Showing papers in "European Journal of Nutrition in 1999"

Comparative analysis of the effects of flavonoids on proliferation, cytotoxicity, and apoptosis in human colon cancer cell lines.

Abstract: Flavonoids are polyphenolic compounds that occur ubiquitously in foods of plant origin. Their proposed protective role in tumor development may prevail especially in the intestinal tract due to direct exposure of intestinal epithelia to these dietary ingredients. We have screened more than 30 flavonoids for their effects on cell proliferation and potential cytotoxicity in the human colon cancer cell lines Caco-2, displaying features of small intestinal epithelial cells, and HT-29, resembling colonic crypt cells. In addition, for selected compounds we assessed whether they induce apoptosis by determining caspase-3 activation. Studies on the dose dependent effects of the flavonoids showed antiproliferative activity of all compounds with EC50 values ranging between 39.7 ± 2.3 μM (baicalein) and 203.6 ± 15.5 μM (diosmin). In almost all cases, growth inhibition by the flavonoids occured in the absence of cytotoxicity. There was no obvious structure-activity relationship in the antiproliferative effects either on basis of the subclasses (i.e., isoflavones, flavones, flavonols, flavanones) or with respect to kind or position of substituents within a class.

Dietary flavonoids protect human colonocyte dna from oxidative attack in vitro

Abstract: Background & Aims: Epidemiological studies suggest that antioxidant polyphenols in the human diet may protect against diseases such as cancer. In this study we investigated the cytoprotective potential of the flavonoids, quercetin, myricetin, kaempferol and rutin against oxidative DNA damage in human colonocytes in vitro.

The concept of iron bioavailability and its assessment.

Abstract: In this review a broad overview of historical and current methods for the assessment of iron bioavailability was given. These methods can be divided into iron solubility studies, iron absorption studies, endpoint measures, and arithmetic models. The pros and cons of all methods were discussed. First, studies on in vitro and in vivo iron solubility have been described. The disadvantages of iron solubility include the impossibility of measuring absorption or incorporation of iron. Furthermore, only the solubility of nonheme iron, and not heme iron, can be studied. Second, we focused on iron absorption studies (either with the use of native iron, radioiron or stable iron isotopes), in which balance techniques, whole-body counting or postabsorption plasma iron measurements can be applied. In vitro determination of iron absorption using intestinal loops or cell lines, was also discussed in this part. As far as absorption studies using animals, duodenal loops, gut sacs or Caco-2 cells were concerned, the difficulty of extrapolating the results to the human situation seemed to be the major drawback. Chemical balance in man has been a good, but laborious and expensive, way to study iron absorption. Whole-body counting has the disadvantage of causing radiation exposure and it is based on a single meal. The measurement of plasma iron response did not seem to be of great value in determining nutritional iron bioavailability. The next part dealt with endpoint measures. According to the definition of iron bioavailability, these methods gave the best figure for it. In animals, the hemoglobin-repletion bioassay was most often used, whereas most studies in humans monitored the fate of radioisotopes or stable isotopes of iron in blood. Repletion bioassays using rats or other animals were of limited use because the accuracy of extrapolation to man is unknown. The use of the rat as a model for iron bioavailability seemed to be empirically based, and there were many reasons to consider the rat as an obsolete model in this respect. The double-isotope technique was probably the best predictor of iron bioavailability in humans. Disadvantages of this method are the single meal basis and the exposure to radiation (as far as radioisotopes were used). Finally, some arithmetic models were described. These models were based on data from iron bioavailability studies and could predict the bioavailability of iron from a meal.

Intestinal absorption of lycopene from different matrices and interactions to other carotenoids, the lipid status, and the antioxidant capacity of human plasma.

