Guest guest Posted September 1, 2005 Report Share Posted September 1, 2005 J Nutr. 2005 Sept;135(9) Hi All. A new issue of Journal of Nutrition has been made available, and the not pdf-available papers for which Medline has no records and abstracts were available and of interest, were: 1 September 2005; Vol. 135, No. 9 ----------------------------------------------------------------- Recent Advances in Nutritional Sciences ----------------------------------------------------------------- Mechanisms by which Dietary Fatty Acids Modulate Plasma Lipids Luz Fernandez and Kristy L. West J. Nutr. 2005;135 2075-2078 Dietary fatty acids have a considerable effect on plasma LDL cholesterol (LDL-C) concentrations and therefore on the risk for coronary heart disease. Numerous studies have been conducted in animal models to elucidate the mechanisms by which different types of fatty acids modulate plasma cholesterol concentrations. In addition, multiple clinical trials and epidemiological data have demonstrated the effects of fatty acids in determining the concentrations of circulating LDL. SFAs and trans fatty acids have a detrimental effect on plasma lipids, whereas PUFAs of the (n-6) family and monounsaturated fatty acids decrease plasma LDL-C concentrations. Among the SFAs, stearic acid (18:0) appears to have a neutral effect on LDL-C, while lauric (12:0), myristic (14:0), and palmitic (16:0) acids are considered to be hypercholesterolemic. SFAs increase plasma LDL-C by increasing the formation of LDL in the plasma compartment and by decreasing LDL turnover. Although unsaturated fatty acids increase cholesterol synthesis, they also increase hepatic LDL receptor number and LDL turnover in vivo. Fatty acids are also ligands of important regulatory elements, which can play a role in determining plasma cholesterol. This article presents a summary of the major effects of various types of fatty acids on plasma lipid concentrations and the mechanisms involved. ----------------------------------------------------------------- Critical Reviews ----------------------------------------------------------------- A Systematic Review of the Effects of Nuts on Blood Lipid Profiles in Humans Janine Mukuddem-sen, Welma Oosthuizen, and Johann C. Jerling J. Nutr. 2005;135 2082-2089 The inverse association of nut consumption and risk markers of coronary heart disease (lipids) has sparked the interest of the scientific and lay community. The objective of this study was to conduct a systematic review to investigate the effects of nuts on the lipid profile. Medline and Web of Science databases were searched from the start of the database to August 2004 and supplemented by cross-checking reference lists of relevant publications. Human intervention trials with the objective of investigating independent effects of nuts on lipid concentrations were included. From the literature search, 415 publications were screened and 23 studies were included. These papers received a rating based upon the methodology as it appeared in the publication. No formal statistical analysis was performed due to the large differences in study designs of the dietary intervention trials. The results of 3 almond (50–100 g/d), 2 peanut (35–68 g/d), 1 pecan nut (72 g/d), and 4 walnut (40–84 g/d) studies showed decreases in total cholesterol between 2 and 16% and LDL cholesterol between 2 and 19% compared with subjects consuming control diets. Consumption of macadamia nuts (50–100 g/d) produced less convincing results. In conclusion, consumption of 50–100 g (1.5–3.5 servings) of nuts 5 times/wk as part of a heart-healthy diet with total fat content (high in mono- and/or polyunsaturated fatty acids) of 35% of energy may significantly decrease total cholesterol and LDL cholesterol in normo- and hyperlipidemic individuals. ----------------------------------------------------------------- Biochemical and Molecular Actions of Nutrients ----------------------------------------------------------------- Isoleucine, a Blood Glucose-Lowering Amino Acid, Increases Glucose Uptake in Rat Skeletal Muscle in the Absence of Increases in AMP-Activated Protein Kinase Activity Masako Doi, Ippei Yamaoka, Mitsuo Nakayama, Shinji Mochizuki, Kunio Sugahara, and Fumiaki Yoshizawa J. Nutr. 2005;135 2103-2108 Leucine and isoleucine were shown to stimulate insulin-independent glucose uptake in skeletal muscle cells in vitro. In this study, we examined the effects of leucine and isoleucine on blood glucose in food-deprived rats and on glucose metabolism in skeletal muscle in vivo. Furthermore, we investigated the possible involvement of the energy sensor, 5'-AMP-activated protein kinase (AMPK), in the modulation of glucose uptake in skeletal muscle, which is independent of