Showing papers in "British Journal of Nutrition in 1999"

Scientific Concepts in Functional Foods in Europe: Consensus Document

Abstract: X Growth, development and differentiation: a functional food science approach. X Functional food science and substrate metabolism. X Functional food science and defence against reactive oxidative species. X Functional food science and the cardiovascular system. X Functional food science and gastrointestinal physiology and function. X Functional food science and behaviour and psychological functions.

Anthropometric measurement error and the assessment of nutritional status

Abstract: Anthropometry involves the external measurement of morphological traits of human beings. It has a widespread and important place in nutritional assessment, and while the literature on anthropometric measurement and its interpretation is enormous, the extent to which measurement error can influence both measurement and interpretation of nutritional status is little considered. In this article, different types of anthropometric measurement error are reviewed, ways of estimating measurement error are critically evaluated, guidelines for acceptable error presented, and ways in which measures of error can be used to improve the interpretation of anthropometric nutritional status discussed. Possible errors are of two sorts; those that are associated with: (1) repeated measures giving the same value (unreliability, imprecision, undependability); and (2) measurements departing from true values (inaccuracy, bias). Imprecision is due largely to observer error, as is the most commonly used measure of anthropometric measurements error. This can be estimated by carrying out repeated anthropometric measures on the same subjects and calculating one or more of the following: technical error of measurement (TEM); percentage TEM, coefficient of reliability (R), and intraclass correlation coefficient. The first three of these measures are mathematically interrelated. Targets for training in anthropometry are at present far from perfect, and further work is needed in developing appropriate protocols for nutritional anthropometry training. Acceptable levels of measurement error are difficult to ascertain because TEM is age dependent, and the value is also related to the anthropometric characteristics of the group or population under investigation R>0.95 should be sought where possible, and reference values of maximum acceptable TEM at set levels of R using published data from the combined National Health and Nutrition Examination Surveys I and II (Frisancho, 1990) are given. There is a clear hierarchy in the precision of different nutritional anthropometric measures, with weight and height being most precise. Waist and hip circumference show strong between-observer differences, and should, where possible, be carried out by one observer. Skinfolds can be associated with such large measurement error that interpretation is problematic. Ways are described in which measurement error can be used to assess the probability that differences in anthropometric measures across time within individuals are due to factors other than imprecision. Anthropometry is an important tool for nutritional assessment, and the techniques reported here should allow increased precision of measurement, and improved interpretation of anthropometric data.

The implications of condensed tannins on the nutritive value of temperate forages fed to ruminants.

Abstract: New methodology for measuring forage condensed tannin (CT) content is described and the effects of CT upon forage feeding and nutritive value for ruminant animals are reviewed. CT react with forage proteins in a pH-reversible manner, with reactivity determined by the concentration, structure and molecular mass of the CT. Increasing concentrations of CT in Lotus corniculatus and Lotus pedunculatus reduce the rates of solubilization and degradation of fraction 1 leaf protein in the rumen and increase duodenal non-NH3 N flow. Action of medium concentrations of total CT in Lotus corniculatus (30-40 g/kg DM) increased the absorption of essential amino acids from the small intestine and increased wool growth, milk secretion and reproductive rate in grazing sheep without affecting voluntary feed intake, thus improving the efficiency of food conversion. High concentrations of CT in Lotus pedunculatus (75-100 g/kg DM) depressed voluntary feed intake and rumen carbohydrate digestion and depressed rates of body and wool growth in grazing sheep. The minimum concentration of CT to prevent rumen frothy bloat in cattle is defined as 5 g/kg DM and sheep grazing CT-containing legumes were shown to better tolerate internal parasite infections than sheep grazing non CT-containing forages. It was concluded that defined concentrations of forage CT can be used to increase the efficiencies of protein digestion and animal productivity in forage-fed ruminants and to develop more ecologically sustainable systems of controlling some diseases under grazing.

Functional Food Properties of Non-Digestible Oligosaccharides: A Consensus Report From the ENDO Project (DGXII AIRII-CT94-1095)

Abstract: This paper results from the final phase of the ENDO project (DGXII AIRII-CT94-1095), a European Commission-funded project on non-digestible oligosaccharides (NDO). All participants in the programme met to perform a consensus exercise on the possible functional food properties of NDO. Topics studied during the project (including a workshop on probiotics and prebiotics) and related aspects, for which considerable evidence has been generated recently, were evaluated on the basis of existing published scientific evidence. There was a general consensus that: (1) there is strong evidence for a prebiotic effect of NDO in human subjects. A prebiotic effect was defined as a food-induced increase in numbers and/or activity predominantly of bifidobacteria and lactic acid bacteria in the human large intestine; (2) there is strong evidence for the impact that NDO have on bowel habit; (3) there is promising evidence that consumption of inulin-type fructans may result in increased Ca absorption in man; (4) there are preliminary indications that inulin-type fructans interact with the functioning of lipid metabolism; (5) there is preliminary evidence in experimental animals of a preventive effect against colon cancer. Human nutrition studies are needed to substantiate these findings. It was concluded that the nutritional properties of NDO may prove to be a key issue in nutritional research in the future.

Inhibition of non-haem iron absorption in man by polyphenolic-containing beverages.

