Gloria Urbano

The role of phytic acid in legumes: antinutrient or beneficial function?

This review describes the present state of knowledge about phytic acid (phytate), which is often present in legume seeds. The antinutritional effects of phytic acid primarily relate to the strong chelating associated with its six reactive phosphate groups. Its ability to complex with proteins and particularly with minerals has been a subject of investigation from chemical and nutritional viewpoints. The hydrolysis of phytate into inositol and phosphates or phosphoric acid occurs as a result of phytase or nonenzymatic cleavage. Enzymes capable of hydrolysing phytates are widely distributed in micro-organisms, plants and animals. Phytases act in a stepwise manner to catalyse the hydrolysis of phytic acid. To reduce or eliminate the chelating ability of phytate, dephosphorylation of hexa- and penta-phosphate forms is essential since a high degree of phosphorylation is necessary to bind minerals. There are several methods of decreasing the inhibitory effect of phytic acid on mineral absorption (cooking, germination, fermentation, soaking, autolysis). Nevertheless, inositol hexaphosphate is receiving increased attention owing to its role in cancer prevention and/or therapy and its hypocholesterolaemic effect.ResumenEsta revisión describe el estado actual de conocimientos sobre el ácido fítico, presente de forma natural en muchos alimentos derivados de plantas, y, sobre todo, en las legumbres. Sus efectos antinutritivos se relacionan con su fuerte capacidad para formar complejos con proteínas y minerales. La hidrólisis del fitato en inositol y fosfatos se produce por acción de fitasas, ampliamente distribuidas en microorganismos, plantas y animales, y también por procesos no enzimáticos. Las fitasas actúan de forma escalonada siendo necesario conseguir la defosforilación del inositol hexa y penta fosfato, ya que estas son las formas con mayor capacidad quelante. Hay varios métodos para disminuir el efecto antinutricional del ácido fítico, tales como el remojo, cocinamiento, la germinación, fermentación y adición de enzimas. Sin embargo, el inositol hexafosfato está siendo objeto de nuevo interés por su papel en la prevención del cáncer y/o en su terapia, y por su efecto anticolesterolémico.

Lentil Starch Content and its Microscopical Structure as Influenced by Natural Fermentation

Lentil seeds (Lens culinaris var. vulgaris, cultivar Magda-20) were allowed to ferment naturally at different lentil flour concentrations (79 g/L, 150 g/L and 221 g/L) and temperatures (28 °C, 35 °C and 42 °C). During fermentation, samples were taken at 24 h intervals. The changes in starch content in all samples were studied. Scanning electron microscopy (SEM) was used to investigate changes in samples fermented for 96 h at two different concentrations (79 g/L and 221 g/L) and two different temperatures (28 °C and 42 °C). A considerable decrease in starch content was observed at 0 h of fermentation, defined as the time when the lentil flour was completly suspended at the established temperature. Once fermentation began, flour concentration and temperature modified starch content. Fermentation brought about a general decrease in starch content and a 32—37 % dry matter content was found in the samples after 96 h. Microscopical studies showed that endocorrosion, i.e., breakdown starting from the center of starch granules, was the main pattern observed during lentil fermentation.

Influence of intracerebroventricular or intraperitoneal administration of cannabinoid receptor agonist (WIN 55,212-2) and inverse agonist (AM 251) on the regulation of food intake and hypothalamic serotonin levels.

The effect of intracerebroventricular or intraperitoneal administration of cannabinoid receptor agonist WIN 55,212-2 or inverse agonist AM 251 on food intake and extracellular levels of serotonin and acetic acid 5-hydroxy-indol from presatiated rats was studied. Compared to the vehicle-injected control, the intracerebroventricular administration of WIN 55,212-2 was associated with a significant increase in food intake, whereas the administration of AM 251 caused a significant reduction in this respect. These results were accompanied by considerable reductions or increases in serotonin and acetic acid 5-hydroxy-indol levels compared to the vehicle-injected control and the baseline values for the different experimental groups studied. Intraperitoneal administration of WIN 55,212-2 at doses of 1 and 2 mg/kg promoted hyperphagia up to 6 h after injection, whereas administration of a higher dose (5 mg/kg) significantly inhibited food intake and motor behaviour in partially satiated rats. Administration of any of the AM 251 doses studied (0.5, 1, 2, 5 mg/kg) led to a significant decrease in the amount of food ingested from 2 h after the injection, compared to the vehicle-injected control group, with the most striking effect being observed when the 5 mg/kg dose was injected.

Effect of heat treatment and mineral and vitamin supplementation on the nutritive use of protein and calcium from lentils (Lens culinaris M.) in growing rats.

