Changes in nutrient intakes of conditioned men during a 5-day period of increased physical activity and other stresses

Summary Nutrient intakes and selected blood and urinary constituents of 16 Navy servicemen were obtained before and during a period of 113 hours of physical activity, sleep deprivation, and psychological stress, to document the dietary adaptation of physically conditioned men to an extended period of hard physical work and other stresses. Food intakes were monitored by 1-day diet records prior to and by direct observation during the period. The factorial method was used to calculate energy expenditure. Carbohydrates provided 45 and 43% of the total energy intake before and during the experiment. Protein intakes and intakes of all the vitamins and minerals studied exceeded the Recommended Dietary Allowances, both before and during the period. Total energy intake averaged 18.7 MJ · d^–1 before and 24.4 MJ · d^–1 during the experiment. Body weight increased significantly by 2.7±0.4 kg (mean±s.e.) during the experiment (p< 0.0001). There was a significant correlation (r=0.74; p<0.001) between the change in body weight and urinary sodium from before to after the experiment suggesting that increased dietary sodium may have contributed to the weight gain. A significant increase in plasma volume (11.9±3.2%; p< 0.0003) provided further support that the observed weight gain was due to sodium intake rather than a positive energy balance. In conclusion, conditioned men increased food consumption adequately to meet increased energy demands.     

Effect of antioxidant vitamin supplementation on muscle function after eccentric exercise

Summary This study investigated the effects of antioxidant vitamin supplementation upon muscle contractile function following eccentric exercise and was performed double blind. Twenty-four physically active young subjects ingested either placebo (400 mg; n = 8), vitamin E (400 mg; n=8) or vitamin C (400 mg; n = 8) for 21 days prior to and for 7 days after performing 60 min of box-stepping exercise. Contractile function of the triceps surae was assessed by the measurement of maximal voluntary contraction (MVC) and the ratio of the force generated at 20 Hz and 50 Hz tetanic stimulation before and after eccentric exercise and for 7 days during recovery. Following eccentric exercise, MVC decreased to 75 (4) % [mean (SE); n = 24; P < 0.05] of the preexercise values and the 20/50 Hz ratio of tetanic tension from 0.76 (0.01) to 0.49 (0.03) [mean (SE); n = 24; P<0.05). Compared to the placebo group no significant changes in MVC were observed immediately post-exercise, though recovery of MVC in the first 24 h post-exercise was greater in the group supplemented with vitamin C. The decrease in 20/50 Hz ratio of tetanic tension was significantly less (P < 0.05) post-exercise and in the initial phase of recovery in subjects supplemented with vitamin C but not with vitamin E. These data suggest that prior vitamin C supplementation may exert a protective effect against eccentric exercise-induced muscle damage.     

Adiposity,inflammation and fat-soluble vitamins in adolescents

ObjectiveEvaluate the association between inflammatory process, adiposity, and vitamins A, D, and E in adolescents, according to gender.MethodsCross-sectional study with adolescents aged 12–19 years old of both genders attending public schools in Recife. A questionnaire was used to collect data on socioeconomic level, lifestyle, and food intake of adolescents. Then, an anthropometric evaluation and a blood sampling were performed to analyze serum concentrations of α-1-acid glycoprotein, retinol, β-carotene, α-tocopherol, and 25-hydroxy-vitamin D.ResultsThe levels of α-1-acid glycoprotein were higher for abdominal obesity in both genders. Male adolescents with insufficient serum α-tocopherol levels had low levels of α-1-acid glycoprotein (p = 0.03) and an increased risk of 25-hydroxy-vitamin D and β-carotene deficiency in relation to total and abdominal fat; female adolescents had an increased risk of insufficient β-carotene with abdominal obesity (PR: 1.33; 95% CI: 1.2–1.5).ConclusionAbdominal adiposity implies a higher risk of inflammation and causes different changes to the levels of fat-soluble vitamins according to gender.     