Abstract: Background: The bioavailability of carotenoids has been investigated in animal studies as well as in human studies, so far mostly for β-carotene. Only few results exist for lycopene. In recent studies, lycopene was significantly better available from processed tomatoes compared to raw tomatoes, when using daily intakes between 16.5 mg and 75 mg lycopene. Aim of the study In a comparative study the availability of a low oral lycopene dosage of 5 mg/d from different food matrices versus soft gel capsules containing tomato oleoresin was assessed. In addition to the plasma carotenoid content, the effect of lycopene ingestion on other plasma carotenoids, the lipid status parameters, and the antioxidant activitys was estimated. Methods Twenty-two female adults (20 – 27 y) were randomized in three groups and were advized to minimize their carotenoid intake for two weeks. After this initial period, two groups received a portion of tomatoes or tomato juice adjusted to a lycopene dose of 5 mg/d, the third group ingested the same dose comprized in soft gel capsules containing tomato oleoresin. During the test period of 6 weeks, the participants continued reducing the intake of carotenoids from food. Fasting blood samples were withdrawn prior to the study, before supplementation started, and then weekly while supplemented. Seven-day dietary records were prepared before the study started and after one week of supplementation. Carotenoids were analyzed by reversed phase HPLC with diode array detection. Dietary records were evaluated using the computer software EBIS 2.1. The plasma total cholesterol, HDL cholesterol, and triglycerides were determined enzymatically. In addition, the antioxidant activity of plasma was estimated by using the TEAC and the TRAP assays. Results The basal levels of lycopene in plasma were comparable for all groups (0.2 – 0.3 μmol/l) and decreased significantly during the two weeks of depletion to approximately 50 % of the basal values. Other plasma carotenoids such as β-carotene and β-cryptoxanthin decreased significantly, too, whereas lutein and zeaxanthin remained unchanged. After supplementation with tomato oleoresin capsules or tomato juice, the plasma lycopene increased significantly, while it remained unchanged during intake of tomatoes. Normal dietary habits were practized of all volunteers before and during the study except vitamin C whose intake was significantly lower during the study period, because the probands were recommended to reduce the intake of fruits and vegetables. Lycopene supplementation did not affect the lipid status parameters of the three groups. After ingestion of lycopene the antioxidant activity of the plasma was not altered. Mean TEAC values were estimated to 0.33 ± 0.05 mmol/l and TRAP values to 1.0 ± 0.1 mmol/l and showed no significant differences in all groups during the whole study period. Conclusions The bioavailability of lycopene varied significantly depending on the administered matrix. Lycopene from tomato oleoresin capsules and tomato juice (processed tomatoes) was better absorbed from the intestine than lycopene from raw tomatoes. The daily intake of 5 mg lycopene, an intake comparable to the usual daily carotenoid intake, did not affect cholesterol and triglycerides in plasma or its antioxidant capacity.

Pollen-related food allergy: cloning and immunological analysis of isoforms and mutants of Mal d 1, the major apple allergen, and Bet v 1, the major birch pollen allergen.

Abstract: Background: Mal d 1, the major apple allergen, cross-reacts with IgE specific for the major birch pollen allergen, Bet v 1, and is responsible for birch pollen related food allergy to apple Isoforms of Bet v 1 showing minor sequence variations display different binding capacitiy for specific IgE antibodies from allergic patients Moreover, strain-dependent variation of allergenicity has been reported for apples

Anthocyanins are potent antioxidants in model systems but do not reduce endogenous oxidative DNA damage in human colon cells.

Abstract: Anthocyanins are common colored plant flavonoids, occurring as glycosides of the respective anthocyanidin-chromophores. Like other flavonoids, anthocyanidins are also expected to have antioxidative and antimutagenic properties in vivo, although only few data are available. To gain more knowledge on possible protective mechanisms in mammalian cells, we have compared their extracellular and intracellular antioxidative potential in vitro and in human colon tumor cells. We used Aronia melanocarpa Elliot anthocyanin (AA) concentrates, fractions thereof, concentrates from Elderberry, Macqui, and Tintorera fruits, as well as pure compounds. In vitro, antioxidative properties of the samples were studied with the ferric reducing ability assay (FRA assay). As a measure of intracellular oxidative/antioxidative effects, H2O2-induced strand breaks as well as oxidized DNA bases were determined in human tumor HT29 clone 19A cells using a microgelelectrophoresis assay (comet test). Major results were that isolated compounds (aglycons and glycosides) and complex plant samples are powerful antioxidants in vitro. In fact their activities by far exceeded those of Trolox and vitamin C in the FRA assay. Also H2O2-induced DNA strand breaks were reduced in cells treated with the complex plant extracts. In contrast, endogenous generation of oxidized DNA bases was not prevented. In summary, the intracellular steady state of oxidized DNA bases is not altered by anthocyanins or anthocyanidins. This findings raises questions with respect to the cancer preventive potential of anthocyanidins within specific tissues, such as the colon. Extracellularly, however, the compounds are potent antioxidants. This points to their potential for providing systemic protection in vivo, e.g., by scavenging oxidants in the blood stream and in the colon. Notably, both aglycons and glycosides have equally strong antioxidant activity.

Plant sterols in vegetables and fruits commonly consumed in Sweden.