Abstract: The effects of different polyphenol-containing beverages on Fe absorption from a bread meal were estimated in adult human subjects from the erythrocyte incorporation of radio-Fe. The test beverages contained different polyphenol structures and were rich in either phenolic acids (chlorogenic acid in coffee), monomeric flavonoids (herb teas, camomile (Matricaria recutita L.), vervain (Verbena officinalis L.), lime flower (Tilia cordata Mill.), pennyroyal (Mentha pulegium L.) and peppermint (Mentha piperita L.), or complex polyphenol polymerization products (black tea and cocoa). All beverages were potent inhibitors of Fe absorption and reduced absorption in a dose-dependent fashion depending on the content of total polyphenols. Compared with a water control meal, beverages containing 20-50 mg total polyphenols/serving reduced Fe absorption from the bread meal by 50-70%, whereas beverages containing 100-400 mg total polyphenols/serving reduced Fe absorption by 60-90%. Inhibition by black tea was 79-94%, peppermint tea 84%, pennyroyal 73%, cocoa 71%, vervain 59%, lime flower 52% and camomile 47%. At an identical concentration of total polyphenols, black tea was more inhibitory than cocoa, and more inhibitory than herb teas camomile, vervain, lime flower and pennyroyal, but was of equal inhibition to peppermint tea. Adding milk to coffee and tea had little or no influence on their inhibitory nature. Our findings demonstrate that herb teas, as well as black tea, coffee and coca can be potent inhibitors of Fe absorption. This property should be considered when giving dietary advice in relation to Fe nutrition.

Healthy dietary habits in relation to social determinants and lifestyle factors

Abstract: The aim of the present study was to evaluate the importance of social status and lifestyle for dietary habits, since these factors may influence life expectancy. We studied the association of four indicators for healthy dietary habits (fruits and vegetables, fibre, fat and Hegsted score) with sex, age, socio-economic status, education, physical leisure exercise, smoking and personal attention paid to keeping a healthy diet. Data were gathered with a self-administered quantitative food-frequency questionnaire distributed to a representative sample of Norwegian men and women aged 16-79 years in a national dietary survey, of whom 3144 subjects (63%) responded. Age and female sex were positively associated with indicators for healthy dietary habits. By separate evaluation length of education, regular physical leisure exercise and degree of attention paid to keeping a healthy diet were positively associated with all four indicators for healthy dietary habits in both sexes. Socio-economic status, location of residence and smoking habits were associated with from one to three indicators for healthy dietary habits. In a multiple regression model, age, education and location of residence together explained from 1 to 9% of the variation (R2) in the four dietary indicators. Length of education was significantly associated with three of four dietary indicators both among men and women. By including the variable 'attention paid to keeping a healthy diet' in the model, R2 increased to between 4 and 15% for the four dietary indicators. Length of education remained correlated to three dietary indicators among women, and one indicator among men, after adjusting for attention to healthy diet, age and location of residence. Residence in cities remained correlated to two indicators among men, but none among women, after adjusting for age, education and attention to healthy diet. In conclusion, education was associated with indicators of a healthy diet. Attention to healthy diet showed the strongest and most consistent association with all four indicators for healthy dietary habits in both sexes. This suggests that personal preferences may be just as important for having a healthy diet as social status determinants.

Dietary nitrate in man: friend or foe?

Abstract: Based on the premise that dietary nitrate is detrimental to human health, increasingly stringent regulations are being instituted to lower nitrate levels in food and water. Not only does this pose a financial challenge to water boards and a threat to vegetable production in Northern Europe, but also may be eliminating an important non-immune mechanism for host defence. Until recently nitrate was perceived as a purely harmful dietary component which causes infantile methaemoglobinaemia, carcinogenesis and possibly even teratogenesis. Epidemiological studies have failed to substantiate this. It has been shown that dietary nitrate undergoes enterosalivary circulation. It is recirculated in the blood, concentrated by the salivary glands, secreted in the saliva and reduced to nitrite by facultative Gram-positive anaerobes (Staphylococcus sciuri and S. intermedius) on the tongue. Salivary nitrite is swallowed into the acidic stomach where it is reduced to large quantities of NO and other oxides of N and, conceivably, also contributes to the formation of systemic S-nitrosothiols. NO and solutions of acidified nitrite, mimicking gastric conditions, have been shown to have antimicrobial activity against a wide range of organisms. In particular, acidified nitrite is bactericidal for a variety of gastrointestinal pathogens such as Yersinia and Salmonella. NO is known to have vasodilator properties and to modulate platelet function, as are S-nitrosothiols. Thus, nitrate in the diet, which determines reactive nitrogen oxide species production in the stomach (McKnight et al. 1997), is emerging as an effective host defence against gastrointestinal pathogens, as a modulator of platelet activity and possibly even of gastrointestinal motility and microcirculation. Therefore dietary nitrate may have an important therapeutic role to play, not least in the immunocompromised and in refugees who are at particular risk of contracting gastroenteritides.

Micronutrients and the pathogenesis of human immunodeficiency virus infection.

Abstract: Micronutrient deficiencies may be common during human immunodeficiency virus (HIV) infection. Insufficient dietary intake, malabsorption, diarrhoea, and impaired storage and altered metabolism of micronutrients can contribute to the development of micronutrient deficiencies. Low plasma or serum levels of vitamins A, E, B6, B12 and C, carotenoids, Se, and Zn are common in many HIV-infected populations. Micronutrient deficiencies may contribute to the pathogenesis of HIV infection through increased oxidative stress and compromised immunity. Low levels or intakes of micronutrients such as vitamins A, E, B6 and B12, Zn and Se have been associated with adverse clinical outcomes during HIV infection, and new studies are emerging which suggest that micronutrient supplementation may help reduce morbidity and mortality during HIV infection.

Effects of inulin on faecal bifidobacteria in human subjects.