Assessment of pre- and post-methionine load homocysteine for prediction of recurrent stroke and coronary artery disease in the Vitamin Intervention for Stroke Prevention Trial

Methionine (Met) loading increases total plasma homocysteine (tHcy) and assesses homocysteine metabolism. We tested the hypothesis that pre- or post-Met tHcy will predict recurrent stroke or coronary artery disease (CAD) in a subgroup analysis of the Vitamin Intervention for Stroke Prevention (VISP) trial. VISP subjects with non-disabling stroke underwent measurement of tHcy at baseline (fasting pre- and post-Met load) and were randomized to high/low-dose B-vitamin therapy for prevention of recurrent stroke or CAD. In the sample cohort of 2124 subjects, mean ± S.D. tHcy levels in μmol/l were pre-Met 13.2 ± 4.3, post-Met 30.4 ± 9.76, and pre/post-Met Δ 17.1 ± 8.3. The hazard ratio (HR) for recurrent stroke was 1.16 (p = 0.026) for 1 S.D. higher pre-Met tHcy and 1.15 (p = 0.054) for 1 S.D. higher post-Met tHcy. For CAD, the HR for 1 S.D. higher pre-Met tHcy was 1.27 (p = 0.001) and was 1.00 (p = 0.99) for post-Met tHcy. In survival analyses using pre- or post-Met as covariates, the coefficient of pre/post-Met Δ was not significant for stroke and was only marginally significant for CAD (p < 0.08), but was negative. We conclude that fasting, pre-Met tHcy is as effective as post-Met tHcy or pre/post-Met Δ in predicting the risk for stroke and CAD.     

Nutritional value,bioactive compounds and health benefits of lettuce (Lactuca sativa L.)

Lettuce is one of the most widely consumed vegetables worldwide, but its nutritional value has been underestimated. Lettuce is low in calories, fat and sodium. It is a good source of fiber, iron, folate, and vitamin C. Lettuce is also a good source of various other health-beneficial bioactive compounds. In vitro and in vivo studies have shown anti-inflammatory, cholesterol-lowering, and anti-diabetic activities attributed to the bioactive compounds in lettuce. However, nutrient composition and bioactive compounds vary among lettuce types. Crisphead lettuce, the most popular type of lettuce in the US, is comparatively low in minerals, vitamins, and bioactive compounds. More nutritious lettuces are leaf type lettuce and romaine with folate content comparable to other rich leafy vegetable sources. Red pigmented lettuce contains higher phenolic compounds than green lettuce. Due to increasing popularity, the nutrient contents in baby lettuce were also examined. Baby green romaine was especially high in vitamin C. In this review composition and nutritional value of different lettuce types were summarized, which can help growers and consumers choose lettuce types with higher nutritional benefits.     

备孕男性的营养素合理补充

随着生活节奏加快,人们饮食结构改变、不良习惯累积、精神压力增加和环境恶化,对男性健康造成很大威胁。不孕不育已成为育龄男性和女性的临床常见和高发疾病。临床上不孕不育育龄女性与男性及备孕夫妻,常常希望医师给予饮食方面的指导,目前关于女性孕前合理补充营养素的研究较多,而关于备孕男性营养素合理补充的研究则不多。笔者拟总结目前对于营养素研究中,与男性生育具有相关性的一些营养素,如矿物质类(锌、铁、钙、镁、硒),维生素类(维生素A、B9、B12、C、D、E),以及其他一些重要辅助营养素类(左旋肉碱、番茄红素、氨基酸、辅酶Q10、果糖、柠檬酸),旨在对备孕男性营养素合理补充有一定临床指导作用。     

Influence of oral vitamin and mineral supplementation on male infertility: a meta-analysis and systematic review

