European Journal of Nutrition (v.41, #2)
Serum depletion and bioavailability of lutein in Type I diabetic patients by F. Granado; B. Olmedilla; I. Blanco (47-53).
Background Lutein, a non-provitamin A carotenoid, is frequently consumed in the human diet. It is distributed preferentially in certain human tissues (i. e., retina) and shows a high antioxidant activity. Type 1 diabetic patients have been considered to be at risk of increased oxidative stress that may contribute to accelerated atherogenesis and to the microangiopathic complications of the disease. Aim of the study To assess the influence of type 1 diabetes mellitus on the serum depletion rate and bioavailability of lutein. Subjects and Methods Ten type 1 diabetics and eight controls consumed a low carotenoid diet for 21 days and the bioavailability study was performed in 7 diabetics and 5 controls on day 15 with the administration of a capsule of lutein esters from marigold extract. Samples were collected at baseline and on days 1, 2, 3, 6, 11, 15 (eight times during 9 h), 16, 17 and 21. Lutein and other carotenoids were determined by HPLC in triglyceride-rich lipoprotein (TRL) fractions and plasma or serum. Results Serum depletion curve, area of concentrations under time curve (AUC) and final concentration percentages were similar in diabetics and controls. In the bioavailability study, all-trans-lutein increased in both groups and AUC, maxima concentrations in TRL and serum and time required for maxima concentration in serum were similar in diabetics and controls. Conclusions These data suggest that in the group of patients assessed, type 1 diabetes mellitus does not apparently influence the absorption and depletion rate of lutein in serum.
Keywords: Key words Lutein – serum depletion rate – bioavailability – carotenoids – type 1 diabetes mellitus
Effects of non-esterified stanols in a liquid emulsion on cholesterol absorption and synthesis in hypercholesterolemic men by G. Gremaud; E. Dalan; C. Piguet; M. Baumgartner; P. Ballabeni; B. Decarli; M. E. Leser; A. Berger; L. B. Fay (54-60).
Background Background Numerous studies have shown that dietary plant sterols (phytosterols and phytostanols) and their esters can decrease cholesterol absorption. However, few researchers have examined the effects of plant sterols on cholesterol absorption and synthesis using stable isotope tracers, instead of relying on endogenous pathway precursors. Further, we have worked with non-esterified lecithin-solubilized stanols as opposed to the more frequently studied esterified sterols and stanols. The vehicle was an oil-in-water liquid emulsion rather than the more common spread vehicle typically employed. Aim of the study To determine the effects of relatively low doses of lecithin-solubilized non-esterified stanols in liquid emulsions on cholesterol absorption and synthesis in mildly hypercholesterolemic subjects. Methods In a randomized, double blind crossover design, 12 mildly hypercholesterolemic men received either a free phytostanol supplement (3 g/d in 3 servings) or a control treatment for 3 days. Cholesterol endogenous synthesis rate was determined using the rate of incorporation of deuterium from body water into newly formed cholesterol molecules. Cholesterol absorption at the intestinal level was determined using the dual isotope method using 13C cholesterol injected intravenously and 18O cholesterol given orally. Results Cholesterol absorption was 55.7 ± 6.5 % for the control and 33.5 ± 5.3 % for the phytostanol treatment. This massive reduction of the cholesterol absorption did not induce, on average, a difference in cholesterol endogenous synthesis which was measured at 0.074 ± 0.0015 pool/d for plant sterols and 0.0736 ± 0.0015 pool/d for controls (p > 0.05). Conclusions The results demonstrated that lecithin-solubilized stanols administrated during a short period of time (3 days) in an oil-in-water emulsion can dramatically decrease cholesterol absorption, without a consistent, concomitant increase in synthesis, which is highly suggestive of effective LDL cholesterol lowering. The effects of synthesis should be verified in a longer study with more subjects.
