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Biomedical subjects

M P Navarro

Publications and source records attributed to M P Navarro.

At least 19 recordsLinked to original sources
PubMed2006

Dietary calcium utilization among a group of Spanish boys aged 11-14 years on their usual diets.

Adolescence constitutes a period of nutritional vulnerability due to increased dietary requirements for growth and development and special dietary habits. A pilot trial was performed to evaluate the dietary calcium utilization among a sample of Spanish boys on their usual diets, in which the calcium intake and consumption of dairy products were as well examined. Nutrient and food intake was recorded using a 24-h dietary recall and a 2-d food consumption record for 21 subjects aged 11-14 years. Dietary calcium utilization was assessed by means of calcium intake in food and calcium output in faeces and urine as measured by flame atomic absorption spectrophotometry. Overall intake of dairy products was 399.3 +/- 22.1 g/d, and the single most consumed item was milk (72% of the total). An inverse relationship was found between dairy product consumption at breakfast (55% of the total) and BMI (p = 0.016, r = -0.5168). Dairy products contributed the majority of dietary calcium (66.9%). Mean calcium intake was 881.7 +/- 39.9 mg/d, 88% of the recommended value for Spanish adolescents. Net calcium absorption (271.7 +/- 51.7 mg/d) and retention (170.6 +/- 50.9 mg/d) seemed not to be sufficient to meet growth demands during puberty. The results shown that adolescents of the study absorbed 31% of dietary calcium and retained nearly 20% of the total intake, but dietary calcium intake and consumption of dairy products failed to meet recommended values. Optimizing calcium intake is of crucial importance among adolescents, to maximize calcium retention and to help prevent osteoporosis in later life.

Adolescent↗
PubMed2004

Effects of different thermal treatments and storage on the proximate composition and protein quality in canned tuna.

The purpose of this project was to study the modifications in nutrient composition, amino acid content, and protein quality of white tuna preserves after each of the thermal treatments involved in the canning process. Also the influence that a three years storage period at room temperature has on the nutritional quality of canned tuna was studied. The biological assays used for the study of the protein utilization were carried out on Wistar rats, fed on semi-synthetic diets for 12 days varying only the protein source, casein or tuna provided as follows: raw, cooked in brine, steamed, sterilized tuna, and canned tuna stored for three years. The sterilization process and storage time led to a great increase in the lipid content of the canned tuna and to a porcentual decrease in protein, and moisture content. Amino acid composition of canned and cooked tuna did not show great modifications compared to raw tuna. Neither protein digestibility nor biological value of the cooked, canned, and stored tuna showed any deterioration. The protein quality of white tuna meat preserves has been compared with preserves made up of red and white tuna meat.

Amino Acids↗
PubMed2002

Degradation, release and bioavailability of 14C DDT and 14C DDE sediment residues to oysters and mussels.

Sediment borne pesticides are one of the major routes of transport of pesticides into the aquatic environment and could affect biota living closely in contact with it. Sediment residues of DDT were found to be easily adsorbed (95.0%) and were released in hard water (8.4%) and seawater (0.1%). DDT and DDE sediment residues were released into sterile and nonsterile brackish water indicating minimal role of micro-organisms. DDT was detected in oyster and in mussel with an average of 46-62% in the shell, 19-31% in the tissues and 19-23% in the fluids. Most of the sediment residues were extractable and released residues in water were in the form of DDT. In the presence oysters, bound was transformed into extractable DDT in sediment after 30 days equivalent to 26% of the total concentration. Most biota residues were extractable and an average of 46% was transformed to DDE. Uptake of residues depend on whether the source of contamination was by direct addition to the water or through sediment residues, if food was given or not, if the source of sediment residues were either aged or freshly treated and if residues were extractable or non-extractable.

Adsorption↗
PubMed2000

Influence of heat treatment of casein in presence of reducing sugars on Zn solubility and Zn uptake by Caco-2 cells after in vitro digestion.