Abstract: A controlled study with eight healthy free-living subjects was carried out, in which energy intake was adjusted to the individual energy requirements. On administration of inulin, blood lipids, the faecal microflora, short-chain fatty acids and accompanying gastrointestinal symptoms were characterized in order to investigate the long-term effect of inulin. During the run-in phase (8 d), subjects received a typical Western diet providing 45% energy as fat and 40% energy as carbohydrate. Subsequently, the subjects consumed a fat-reduced diet which provided 30% energy as fat and 55% energy as carbohydrate for a period of 64 d using inulin as a fat replacer. The amounts of inulin consumed by the subjects (up to 34 g/d) were based on individual energy requirements with the aim to keep the diet isoenergetic with that used in the run-in period. To assess the effects of inulin administration, a control study (run-in and intervention) was carried out in which subjects consumed the same diet but devoid of inulin during the whole course of the study. To investigate the effect of inulin on faecal flora composition total bacteria and bifidobacteria in the faeces were enumerated by in situ hybridization with 16S rRNA targeted oligonucleotide probes. Inulin significantly increased bifidobacteria from 9.8 to 11.0 log10/g dry faeces and caused a moderate increase in gastrointestinal symptoms such as flatulence and bloatedness, whereas blood lipids and short-chain fatty acids remained essentially unaffected.

Insulin-releasing and insulin-like activity of the traditional anti-diabetic plant Coriandrum sativum (coriander).

Abstract: Coriandrum sativum (coriander) has been documented as a traditional treatment of diabetes. In the present study, coriander incorporated into the diet (62.5 g/kg) and drinking water (2.5 g/l, prepared by 15 min decoction) reduced hyperglycaemia of streptozotocin-diabetic mice. An aqueous extract of coriander (1 mg/ml) increased 2-deoxyglucose transport (1.6-fold), glucose oxidation (1.4-fold) and incorporation of glucose into glycogen (1.7-fold) of isolated murine abdominal muscle comparable with 10(-8) M-insulin. In acute 20 min tests, 0.25-10 mg/ml aqueous extract of coriander evoked a stepwise 1.3-5.7-fold stimulation of insulin secretion from a clonal B-cell line. This effect was abolished by 0.5 mM-diazoxide and prior exposure to extract did not alter subsequent stimulation of insulin secretion by 10 mM-L-alanine, thereby negating an effect due to detrimental cell damage. The effect of extract was potentiated by 16.7 mM-glucose and 10 mM-L-alanine but not by 1 mM-3-isobutyl-1-methylxanthine. Insulin secretion by hyperpolarized B-cells (16.7 mM-glucose, 25 mM-KCl) was further enhanced by the presence of extract. Activity of the extract was found to be heat stable, acetone soluble and unaltered by overnight exposure to acid (0.1 M-HCl) or dialysis to remove components with molecular mass < 2000 Da. Activity was reduced by overnight exposure to alkali (0.1 M-NaOH). Sequential extraction with solvents revealed insulin-releasing activity in hexane and water fractions indicating a possible cumulative effect of more than one extract constituent. These results demonstrate the presence of antihyperglycaemic, insulin-releasing and insulin-like activity in Coriandrum sativum.

Perceived barriers in trying to eat healthier – results of a pan-EU consumer attitudinal survey

Abstract: Information on the perceived difficulties in trying to eat a healthier diet is important in assisting those in nutrition education devise more effective programmes. The objective of this study was to determine the main perceived barriers that people have in trying to eat a healthy diet in the 15 member states of the European Union (EU). A cross-sectional study in which quota-controlled nationally representative samples of approximately 1000 adults (15 years upwards) from each member state completed a face-to-face interview-assisted questionnaire. The most frequently mentioned perceived barriers to healthy eating concerned time and taste factors. Time-related factors were more important for younger respondents and those with a higher level of education, who appear to regard taste as being compromised by healthy eating. Variation exists both between member states and between demographic groups in the frequency of barriers mentioned. A lack of knowledge about healthy eating was not selected by many as an important barrier. A major obstacle to nutrition education is the fact that 70 % of EU subjects believe their diets are already healthy. It may be that nutrition educators should concentrate on showing consumers how to evaluate their own diet appropriately in terms of fat, fibre, and fruit and vegetables. Food-based guidelines may be useful in this endeavour.

Effect of parsley (Petroselinum crispum) intake on urinary apigenin excretion, blood antioxidant enzymes and biomarkers for oxidative stress in human subjects.

Abstract: Seven men and seven women participated in a randomized crossover trial to study the effect of intake of parsley (Petroselinum crispum), containing high levels of the flavone apigenin, on the urinary excretion of flavones and on biomarkers for oxidative stress. The subjects received a strictly controlled diet low in flavones and other naturally occurring antioxidants during the 2 weeks of intervention. This basic diet was supplemented with parsley providing 3.73-4.49 mg apigenin/MJ in one of the intervention weeks. Urinary excretion of apigenin was 1.59-409.09 micrograms/MJ per 24 h during intervention with parsley and 0-112.27 micrograms/MJ per 24 h on the basic diet (P < 0.05). The fraction of apigenin intake excreted in the urine was 0.58 (SE 0.16)% during parsley intervention. Erythrocyte glutathione reductase (EC 1.6.4.1; GR) and superoxide dismutase (EC 1.15.1.1; SOD) activities increased during intervention with parsley (P < 0.005) as compared with the levels on the basic diet, whereas erythrocyte catalase (EC 1.11.1.6) and glutathione peroxidase (EC 1.11.1.9) activities did not change. No significant changes were observed in plasma protein 2-adipic semialdehyde residues, a biomarker of plasma protein oxidation. In this short-term investigation, an overall decreasing trend in the activity of antioxidant enzymes was observed during the 2-week study. The decreased activity of SOD was strongly correlated at the individual level with an increased oxidative damage to plasma proteins. However, the intervention with parsley seemed, partly, to overcome this decrease and resulted in increased levels of GR and SOD.