Keywords: Key words Plant sterols – stanols – phytostanols – cholesterol – absorption – synthesis – stable isotopes – IRMS – plant sterol – hypercholesterolemia – sitostanol
Use of BMI as a measure of overweight and obesity in a field study on 5–7 year old children by M. Mast; K. Langnäse; K. Labitzke; U. Bruse; U. Preuß; M. J. Müller (61-67).
Objective The present field study examines the use of BMI in comparison with estimates of percent fat mass to screen for overweight and obesity in children. Design Cross-sectional field study. Setting Four waves of children 1996–1999 at Kiel, North West Germany. Subjects A representative large sample of 2286 5–7 year old children representing 40 % of the total child population examined by school physicians within the same period in Kiel. Main outcome measures BMI was compared with anthropometric measures (TSF, BSF, SIF, SSF) and bioelectrical impedance analysis (BIA). The 90th and 97th BMI percentiles were used as cut offs for overweight and obesity, respectively. Results BMI reached a low sensitivity to identify overweight children when compared with the two estimates of % FM (0.60 to 0.78 for girls, 0.71 to 0.82 for boys, respectively). The specificity of BMI was 93 to 95 %. By contrast, BMI reached higher sensitivity to screen for obese children of 0.83 to 0.85 for boys and 0.62 to 0.80 for girls at a concomitant specificity of 0.95 to 0.98 for boys and 0.96 to 0.97 for girls as defined by assessment of body fat mass. Comparing nutritional status of overweight children classified as overweight or non overweight by BMI shows that BMI only identified obese but not-overweight children. Conclusion BMI can be used to screen for obese children. In contrast BMI has a poor sensitivity to screen for overweight children. Body composition analysis should be used to screen for children at risk of becoming obese.
Keywords: Key words BMI – fat mass – overweight – obesity – children
Hyperhomocysteinemia, and low intakes of folic acid and vitamin B12 in urban North India by Anoop Misra; Naval K. Vikram; R. M. Pandey; Manjari Dwivedi; Faiz Uddin Ahmad; Kalpana Luthra; Kajal Jain; Nidhi Khanna; J. Rama Devi; Rekha Sharma; Randeep Guleria (68-77).
Background and Aim An adverse coronary risk profile has been reported amongst rural-to-urban migrant population living in urban slums undergoing stressful socio-economic transition. These individuals are likely to have low intakes of folic acid and vitamin B12, which may have an adverse impact on serum levels of homocysteine (Hcy). To test this hypothesis, we studied serum levels of Hcy in subjects living in an urban slum of North India and healthy subjects from urban non-slum area. Methods Group I consisted of 46 subjects (22 males and 24 females) living in an urban slum, while group II consisted of healthy subjects (n = 26, 13 males and 13 females) living in the adjacent non-slum area. Anthropometric measurements, biochemical profile (fasting blood glucose, total cholesterol, serum triglycerides, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol) and fasting serum levels of Hcy were measured. Dietary intakes of folic acid, vitamin B12, vitamin B1, and iron were calculated by the 24-hour dietary recall method. Serum levels of Hcy were correlated with dietary intakes of nutrients, anthropometry, and metabolic variables. Results Sex-adjusted serum levels of Hcy in mmol/L (Mean ± SD) were high, though statistically comparable, in both the groups (group I: 20.8 ± 5.9 and group II: 23.2 ± 5.9). Overall, higher than normal serum levels of Hcy (> 15 μmol/L) were recorded in 84 % of the subjects. A substantial proportion of subjects in both groups had daily nutrient intakes below that recommended for the Asian Indian population (folic acid: 93.4 % in group I and 96.7 % in group II, vitamin B12: 76.1 % in group I and 88.4 % in group II). However, between the two groups, average daily dietary intakes of both the nutrients were statistically comparable. As compared to non-vegetarians, vegetarians showed lower intakes of folic acid (p < 0.01) and vitamin B12 (p < 0.01) in both groups. On multivariate linear regression analysis with serum Hcy as the response variable and vegetarian/non-vegetarian status and sex (male/female) as predictor variables, higher serum levels of Hcy were observed in vegetarians vs non-vegetarians (β = 4.6, p < 0.05) and males vs females (β = 5.3, p < 0.01). Conclusions Low intakes of folic acid and vitamin B12, and hyperhomocysteinemia, in both the healthy population living in urban slums and adjacent urban non-slum areas, are important observations for the prevention of nutritional and cardiovascular diseases in the Indian subcontinent.