The effect of the heat treatment of casein in presence of reducing sugars on some aspects of Zn availability was investigated. Samples were prepared by mixing casein with glucose-fructose, and were used unprocessed (C) or heated (HC). Changes in Zn speciation after the in vitro digestion of the samples, both as part of a diet and in isolation, were studied. The uptake of soluble Zn from the digested samples was investigated in Caco-2 cells. After in vitro digestion, the percentage of precipitated Zn was significantly higher with the HC sample, both when digested alone and as a part of the diet. In assays with Caco-2 cells, a significant decrease in Zn uptake was observed when the uptake buffer contained the sample C digest, by comparison with the control buffer, without casein digest. When the digested heated mixture was added, Zn uptake by the cells was significantly lower than in either of the two other cases. It may be concluded that the heat treatment of casein in the presence of glucose-fructose has a negative effect on Zn availability because, after in vitro digestion, Zn insolubilization was enhanced and Zn uptake by the enterocyte was impaired, compared with the unheated mixture. In addition, the usefulness of Caco-2 cells in this kind of research has been shown.

Caco-2 Cells↗
PubMed1996

Relationship between moderate food restriction during pregnancy and Fe, Zn and Cu contents in maternal tissues and foetuses.

This study was undertaken to monitor Fe, Zn and Cu contents in several maternal tissues and the products of conception of rats submitted to moderate food restriction during pregnancy. Two groups of female rats, nonpregnant (NP) and pregnant (P1), were fed ad libitum. A second group of pregnant rats (restricted diet, P2) was fed for 14 days with the same intake as NP, then the intake was increased by 5% from day 14 to day 21. A significant decrease in liver Fe content was noted in P1 and P2 pregnant rats on day 21, being more marked in livers of P2. Increases in Cu and Zn contents in liver were induced during pregnancy, but the values were significantly lower in P2 than in P1. On day 21, no significant differences due to food restriction were noted in serum concentrations of these trace elements, placental weight and placental Fe. However, dam body weight gain, placental Zn and Cu contents were reduced in P2. Foetuses of undernourished dams exhibited at term lower weight and smaller amounts of Fe, Zn and Cu than those in P1. These results confirm that moderate food restriction during pregnancy produces intrauterine growth retardation and that newborns have low trace element contents (particularly in Cu), which make them dependent on correct postnatal supply.

Animals↗
PubMed1995

Iron metabolism in rats consuming oil from fresh or fried sardines.

The influence of the consumption of diets containing oil from either fresh sardines or fried sardines, under domestic conditions, on the dietary iron metabolism of rats has been investigated. Three groups of rats were fed, over 28 d, semipurified diets containing 8% of: olive oil (OO), fresh sardine (Clupea pilchardus) oil (SO) and oil from sardines previously fried in olive oil (FSO). Body mass and food intake were monitored and, during the periods 5-12 d and 21-28 d, faeces and urine were collected. At the end of the experiment, the animals were killed and blood, liver, spleen and a segment of skin were stored. Food intake and body mass decreased markedly in the SO rats. These parameters were slightly increased in the FSO group compared with OO. Iron absorption and retention were lower in SO than in OO or FSO. This was primarily caused by the poor food intake but also by the lower efficiency of absorption and high urinary Fe losses. Liver and spleen iron contents were reduced by half in SO compared with the other groups, partly owing to the smaller size of the organs, and liver Fe concentration also decreased. These results, together with the high total iron binding capacity, the decreased level of hemoglobin and total erythrocytic iron found in the SO animals, indicate that the consumption of fresh sardine oil as the only dietary fat resulted in iron depletion. The SO animals showed a higher Fe accumulation in skin than OO or FSO. It was concluded that a diet high in sardine fatty acid administered as a unique source of fat, can cause metabolic alterations including iron depletion, but these negative effects of sardine oil disappear with frying, probably owing to the exchange that takes place between fatty acids in the olive oil used in frying and those in the sardine oil.

Absorption↗
PubMed1994

[Isolated ACTH deficiency].

