 to 42 years. Dietary intake of isoflavones (genistein and daidzein) and lignans (secoisolariciresinol and matairesinol) were estimated by a 53-item interviewer-administered FFQ on two occasions, reflecting 'habitual' (previous 2 months) and 'recent' (previous 2 days) dietary intake. Isoflavone (genistein, daidzein) and lignan (enterolactone, enterodiol and secoisolariciresinol) concentrations were measured in 24-hour urine samples by gas chromatography-mass spectrometry. Correlations between FFQ (habitual and recent, separately) and urinary metabolite values were assessed using Spearman correlation coefficients. RESULTS: Mean habitual isoflavone and lignan intakes were 13.7 mg/day and 13.8 mg/day, respectively. Mean urinary concentrations of isoflavones and lignans were 17.4 micromol/day and 20.6 micromol/day, respectively. Recent and habitual isoflavone intakes were correlated with urinary excretion of metabolites (r = 0.64, p < 0.001 and r = 0.54, p = 0.004, respectively). Urinary excretion of lignans was also modestly correlated with recent and habitual lignan intakes (r = 0.46, p = 0.02 and r = 0.40, p = 0.05, respectively). CONCLUSIONS: Our results support the use of this FFQ as a measure of dietary isoflavone and lignan intake in epidemiological studies.  相似文献   

12.
BACKGROUND: The finding that plasma glutathione turnover decreases as dietary protein intake decreases suggests that the safe amount of dietary protein, although sufficient for maintenance of nitrogen balance, may be insufficient for maintenance of cellular glutathione. OBJECTIVE: Our objective was to determine the effect of the safe protein intake on the erythrocyte glutathione synthesis rate and its relation with urinary 5-L-oxoproline excretion. DESIGN: Erythrocyte glutathione synthesis and urinary 5-L-oxoproline excretion were measured in young adults (6 men and 6 women) by using an infusion of [(13)C(2)]glycine on 3 occasions: initially during the subjects' habitual protein intake (1.13 g.kg(-1).d(-1)) and on days 3 and 10 of consumption of a diet providing the safe protein intake (0.75 g.kg(-1).d(-1)). RESULTS: Compared with baseline values, the fractional synthesis rate of erythrocyte glutathione was significantly lower (P < 0.05) on days 3 and 10 of the diet with the safe protein intake. Urinary 5-L-oxoproline excretion increased significantly (P < 0.05) above baseline by the third day of the diet with the safe protein intake and remained elevated. Erythrocyte glutathione concentrations and absolute synthesis rates decreased by day 3 but recovered to baseline values by day 10. Erythrocyte concentrations of cysteine, methionine, and serine remained unchanged, whereas erythrocyte concentrations of glycine, glutamic acid, and glutamine increased significantly by day 10. CONCLUSION: During adaptation to the safe amount of dietary protein, there are changes in the concentration and kinetics of erythrocyte glutathione that suggest a reduced antioxidant capacity and possible increased susceptibility to oxidant stress.  相似文献   

13.
Plasma carnitine levels and urinary carnitine excretion during sepsis   总被引:1,自引:0,他引:1  
Carnitine is an indispensable factor for the beta-oxidation of medium- and long-chain fatty acids, and it plays a possible role in the oxidation of branched-chain amino acids. Plasma and urinary levels of free carnitine and short-chain acyl-carnitines were studied in 67 surgical patients, after non-septic surgical procedures or during sepsis. The septic state was associated with increased urinary excretion of free carnitine (p less than 0.001), as well as with lower plasma levels of short-chain acyl-carnitines (p less than 0.001); the latter feature correlated with the level of hypermetabolism, as evaluated by the metabolic rate and by the arterial-mixed venous O2 difference. In 26 patients during total parenteral nutrition D, L-acetyl-carnitine was administered (100 mg/kg/24 hrs, in continuous iv infusion) and was associated, in septic patients only, with a significant decrease in the respiratory quotient, suggesting enhanced oxidation of low respiratory quotient substrates (fatty acids and/or branched-chain amino acids). Carnitine supplementation during total parenteral nutrition might be of theoretical benefit in some clinical conditions, such as sepsis, in which the following conditions coexist enhanced utilization of substrates whose oxidation is partially or totally carnitine dependent; prolonged absence of exogenous intake of carnitine (as in long-term total parenteral nutrition); eventual impairment of carnitine synthesis due to hepatic dysfunction; increased, massive urinary loss of carnitine.  相似文献   