This meta-analysis and systematic review investigated evidence of the effect of oral micronutrient supplementation on male fertility. Following searches of PubMed, Ovid/Ovid Medline(r) and Embase, 18 randomized, double-blind, placebo-controlled trials were included in the meta-analysis (seven studies) and/or the systematic review (12 studies). The meta-analysis showed significant improvement in semen parameters for selenium (200µg/day and 100µg/day) (standard mean difference [SMD] 0.64 for oligozoospermia, 1.39 for asthenozoospermia), L-carnitine (2 g/day) and acetyl-L-carnitine (LAC; 1 g/day) combined (SMD 0.57 for asthenozoospermia), and co-enzyme Q10 (200 and 300 mg/day) (SMD 0.95 for oligozoospermia, 1.48 for asthenozoospermia, 0.63 for teratozoospermia). The systematic review identified promising data for supplementation with 66 mg/day zinc combined with folic acid (5 mg/day), and the polyunsaturated fatty acids eicosapentaenoic acid (EPA; 1.12 g/day) and docosahexaenoic acid (DHA; 0.72 g/day). Pregnancy rate was evaluated in a limited number of trials (four in the meta-analysis, three in the systematic review). This analysis suggests supplementation with selenium (alone or combined with N-acetylcysteine), co-enzyme Q10 and the combinations L-carnitine + acetyl-L-carnitine, folic acid + zinc and EPA + DHA is beneficial in the treatment of male infertility. Because of the small number of available studies and low number of participants, further well-designed clinical studies are needed to obtain a better overview of efficient methods of treating male infertility.     

Determination of Some Ethnomedicinally Important Constituents of Aegle marmelos Fruit During Different Stages of Ripening

AIM:Aegle marmelos is a medicinal herb belonging to the Rutacae family.The fruit of A.marmelos at each stage of ripening is used as ethnomedicine to cure various diseases.The aim of the present study was to determine the components contributing to the medicinal value of the A.marmelos fruit at different stages of ripening.METHODS:High-performance liquid chromatography(HPLC)was used to determine polyphenol,vitamins,organic acids and sugars in A.marmelos fruit at different stages of ripening.RESULTS:Tannin,a ...     

Micronutrients reduce stress and anxiety in adults with Attention-Deficit/Hyperactivity Disorder following a 7.1 earthquake

The role of good nutrition for resilience in the face of stress is a topic of interest, but difficult to study. A 7.1 earthquake took place in the midst of research on a micronutrient treatment for Attention-Deficit/Hyperactivity Disorder (ADHD), providing a unique opportunity to examine whether individuals with ADHD taking micronutrients demonstrated more emotional resilience post-earthquake than individuals with ADHD not taking micronutrients. Thirty-three adults with ADHD were assessed twice following the earthquake using a measure of depression, anxiety and stress also completed at some point pre-earthquake (baseline). Seventeen were not taking micronutrients at the time of the earthquake (control group), 16 were (micronutrient group). While there were no between-group differences one week post-quake (Time 1), at two weeks post-quake (Time 2), the micronutrient group reported significantly less anxiety and stress than the controls (effect size 0.69). These between group differences could not be explained by other variables, such as pre-earthquake measures of emotions, demographics, psychiatric status, and personal loss or damage following the earthquake. The results suggest that micronutrients may increase resilience to ongoing stress and anxiety associated with a highly stressful event in individuals with ADHD and are consistent with controlled studies showing benefit of micronutrients for mental health.     

Metabolomic study on vitamins B₁, B₂, and PP supplementation to improve serum metabolic profiles in mice under acute hypoxia based on ¹H NMR analysis

Objective To explore metabolic changes after acute hypoxia and modulating effect of vitamins B1, B2, and PP supplementation in mice exposed to acute hypoxia. Methods Fifty male Kunming mice were randomly divided into 5 groups： normal, acute hypoxia, acute hypoxia with 2, 4 and 8 time- vitamins B1, B2, and PP supplementation . All mice were fed with corresponding diets for two weeks and then were exposed to a simulated altitude of 6 000 meters for 8 h, except for the normal group. Nuclear magnetic resonance analysis was used to identify the changes of serum metabolic profiles. Results There were significant changes in some serum metabolites under induced acute hypoxia, essentially relative increase in the concentrations of lactate, sugar and lipids and decrease in ethanol. The serum levels of choline, succinate, taurine, alanine, and glutamine also increased and phosphocholine decreased in the acute hypoxia group. After vitamins B1, B2, and PP supplementation, all these metabolic changes gradually recovered. Conclusion Significant changes in serum metabolic profile were observed by metabolomics in mice exposed to acute hypoxia, and vitamins B1, B2, and PP supplementation proved to be beneficial to improving some metabolic pathways. It is suggested that the dietary intakes of vitamins B1, B2, and PP should be increased under hypoxia condition.