Abstract: Plant sterols are known to have serum cholesterol lowering effects. A high dietary intake might therefore have a positive impact on health. All food items of vegetable origin contain some amount of plant sterols. The aim of this study was to analyse the plant sterol content of vegetables and fruits commonly consumed in Sweden, and to compare fresh and cooked samples of the same items. Altogether 20 different vegetables and 14 fruits were analysed. All vegetables and fruits were purchased in two shops in the city of Gothenburg, Sweden. Lyophilization was performed within one month of the items being purchased. The samples were frozen at -20 (C and analysed within six months, with a GLC method after acid hydrolysis, alkaline hydrolysis and silylation with tri-methylsilylether. The acid hydrolysis was done in order to detect the fraction of glycosylated plant sterols, which are split during boiling with HCl. The median plant sterol content of vegetables was 14 (3.8-50) mg/100 g edible portion. The highest concentrations were found in broccoli. Brussels sprouts, cauliflower and olives. The median plant sterol content of fruits was 16 (3-44) mg/100 g edible portion. The highest concentrations were found in oranges and passion fruits. The plant sterol concentrations were thus low in vegetables and fruits commonly consumed in Sweden. A serum cholesterol lowering effect attributed to the plant sterols in vegetables and fruits would therefore be of limited significance.

Validation of a self-administered 3-day estimated dietary record for use in the elderly

Abstract: The aim of this study was to assess the validity of a 3-day estimated dietary record, especially developed for the longitudinal study on nutrition and health status in an aging population (aged ≥ 60 years) in Giessen, Germany. Methods The dietary record comprises 146 food items. Portion sizes of the foods consumed were estimated by means of household measures and corresponding dimensions. The validity of the dietary record was evaluated by means of nitrogen excretion in the 24 h urine in 14 women and 9 men, and by comparing energy intake and basal metabolic rate determined by indirect calorimetry in 238 women and 105 men. Results Neither in women nor in men were any differences found between calculated nitrogen intake (13.4 ± 2.2 g and 15.0 ± 2.0 g, respectively) and nitrogen excretion (12.9 ± 2.1 g and 15.7 ± 3.0 g, respectively). The ratio between reported energy intake and basal metabolic rate was 1.62 ± 0.46 in women and 1.53 ± 0.46 in men. Regarding energy intake, 7.6% of the females and 16.2% of the males were classified as underreporters. They show a significantly higher body weight and BMI than the adequate reporters. Conclusion The results have proved the new 3-day estimated dietary record as suitable to determine energy and nutrient supply of the elderly.

Plasma concentrations of carotenoids in healthy volunteers after intervention with carotenoid-rich foods.

Abstract: Aim of the study: The present study was conducted to investigate changes in the plasma concentration of carotenoids and carotenoid oxidation products, vitamin A, α- and γ-tocopherol, and ubiquinone-10 during a dietary intervention trial with 23 male healthy volunteers. Method: A two week carotenoid depletion period was followed by a daily consumption of 330 mL tomato juice (40 mg lycopene), then by 330 mL carrot juice (15.7 mg α-carotene and 22.3 mg β-carotene), and then by a 10 g spinach powder preparation (11.3 mg lutein and 3.1 mg β-carotene) served with main meals for two weeks, respectively. Blood samples were collected in the morning after an overnight fasting and carotenoids, vitamin A, tocopherols, and ubichinone were analyzed by reversed-phase HPLC. Results: During the tomato juice intervention, plasma concentrations of trans- and cis-lycopene increased 2-fold compared to the depletion period. Lycopene oxidation products could be demonstrated in plasma and were significantly elevated compared to control (p<0.001). After two weeks of carrot juice consumption, α-carotene and β-carotene concentrations increased 8.6- and 3.2-fold, respectively. Finally, during the spinach consumption period the lutein concentration increased 2-fold, while the β-carotene concentrations were still elevated 2-fold. Conclusions: The moderate change in dietary habits, e.g., the consumption of 330 mL of carotenoid-rich vegetable juices caused significant changes in the plasma carotenoid concentrations, indicating a high bioavailability of carotenoids from the processed vegetable products. The changes in plasma carotenoid concentrations reflected the carotenoid composition of the consumed foods. However, particularly during the tomato juice intervention period the occurrence of lycopene oxidation products and cis-lycopene isomers in plasma was eminent. The formation may be due to antioxidant reactions of lycopene in the organism.

Effects of a soy milk supplement on plasma cholesterol levels and oxidative DNA damage in men--a pilot study.

Abstract: Background: Phytoestrogens are a major component of Asian diets and may be protective against certain hormone-dependent cancers (breast and prostate) and coronary heart disease. They may also have antioxidant function in scavenging potentially harmful free radicals and thus decreasing oxidative attack on DNA.

Green tea extract decreases plasma malondialdehyde concentration but does not affect other indicators of oxidative stress, nitric oxide production, or hemostatic factors during a high-linoleic acid diet in healthy females.

Abstract: Background: Green tea contains polyphenolic catechins which can act as antioxidants and thus decrease the risk for cardiovascular diseases.