14.
BackgroundEmerging evidence suggests that increasing dietary nitrate intake may be an effective approach to reduce blood pressure. Beetroot juice is often used to supplement dietary nitrate, whereas nitrate intake levels from habitual diet are low. An increase in the habitual intake of nitrate-rich vegetables may represent an alternative to nitrate supplementation. However, the effectiveness and acceptability of a nitrate–rich-vegetables diet remain to be established.ObjectiveThe aim was to investigate the effect and feasibility of two different intervention strategies to increase dietary nitrate intake, on plasma nitrate/nitrite concentrations and blood pressure.DesignA randomized, crossover trial was used.ParticipantsParticipants were healthy men and women (both n=15; age: 24±6 years) from the Netherlands.InterventionParticipants were instructed to consume ∼400 mg nitrate at lunch, provided through nitrate-rich vegetables and dietary counseling, or beetroot juice supplementation. Both interventions lasted 1 week, with 1-week washout (January to April 2017).Main outcomePlasma nitrate and nitrite concentrations and resting systolic and diastolic blood pressure were measured in an overnight fasted state (before and after intervention) and ∼2.5 hours after lunch (before and throughout intervention on day 1, 4, and 7).Statistical analysisTwo-factor (time × treatment) repeated-measures analyses of variance were performed.ResultsMean plasma nitrate concentrations increased with both interventions, with a larger increase in beetroot juice vs nitrate-rich vegetables, both in a fasted state and ∼2.5 hours after lunch (day 1, beetroot juice: 2.31±0.56 mg/dL [373±90 μmol/L] vs nitrate-rich vegetables: 1.71±0.83 mg/dL [277±134 μmol/L]; P<0.001). Likewise, mean plasma nitrite concentrations increased with both interventions, but were higher after lunch in beetroot juice than in nitrate-rich vegetables (day 1: 2.58±1.52 μg/dL [560±331 nmol/L] vs 2.15±1.21 μg/dL [468±263 nmol/L]; P=0.020). Fasting mean systolic and diastolic blood pressure did not change, but mean systolic and diastolic blood pressure assessed ∼2.5 hours after lunch were significantly reduced throughout both intervention periods (P<0.05), with no differences between beetroot juice and nitrate-rich vegetables (day 1, systolic blood pressure: –5.1±9.5 mm Hg and diastolic blood pressure: –5.3±8.9 mm Hg).ConclusionShort-term consumption of dietary nitrate in the form of nitrate-rich vegetables represents an effective means to increase plasma nitrate and nitrite concentrations, and reduces blood pressure to the same extent as beetroot juice supplementation.  相似文献   

15.
Carnitine is necessary for the transport of long-chain fatty acids across the mitochondrial membrane. Thirteen severely injured patients on total parenteral nutrition were studied during days 2-8 post injury. Initially plasma and skeletal muscle carnitine values were within the range earlier found for normal subjects, whereas the urinary carnitine excretion was markedly increased. On day 4 there was a simultaneous decrease in the carnitine concentration in plasma (alpha < 0.01) and urine (alpha < 0.05) as well as in skeletal muscle tissue (alpha < 0.05 using only the values that could be paired i.e. from eight subjects), whereas no difference was found between day 2 and 8. One explanation of this pattern might be that a redistribution of carnitine occurs to other organs not measured, for example the liver. In skeletal muscle tissue, statistically significant positive correlations were found between the carnitine level and ATP (alpha < 0.01) and phosphocreatine (alpha < 0.02) as well as between carnitine and glycogen (alpha < 0.05).  相似文献   

16.
Objective: Strategies that aim to facilitate reduction of the salt content of foods in Australia are hampered by sparse and outdated data on habitual salt intakes. This study assessed habitual sodium intake through urinary excretion analyses, and identified food sources of dietary sodium, as well as knowledge and practices related to salt use in healthy women. Methods: Cross‐sectional, convenient sample of 76 women aged 20 to 55 years, Wollongong, NSW. Data included a 24 hour urine sample, three‐day food diary and a self‐administered questionnaire. Results: Mean Na excretion equated to a NaCl (salt) intake of 6.41 (SD=2.61) g/day; 43% had values <6 g/day. Food groups contributing to dietary sodium were: bread and cereals (27%); dressings/sauces (20%); meat/egg‐based dishes (18%); snacks/desserts/extras (11%); and milk and dairy products (11%). Approximately half the sample reported using salt in cooking or at the table. Dietary practices reflected a high awareness of salt‐related health issues and a good knowledge of food sources of sodium. Conclusion: These findings from a sample of healthy women in the Illawarra indicate that dietary sodium intakes are lower in this group than previously reported in Australia. However, personal food choices and high levels of awareness of the salt reduction messages are not enough to achieve more stringent dietary targets of <4 g salt per day. Implications: Urinary Na excretion data are required from a larger nationally representative sample to confirm habitual salt intakes. The bread and cereals food group are an obvious target for sodium reduction strategies in manufactured foods.  相似文献   