OBJECTIVE The effects of heat treatment, supplementation of a mineral and vitamin premix, and 4% olive oil on the bioavailability of protein and calcium from Lens culinaris M., var vulgaris, cultivar. magda-20 were studied in growing rats. METHODS Nutrition assessment was based on chemical analysis of lentil protein, energy, total and available starch, lipid and calcium composition, and the digestive and metabolic use of nitrogen and calcium by rats. Lentils used for the present study had crude protein and calcium contents of 25.5% and 0.07%, respectively. Heating lentils to 120 degrees C at 1 atm for 30 min decreased trypsin inhibitor activity, phytate, and tannin content by 76%, 8%, and 12%, respectively, but did not improve dietary intake or digestive use of protein compared with untreated raw control lentils. RESULTS Mineral, vitamin, and olive oil supplementation of raw or autoclaved lentils significantly improved daily food intake and nutritive use of nitrogen and calcium. The best results were obtained for the rats fed with a diet of raw lentils supplemented with a premix of minerals and vitamins. CONCLUSIONS There was a direct correlation between calcium balance and weight gain in animals (r = 0.89) and between the calcium balance and nitrogen balance (r = 0.86).

Ca AND P BIOAVAILABILITY OF PROCESSED LENTILS AS AFFECTED BY DIETARY FIBER AND PHYTIC ACID CONTENT

The influence of germination for 6 days and dry-heating at 120°C for 15 min on the content of calcium, phosphorus, phytic acid and dietary fiber in lentils was studied. Germination lowered total phosphorus (P) and phytic acid content whereas dry-heating did not modify total P but slightly decreased phytic acid. Both treatments increased cellulose (CL) and lignin (LN) content and reduced hemicellulose (HMC) of lentils. The apparent digestibility coefficient (ADC) and balance of calcium (Ca) improved in animals fed dry-heated and germinated lentils which was related with the decrease in HMC. Phytic acid intake was significantly reduced by dry-heating and germination, the lowest P intake and P absorption observed in animals fed germinated lentils led to a null P balance. The results obtained in muscle and femur by comparing control (casein) and experimental diets indicated that muscle is more sensitive tissue than bone at lower Ca and P retention.

Nutritional evaluation of protein, phosphorus, calcium and magnesium bioavailability from lupin (Lupinus albus var. multolupa)-based diets in growing rats: effect of alpha-galactoside oligosaccharide extraction and phytase supplementation.

The nutritional composition of the legume Lupinus albus var. multolupa, raw or after alpha-galactoside extraction, and its effect on the bioavailability of protein, P, Ca, and Mg by growing rats was evaluated using a balance technique. The protein and dietary fibre content of the lupin flours studied was high, and 89-94% of the dietary fibre was present as insoluble dietary fibre. The alpha-galactoside extraction process did not disrupt the nutritional quality of protein, and the digestive and metabolic utilisation of this nutrient was high and comparable with that obtained from a casein-cystine control diet (pair-fed to the average daily food intake of the experimental groups fed the different lupin diets). Bioavailability of P, Ca, and Mg from the lupin diets tested was high, and supplementation of an exogenous microbial phytase (750 phytase units/kg) did not cause any further improvement. Mineral content in the bone tissue (femur and sternum) did not correlate to mineral balance, which, on the other hand, was related to the mineral content of other tissues such as blood, plasma, liver and kidney. Due to its ability to grow under adverse edaphic and climatic conditions and to its good nutritional quality, alpha-galactoside-free lupin flour supplemented with the required amounts of minerals and vitamins to meet nutrient requirements can be used as an excellent dietary source for the preparation of dietetic products.

Lifestyle changes in free-living patients with peripheralvascular disease (Fontaine stage II) related to plasma and LDL lipid composition: a 15 month follow-up study