insulin, and also in leucine- or isoleucine-stimulated glucose uptake. Oral administration of isoleucine, but not leucine, significantly decreased the plasma glucose concentration. An i.v. bolus of 2-[1,2-3H]-deoxyglucose (2-[3H]DG) was administered to calculate glucose uptake. Glucose uptake in the skeletal muscle did not differ after leucine administration, but glucose uptake in the muscles of rats administered isoleucine was 73% greater than in controls, suggesting that isoleucine increases skeletal muscle glucose uptake in vivo. On the contrary, in the skeletal muscles, administration of leucine but not isoleucine significantly increased [u-14C]-glucose incorporation into glycogen compared with controls. AMPK 1 activity in skeletal muscle was not affected by leucine or isoleucine administration. However, isoleucine, but not leucine, significantly decreased AMPK 2 activity. The decrease in AMPK 2 activity was thought to be due to decreases in AMP content and the AMP:ATP ratio, which were related to the isoleucine administration. This is the first report of isoleucine stimulating glucose uptake in rat skeletal muscle in vivo, and these results indicate that there might be a relation between the reduction in blood glucose and the increase in skeletal muscle glucose uptake that occur with isoleucine administration in rats. The alterations in glucose metabolism caused by isoleucine may result in an improvement of the availability of ATP in the absence of increases in AMP-activated protein kinase activity in skeletal muscle. ----------------------------------------------------------------- Nutrition and Cancer ----------------------------------------------------------------- Lycopene Inhibits Cell Migration and Invasion and Upregulates Nm23-H1 in a Highly Invasive Hepatocarcinoma, SK-Hep-1 Cells Chin-Shiu Huang, Ming-Kuei Shih, Cheng-Hung Chuang, and Miao-Lin Hu J. Nutr. 2005;135 2119-2123 The carotenoid lycopene has been associated with decreased risks of several types of cancer, such as prostate cancer and hepatoma. Tumor metastasis is the most important cause of cancer death. Although lycopene was shown to inhibit metastasis, the mechanism underlying this action is not well understood. Here, we tested the possibility that lycopene may inhibit cancer cell metastasis by upregulating the expression of nm23-H1, a metastasis suppressor gene, in SK-Hep-1 cells, a highly invasive hepatoma cell line, and we determined migration and invasion activities and the expression of nm23-H1 protein and mRNA. We showed that lycopene inhibited SK-Hep-1 migration and invasion in a bell-shaped manner, with the highest effect at 5 µmol/L (91 and 63% inhibition for migration and invasion, respectively; P < 0.05). At the same test level (10 µmol/L), lycopene was much more effective than ß-carotene in reducing cell invasion (by 870%). In contrast to the effects on migration and invasion, lycopene enhanced nm23-H1 expression at both the protein and mRNA levels; the effects were also bell shaped, and at 5 µmol/L, lycopene enhanced nm23-H1 protein and mRNA expressions by 220 ± 33 and 153 ± 22% (P < 0.01), respectively. These bell-shaped effects of lycopene may be related to autoxidation of lycopene at elevated concentrations (10 µmol/L). Significant correlations existed between nm23-H1 protein expression and migration (r2 = 0.78, P < 0.001) and between nm23-H1 protein expression and invasion (r2 = 0.84, P < 0.001) in lycopene-treated SK-Hep-1 cells. We conclude that lycopene has significant antimigration and anti-invasion activity, and that this effect is associated with its induction of nm23-H1 expression. ----------------------------------------------------------------- Human Nutrition and Metabolism ----------------------------------------------------------------- Ingested Fat Oxidation Contributes 8% of 24-h Total Energy Expenditure in Moderately Obese Subjects Bakary J. Sonko, V. Fennessey, ph E. Donnelly, Bessesen, A. Sharp, Dennis J. sen, H. , and O. Hill J. Nutr. 2005;135 2159-2165 .... The aims of this study were to determine the contributions of ingested fat oxidation to: 1) 24-h total energy expenditure (TEE), and 2) substrate oxidation during acute stationary cycle exercises in adult humans. Healthy, moderately obese (n = 18; BMI = 31 ± 1 kg/m2) subjects (8 men; 10 women) were each studied in a whole-room calorimeter for 24 h. They were fed mixed meals (55, 30, and 15% as energy from carbohydrate, fat and protein, respectively) to maintain energy balance. Each subject performed 1255-kJ cycle exercises at 50% VO2max in the calorimeter. Study test meal fat was labeled with carbon-13 (13C). Ingested fat oxidation was estimated from breath 13CO2 excretion and the subject’s chamber CO2 production. Total