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Biomedical subjects

N Darmon

Publications and source records attributed to N Darmon.

At least 19 recordsLinked to original sources
PubMed2006

Low-cost diets: more energy, fewer nutrients.

Energy-dense diets offer a low-cost dietary option to the consumer. However, they are more likely to be nutrient-poor. In this study, based on the French national food consumption survey, the diet costs were estimated using retail food prices in France. Adult participants were stratified by quartiles of energy cost (in euro/10 MJ). Dietary energy density, energy and nutrient intakes were then compared across groups. Participants in the lowest quartile of energy cost had the highest energy intakes, the most energy-dense diets and the lowest daily intakes of key vitamins and micronutrients. Participants in the highest quartile of energy cost had lower energy intakes, and diets that were higher in nutrients and lower in energy density. However, their daily diet costs were 165% higher. In this observational study, the more nutrient-dense diets were associated with higher diet costs.

Adult↗
PubMed2006

Identification of nutritionally adequate mixtures of vegetable oils by linear programming.

OBJECTIVE: To determine the types and proportions of vegetable oils to recommend for a healthy diet. METHODS: Optimal vegetable oil combinations were designed, using linear programming and, as decision variables, nine single oils and 29 basic food items. 'Oil models' were run to determine whether reasonable amounts of individuals oils or oil mixtures satisfied a set of constraints on essential fatty acids and vitamin E. 'Meal models' were run to test whether selected mixtures could be used as the sole source of added fat in a meal that met micronutrient and macronutrient recommendations. RESULTS: The cheapest mixture (0.97 euro L(-1)) that solved the oil models contained 81% rapeseed and 19% sunflower oils. About 10-15 g of this mixture, alone or with olive, soya bean, wheat germ or walnut oils, also solved the meal models. Mixtures that contained a high proportion (>or=50%) of the tasty olive and walnut oils also solved the models but were more expensive (4.9 euro L(-1) and 8.5 euro L(-1), respectively). CONCLUSIONS: The consumption of a mixture composed of rapeseed and sunflower oils in a 4 : 1 proportion is an inexpensive and simple way to meet current dietary recommendations for essential fatty acids and vitamin E, favouring overall dietary nutrient adequacy.

Cost-Benefit Analysis↗
PubMed2001

Dietary inadequacies observed in homeless men visiting an emergency night shelter in Paris.

OBJECTIVE: To assess the dietary intake and the nutritional status of homeless men. SETTING: A night emergency shelter in Paris, France. DESIGN: Dietary survey (48-h) including alcohol intake and a questionnaire on age, duration of homelessness, smoking habits. Subjects were also weighed and measured. SUBJECTS: Ninety-seven men aged 18-72 years (mean 43.3), of whom 54% were homeless for more than 18 months, 82% were smokers and 53% were regular and/or excessive drinkers. RESULTS: The BMI distribution was shifted towards low values, the percentage of wasted persons being four times higher than in the reference population. The mean total energy intake was 2376 kcal and included a high and highly variable percentage of energy derived from alcohol (12.0% Among drinkers, the mean ethanol intake was 90 g and there was a significant negative correlation between ethanol and non-alcoholic energy intakes. The median intakes of potassium, calcium, zinc, vitamins B1, B2, and niacin were lower than European Population Reference Intakes but only the mean intake of vitamin B1 was significantly lower. Eighty percent of non-alcoholic energy was provided by charitable organisations. For most nutrients, the nutritional density of the shelter ration was not significantly different from the density of the foods purchased by the homeless. CONCLUSIONS: These data suggest that the content of some nutrients should be increased in existing food assistance programs for homeless people in France.

Adolescent↗
PubMed2001

An overview of the health status of migrants in France, in relation to their dietary practices.