Peripheral vascular disease (PVD) is characterized by arteriosclerosis and lower extremity ischemia which cause intermittent claudication. Patients grouped in the Fontaine stage II have more than 75% organic stenosis in their large coronary arteries and exhibit a number of alterations in blood coagulation and plasma lipids. The aim of this study was to evaluate an intervention program of lifestyle habits including dietary recommendations, moderate exercise and decreased smoking in a population of patients with PVD for a period of 15 months, with respect to plasma-lipid and lipoprotein composition as well as LDL susceptibility to peroxidation. These parameters are well known risk indicators of arteriosclerosis and coronary heart disease. A total 13 subjects diagnosed with PVD (Fontaine stage II) were selected, while a healthy age-matched group (n=20) was used as a reference. This study design was an uncontrolled trial of lifestyle interventions. The group of patients was examined at 0, 3, 6, 9, 12 and 15 months. Patients smoking one or more packets of cigarettes per day at the beginning of the study (54.2%) decreased smoking by as much as 7.7% 15 months later. In addition, physical activity intensified significantly (walking > 1 km: 13.1-77%) and treadmill running increased over the study period while the energy intake decreased by 10%. The percentage of saturated fat in the diet decreased by 10% while the intake of polyunsaturated fat rose, and monounsaturated-fat intake showed a parallel trend to increase; the average intake of cholesterol also fell by 10% and plasma triglycerides and HDL-cholesterol showed a trend to decrease and increase, respectively. No permanent changes in LDL lipid fractions for patients were detected during the follow-up period and no differences between patients and the age-matched reference group were found. The macrophage uptake of plasma-oxidized LDL was significantly higher in patients than in the reference group and no differences due to the intervention period were detected. In conclusion, the education in lifestyle and nutritional habits of patients with PVD led to reduced energy intake parallel with augmented physical activity as well to a fall in plasma triglycerides and a rise in HDL-cholesterol, which are good indicators of a reduced risk of vascular and myocardial complications.

Effects of lifestyle modification and lipid intake variations on patients with peripheral vascular disease.

The aim of the present study was to evaluate the effects of diets enriched in monounsaturated fatty acids (MUFA) (olive oil) or MUFA plus n-3 polyunsaturated fatty acids (PUFA) (olive oil plus fish oil), associated with an intervention program that focused on lifestyle habits, physical performance, plasma lipids, and lipoprotein composition in patients with peripheral vascular disease (PVD). A 15-month longitudinal nutritional and lifestyle intervention study was carried out with 24 free-living male patients aged 58.0 +/- 2.2 years diagnosed with PVD (Fontaine grade II). The patients were clinically evaluated and counseled to change their dietary and lifestyle habits for six months, after this period they consumed an olive oil-based diet for three months: after a three-month wash-out period, their diet was supplemented with a combination of fish oil and olive oil for the final three months. Lifestyle interventions resulted in a significant decrease in cigarette smoking and an increase in physical activity. Claudicometry was lower at the end of the study than at the beginning. Intake of the fish oil supplement led to significant changes in lipid lipoprotein composition, decreasing low-density lipoprotein (LDL) cholesterol. The lifestyle intervention program, together with a high intake of olive plus fish oil, seems to produce important beneficial effects in nutritional management, physical performance, and clinical parameters of PVD patients.

Influence of Dietary Supplementation with Fish on Plasma Fatty Acid Composition in Coronary Heart Disease Patients

The effects of dietary supplementation with fish on plasma fatty acid levels were studied in 20 coronary heart disease patients who had suffered acute myocardial infarction. The study was divided into three periods: hospital admission, after 8 weeks on a heart-healthy diet designed for patients with ischemic heart disease, and after 4 weeks on an n-3 fatty acid-supplemented diet in which red meat was replaced with lean and fatty fish. At the end of each period, the subjects responded to a 48-hour recall questionnaire, so that we could assess their compliance with the diet, and blood samples were collected for the determination of plasma fatty acids. Stearic fatty acid was significantly decreased after the fish diet. n-7 and n-9 fatty acids showed no significant changes throughout the study. At the end of the 4-week period when the fish diet was consumed, linoleic acid and its long-chain derivative docosapentaenoic acid (22:5 n-6) were significantly increased. The most notable changes in n-3 series fatty acids at the end of the third period were the significant decrease in linolenic acid and the significant increase in its long-chain derivatives eicosapentaenoic (20:5 n-3) and docosahexaneoic acid (22:6 n-3). These changes in plasma fatty acid levels may have beneficial effects on coronary heart disease.

Effect of cortisol on some nutritional and biochemical parameters in pregnant rats and their foetuses

The influence of hydrocortisone acetate treatment (4 mg/100 g body weight i.m. and daily injected) was studied in pregnant rats and their litters. The parameters controlled were: food intake, body weight and body nitrogen, and liver enzimatic activity of PEPCK, in the mothers and number of foetus, weight, body nitrogen content and liver PEPCK activity in the litter. The hormonal treatment induces a significant reduction of food intake and weight of the mothers. In the same way the total body nitrogen content, is reduced but not its concentration (body nitrogen content/g body weight). Likewise, cortisone injection reduces the number of newborns, and, significantly, the individual weight of the same. At the 21st gestation day, the nitrogen content of the litter, given by g of weight, is also significantly reduced. Liver activity of PEPCK was significantly increased in the pregnant rat in all days under study and was not detected in the foetus in the 21st day.