European Journal of Nutrition (v.48, #7)
Hypocholesterolemic effect of Nostoc commune var. sphaeroides Kützing, an edible blue-green alga by Heather E. Rasmussen; Kara R. Blobaum; Elliot D. Jesch; Chai Siah Ku; Young-Ki Park; Fan Lu; Timothy P. Carr; Ji-Young Lee (387-394).
Intake of an edible blue-green alga Nostoc commune var. sphaeroides Kützing (N. Commune) has been shown to lower plasma total cholesterol concentration, but the mechanisms behind the hypocholesterolemic effect have not been elucidated.To elucidate the mechanisms underlying the cholesterol-lowering effect of N. commune in mice. Male C57BL/6J mice were fed the AIN-93 M diet supplemented with 0 or 5% (wt/wt) dried N. Commune for 4 weeks. Lipid levels in the plasma and liver, intestinal cholesterol absorption and fecal sterol excretion were measured. Expression of hepatic and intestinal genes involved in cholesterol metabolism was evaluated by quantitative realtime PCR. N. commune supplementation significantly reduced total plasma cholesterol and triglyceride concentrations by ~ 20% compared to controls. Intestinal cholesterol absorption was significantly decreased, while fecal neutral sterol output was significantly increased in N. commune-fed mice. mRNA levels of the cholesterol transporters such as Niemann Pick C1 Like 1, scavenger receptor class B type 1, ATP-binding cassette transporters G5 and A1 in small intestine were not significantly different between two groups. Hepatic lipid contents including total cholesterol, triglyceride and free cholesterol in N. commune-fed mice were not significantly altered. However, the expression of cholesterol modulating genes including sterol regulatory element binding protein-2 and 3-hydroxy-3-methylglutaryl coenzyme A reductase were significantly increased in mice fed N. commune. N. commune supplementation exerted a hypocholesterolemic effect in mice, largely in part, by reducing intestinal cholesterol absorption and promoting fecal neutral sterol excretion.
Keywords: Blue-green algae; Nostoc commune var. sphaeroides Kützing ; Cholesterol metabolism; Cholesterol absorption
The influence of dietary fibre source and gender on the postprandial glucose and lipid response in healthy subjects by Matilda Ulmius; Anna Johansson; Gunilla Önning (395-402).
Consumption of soluble dietary fibre is correlated with decreased postprandial glucose and insulin responses and hence has beneficial effects on the metabolic syndrome.To investigate the effects on postprandial glucose, insulin and triglyceride concentrations of meals enriched with soluble dietary fibres from oats, rye bran, sugar beet fibre or a mixture of these three fibres.Thirteen healthy human volunteers (6 men and 7 women, aged 20–28 years) were included in the study. The subjects came to the study centre once a week after an overnight fast to ingest test meals and a control meal in random order. The meals contained either oat powder (62 g, of which 2.7 soluble fibre), rye bran (31 g, of which 1.7 g soluble fibre), sugar beet fibre (19 g, of which 5 g soluble fibre), a mixture of these three fibres (74 g, of which 1.7 g soluble fibre from each source, giving 5 g soluble fibre) or no added fibre (control) and were all adjusted to contain the same total amount of available carbohydrates. Blood samples were drawn before and every 30 min up to 180 min after the meals.Meals with rye bran gave a lower postprandial glucose peak when compared with the control meal, and this effect was more pronounced in women compared to men. Oat powder, containing a low amount of total fibre and a high amount of carbohydrates in liquid matrix, gave a higher incremental glucose peak concentration compared to rye bran and sugar beet fibre and higher insulin incremental area under curve compared to control. The oat powder also influenced the effects of the mixed meal, diminishing the glucose-lowering effects. Postprandial triglyceride levels tended to be higher after all fibre-rich meals, but only significant for oat powder and the mixed meal when compared with the control meal.Postprandial glucose, insulin and triglyceride concentrations are influenced by dietary fibre-rich meals, depending on fibre source, dose of soluble and total fibre and possibly gender.
Keywords: Oats; Rye; Sugar beet fibre; Glucose; Insulin; Triglyceride; Gender
Adipocyte fatty acid binding protein during refeeding of female patients with anorexia nervosa by Julia Engl; Alexander Tschoner; Michael Willis; Ingrid Schuster; Susanne Kaser; Markus Laimer; Wilfried Biebl; Josef R. Patsch; Barbara Mangweth; Christoph F. Ebenbichler (403-408).