Conjugated linoleic acid effects on circulating hormones, metabolites and lipoproteins, and its proportion in fasting serum and erythrocyte membranes of swine.

Abstract: Background: Conjugated linoleic acids (CLA)# refer to a group of linoleic acid (18:2)-derived isomers with conjugated double bonds mostly at carbon atoms 9 and 11 or 10 and 12, and with all possible cis and trans combinations. CLA is a newly recognized nutrient that functions to regulate energy retention and metabolism and that causes a serum lipoprotein profile considered to be less atherogenic. However, rodent models that have been frequently used for these studies are only of limited use because of distinct differences in physiology, compared with man. Additionally, possible differences in food intake between the experimental groups remained often unconsidered in those studies. Thus, it can not be excluded that the beneficial effects of CLA reported in a series of studies may be due, at least partially, to differences in nutrient and energy ingested.

New approaches in the pharmacological treatment of obesity.

Abstract: Many new substances are currently being investigated for their usefulness in the pharmacotherapy of obesity. Most drugs interfere with monoamine neurotransmitter (serotonin, noradrenalin, dopamine and histamine) effects and act as an appetite suppressant. Other approaches are to primarily increase thermogenesis (e.g. β3-adrenoceptor agonists), or to decrease fat absorption by inhibiting the pancreatic lipase (orlistat). New promising agents are substances that increase the effect of corticotropin releasing factor (CRF) or urocortin in the brain (CRF-binding protein ligand inhibitor) and a neuropeptide Y (NPY) Y5 receptor antagonist. The clinical relevance of leptin in the therapy of obesity is probably limited, but can not be fully evaluated at the moment. As obesity has a multifactorial basis, all these substances have in common the fact that they can not cure obesity. They should only be used as an adjunct to classical strategies like diet and exercise in severe obesity. For developing new, perhaps even more specific pharmacological agents, further research is needed to understand the individually different genetic and physiological basis of obesity.

Nutrient oxidation and metabolic rate as affected by meals containing different proportions of carbohydrate and fat, in healthy young women.

Abstract: The amount and composition of food eaten influence body weight regulation, which requires that, in the long term, energy intake matches energy expenditure and that the oxidation rate to be equal to intake for each and separate nutrients. The aim of this study was to examine the influence of two liquid formulas with different macronutrient composition, a high carbohydrate (HC) meal as compared to a high fat (HF) meal, on substrate oxidation and on thermic effect of food (TEF). Eighteen lean and healthy women which were fed a HC diet during the 3 preceding d were studied for a further 4 h after meal intake. The test meals provided fixed energy intake and whose calculated FQ were 0.77 for HF meal, and 0.96 for HC meal. The mean NPRQs were higher (P < 0.01) in the HC group than in the HF group, even with values greater than 1.00 indicating net lipid synthesis (NL), and which correlated with metabolic rate (MR) value (P < 0.05), glucose (P < 0.05), and heart rate (HR) values. Carbohydrate (CHO) oxidation was higher with the HC than with HF meal (P < 0.01) and correlated with the MR (P < 0.05). Protein oxidation rate rose above baseline (P < 0.01); this increase was accompanied by with a negative CHO balance. It is concluded that the change in fuel selection and the increase of TEF is mainly due to CHO intake and metabolism, respectively, and that surplus of dietary CHO of preceding days together with a large load of CHO can exceed the glycogen storage capacity and trigger NL.

Chronic arginine aspartate supplementation in runners reduces total plasma amino acid level at rest and during a marathon run.

Abstract: Background: Athletes consume arginine and/or aspartate as potential nutritional ergogenics. Their metabolic effects are controversial and there is some evidence that ingestion of large doses of single amino acids can adversely affect the nitrogen balance or induce an amino acid imbalance. Nevertheless, the general metabolic influence of an arginine aspartate supplementation during a prolonged exercise bout has not yet been investigated.

Estrone in food: a factor influencing the development of obesity?