The effect of the daily intake of inulin on fasting lipid, insulin and glucose concentrations in middle-aged men and women.

Abstract: The present study was carried out to examine the effect of the daily intake of 10 g inulin on fasting blood lipid, glucose and insulin levels in healthy middle-aged men and women with moderately raised total plasma cholesterol (TC) and triacylglycerol (TAG) levels. This study was a double-blind randomized placebo-controlled parallel study in which fifty-four middle-aged subjects received either inulin or placebo for a period of 8 weeks. Fasting blood samples were collected before the supplementation period (baseline samples 1 and 2, separated by 1 week) and at weeks 4 and 8, with a follow-up at week 12. Compared with baseline values, insulin concentrations were significantly lower at 4 weeks (P < 0.01) in the inulin group. There was a trend for TAG values, compared with baseline, to be lower in the inulin group at 8 weeks (P < 0.08) returning to baseline concentrations at week 12. On comparison of the inulin and placebo groups, the fasting TAG responses over the 8-week test period were shown to be significantly different (P < 0.05, repeated measures ANOVA), which was largely due to lower plasma TAG levels in the inulin group at week 8. The percentage change in TAG levels in the inulin group during the 8-week study was shown to correlate with the initial TAG level of the subjects (rs -0.499, P = 0.004). We therefore conclude that the daily addition of 10 g inulin to the diet significantly reduced fasting insulin concentrations during the 8-week test period and resulted in lower plasma TAG levels, particularly in subjects in whom fasting TAG levels were greater than 1.5 mmol/l. These data support findings from animal studies that fructans influence the formation and/or degradation of TAG-rich lipoprotein particles, and the insulin data are also consistent with recent studies showing attenuation of insulin levels in fructan-treated rats.

Effects of conjugated linoleic acid (CLA) isomers on lipid levels and peroxisome proliferation in the hamster.

Abstract: Effects of the conjugated linoleic acid (CLA) isomers cis-9, trans-11 (c9,t11 CLA) and trans-10, cis-12 (t10,c12 CLA) on lipid metabolism and markers of peroxisome proliferation were investigated in hamsters fed on purified diets containing 30% energy as fat and 0.1 g cholesterol/kg for 8 weeks. Four groups (n 32 each) received diets without CLA (control), with a mixture of equal amounts of c9,t11 and t10,c12 CLA (CLA mix), with c9,t11 CLA, and with t10,c12 CLA. The total amount of CLA isomers was 1.5% energy of 6.6g/ kg diet. CLA was incorporated into glycerides and exchanged for linoleic acid in the diet. Compared with the control, the CLA mix and t10,c12 CLA decreased fasting values of LDL- (21 and 18% respectively) and HDL-cholesterol (8 and 11%), increased VLDL-triacylglycerol (80 and 61%, and decreased epididymal fat pad weights (9 and 16%), whereas c9,t11 CLA had no significant effects. All CLA preparations increased liver weight, but not liver lipids. However, the increase in liver weight was much less in the c9,t11 CLA group (8%) than in the other two groups (25%) and might have been caused by the small amount of t10,c12 CLA present in the c9,t11 CLA preparation. Liver histology revealed that increased weight was due to hypertrophy. Markers of peroxisome proliferation, such as cyanide-insensitive palmitoyl CoA oxidase (EC 1.3.3.6) and carnitine acetyl transferase (EC 2.3.1.7) activities, were not increased by CLA. Both c9,t11 CLA and t10,c12 CLA were incorporated into phospholipids and triacylglycerols, but t10,c12 CLA only about half as much as c9,t11 CLA. In addition, linoleic acid and linolenic acid concentrations were lower in lipids of the t10,c12 CLA group compared with the c9,t11 CLA group. These data suggest that t10,c12 CLA stimulated the oxidation of all C18 polyunsaturated fatty acids. The results indicate that the t10,c12 CLA isomer, and not the so-called natural CLA isomer (c9,t11), is the active isomer affecting lipid levels in hamsters.

Methane production and energy partition of cattle in the tropics.

Abstract: The aim of this experiment was to determine CH 4 production and energy partition for a range of diets fed to Bos indicus cattle. Six Brahman cattle were fed on three different diets in a replicated Latin square experiment over three periods. The diets were (1) long-chopped Angleton grass (Dicanthium aristatum) hay ad libitum (DM digestibility (DMD) 41 (SE 2) %; 4 g N/kg), (2) long-chopped Rhodes grass (Chloris gayana) hay ad libitum (DMD 60 (SE 1) %; 14 g N/kg) or (3) 2 kg long-chopped luceme (Medicago sativa) hay/d plus a high-grain diet (ad libitum) (DMD 70 (SE 1) %; 31 g N/kg). CH4 production was measured using confinement-type respiration chambers. Metabolizable energy intake (MJ/d) of cattle fed on Angleton grass (18.4 (SE 2.0)) was lower (P < 0.01) than that for Rhodes grass (54.9 (SE 2.1)), which was lower (P< 0.01) than that for the high-grain diet (76.7 (SE 5.8)). CH4 production (g/d) for cattle fed on Rhodes grass (257 (SE 14)) was higher (P<0.01) than that for cattle fed on both the high-grain diet (160 (SE 24)) and Angleton grass (113 (SE 16)). CH4 conversion rate (MJ CH4 produced per 100 MJ gross energy intake) was not significantly different between cattle fed on Angleton (10.4 (SE 1.1)) and Rhodes (11.4 (SE 0.3)) grass, but was higher (P< 0.01) than for cattle fed on the high-grain diet (6.7 (SE 0.7)). CH4 production (g/kg live-weight gain) was associated (P< 0.001) with both live-weight gain and feed: gain ratio. We conclude that the relationships between CH4 production, energy utilization and live-weight change of cattle fed on tropical forages differ from those of cattle fed on diets based on temperate forages.