OBJECTIVE: To review studies on the morbidity, mortality and nutrition of migrant populations in France. DESIGN: A systematic search of the bibliographic database Medline, and direct contact with associations and institutions concerned with migrants' health. RESULTS: In France, as in other host countries, migrants belong to the lowest socio-economic strata. They have on average better health and lower mortality than the local-born population. Health benefits are particularly noticeable in Mediterranean men, especially for affluence-related diseases such as cancer and cardiovascular diseases. North African men smoke as heavily as the local-born of the same occupational categories, and yet their mortality rates from lung cancer are notably lower. Such a paradox may be the result of a synergy between different phenomena such as the selection of the fittest applicants for immigration and the maintenance of healthy lifestyles from the countries of origin. In contrast, migrant women do not enjoy the same health advantages, possibly because they are less likely to be selected on the basis of their health and because they are often non-working. Adult migrants from southern Europe and North Africa report dietary practices consistent with the typical Mediterranean diet, which is renowned for its positive effects on health. CONCLUSIONS: The diet of Mediterranean adults living in France may partly explain the low rates of chronic diseases and high adult life expectancy observed in migrant men from northern Africa. Information about their diets might provide clues for the design of nutritional education campaigns aimed at low-income people.

Africa, Northern↗
PubMed1998

Sensitization to cow's milk proteins during refeeding of guinea pigs recovering from polydeficient malnutrition.

We have previously shown that milk sensitization aggravates intestinal dysfunction in the malnourished guinea pigs, suggesting that it may also impair the recovery from malnutrition. To test this hypothesis, the growing guinea pigs were malnourished by feeding only maize for 7 d and then were refed for 21 d with a balanced diet containing either intact or hydrolyzed cow's milk proteins. The control animals received the hydrolyzed milk protein diet for 28 d. After an initial period of total inhibition of growth owing to maize, guinea pigs gained weight regularly, with both balanced diets, and there was no evidence of mucosal damage at the end of the refeeding period. However, refeeding with intact milk proteins induced milk sensitization, which was demonstrated on the systemic level by the presence of anti-beta-lactoglobulin IgG1 antibodies, and on the local level by the intestinal anaphylaxis measured by the increase in short circuit current induced by beta-lactoglobulin (16.4 +/- 2.6 microA/cm2) in jejunal segments mounted in Ussing chambers. Such an immune sensitization was associated with impaired intestinal permeability, as both the ionic conductance (21.0 +/- 1.6 versus 14.6 +/- 0.7 mS/cm2) and the transepithelial fluxes of horseradish peroxidase (537 +/- 203 versus 152 +/- 28 ng/h x cm2) were significantly increased in guinea pigs refed with the intact milk proteins compared with controls. In contrast, there was no difference in intestinal permeability between controls and guinea pigs refed with the hydrolyzed milk protein diet. These data show that sensitization to cow's milk proteins can develop in guinea pigs recovering from severe malnutrition and may impair full intestinal repair.

Anaphylaxis↗
PubMed1997

Zinc and intestinal anaphylaxis to cow's milk proteins in malnourished guinea pigs.

Zinc supplementation could favor recovery from diarrhea in malnourished children. As the recent experimental evidence suggests that oxidative stress and intestinal anaphylaxis may contribute to the intestinal dysfunction associated with malnutrition, we postulated that zinc could act through antioxidant or antianaphylactic properties. Control (C), malnourished (M), and malnourished zinc-treated (MZ) guinea pigs were, respectively, fed a normal 30% protein diet, a low 4% protein diet, and a low 4% protein diet plus 1800 ppm of zinc. Milk proteins were included in the diets to trigger intestinal anaphylaxis. Milk sensitization was assessed by passive cutaneous anaphylaxis (PCA) against beta-lactoglobulin and by intestinal anaphylaxis measured in Ussing chambers by the increase in short circuit-current after addition of beta-lactoglobulin (deltaIsc(betaLg)). Oxidative stress was assessed by intestinal lipid peroxidation. The intestinal secretion was assessed by deltaIsc induced by inflammatory mediators. Malnutrition increased the level of anti-betaLg reaginic antibodies [PCA = 1.19 +/- 0.79 and 0.69 +/- 0.67 log(l/titer) in M versus C guinea pigs, p = 0.07] and enhanced intestinal anaphylaxis (deltaIsc(betaLg)) = 16.4 +/- 9.9 and 9.1 +/- 5.8 microA/cm2 in M versus C guinea pigs, p = 0.07), without inducing intestinal lipid peroxidation. Moreover, malnutrition enhanced significantly the intestinal secretory response to histamine and 5-hydroxytryptamine. Administration of pharmacologic doses of zinc during malnutrition inhibited the increase in milk sensitization induced by malnutrition, both at the systemic [PCA = 0.35 +/- 0.55 log(l/titer) in MZ guinea pigs, p = 0.03 versus M] and intestinal (deltaIsc(betaLg)) = 2.8 +/- 2.5 microA/cm2 in MZ guinea pigs; p = 0.001 versus M) level, and prevented the hypersecretion in response to histamine and 5-hydroxytryptamine. These data suggest that zinc has antianaphylactic and antisecretory properties that may contribute to its capacity to prevent intestinal dysfunction during malnutrition.