Abstract: Background Estrone is a relatively abundant hormone widely distributed in tissues of animal and plant origin. It is a mild estrogen that induces increases in body weigt in experimental animals. The relative abundance of estrone esters in animal tissues suggests that it may also be found in foods, from which it may alter the mechanisms of body weight control. Aim of the study To measure the total estrone content in food and to determine whether this may affect body weight. Methods In the first part of the study, a method was devised for the measurement of total estrone content in food. This was applied to the analysis of estrone content in a variety of food. Finally, hyperlipidic diets (18.6 MJ/kg) with a total estrone content 0.89 ± 0.21 μmol/kg (control group) and 1.37 ± 0.13 μmol/kg (laced with estrone fatty esters) were given to rats during 15 days, in order to determine the influence of dietary estrone on the body mass. Zucker lean (Fa/?) rats weighting initially 200–215 g were used. The total estrone (essentially as fatty esters) content of food was investigated by combining a dried methanol extraction with saponification and measurement of the free estrone evolved through radioimmunoassay. Result The content of estrone was zero in some vegetables, but significant in fruits, meats, and especially fats, both of plant and animal origin. The application of these analyses to a standard recommended diet for humans may result in intakes of more than 1 μmol of estrone per day, a figure comparable to the estrogen production by women. When rats were exposed to a raised estrone content in a fat-rich diet, they significantly increased their body weights, doubling their rate off growth (1.99 g/day) compared with controls (0.81 g/day), but maintaining their plasma composition and the proportions of lipid, water, and protein in their carcasses. Conclusion The widely distributed estrone esters in food and their relatively high concentrations may result in high free hormone intakes in humans. The continued and massive intake of estrone may enhance tissue deposition and lead to obesity.

Oxysterol-induced cell death in U937 and HepG2 cells at reduced and normal serum concentrations

Abstract: Background and aims: Cholesterol oxidation products (oxysterols) are commonly found in foods of animal origin and are also produced endogenously in the body. Oxysterols are cytotoxic to certain cell lines and in some cases have been shown to induce apoptosis. The aim of this study was to investigate the effects of 7β-hydroxy-cholesterol (7β-OHC) and 25-hydroxycholesterol (25-OHC) on cytotoxicity and induction of apoptosis in U937 and HepG2 cells, treated in media containing either 2.5% foetal calf serum (FCS) or 10% FCS to examine the effect of increasing the cholesterol level.

The carbohydrate crystalean and colonic microflora modulate expression of glutathione S-transferase subunits in colon of rats

Abstract: Background Glutathione S-transferases (GSTs)* are an important class of phase II, predominantly detoxifying, enzymes. The supergene family is composed of several isoenzymes, hetero- and homodimers, with tissue specific distribution and levels of expression. The hypothesis is that a higher expression of individual proteins within a specific tissue may be associated with a decreased burden of exposure to reactive carcinogens and ultimately with a decreased cancer risk in this tissue. Aims of the study Since nutrition is expected to contribute to the gene expression, it was the aim of this study to investigate the impact of dietary factors, especially resistant starch, and of the gut microflora, which may be influenced by diet, on the GSTs in colon cells of rats. Methods For this, a technique using high pressure liquid chromatography was established with which for the first time GST isoenzymes were analysed in colon cells and compared to the levels of the corresponding proteins in the liver of the same rat. Results It was found that colon cells contain mainly GST π and low amounts of μ but not GST α. In contrast, the predominant form of GSTs in the liver was α, then μ and hardly any π. Altogether, liver cells had approximately tenfold more total GSTs than colon cells. The feeding of “Crystalean”, a retrograded, high amylose starch which alters the fermentation profile and the composition of the microflora, led to higher levels of GST π in the colon. Furthermore, the comparison of GSTs in colon cells of germ-free rats revealed they were much lower than those observed in rats with conventional microflora. Conclusions These findings clearly demonstrate that the gut bacteria, or their metabolic products, enhance GST expression. The studies support the hypothesis that nutrition – by affecting the gut flora – may induce this potentially protective and important class of phase II enzymes in important tumor target cells.

Dietary fiber reduces the antioxidative effect of a carotenoid and alpha-tocopherol mixture on LDL oxidation ex vivo in humans.

Abstract: Background: Antioxidant concentrations in low density lipoproteins (LDL) are an important determinant for their susceptability to oxidation and can be modulated by dietary intake. Aim of the study: In the present study, the influence of dietary fiber on the antioxidant enrichment and the oxidation resistance of LDL after antioxidant supplementation is investigated. Method: An antioxidant supplement consisting of β-carotene, lycopene, lutein, canthaxanthin and α-tocopherol was given to six young women together with a standard meal. Using a cross-over study design, each subject received the standard meal without additional dietary fiber and enriched with pectin, guar, or cellulose in a random order. To determine the resistance of LDL against copper ion-induced oxidation, the formation of conjugated dienes was measured. Results: Eight, 10, and 24 hours after antioxidant supplementation the isolated LDL revealed significantly (p < 0.05) increased antioxidant concentrations; addition of pectin, guar, or cellulose to the meal depressed this increase. Concomitantly, the observed increase in the resistance of LDL against oxidation (measured as lag phase) was lower with dietary fiber supplementation than that found without. On average, pectin, guar, and cellulose reduced the increase of the lag phase (measured without addition of dietary fiber) by 38%, 22%, and 18%, respectively. Conclusions: These results indicate that dietary fiber supplementation decreases the antioxidative effect of a supplement consisting of carotenoids and α-tocopherol in LDL, an effect that is likely to be mediated by a reduced bioavailability of these antioxidants in the gut.