Effects of red pepper on appetite and energy intake

Abstract: Two studies were conducted to investigate the effects of red pepper (capsaicin) on feeding behaviour and energy intake. In the first study, the effects of dietary red pepper added to high-fat (HF) and high-carbohydrate (HC) meals on subsequent energy and macronutrient intakes were examined in thirteen Japanese female subjects. After the ingestion of a standardized dinner on the previous evening, the subjects ate an experimental breakfast (1883 kJ) of one of the following four types: (1) HF; (2) HF and red pepper (10 g); (3) HC; (4) HC and red pepper. Ad libitum energy and macronutrient intakes were measured at lunch-time. The HC breakfast significantly reduced the desire to eat and hunger after breakfast. The addition of red pepper to the HC breakfast also significantly decreased the desire to eat and hunger before lunch. Differences in diet composition at breakfast time did not affect energy and macronutrient intakes at lunch-time. However, the addition of red pepper to the breakfast significantly decreased protein and fat intakes at lunch-time. In Study 2, the effects of a red-pepper appetizer on subsequent energy and macronutrient intakes were examined in ten Caucasian male subjects. After ingesting a standardized breakfast, the subjects took an experimental appetizer (644 kJ) at lunch-time of one of the following two types: (1) mixed diet and appetizer; (2) mixed diet and red-pepper (6 g) appetizer. The addition of red pepper to the appetizer significantly reduced the cumulative ad libitum energy and carbohydrate intakes during the rest of the lunch and in the snack served several hours later. Moreover, the power spectral analysis of heart rate revealed that this effect of red pepper was associated with an increase in the ratio sympathetic: parasympathetic nervous system activity. These results indicate that the ingestion of red pepper decreases appetite and subsequent protein and fat intakes in Japanese females and energy intake in Caucasian males. Moreover, this effect might be related to an increase in sympathetic nervous system activity in Caucasian males.

Are the advantages of the Mediterranean diet transferable to other populations? A cohort study in Melbourne, Australia

Abstract: A prospective cohort study, involving 141 Anglo-Celts and 189 Greek-Australians of both sexes aged 70 years or more, was undertaken in Melbourne, Australia. The objective was to evaluate whether adherence to the principles of the Mediterranean diet affects survival of elderly people in developed non-Mediterranean countries. Diet was assessed using an extensive validated questionnaire on food intake. A one unit increase in a diet score, devised a priori on the basis of eight key features of the traditional common diet in the Mediterranean region, was associated with a 17% reduction in overall mortality (two-tailed P value 0.07). Mortality reduction with increasing diet score was at least as evident among Anglo-Celts as among Greek-Australians. We conclude that a diet that adheres to the principles of the traditional Mediterranean diet is associated with longer survival among Australians of either Greek or Anglo-Celtic origin.

Effect of diet composition and ration size on key enzyme activities of glycolysis-gluconeogenesis, the pentose phosphate pathway and amino acid metabolism in liver of gilthead sea bream (Sparus aurata).

Abstract: The effects of diet composition and ration size on the activities of key enzymes involved in intermediary metabolism were studied in the liver of gilthead sea bream (Sparus aurata). High-carbohydrate, low-protein diets stimulated 6-phosphofructo 1-kinase (EC 2.7.1.11), pyruvate kinase (EC 2.7.1.40), glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (EC 1.1.1.44) enzyme activities, while they decreased alanine aminotransferase (EC 2.6.1.2) activity. A high degree of correlation was found between food ration size and the activity of the enzymes 6-phosphofructo 1-kinase, pyruvate kinase, glucose-6-phosphate dehydrogenase (positive correlations) and fructose-1,6-bisphosphatase (EC 3.1.3.11) (negative correlation). These correlations matched well with the high correlation also found between ration size and growth rate in starved fish refed for 22 d. Limited feeding (5 g/kg body weight) for 22 d decreased the activities of the key enzymes for glycolysis and lipogenesis, and alanine aminotransferase activity. The findings presented here indicate a high level of metabolic adaptation to both diet type and ration size. In particular, adaptation of enzyme activities to the consumption of a diet with a high carbohydrate level suggests that a carnivorous fish like Sparus aurata can tolerate partial replacement of protein by carbohydrate in the commercial diets supplied in culture. The relationship between enzyme activities, ration size and fish growth indicates that the enzymes quickly respond to dietary manipulations of cultured fish.

Dietary conjugated linoleic acids promote fatty streak formation in the C57BL/6 mouse atherosclerosis model.

Abstract: Conjugated linoleic acids (CLA) are positional isomers of linoleic acid which have been suggested by some to possess antiatherosclerotic properties. To test this hypothesis, three groups of twenty C57BL/6 mice were fed on atherogenic diets containing: 5 g CLA/kg, 2.5 g CLA + 2.5 g linoleic acid/kg or 5 g linoleic acid/kg. All diets were fed for 15 weeks and contained (g/kg): triacylglycerol 145, free fatty acids 5, cholesterol 10 and cholic acid 5. At the completion of the experimental period, when data from both groups fed on CLA were combined, dietary CLA did not produce significant differences in body weight, serum total cholesterol concentration or serum HDL-cholesterol concentration. However, mice receiving CLA developed a significantly higher serum HDL-cholesterol: total cholesterol ratio and a significantly lower serum triacylglycerol concentration than controls. Despite causing a serum lipoprotein profile considered to be less atherogenic, the addition of CLA to the atherogenic diet increased the development of aortic fatty streaks. Considering the increased atherogenesis associated with dietary CLA in the present study, and the failure to demonstrate a significant beneficial effect of CLA in other animal studies, there is currently no conclusive evidence to support the hypothesis that CLA protect against atherogenesis.