Anaphylaxis↗
PubMed1996

The threshold for immune cell reactivity to milk antigens decreases in cow's milk allergy with intestinal symptoms.

BACKGROUND: In cow's milk allergy (CMA) with intestinal symptoms, peripheral blood mononuclear cells (PBMCs) secrete tumor necrosis factor-alpha (TNF-alpha), altering intestinal function. However, the type of cow's milk protein (CMP) that triggers symptoms (intact or intestinally processed) is not known, and neither is the minimal amount required. METHODS: PBMCs were isolated from infants with active CMA or cured infants just before a new challenge and stimulated with intact or intestinally processed CMP. Supernatants were tested for cytokine content and for their ability to perturb intestinal barrier capacity, measured in Using chambers in HT29-19A intestinal cells. RESULTS: PBMCs from infants with active CMA secreted more TNF-alpha, when they were stimulated with intact rather than intestinally processed CMPs, and more TNF-alpha than PBMCs from cured infants. Accordingly, supernatants from PBMCs stimulated with intact but not intestinally processed CMPs significantly increased intestinal permeability. The CMP concentration required to trigger TNF-alpha secretion capable of altering intestinal function was very small in infants with active CMA (approximately 2 micrograms/ml), but about 300 times higher in cured infants. CONCLUSION: Intact rather than intestinally processed proteins stimulate PBMCs to release TNF-alpha and alter intestinal barrier capacity. The threshold for PBMC reactivity to milk antigens drops considerably during active CMA with intestinal symptoms.

Animals↗
PubMed1996

Intestinal paracellular permeability during malnutrition in guinea pigs: effect of high dietary zinc.

BACKGROUND: Zinc has been shown to have beneficial effects in vitro on epithelial barrier function, and in vivo to reduce intestinal permeability in malnourished children with diarrhoea. AIMS: To determine whether malnutrition alters intestinal paracellular permeability, and whether zinc prevents such alterations. METHODS: Guinea pigs were fed a normal protein diet (NP group), a low protein diet (LP group), or a low protein diet enriched with 1800 ppm zinc (LPZn group) for three weeks. Intestinal permeability was measured on jejunal segments mounted in Ussing chambers by measuring ionic conductance and mucosal to serosal fluxes of 14C-mannitol, 22Na, and horseradish peroxidase. Tight junction morphology was assessed on cryofracture replicas. RESULTS: Mannitol and Na fluxes and ionic conductance increased in the LP group compared with the NP group but remained normal in the LPZn group. Accordingly, jejunal epithelia from the LP group, but not from the LPZn group, showed a small decrease in number of tight junctional strands compared with epithelia from the NP group. Neither malnutrition nor zinc treatment modified horseradish peroxidase fluxes. CONCLUSIONS: Malnutrition is associated with increased intestinal paracellular permeability to small molecules, and pharmacological doses of zinc prevent such functional abnormality.

Animals↗
PubMed1996

Anaphylactic intestinal response to milk proteins during malnutrition in guinea pigs.