Effect of high-fat diet on lypolisis in isolated adipocytes from visceral and subcutaneous WAT.

Abstract: Variations in total energy intake and composition of daily food play an important role in the regulation of metabolic processes and so, in the control of body weight. This study was designed in order to investigate the effect of a high-fat diet on lipolysis in isolated adipocytes. For this purpose, fourteen Wistar rats were divided into two groups and fed either a standard-fat diet or a high-fat diet ad libitum for 7 weeks. Adipocytes were prepared from fat pads by collagenase digestion and incubated in vitro in the absence or presence of various lipolytic agents. Lipolysis was measured by the release of glycerol into the medium during 90 min of incubation. We observed that a high amount of fat in the diet induced an enlargement of adipose tissue, which was accompanied by a reduction of β-adrenergic agonist-induced lipolysis, that could be due to a loss of β1 and β3-adrenoceptor number or to alterations of their coupling to adenylate-cyclase through the guanine nucleotide regulatory protein. New data about regional differences were provided by comparing two adipose locations (subcutaneous and visceral).

Plasma levels of antioxidant vitamins and cholesterol in a large population sample in central-northern Italy.

Abstract: Background: In a population-based multicenter case-control study of diet, life-style, and gastric cancer a large series of adults, aged 30–75 years (mean 58.9 yearss), were randomly sampled from the general population in 3 areas of Central-Northern Italy. Aim of the study: To evaluate the relationship between plasma levels of antioxidant vitamins and cholesterol, and sociodemographic characteristics, life-style factors, and dietary intake of selected nutrients in a sample of the Italian population. Methods: A fasting blood sample was available for 945 subjects (553 men, 392 women). The plasma concentrations of ascorbic acid, carotene, retinol, alpha-tocopherol, and cholesterol were determined by a centralized laboratory. All participants answered to a detailed questionnaire collecting information on sociodemographic and anthropometric characteristics, smoking, alcohol drinking, and dietary habits. Covariance analysis models, with post hoc Dunnett tests, including terms for age, sex, study center, and period of blood drawing, were used for selected multiple-way comparisons of mean values of plasma nutrients. Results: Mean plasma values of retinol were higher among men while women had higher levels of plasma carotene, ascorbic acid, alpha-tocopherol, and cholesterol. Plasma carotene levels showed an inverse association with body mass index, alcohol consumption, and smoking and a positive association with social class. Carotene concentrations were higher in plasma samples obtained in spring/summer, while ascorbic acid levels were higher in autumn/winter. Partial correlation coefficients between carotene and ascorbic acid (0.69 in men; 0.74 in women), between carotene and alpha-tocopherol (0.44; 0.37), and between alpha-tocopherol and ascorbic acid (0.45; 0.41). Plasma alpha-tocopherol and retinol correlated with plasma cholesterol. On the other hand, plasma carotene and ascorbic acid were correlated with their estimated dietary intakes, while the intakes of other nutrients, as expected, correlated rather poorly with the respective plasma concentrations. Conclusions: Socio-economic factors, life-style, and specific nutrient intake, in addition to gender, are related to nutrient plasma levels in Italian adults and may provide specific suggestions for the prevention of chronic diseases.

Effect of complex polyphenols and tannins from red wine (WCPT) on chemically induced oxidative DNA damage in the rat

Abstract: Background: Flavonoids are polyphenolic antioxidants occuring in vegetables and fruits as well as beverages such as tea and wine which have been thought to influence oxidative damage. Aim of the study: We wanted to verify whether a complex mixture of wine tannins (wine complex polyphenols and tannins, WCPT) prevent chemically-induced oxidative DNA damage in vivo. Methods: Oxidative DNA damage was evaluated by measuring the ratio of 8-hydroxy-2'-deoxyguanosine (80HdG)/ 2-deoxyguanosine (2dG) × 10−6 in hydrolyzed DNA using HPLC coupled with electrochemical and UV detectors. Results: We treated rats with WCPT (57 mg/kg p.o.) for 14 d, a dose 10-fold higher than what a moderate wine drinker would be exposed to. WCPT administration significantly reduced the ratio of 80HdG/2dG × 10−6 in liver DNA obtained from rats treated with 2-nitropropane (2NP) relative to controls administered 2NP only (33.3 ± 2.5 vs. 44.9 ± 3.2 × 10−6 2dG; μ± SE; p<0.05). On the contrary, pretreatment with WCPT for 10 d did not protect the colon mucosa from oxidative DNA damage induced by 1,2-dimethylhydrazine (DMH). 2NP and DMH are hepatic and colon carcinogens, respectively, capable of inducing oxidative DNA damage. Conclusions: WCPT have protective action against some types of chemically-induced oxidative DNA damage in vivo.