The isolated ACTH deficiency is a scarcely diagnosed disease of heterogeneous nature. Two patients with isolated deficiency of ACTH in whom the initial diagnosis was of primary suprarrenal failure are reported. In the first case this diagnosis was performed after hospital admission for deterioration of the level of consciousness and the development of an acute suprarrenal crisis in the course of nosocomial pneumonia. In the second case the clinical manifestations began as weakness, anorexia, weight loss and lymphocytosis with eosinophilia. In both patients an increase in the thyrotropic hormone was detected leading to suspicion of the existence of associated primary hypothyroidism. Finally, several studies were carried out (basal measurements of cortisol and ACTH, stimulation with continual perfusion of ACTH, insulinic hypoglycemia, global study of adenohypophysary function, ACTH CRF release factor test, computerized tomography of the pituitary region) in both patients leading to the definitive diagnosis of isolated ACTH deficiency of idiopathic cause of possible pituitary origin without the existence of other associated hormonal deficiencies.

Adrenocorticotropic Hormone↗
PubMed1994

Influence of the consumption of casein, or tuna in the raw, cooked or canned form, on the utilization of iron in the diet of weanling rats.

A study was made of the influence of the consumption of white tuna (subjected to various thermal treatments) on the bioavailability of dietary iron. Biological assays were carried out on Wistar rats fed semi-synthetic diets varying only in the protein source, casein-methionine, or tuna provided in the following forms: raw, cooked in brine, sterilized with or without soybean oil, and canned and stored for a period of 1 or 3 years. Feed intake, the fecal and urinary excretion of iron, and the iron content of the liver were monitored. Absorption of iron was enhanced by consuming the diet containing raw white tuna. However, the beneficial effect of raw tuna was greatly reduced by cooking it in brine, and even more so by sterilization, especially in the presence of oil. The benefit was partly restored by storing the conserves for a period of 1 or 3 years. It is hypothesized that structural alterations to the protein caused by thermal processes can affect the solubility and bioavailability of iron.

Animals↗
PubMed1993

Influence of moderate food restriction on calcium metabolism in pregnant rats.

Two groups of female rats, non-pregnant (NP) and pregnant (P1), were fed ad libitum. A second group of pregnant rats (restricted diet, P2) were restricted for 14 d to the same intake as NP, and their ration was then increased by 5% from d 14 to d 21. For the first 3 d P1 and P2 absorbed a higher percentage of calcium than NP. During the final wk of pregnancy serum calcium decreased and 1,25-dihydroxycholecalciferol increased regardless of the dietary regimen. In both P1 and P2, femur calcium was higher than in NP on d 7 and apparent bone density increased during the 2nd wk of pregnancy and decreased from then on, this decrease being more pronounced in P2. On d 21, P2 fetuses were smaller and contained a smaller amount of calcium than those in P1, although the calcium concentration in the body remained similar in both groups of fetuses.

Absorption↗
PubMed1993

Bioavailability of zinc in rats fed on tuna as a protein source in the diet.

The objective of this study was to investigate the dietary zinc bioavailability in diets containing raw, cooked, steamed, and canned tuna as a protein source in the diet, and to evaluate different means of preparation, as well as various storage periods of the canned tuna, which was prepared according to industrial standards. Sterilized oil-free canned tuna was also made. The biological assays used for the study of the zinc utilization were carried out on Wistar rats fed with semi-synthetic diets for 12 days varying only in the protein source, which was casein-methionine or tuna provided as follows: raw, cooked in brine, steamed, sterilized with or without soybean oil, canned and stored for one or three years. Body weight, food intake, faecal and urinary zinc excretion, and zinc content in rat liver were monitored. No modifications were shown in food efficiency when diets including tuna were used, compared with those values from the casein-methionine diet. Thus, final body weight results were similar in all groups tested. Dietary zinc absorption was enhanced by consuming a raw white tuna diet. This beneficial effect disappeared after steaming or cooking in brine, but it was slightly recovered after sterilization with oil and storage of the canned tuna. Animals fed on the diets including the oil-free canned tuna, showed two or three times higher faecal and urinary zinc excretion than those fed on casein and canned tuna stored for 0, 1 or 3 years, reaching a negative balance. A negative effect was therefore found in both dietary and endogenous zinc utilization due to the consumption of oil-free canned tuna.

Animals↗
PubMed1992

Zinc status in anorexia nervosa.