We investigated whether sensitization to cow's milk occurs during malnutrition and alters intestinal ion and macromolecular transport. Malnourished guinea pigs received a low-protein diet containing either 4% soy or 4% milk proteins, and well-nourished sensitized controls received 26% soy plus 4% milk proteins. To assess milk sensitization, we measured immunoglobulin (Ig) G and passive cutaneous anaphylactic (PCA) responses to beta-lactoglobulin (beta-Lg) and the intestinal anaphylaxis, reflected by the rise in short-circuit current (delta Isc) induced by beta-Lg in tissues mounted in Ussing chambers. To assess intestinal function, we measured ionic conductance and unidirectional fluxes of -14C-mannitol and -3H-horseradish peroxidase (HRP). In malnourished animals fed milk proteins, IgG, PCA, and delta Isc (beta-Lg) increased more than in well-nourished animals. Ionic conductance and mannitol permeability rose in both malnourished groups. Malnourished animals fed milk proteins also displayed enhanced permeability to HRP. These data suggest that increased paracellular permeability is due to malnutrition per se, whereas increased macromolecular transport seems to require both malnutrition and sensitization. They indicate that intestinal anaphylaxis in response to milk proteins is persistent and even enhanced during experimental malnutrition.

Analysis of Variance↗
PubMed1994

Mononuclear cells from infants allergic to cow's milk secrete tumor necrosis factor alpha, altering intestinal function.

BACKGROUND/AIMS: Intestinal dysfunction observed during cow's milk allergy (CMA) is incompletely understood, and neither the effector cells nor the mediators responsible have been clearly identified. This study was undertaken to better characterize the implication of mononuclear cells in food allergy. METHODS: Peripheral blood mononuclear cells (PBMC) from infants with CMA were cultured in the presence of cow's milk proteins (CMP), and the release of tumor necrosis factor alpha (TNF-alpha), interferon gamma (IFN-gamma), and interleukin 4 and 6 was measured. The effect of culture supernatants was tested on HT29 cl.19A intestinal cell monolayers mounted in Ussing chambers. RESULTS: When stimulated by CMP, PBMC from infants with CMA released more TNF-alpha than those from control infants (429 +/- 92 vs. 205 +/- 34 pg/mL). Culture supernatants did not directly stimulate electrogenic chloride secretion by HT29 cl.19A cells, but epithelial barrier capacity was altered as shown by the significant decrease in electrical resistance (85 +/- 17 vs. 135 +/- 14 omega.cm2 in controls) and the increases in intact horseradish peroxidase, [14C]mannitol, and 22Na+ fluxes. These effects were reversed when culture supernatants were neutralized with anti-TNF-alpha antibodies. Recombinant human-TNF-alpha altered the HT29 cl.19A epithelial barrier capacity, and its effect was highly potentiated by IFN-gamma. CONCLUSIONS: These results indicate that during CMA, the high level of TNF-alpha released by mononuclear cells after milk protein challenge acts synergistically with IFN-gamma to increase the intestinal permeability.

Cell Line↗
PubMed1994

Characterization of proteoglycans synthesized by different layers of adult human femoral head cartilage.

Full thickness human femoral head cartilage fragments were labeled in vitro with 35S-SO4 and 3H-proline and cut tangentially to the surface in a cryostat. Sixteen-micrometer thick sections were pooled from four zones: I (0-160 microns); II (160-480 microns); III (480-960 microns); and IV (> 960 microns). The pooled sections were extracted with 4 M guanidinium chloride solvent and the extracts and 35S-labeled proteoglycans (35S-PGs) were characterized. The superficial layer gave lowest extraction yields and the deep layers gave the highest yields. The highest specific activity (dpm/mg of dry weight) of 35S-SO4 labeling was in zones II and III and that of [3H] proline in zone I. The superficial layer I also contained: (1) the highest proportions of 35S-PG monomers of small hydrodynamic size and low buoyant density; (2) an increased proportion of hydrodynamically small 35S-PG monomers; (3) the smallest proportion of endogenously reassociated 35S-PG aggregates, although similar proportions of 35S-PG monomers extracted from all layers interacted with exogenous hyaluronan (HA); and (4) the more heterogeneous population of 35S-glycosaminoglycan (GAG) side chains with respect to their size, although their chemical compositions were similar in all layers. In addition, extracted 35S-PGs had shorter GAG chains than the residual nonextracted molecules and were enriched in chondroitin-6 sulfate whereas residual/non-extracted 35S-PGs were enriched in chondroitin-4 sulfate. The extraction yields of keratan sulfate (KS)-enriched 35S-PGs also decreased with the depth of tissue, though the overall 35S-KS chain content varied little with depth of tissue, being slightly higher in the deepest zone IV.