Purine quantification in digesta from ruminants by spectrophotometric and HPLC methods.

Abstract: The method of Zinn & Owens (1986; Canadian Journal of Animal Science 66, 157-166), based on release of purine bases by HClO4 followed by their precipitation with AgNO3, was used to study recovery of purines from lyophilized rumen microbial or Escherichia coli preparations added to matrices such as cellulose, starch and neutral-detergent fibre. The recovery of purines was poor (approximately 50%). Under the hydrolysis conditions (12 M-HClO4, 90-95 degrees for 1 h) used in the method of Zinn & Owens (1986), the recovery of purines from the rumen microbial preparations added to matrices measured using an HPLC method was 95-102%, suggesting that the lower recovery of purines in the method of Zinn & Owens (1986) was not due to incomplete hydrolysis of nucleic acids. Using the HPLC method, adenine and allopurinol (an internal standard) were found to be heat-labile as substantial destruction was observed on heating at 121 degrees. On the other hand, another commonly used internal standard, caffeine, was stable at 121 degrees. A complete hydrolysis of nucleic acids from the rumen microbial preparation was observed with 2.5 ml 0.6 M-HClO4 in a total volume of 3 ml (0.5 M-HClO4 during hydrolysis) at 90-95 degrees for 1 h, and under these conditions adenine, guanine, allopurinol and caffeine were stable. Moreover, under these milder hydrolysis conditions, the recovery of purine bases from the rumen microbial or E. coli preparations added to matrices ranged from 92 to 108% using the method of Zinn & Owens (1986). Based on the results, changes in hydrolysis conditions have been proposed for accurate determination of purine bases using spectrophotometric or HPLC methods.

The 'Mini Nutritional Assessment' (MNA) and the 'Determine Your Nutritional Health' Checklist (NSI Checklist) as predictors of morbidity and mortality in an elderly Danish population

Abstract: The purpose of the present study was to evaluate the capacity of the 'Determine Your Nutritional Health' Checklist (NSI Checklist) and the 'Mini Nutritional Assessment' (MNA) methods to predict nutrition-related health problems. Data were from the Danish part of the 'Survey in Europe of Nutrition in the Elderly, a Concerted Action' (SENECA) baseline survey from 1988, and the follow-up study from 1993. Based on the baseline survey thirty-nine (19.3%) of the subjects were classified at high nutritional risk, 103 (51%) were considered at moderate nutritional risk and sixty (29.7%) were within the 'good' range according to the criteria in the NSI Checklist. With the MNA, 171 subjects were classified according to their nutritional risk into a well-nourished group, comprising 78.4%, and a group who were at risk of undernutrition, comprising 21.6% at baseline. A total of 115 subjects participated in the follow-up study. The mortality rate and the prevalence of various morbidity indicators were compared between the different risk groups. The analysis showed that subjects with a high MNA score (> or = 24) had significantly lower mortality (rate ratio estimate: 0.35; 95% Cl 0.18, 0.66) compared with subjects with a low MNA score (< or = 23.5). In contrast, the NSI Checklist score was not a significant predictor of mortality (rate ratio estimate: 1.45; 95% Cl 0.78, 2.71). The sixteen Danes judged to be at high nutritional risk by the NSI Checklist in 1988, had more acute diseases (P < 0.001) than the rest of the participants, between 1988 and 1993. No significant differences were found in the participation rates, hospitalization rates, physician visits, need of help or weight loss between the groups. The thirteen Danes judged to be at risk of undernutrition in 1988 by the MNA, had a lower participation rate (P < 0.01) and higher occurrence of acute disease (P < 0.05), need of help (P < 0.05), and weight loss (P < 0.001) than the well-nourished group, between 1988 and 1993. No significant differences were found in hospitalization rates and physician visits between the two groups. In conclusion, the results indicate that modified versions of the NSI Checklist and the MNA are capable of identifying a group of 70-75-year-old subjects with increased risk of certain nutrition-related health problems. Further, an MNA score < or = 23.5 predicts mortality in a Danish population.

Maternal food restriction in the second half of pregnancy affects vascular function but not blood pressure of rat female offspring

Abstract: Food restriction during pregnancy in rats induces intrauterine growth retardation with consequences persisting into adulthood. In the present study we have investigated the hypothesis that malnutrition in pregnant rats may lead to altered cardiovascular function in adult female offspring. Perinatal growth retardation was induced by a 50% reduction of normal dietary intake in rats during the second half of pregnancy. Systolic and diastolic blood pressure values and heart rate were recorded in conscious female offspring (100 d old) using a femoral artery probe. No significant differences in heart rate, or in systolic and diastolic blood pressures were recorded between control offspring and offspring of nutritionally deprived rats. In order to ascertain whether cardiovascular variables in the offspring were influenced by lactation, subgroups of offspring from food-restricted dams were fostered with lactating dams fed on a normal diet. Blood pressure and heart rate were also found to be normal in these offspring. The rise in blood pressure associated with NO inhibition was similar in all groups. Isolated resistance artery function was assessed in vitro in offspring (100-120 d old) of a second group of semi-starved dams. Small mesenteric arteries from these animals showed reduced endothelium-dependent relaxation (to acetylcholine and bradykinin), but enhanced sensitivity to exogenous NO (sodium nitroprusside). We conclude that food restriction during the second half of pregnancy and/or lactation does not induce hypertension in adult offspring, but may effect subtle changes in vascular function.