Keywords: Key words Homocysteine – Vegetarians – Coronary heart disease – Asian Indians – Folic acid – Vitamin B12
Biotinidase catalyzes debiotinylation of histones by Tyrie D. Ballard; Jon Wolff; Jacob B. Griffin; J. Steven Stanley; Sandy van Calcar; Janos Zempleni (78-84).
Background Posttranslational modifications of histones play important roles in processes such as regulation of gene expression and DNA repair. Recently, evidence has been provided that histones in human cells are modified by covalent attachment of biotin. Aim of the study To determine whether the reverse process (debiotinylation of histones) occurs in biological samples and whether debiotinylation is an enzyme-mediated process; and to characterize the enzyme that mediates debiotinylation of histones. Methods Plasma and lymphocytes from healthy adults and a biotinidase-deficient patient were used as sources of debiotinylating enzymes. Debiotinylation of histones by plasma and lymphocyte proteins was measured using a colorimetric 96-well plate assay. Results Histones were debiotinylated rapidly if incubated with human plasma or lysates of lymphocytes. The following observations are consistent with the hypothesis that debiotinylation is an enzyme-mediated process: (i) Hydrolysis was slower at 4 °C compared to 37 °C; (ii) debiotinylating activity was destroyed when biological samples were heated at 90 °C for 30 min preceding incubation with biotinylated histones; and (iii) rates of debiotinylation were pH dependent. Rates of histone debiotinylation were significantly decreased in biotinidase-deficient samples. Conclusion Debiotinylation of histones in human samples is an enzyme-mediated process that is at least partly catalyzed by biotinidase.
Keywords: Key words Biotin – Biotinidase – Biotinylation – Debiotinylation – Histone
Detection of ligands for selectins in the oligosaccharide fraction of human milk by Silvia Rudloff; Christina Stefan; Gottfried Pohlentz; Clemens Kunz (85-92).
Background Human milk contains a large variety of oligosaccharides which show structural similarities with ligands for selectins, a family of cell adhesion molecules which are involved in many cell-cell interactions. Aim of the study Due to their structural similarity with selectin ligands, human milk oligosaccharides were labelled with phosphatidyl ethanolamine to be able to investigate specific effects of antibodies against carbohydrate epitopes. Methods Various monoclonal antibodies against physiological selectin ligands were used to determine whether epitopes within human milk oligosaccharides are recognized. Oligosaccharides were isolated from human milk, transferred into neoglycolipids and separated using high performance thin layer chromatography prior to incubation with monoclonal antibodies for the selectin ligands sialyl-Lewis a (sLe a), sialyl-Lewis x (sLe x), Lewis x (Le x) and Lewis y (Le y) after Western blotting. Fast atom bombardment-mass spectrometry was then used to identify antibody-binding compounds. Results In the immunoassays all ligand epitopes except for Le y were detected in the oligosaccharide fraction of human milk. Anti-sLe a showed the most distinct reaction with N-acetylneuraminic acid containing neoglycolipids of which two were identified as neuraminyl-fucosyl-lacto-N-hexaose and neuraminyl-lacto-N-tetraose. Such oligosaccharides as well as similar structures are present in relatively high concentrations in human milk. Conclusions The presence of sialyl-Lewis ligands on milk oligosaccharides together with their abundancy in human milk may suggest that they could be selectin ligands and they may be part of inflammatory processes.
Keywords: Key words Human milk – selectin ligands – oligosaccharides – neoglycolipids
Congress Announcements (93-93).