Aged↗
PubMed1993

Effects of protein deficiency on lipid peroxidation in the small intestine and liver of rats.

This study investigated the influence of protein restriction on lipid peroxide content (thiobarbituric acid-reactive substances) and the intracellular antioxidant defence system in the small intestine and the liver. Weanling male Sprague-Dawley rats were divided into two groups: a low-protein group fed ad lib. a diet containing 6% casein for 4 wk, and a control group fed a diet containing 22% casein but restricted to the same dietary intake as that of the low-protein group. Compared with pair-fed controls, the protein-deficient rats exhibited a decrease in glutathione content in the small intestine and the liver. Thiobarbituric acid-reactive substances were increased in the intestine only. Data on the enzymatic antioxidant defence system in the protein-deficient animals showed an increase in catalase activity in the intestine but a decrease of this activity in the liver. The activity of selenium-dependent glutathione peroxidase was decreased in the liver and remained unchanged in the intestine. Superoxide dismutase was not modified by protein deficiency in either tissue. In control rats, enzyme activities were 6-43 times higher in the liver than in the intestine. The deleterious effects of protein deficiency appeared more marked in the intestine.

Animals↗
PubMed1993

Oxidative stress may contribute to the intestinal dysfunction of weanling rats fed a low protein diet.

Intestinal function is impaired in malnutrition. Because oxidative stress is a component of gastrointestinal injury, and malnutrition may reduce antioxidant defenses, we investigated the involvement of oxidative stress in the intestinal dysfunction due to malnutrition. Weanling rats were fed either a normal protein (22% casein) or a low protein (6% casein) diet for 4 wk. In intestinal homogenates, we assessed free radical damage and enzymatic antioxidant defenses. In jejunal fragments mounted in Ussing chambers, we measured ionic transport by short-circuit current (Isc) and protein permeability by transepithelial fluxes of beta-lactoglobulin. Catalase activity and the thiobarbituric acid-reacting substances concentration were greater in intestinal mucosa of the low protein group, whereas the glutathione concentration and the activities of superoxide dismutase and Se-dependent glutathione peroxidase were the same as in the normal protein group intestinal mucosa. Both basal Isc and the delta Isc induced by glucose and forskolin, as well as beta-lactoglobulin fluxes, were higher in the low protein group. Exogenous H2O2 stress increased Isc significantly more in the low protein than the normal protein group but did not alter protein permeability. These results show that malnutrition induces both intestinal free radical damage and altered epithelial transport, suggesting that oxidative stress may contribute to the intestinal dysfunction associated with malnutrition.

Animals↗
PubMed1992

Superoxide anion scavenging capacity measured by a polarographic method. Comparison with a colourimetric method.

A polarographic method to assess the scavenging capacity of a molecule for O2-. is proposed. This method is based on the fact that O2-. is not detected by the Clark electrode and that a scavenger competes with spontaneous dismutation of O2-. So, the reduction of O2 into O2-. and the decomposition of H2O2 by catalase, releasing O2, show a biphasic kinetic. Various kinetic parameters can be used to calculate the nmol of O2-. scavenged and also supply data on the reaction mechanisms (oxidation or reduction of O2-.) involved in scavenging. This method presents several other advantages: scavenging capacity can be assayed without added indicators which themselves behave as scavengers (as demonstrated for NBT), the presence of scavengers which interfere with the O2-. generating system (xanthine-xanthine oxidase) does not invalidate the measurements made.

Anions↗
PubMed1990

Structural and biochemical abnormalities of articular cartilage in rheumatoid arthritis.

Compared with normal cartilage, the water content, extraction yields, and capacity of 34SO4 incorporation, were found to be increased in articular cartilage from rheumatoid joints, which also synthesizes an increased proportion of low and middle density small size proteoglycans (PGs), enriched in dermatan sulfate. These small [35S]-PGs also possess longer glycosaminoglycan side chains and lack the ability to interact with hyaluronan. An altered pattern of PG synthesis of rheumatoid chondrocytes may contribute to cartilage damage in this condition.

Adult↗