Effect of supplementing a fibre basal diet with different nitrogen forms on ruminal fermentation and microbial growth in an in vitro semi-continuous culture system (RUSITEC)

Abstract: Incubation trials were carried out with the rumen simulation technique (RUSITEC) to study the effects of four forms of N on the growth of ruminal micro-organisms and the fermentation variables when an all-fibre basal diet was incubated. The basal diet consisted of 10 g neutral-detergent fibre (NDF) from grass hay plus 2 g NDF from sugarbeet pulp. N forms were isolated soyabean protein, soyabean peptides, amino acids blended to profile soyabean protein and NH3 as NH4Cl. Half of the daily N supply was infused as NH4Cl and the other half was infused as each of the four treatments described. Non-NH3 N (NAN) forms increased NDF (P = 0.006), acid-detergent fibre (P = 0.003) and cellulose (P = 0.015) disappearance after 48 h incubation, CO2 (P amino acids > peptides > protein treatments, indicating preferential uptake of peptides without passage through the NH3 pool. Microbial efficiency (g microbial N/kg organic matter apparent disappearance) was greater (P = 0.002) for the NAN forms than for the NH3 treatment, with peptides and protein treatments supporting higher (P = 0.009) values than amino acid treatment. These results indicate that N forms other than NH3 are required for optimal fibre digestion and microbial growth.

Influence of feeding different vegetables on plasma levels of carotenoids, folate and vitamin C. Effect of disruption of the vegetable matrix.

Abstract: Carotenoids, folate and vitamin C may contribute to the observed beneficial effects of increased vegetable intake. Currently, knowledge on the bioavailability of these compounds from vegetables is limited. We compared the efficacy of different vegetables, at the same level of intake (i.e. 300 g/d), in increasing plasma levels of carotenoids, folate and vitamin C and we investigated if disruption of the vegetable matrix would enhance the bioavailability of these micronutrients. In an incomplete block design, sixty-nine volunteers consumed a control meal without vegetables and three out of four vegetable meals (i.e. broccoli, green peas, whole leaf spinach, chopped spinach; containing between 1·7 and 24· 6m g b-carotene, 3·8 and 26 mg lutein, 0·22 and 0·60 mg folate and 26 and 93 mg vitamin C) or a meal supplemented with synthetic b-carotene (33·3 mg). Meals were consumed for 4 d and fasting blood samples were taken at the end of each period. Consumption of the spinach-supplemented meal did not affect plasma levels of b-carotene, although the b-carotene content was 10-fold those of broccoli and green peas, which induced significant increases in plasma b-carotene levels (28 (95 % CI 6·4, 55) % and 26 (95 % CI 2·6, 54) % respectively). The b-carotene-supplemented meal increased plasma concentrations of b-carotene effectively (517 (95 % CI 409, 648) %). All vegetable meals increased the plasma concentrations of lutein and vitamin C significantly. Broccoli and green peas were, when expressed per mg carotenoid consumed, also more effective sources of lutein than spinach. A significant increase in plasma folate concentration was found only after consumption of the spinach-supplemented meal, which provided the highest level of folate. Disruption of the spinach matrix increased the plasma responses to both lutein (14 (95 % CI 3·7, 25) %) and folate (10 (95 % CI 2·2, 18) %), whereas it did not affect the response to b-carotene. We conclude that the bioavailabilities of b-carotene and lutein vary substantially among different vegetables and that the bioavailabilities of lutein and folate from spinach can be improved by disruption of the vegetable matrix. Folate: Carotenoids: Bioavailability: Vegetable consumption

Effect of dietary supplementation with carotenoids on xenobiotic metabolizing enzymes in the liver, lung, kidney and small intestine of the rat.

Abstract: The effect of 16 d intake of 300 mg carotenoids/kg diet (beta-carotene (beta C), bixin (BX), lycopene (LY), lutein (LU), canthaxanthin (CX) or astaxanthin (AX) on xenobiotic metabolizing enzymes in the liver, lung, kidney and small intestine of male Wistar rats was assessed. A control group received the basal diet (AIN-76) without carotenoids and a positive control group for enzyme induction received 3-methylcholanthrene (3-MC) at 666 mg/kg diet. Cytochrome P450 activity was assessed using the substrates ethoxyresorufin for P450 1A1, methoxyresorufin for P450 1A2, pentoxyresorufin for P450 2B1/2 and benzyloxyresorufin for P450 types 1A1/2, 2B1/2 and 3A. Glutathione-S-transferase (EC 2.5.1.18) and reduced glutathione status were assessed. Carotenoid uptake by the tissues was also determined. 3-MC and the carotenoids BX, CX and AX led to significant increases compared with control in liver, lung and kidney ethoxyresorufin-O-deethylation. Methoxyresorufin-O-demethylation activity was significantly increased in liver and lung by BX, CX and AX but only CX and AX significantly increased activity in kidney. Pentoxyresorufin-O-depentylation and benzyloxyresorufin-O-dearylation increased in liver of 3-MC-, BX-, CX- and AX-treated rats, but to a much lesser degree than for the other two substrates. Benzyloxyresorufin-O-dearylation in lung was significantly decreased by all carotenoids. Activities of any of the measured enzymes in the small intestine were undetectable in all treatment groups except the 3-MC group. Glutathione status was unaffected by any of the treatments. This is the first study identifying the carotenoids BX, CX and AX as inducers of rat lung and kidney xenobiotic metabolizing enzymes.

Influence of sodium fumarate addition on rumen fermentation in vitro.