fat and carbohydrate oxidations were estimated from nonprotein respiratory quotient (NP-RQ) values. Endogenous fat oxidation was estimated as the difference between total fat and ingested fat oxidations. TEE was estimated from gas exchanges; 28 ± 3% of ingested fat was oxidized and it provided 8 ± 1% of 24-h TEE. During cycle exercises, ingested fat provided 50% of total fat oxidized and 13.0 ± 2% of energy expended. Endogenous fat oxidation contributed 10.4 ± 3% of energy expenditure during cycle exercises. This study extended to 24-h observations of previous studies that lasted 6–9 h on ingested fat oxidation in humans. ... ----------------------------------------------------------------- Nutrient Metabolism ----------------------------------------------------------------- The Biodistribution of a Single Oral Dose of [14C]-Lycopene in Rats Prefed Either a Control or Lycopene-Enriched Diet Zaripheh and W. Erdman, Jr. J. Nutr. 2005;135 2212-2218 Lycopene (lyc) has emerged as a primary candidate for dietary interventions of prostate cancer; however, research regarding its absorption, tissue distribution, and metabolism is limited. Previously, we evaluated the biodistribution (3–168 h) of a single oral dose of 14C-lyc in rats prefed lyc for 30 d. The liver was the primary depot for lyc, and the 14C and 14C-polar products appeared in tissues as early as 3 h after dosing. In the current study, F344 rats (n = 48) were randomly assigned to 1 of 4 groups prefed either a control or lyc-enriched diet (0.25 g lyc/kg diet) for 30 d and killed at 5 or 24 h after receiving a single oral dose of 14C-lyc. The percentage of the 14C dose absorbed at 24 h was lower (5.5 ± 0.5%) in lyc-prefed (LP) rats than in control-prefed (CP) rats (6.9 ± 0.4%, P < 0.04). Hepatic total 14C and 14C-lyc in CP rats was greater than in LP rats at 24 h (P < 0.005). A portion of 14C was delivered to extrahepatic tissues as early as 5 h, irrespective of diet. Of the tissues analyzed, an increase in the percentage in 14C-polar products occurred between 5 and 24 h only in the prostate and seminal vesicles, suggesting increased accumulation of 14C-polar products in these tissues, irrespective of prior dietary treatment. These data suggest that lyc absorption, tissue uptake, and catabolism were affected by prefeeding and that lyc can be partially taken up by extrahepatic tissues from the postprandial triglyceride-rich fraction. ----------------------------------------------------------------- Nutritional Epidemiology ----------------------------------------------------------------- Elevated Serum Fluoride Concentrations in Women Are Not Related to Fractures and Bone Mineral Density Fran Sowers, M. Whitford, M. Kathleen , and L. Jannausch J. Nutr. 2005;135 2247-2252 Epidemiologic studies of the relations between drinking-water fluoride levels and bone mineral density (BMD) and fracture are characterized by disparate conclusions and an absence of information about individual circulating fluoride levels. This study relates serum fluoride concentrations, which reflect individual fluoride exposures, to BMD and bone fractures. Data are from 1300 female residents of 3 small communities in which the water fluoride concentrations were 52.6 or 210.4 µmol/L. Circulating serum fluoride concentrations were assessed by ion-specific electrode. Fluoride intake was estimated from interviews describing water and water-based beverage consumption and duration of residence in the community. BMD was measured by dual-energy X-ray densitometry and single-photon densitometry. Self-reported fractures were confirmed by medical record abstraction. The mean serum fluoride concentration in the high-fluoride community, 2.11 ± 0.05 µmol/L, was significantly higher than serum fluoride concentrations in the control and high-calcium communities with water fluoridation to 52.6 µmol/L. The mean serum fluoride concentrations in these latter 2 communities were 1.6 ± 0.04 and 1.22 ± 0.05 µmol/L, respectively. Serum fluoride was not significantly related to BMD after adjusting for covariates including age and body size. The mean distal radius BMD, however, was significantly higher in the high-fluoride community. Serum fluoride concentrations were not related to incident osteoporotic fractures with 4 y of observation. Serum fluoride concentrations were not associated with BMD or osteoporotic fractures among female residents of communities with water fluoride concentrations of 52.6 or 210.4 µmol/L. Al Pater, PhD; email: old542000@... ____________________________________________________ Start your day with - make it your home page http://www./r/hs Quote Link to comment Share on other sites More sharing options...
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