17.
Aim: To compare the dietary intake and nutritional status of users and non‐users of proton pump inhibitor medications. Methods: Cross‐sectional study of subacute rehabilitation inpatients. Forty‐nine patients (nine men and 40 women) without dementia fulfilled the study criteria. Information was collected on admission and included medical history, duration of proton pump inhibitor medication use, nutritional status and cognitive scores. Dietary data were collected by food frequency questionnaire and blood samples were analysed for vitamin B12, homocysteine and methylmalonic acid concentrations. Results: Age was 80.4 ± 7.7 (mean ± SD) years and body mass index was 26 ± 6.7 kg/m2. Twenty‐one (of 49) subjects had subclinical vitamin B12 deficiency, which was defined as serum vitamin B12 <148 pmol/L or 148–258 pmol/L and methylmalonic acid >0.30 µmol/L or tHcy >13 µmol/L (women) and >15 µmol/L (men). Subjects were stratified according to proton pump inhibitor use and vitamin B12 status. The presence of subclinical deficiency was similar between the groups (χ2‐test P= 0.17). Proton pump inhibitor users had higher dietary protein and calcium intakes (but not supplement calcium intakes) compared with non‐users (93 vs 81 g/day, P= 0.002 and 968 vs 742 mg/day, P= 0.038, respectively). Conclusions: Subjects using proton pump inhibitor medications did not have lower vitamin B12 status, but had higher dietary protein intakes suggesting higher intakes of meats, eggs and dairy foods may reduce the risk of developing vitamin B12 deficiency whilst taking proton pump inhibitor medications.  相似文献   

18.
Abstract

The potential for B-vitamins to reduce plasma homocysteine (Hcy) and reduce the risk of Alzheimer’s disease (AD) has been described previously. However, the role of Apolipoprotein E ?4 (APOE4) in this relationship has not been adequately addressed. This case-control study explored APOE4 genotype in an Australian sample of 63 healthy individuals (female?=?38; age?=?76.9?±?4.7 y) and 63 individuals with AD (female?=?35, age?=?77.1?±?5.3 y). Findings revealed 55 of 126 participants expressed the APOE4 genotype with 37 of 126 having both AD and the APOE4 genotype. Analysis revealed an increased likelihood of AD when Hcy levels are >11.0 µmol/L (p?=?0.012), cysteine levels were <255?µmol/L (p?=?0.033) and serum folate was <22.0?nmol/L (p?=?0.003; in males only). In females, dietary intake of total folate <336 µg/day (p=0.001), natural folate <270?µg/day (p?=?0.011), and vitamin B2?<?1.12?mg/day (p?=?0.028) was associated with an increased AD risk. These results support Hcy, Cys, and SF as useful biomarkers for AD, irrespective of APOE4 genotype and as such should be considered as part of screening and managing risk of AD.  相似文献   

19.
Results of kinetic and pharmacokinetic studies have suggested that dietary carnitine is not totally absorbed and is in part degraded in the gastrointestinal tract of humans. To determine the metabolic fate of dietary carnitine in humans, we administered orally a tracer dose of [methyl-3H]L-carnitine with a meal to subjects who had been adapted to a low-carnitine diet or a high-carnitine diet. Urinary and fecal excretion of radiolabeled carnitine and metabolites was monitored for 5 to 11 d following administration of the test dose. Total radioactive metabolites excreted ranged from 13 to 34% (low carnitine diet) and 27 to 46% (high carnitine diet) of the ingested tracer. Major metabolites found were [3H]trimethylamine N-oxide (8 to 39% of the administered dose; excreted primarily in urine) and [3H]gamma-butyrobetaine (0.09 to 8% of the administered dose; excreted primarily in feces). Urinary excretion of total carnitine was 42 to 95% (high carnitine diet) and 190 to 364% (low carnitine diet) of intake. These results indicate that oral carnitine is 54 to 87% bioavailable from normal Western diets; the percentage of intake absorbed is related to the quantity ingested.  相似文献   

20.
In Morocco, the high consumption of dietary sodium increases the risk of non-communicable diseases (NCDs) and predisposes to cardiovascular diseases (CVDs) and hypertension. This study aims to assess the dietary sodium and potassium intake in a random sample of Moroccan adult students as a benchmark informing a national strategy for reducing salt intake. This cross-sectional study was conducted with 103 adults aged 18 to 25 years recruited in Casablanca. The 24-hour urinary excretion was used to measure the sodium and potassium. Urine volume and creatinine excretion level were used to validate the completeness of the collected samples. The average urinary sodium excretion was 3.1 ± 0.1 g/day, 13.5% consumed less than 5 g/day, while 69% consumed more than 5 g/day of which 17.5% consumed more than twice the recommendations. For the average urinary potassium excretion was 1.83 ± 0.06 g/day, and more than 98% of the students consumed less than the adequate intake. The Na/K ratio is significantly higher than the recommended amounts. The results of this pilot study show that the population studied has a high sodium intake and low potassium intake which does not meet World Health Organization (WHO) recommendations, which requires implementing an action plan to reduce salt intake.  相似文献   

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