Adipocyte fatty acid binding protein (A-FABP) has been suggested to play an important role in fat metabolism linking obesity and the metabolic syndrome. Increasing A-FABP plasma levels were observed during greatest weight loss after bariatric surgery suggesting that A-FABP may indicate changes in fat mass in dynamic situations.As there are no data on weight gain, we investigated the effect of refeeding anorexic patients on body composition and A-FABP plasma levels.Parameters of glucose and lipid metabolism as well as plasma levels of leptin and A-FABP were prospectively assessed in 16 female patients with anorexia nervosa during inpatient weight restoration. Body composition was determined by multifrequency body impedance analysis.After 28 days, fat mass increased from 4.4 ± 2.5 kg at baseline to 5.5 ± 2.2 kg (P < 0.01), constituting 40% of total weight gain. Conversely, A-FABP concentrations decreased from 32.56 ± 35.59 ng/ml at baseline to 21.27 ± 13.68 ng/ml (P < 0.05), which corresponds to a significant decrease in the proportion of A-FABP per kilogram fat mass from 7.86 ± 5.23 to 4.09 ± 2.12 ng/ml/kg (P ≤ 0.001). Variation in A-FABP plasma concentration was predictive for changes in total cholesterol levels (adjusted r 2 = 0.239; P ≤ 0.05), but not for gain in weight, fat mass, or percent body fat.The present results indicate that variation in A-FABP plasma levels reflect alterations in nutritional status in patients with anorexia nervosa.
Keywords: A-FABP; Weight gain; Metabolism; Anorexia nervosa
Effect of CLA isomers and their mixture on aging C57Bl/6J mice by Ganesh V. Halade; Md. M. Rahman; Gabriel Fernandes (409-418).
Dietary supplements containing conjugated linoleic acid (CLA) are widely promoted for weight loss management over the counter. Recently, FDA approved the CLA as Generally Recognized as Safe category so that it can be used in various food and beverages. The combined effect of CLA isomers have been studied extensively in animals and humans, however, the role of individual isomers remains unraveled.The present investigation addresses the effects of CLA isomers on body composition and body weight as well as safety using female C57Bl/6J aging mice.Two main CLA isomers and their mixture were fed to 12-months-old female C57Bl/6J mice. Ten percent corn oil (CO) based fat diet supplemented with 0.5% purified cis 9 trans 11 (c9,t11) CLA or trans 10 cis 12 (t10,c12) CLA or their mixture (CLA mix, 50:50) for 6 months. The lean mass, fat mass, glucose, non-esterified fatty acids, and insulin were examined at the end of study.As a result of 6 months dietary intervention, both t10,c12 CLA and CLA mix groups showed increased lean mass and reduced fat mass compared to that of c9,t11 CLA and CO group. However, insulin resistance and liver hypertrophy were observed in t10,c12 CLA and CLA mix groups based on the results of homeostasis model assessment, revised quantitative insulin-sensitivity check index (R-QUICKI), intravenous glucose tolerance test, and liver histology. Liver histology revealed that increased liver weight was due to hypertrophy.In conclusion, the major CLA isomers have a distinct effect on fat mass, glucose, and insulin metabolism. The t10,c12 isomer was found to reduce the fat mass and to increase the lean mass but significantly contributed to increase insulin resistance and liver hypertrophy, whereas c9,t11 isomer prevented the insulin resistance. Between the two major CLA isomers, the t10,c12 was attributed to reduce fat mass whereas, c9,t11 improves the insulin sensitivity.
Keywords: Obesity; Conjugated linoleic acid; Fat mass; Glucose; Insulin
Ability of probiotic Lactobacillus casei DN 114001 to bind or/and metabolise heterocyclic aromatic amines in vitro by Adriana Nowak; Zdzislawa Libudzisz (419-427).
Heterocyclic aromatic amines (HCA) are compounds with high mutagenic potential, formed when meat is cooked at high temperatures of 150–300 °C. These compounds contribute to development of colon and gastric cancer. Western diet provides a lot of HCA and influences the available substrates for the intestinal microbiota which can activate HCA to direct acting mutagens. On the other hand, lactic acid bacteria existing in the colon and ingested with food including probiotics, may exert an anti-carcinogenic action, but the mechanism is still poorly understood.In the present study we determined the ability of probiotic Lactobacillus casei DN 114001 (Actimel strain) to metabolise or adsorb three HCA: IQ, MelQx and PhIP in vitro. Lactobacilli were cultivated in MRS and in a modified MRS broth with reduced concentrations of nitrogen and carbon (MRS NC), with addition of 25 μg/ml of IQ, MelQx or PhIP. Their concentration after cultivation with L. casei DN 114001 was measured with high-performance liquid chromatography and the genotoxicity was evaluated by the alkaline comet assay.It was measured, that after 24 h cultivation in MRS (cell density was 109 cfu/ml), rapid decrease of IQ and PhIP (98–99%) was observed, and the peaks on chromatograms were almost completely reduced. In case of MeIQx the decrease was about 27%. In a modified MRS broth (cell density was 108 cfu/ml), the ability to decrease HCA concentration during prolonged cultivation (to 168 h) depended on the growth phase of bacteria, and it was about 51.5% for IQ and at about 11.2% for MeIQx. Non-growing cells (in phosphate buffer), could reduce the content of IQ and PhIP from 72 h to the end of incubation. L. casei DN 114001 reduced genotoxicity of HCA (IQ from 46 to 48%; MeIQx from 35 to 65% and PhIP from 32 to 81%), and the degree depended on the incubation time, cell growth and the medium used. It may suggest that bacteria can metabolise or adsorb HCA.