Abstract: The influence of sodium fumarate on rumen fermentation was investigated in vitro using batch and semi-continuous cultures of mixed rumen micro-organisms taken from three sheep receiving a basal diet of hay, barley, molasses, fish meal and a mineral-vitamin supplement (500, 299.5, 100, 91 and 9.5 g/kg DM respectively). Batch cultures consisted of 10 ml strained rumen fluid in 40 ml anaerobic buffer containing 200 mg of the same feed given to the sheep. Sodium fumarate was added to achieve a final concentration of 0, 5 or 10 mmol/l, as a result of the addition of 0, 250 or 500 mumol, equivalent to 0, 200 and 400 g/kg feed. CH4 production at 24 h (360 mumol in the control cultures) fell (P 0.05) effect on total bacterial numbers or on the number of methanogenic archaea, but numbers of cellulolytic bacteria were increased (8.8 v. 23.9 (SED 2.49) x 10(5) per ml, P < 0.01). Fumarate also increased DM digestibility of the basal diet after 48 h incubation (0.476 v. 0.508 (SED 0.0123), P < 0.05). Thus, it was concluded that sodium fumarate may be a useful dietary additive for ruminants, because it diverts some H2 from CH4 production and because it is able to stimulate proliferation of cellulolytic bacteria and digestion of fibre.

The effect of a model melanoidin mixture on faecal bacterial populations in vitro

Abstract: The Maillard reaction produces coloured, macromolecular materials (melanoidins) in a variety of foods, on heating. Significant quantities may enter the human gut on a daily basis, but there is little information on their metabolism in the human colon. As the large bowel contains a diverse population of bacteria involved in normal bowel function, it is possible that melanoidins are metabolized therein. Depending on the bacteria involved, there may be disease or health implications. The aim of the present study was to use in vitro models to determine the digestibility of melanoidins and the effect of melanoidins on colonic bacteria in the gastrointestinal tract. Melanoidins were prepared and the effects of simulated upper-gut secretions on their stability determined in a model system. The effects of faecal bacteria were also determined, in batch culture, with a combination of phenotypic and genotypic (probes) criteria being used to identify the microbial diversity involved. Simulation of peptic and pancreatic digestion showed that the melanoidins did not produce detectable amounts of low-molecular-mass degradation products. However, melanoidins affected the growth of gut bacteria during mixed culture growth. The effect was to cause a non-specific increase in the anaerobic bacteria enumerated. This in vitro study indicates that melanoidins can affect the growth of human large-bowel bacteria and serves to demonstrate possible effects that may occur in vivo. Given the large and varied number of food items that contain Maillard reaction products, this may have relevance for lower-gut health.

Spreads enriched with plant sterols, either esterified 4,4-dimethylsterols or free 4-desmethylsterols, and plasma total- and LDL-cholesterol concentrations.

Abstract: In a 9-week study seventy-six healthy adult volunteers with an average age of 44 (SD 11) years, with baseline plasma total cholesterol levels below 8 mmol/l, received in a balanced, double-blind, crossover design, a total of three different table spreads for personal use. Two spreads were fortified either with free (non-esterified) vegetable-oil sterols, mainly from soyabean oil (31 g sterol equivalents/kg; 0.8 g/d) or sheanut-oil sterols (133 g sterol equivalents/kg; 3.3 g/d). One spread was not fortified (control). Average intake of spread was 25 g/d for 3 weeks. None of the spreads induced changes in blood clinical chemistry or haematology. Plasma total- and LDL-cholesterol concentrations were statistically significantly reduced by 3.8% and 6% (both 0.19 mmol/l) respectively, for the spread enriched with free soyabean-oil sterols compared with the control spread. The spread enriched with sheanut-oil sterols did not lower plasma total- and LDL-cholesterol levels. None of the plant-sterol-enriched spreads affected plasma HDL-cholesterol concentrations. Plasma-lipid-standardized concentrations of alpha- plus beta-carotene were not statistically significantly affected by the soyabean-oil sterol spread in contrast to lipid-standardized plasma lycopene levels which showed a statistically significant decrease (9.5%). These findings indicate that a daily intake of free soyabean-oil sterols as low as 0.8 g added to a spread is effective in lowering blood total- and LDL-cholesterol levels with limited effects on blood carotenoid levels. The lowering in total- and LDL-cholesterol blood levels due to consumption of the vegetable-oil-sterol-enriched spread may be helpful in reducing the risk of CHD for the population.

Lactose-derived oligosaccharides in the milk of elephants: comparison with human milk.

Abstract: Human milk is commonly considered to be unique when compared with the milk of other species with regard to its high content of complex fucosylated and sialylated lactose-derived oligosaccharides. We describe the application of high-pH anion-exchange chromatography with pulsed amperometric detection and TLC to characterize and quantitate neutral and sialylated lactose-derived oligosaccharides in milk from three Asian elephants and human milk. The lactose contents of elephant and human milks were 25-30 g/l and about 66 g/l respectively, whereas total oligosaccharide concentration was about three times higher in elephant milk and comprised up to 40% (10% in human milk) of the carbohydrate content. The ratio neutral: acidic components was different in the milk of the two species; in elephant milk, the N-acetylneuraminic acid-containing oligosaccharides made up almost half of the total amount v. 30% in human milk. Most oligosaccharides in elephant milk were more fucosylated and/or sialylated compared with human milk components. By mild acid hydrolysis, fucose and N-acetylneuraminic acid were cleaved off from complex components, and this resulted in increased amounts of fucose, galactose, N-acetylneuraminic acid, lactose and lacto-N-neo-tetraose. Unique to elephant milk are the high levels of 3'-galactosyllactose (up to 4 g/l) and lacto-N-neo-tetraose which are present in human milk only in trace amounts. Elephant and human milks have high levels and unique patterns of oligosaccharides which may reflect the relative importance of these components in neonatal host defence, in endothelial leucocyte interactions or in brain development.