Some aspects of zinc nutritive status in patients suffering from anorexia nervosa were evaluated. Basic anthropometric measurements, Zn levels in serum, urine and hair as well as serum alkaline phosphatase (ALP) and lactate dehydrogenase (LDH; Zn-dependent enzymes) and delayed dermal hypersensitivity were tested both in patients and in control subjects. The patients showed higher Zn levels in serum (123%), hair (85%) and urine (215%) than controls, whereas ALP and LDH values were 38 and 21%, respectively, lower than those from the control group. Half of the patients showed hypoergy, and less than 50% of them were able to show a normal immune response. These results suggest that Zn-dependent functions may be impaired in anorexia nervosa as a consequence of Zn unavailability.

Adolescent↗
PubMed1992

[Protein nutrition and physical activity].

The relationship between physical exercise and diet in order to optimize performance is getting growing interest. This review examines protein needs and protein intakes as well as the role of protein in the body and the metabolic changes occurring at the synthesis and catabolic levels during exercise. Protein synthesis in muscle or liver, amino acids oxidation, glucose production via gluconeogenesis from amino acids, etc., are modified, and consequently plasma and urinary nitrogen metabolites are affected. A brief comment on the advantages, disadvantages and forms of different protein supplements for sportsmen is given.

Dietary Proteins↗
PubMed1988

Effects of consuming toxic oils and oleoanilides on fat digestibility and adipose tissue composition of rats.

An oil implicated in the Spanish "toxic syndrome" was studied for its effect on fat digestibility and adipose-tissue composition in rats. The effects produced by the mixture of oils and those induced by the presence of oleoanilides were assessed separately. For 4 wk, Wistar rats were fed diets containing either a mixture of oils similar to that constituting the toxic oil, the same mixture of oils supplemented with oleoanilides, or the toxic oil (which also contained oleoanilides) and were then compared with a group fed olive oil. Food consumption fluctuated sharply in the group fed the toxic oil, falling significantly in the last week of the study. The digestibility coefficient of the various fats was similar, although the rats fed the toxic oil did absorb less fat because of the lower intake. The nitrogen content of the periovarian adipose tissue was highest in the rats fed the toxic oil, and the adipose-tissue fatty acids most affected by this treatment were linoleic and linolenic acid. The delta-9 desaturase activity, measured in terms of the C16:1/C16:0 and C18:1/C18:0 ratios, was significantly less in the group fed the toxic oil, which suggests functional modifications of the adipocyte related to lipogenesis.

Acetanilides↗
PubMed1988

Several aspects of mineral/protein nutrition in relation to consumption of an oil involved in the toxic syndrome.

An oil involved in the 'toxic syndrome' and two similar mixtures of oils, one with and the other without added oleoanilides, were studied for their effects on the utilization of protein, calcium, magnesium, phosphorus, sodium, potassium and zinc. Forty-eight female Wistar rats initially weighing about 75 g were fed for 28 days on the same semi-synthetic diet containing: virgin olive oil, or a mixture of canbra oil (50%), refined olive-pomace oil (20%), grapeseed oil (20%) and animal fat (10%), or the same dietary mixture supplemented with either 700 ppm oleoanilides or the alleged toxic oil. Weight, food intake and nutritional balances were monitored. The food intake of the animals fed the toxic oil began to decrease at the end of the trial, producing a reduction in the amount of nutrients ingested, but no weight loss. This oil also negatively affected the digestion of protein, potassium, sodium and zinc, the mechanism of which, in the case of the first two, appears to be related to the source of the fat. It also decreased metabolic utilization while favouring protein catabolism and the elimination of phosphorus, magnesium and potassium. No substantial modifications were noted in the animals' bones.

Animals↗
PubMed1987

[Changes in serum and urinary levels of phosphorus in pregnant women, induced by effect of milk supplementation].

It was studied the levels of phosphorus in serum and urine in two groups of pregnant women. One group was advised to follow their usual intake and the other to supplement the diet with 750 ml of milk. A control group of healthy non pregnant women were conformed to the same protocol. Pregnant women that followed their usual intake had the same levels of serum phosphorus and maximum phosphate transport as controls. Pregnant women who had taken milk supplement showed in the second and third trimester of pregnancy significantly lower serum phosphorus and maximum phosphate transport levels than controls and also with respect to pregnant women in the first trimester. It suggests a possible influence of diet on these parameters. Both groups of pregnant women showed hyperphosphaturia through the three trimesters.

Adult↗