Keywords: Probiotics; Lactobacillus ; Heterocyclic aromatic amines; DNA damage
Mitochondrial DNA deletions of blood lymphocytes as genetic markers of low folate-related mitochondrial genotoxicity in peripheral tissues by Yi-Fang Chou; Rwei-Fen S. Huang (429-436).
A low folate status and mitochondrial DNA (mtDNA) mutations are risk factors for various cancers and degenerative diseases. It is not known if lymphocytic mtDNA deletions can be used as genetic “markers” to reflect global mtDNA damage during folate deficiency.The aim of this study was to characterize folate-related mtDNA deletions in lymphocytes and their associations with mt genotoxicity in peripheral tissues.Weaning Wistar rats were fed folate-deficient and folate-replete (control) diets for 2 and 4 weeks. Folate levels of blood lymphocytes and various tissues were assayed by the Lactobacillus casei method. mtDNA deletions were measured by a real-time polymerase chain reaction analysis of whole DNA extracts.Compared to the control counterparts, mtDNA deletions of lymphocytes increased by 3.5-fold (P < 0.05) after 4 weeks of folate deficiency. Lymphocytic mtDNA deletions were inversely associated with plasma (r = −0.619, P = 0.018), red blood cell (r = −0.668, P = 0.009), and lymphocytic folate levels (r = −0.536, P = 0.048). Frequencies of lymphatic mtDNA deletions were positively correlated with mtDNA deletions in tissues including the lungs (r = 0.803, P = 0.0005), muscles (r = 0.755, P = 0.001), heart (r = 0.633, P = 0.015), liver (r = 0.722, P = 0.003), kidneys (r = 0.737, P = 0.006), pancreas (r = 0.666, P = 0.009), and brain (r = 0.917, P < 0.0001). Conclusions: Our data demonstrate that accumulated mtDNA deletions of lymphocytes depended upon dietary folate deprivation. The accumulated mt deletions in lymphocytes closely reflected the mt genotoxicity in the peripheral tissues during folate deficiency.
Keywords: Folate deficiency; mtDNA deletions; Lymphocytes; Genetic marker; Peripheral tissues
Chronic undernutrition alters renal active Na+ transport in young rats: potential hidden basis for pathophysiological alterations in adulthood? by João H. Costa-Silva; Paulo A. Silva; Nadir Pedi; Ricardo Luzardo; Marcelo Einicker-Lamas; Lucienne S. Lara; Amélia M. Bezerra; Carmen Castro-Chaves; Adalberto Vieyra (437-445).
Epidemiological studies in the northeastern region of Brazil show an association between hypertension and malnutrition, especially in areas where protein-deficient diets are combined with high salt intake. We studied the consequences of a widely consumed deficient diet (basic regional diet, BRD), combined with high NaCl, on growth, renal Na+ and water handling and activities of ATP-dependent Na+ transporters in kidney proximal tubules.Young rats were fed after weaning with a low-protein and high-salt diet, which mimics that used in a vast region of Brazil. Body mass was evaluated from weaning up to the 19th week of age. Glomerular filtration rate, proximal Na+ reabsorption, distal Na+ delivery, urinary excretion of Na+ and water, and urine concentration capacity were evaluated from serum and urine concentrations of creatinine, Na+ and Li+, and by measurement of urinary volume and density. The (Na+ + K+)ATPase and the ouabain-insensitive Na+-ATPase were studied in vitro by measuring ATP hydrolysis. Expression of (Na+ + K+)ATPase was evaluated by immunodetection with the use of a specific antibody anti α1-catalytic subunit isoform.Undernourished rats reached early adulthood (14 weeks) with body and renal masses that were 2.3 times lower than controls. These rats became hypertensive (mean arterial pressure 18.7 ± 0.6 kPa vs 15.5 ± 0.9 kPa in control group) and showed augmented fractional proximal Na+ reabsorption (61.0 ± 0.3% vs 81.8 ± 2.2%) with a concomitant decrease in distal Na+ delivery (9.5 ± 0.5 μmol/min vs 14.0 ± 0.2 μmol/min per 100 g body weight). Urinary Na+ excretion was higher in BRD rats, (juvenile and adult) being however twice the increase in Na+ intake. The ATP-dependent Na+ transporters were affected in opposite ways. The (Na+ + K+)ATPase activity from undernourished rats fell by 30%, in parallel with a 20% decrease in its immunodetection, whereas the ouabain-insensitive Na+-ATPase, which is responsible for the fine-tune control of Na+ reabsorption, increased threefold.We conclude that early alterations in proximal tubule Na+ pumps, together with an abnormally augmented urinary Na+ excretion, might be the link between undernutrition and late renal dysfunction.
Keywords: Chronic undernutrition; (Na+ + K+)ATPase; Na+-ATPase; Renal sodium handling; Alterations in renal transporters