Small supplements of N-3 fatty acids change serum low density lipoprotein composition by decreasing phospholipid and apolipoprotein B concentrations in young adult women

Abstract: In order to investigate the effect of a short-term application of marine n-3 polyunsaturated fatty acids on the composition of serum very low density lipoproteins (VLDL), low density lipoproteins (LDL), and high density lipoproteins (HDL), nine women aged 29±4.2 years, following a diet with a SFA/MUFA/PUFA profile of 2.4/3/1, received supplements of six capsules daily, each capsule containing 0.137 g of n-3 fatty acids (14.5% eicosapentaenoic acid (EPA) and 8.9% docosahexaenoic acid (DHA)) for 10 d. Food consumption, assessed during two 10-days periods indicates that percentage contribution of SFA, MUFA, and PUFA to the daily energy intake did not change through the fish-oil supplementation period, but the daily consumption of n-3 fatty acids increased 2.3 times. N-3 fatty supplementation increased EPA and DHA percentages in serum phospholipids, but failed to decrease (p>0.05) the cholesterol and triglyceride concentration in serum LDL and HDL, although it did so in VLDL. In contrast, the lipoprotein-phospholipid and lipoprotein-protein concentrations were markedly affected, mainly in LDL and HDL (at least p<0.01). HDL and VLDL compositions were not affected but the total mass (lipid+protein in mg/dl) concentration of these lipoproteins significantly decreased (p<0.05), suggesting a lower number of these particles in circulating blood after the n-3 treatment. The LDL-cholesterol/LDL-apolipoprotein B ratio increased (p<0.01) reflecting a probable increase in LDL size. Following fish oil supplementation, LDL particles contained a significantly lower amount of phospholipids, which also suggests changes in the surface/core ratio of the average LDL. Changes in serum lipoprotein lipids did not significantly correlate with any dietary change other than the n-3 fatty acid increase. The results indicate that a 10-day application of a small supplement of n-3 change the LDL composition leading to less atherogenic LDL particles with lower phospholipid and apolipoprotein (Apo) B concentrations.

Mediation of differentiating effects of Butyrate on the intestinal cell line Caco-2 by transforming growth factor-β1

Abstract: Background: Beside their role as the main energy source in the colonic mucosa, short chain fatty acids were found to act as potent antiproliferative and differentiation agents in various cancer cell lines. It has recently been shown that butyrate also induces TGF-β1 mRNA in human keratinocytes, suggesting that TGF-β1 may play a role in butyrate induced cell differentiation. Aim of the study: The objective of our study was to investigate the possible role of exogenous and endogenous TGF-β on butyrate induced differentiation of intestinal epithelium. Methods: Studies were performed in Caco-2 cells, a cell line resembling functionally normal enterocytes. Cells, cultured in standard medium were studied over a 15-day period. Sodium butyrate (5 mM), TGF-β1 (2 ng/ml) or butyrate (5 mM)+anti-human TGF-β1 antibody (30 μg/ml) were added to the medium. At day 4, 8, 11 and 15 total protein content, alkaline phosphatase activity, lactate dehydrogenase activity and transepithelial resistance were measured. Results: Under culture conditions both, butyrate and TGF-β1 inhibited growth accompanied by an induction of cell differentiation approved by increased alkaline phosphatase activity and transepithelial resistance. The differentiating effect of butyrate was accompanied by an increased endogenous TGF-β1, but not TGF-β2 expression in Caco-2 cells. Co-incubation of butyrate with anti-human TGF-β1 antibody suppressed at least in part the differentiating effects of butyrate. Conclusions: Our results directly implicate that the TGF-β isoform TGF-β1 is necessary for butyrate-induced Caco-2 cell differentiation, but other molecular mechanisms may also play a role in the differentiation of this cell line.

Effect of complex polyphenols on colon carcinogenesis

Abstract: Background: Complex polyphenols and tannins from wine (WCPT) are being considered increasingly as potential cancer chemopreventive agents, since epidemiological studies suggest that populations consuming a high amount of polyphenols in the diet may have a lower incidence of some types of cancer.

Impact of diets with corn oil or olive/sunflower oils on DNA damage in healthy young men

Abstract: Background: Plant fats and oils are major sources of mono- and polyunsaturated fatty acids as well as vitamin E, the major fat-soluble antioxidants in human nutrition Dietary antioxidants are expected to reduce cancer risk by minimizing DNA damage

Addition of vitamin E to long-chain polyunsaturated fatty acid-enriched diets protects neonatal tissue lipids against peroxidation in rats.

Abstract: Background: Tissue 10:4(n-6) and 22:6(n-3) status have been correlated with neonatal development and growth. Artificial formulas for neonates have been supplemented with long chain polyunsaturated fatty acids (LCP) from animal and marine sources which may enhance sensitivity of cellular membranes to oxidative damage. Diet-derived antioxidants like vitamin E play a key role in the protection of tissue lipids against oxidation. Aim of the study: We seek to determine the influence of dietary vitamin E on tissue sensitivity to oxidative stress in rats fed for 4 weeks on diets enriched in (n-3) and (n-6) long-chain polyunsaturated fatty acids. Methods: Weanling rats received 10% fat diets that provided 18:1(n-9), 18:2(n-6) and 18:3(n-3) in a similar ratio to that of rat milk (group A), supplemented with fish oil (groups B and B+E) and supplemented with (n-6) and (n-3) LCP from an animal phospholipid concentrate (groups C and C+E). Vitamin E (500 mg vitamin E/kg fat) was added to diets B+E and C+E. Tissue fatty acid content and the activities of catalase, superoxide dismutase, glutathione transferase und glutathione peroxidase in liver and brain were measured.

Leptin enhances the synthesis of oleoyl-estrone from estrone in white adipose tissue.

Abstract: Background: Oleoyl-estrone elicits powerful slimming effects on lean and obese rats, sparing protein, lowering appetite and maintaining energy expenditure. Leptin synthesis is markedly reduced by oleoyl-estrone. However, this effect is not observed in the obese Zucker fa/fa rats; these rats do not fully respond to leptin but they lose fat under oleoyl-estrone treatment.

Investigations on the intestinal availability of native thiamin in selected foods and feedstuffs.

Abstract: The aim of the present study was to investigate the precaecal digestibility as a quantitative measure for the intestinal availability of naturally occuring thiamin from selected foods and feedstuffs. Therefore, three experiments were conducted to examine the following foods and feedstuffs: Eggs, bananas, white cabbage, corn, milk, fish, barley, soybeans, rice, wheat bran, brewer's yeast, rye and soybean meal. The foods and food processing procedures were made with regard to their relevance in human and animal nutrition. For all experiments male pigs with an initial live weight between 33 and 40 kg were fitted with an end-to-end ileo-rectal anastamosis with preserved ileo-caeco-colic-valve. Three weeks after surgery, the digestibility trials were carried out from week 4 to week 9 and week 12 to week 17 after surgery. The animals were fed the individual experimentals diets for a period of 12 days while digesta were collected twice a day quantitatively during the final 5 days of this period. Precaecal digestibility for thiamin from all tested foods and feedstuffs was within a range from 73% to 94% with the highest values from boiled soybeans, boiled rice and barley, and the lowest value from steamed fish. In comparison with the animal products the plant products show on average a nearly equal precaecal digestibility for thiamin (87.3% versus 83.5%). Moreover, all tested foods and feedstuffs exhibit a relatively good intestinal availability of thiamin.

Effects on parameters of glucose homeostasis in healthy humans from ingestion of leguminous versus maize starches.

Abstract: Background: Due to their lower glycaemic index, leguminous seeds affect human carbohydrate metabolism lesser than do cereals. Problems, however, could arise from side effects, e.g., increasing flatulence. Aim of the study and methods: In 26 healthy subjects, metabolic and symptomatic responses following acute ingestion of equivalent amounts of pure pea starch (NASTAR (Cosucra BV, Rosendaal/The Netherlands), crude yellow pea flour (CPC Deutschland, Germany), and modified and unmodified cornstarches (SNOWFLAKE and SIRONA, Cerestar/Germany) were assessed, i.e., plasma glucose, serum insulin, C-peptide, hydrogen exhalation, and flatulence. Results: Pure pea starch elicited less hyperglycaemia (minus 47 %), hyperinsulinaemia (minus 54 %), and C-peptide secretion (minus 37 %) as compared to cornstarch (p<0.05), while the responses to modified versus unmodified corn starch were similar (8 subjects, n.s.). Pure pea and corn starches were equally well tolerated, while flatulence and breath hydrogen concentration were increased only after the intake of crude pea flour. Maldigestion of pea flour was calculated to be around 10 % (reference lactulose). Conclusions: The well-known metabolic advantages of pea starch over cornstarch were confirmed. Tolerability of pure pea starch was excellent, but not of crude pea flour. Provided it has the same technical characteristics, pure pea starch as a “prebiotic” could replace cornstarch in industrial food production.