María López-Jurado

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.

Factors associated with obesity in an adult Mediterranean population: influence on plasma lipid profile.

Objective: The aim of the study was to identify factors associated with obesity, and their influence on plasma lipid profile in an adult Mediterranean population. Design: The data were obtained from a cross-sectional epidemiological survey. Setting: The study population resided in Andalusia, a western Mediterranean region in southern Spain. Subjects: The survey was carried out with a random sample of 3421 subjects (1747 men, 1674 women) between 25 and 60 years of age. Blood samples were obtained for biochemical assays in a random subsample of 340 subjects (167 men, 173 women). Interventions: Food consumption was assessed by 48-h recall. Height, weight, triceps, biceps, subscapular and suprailiac skinfolds, mid-upper arm, waist (WC) and hip circumferences, glucose, total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides were measured. Information about lifestyles was obtained with a questionnaire. Results: Of the adult population we studied, 18.9% were obese (body mass index [BMI] ≥ 30 kg/m2). A larger proportion of men than women were overweight, but the opposite was found for obesity. Mean plasma lipid values were not modified significantly by obesity or lifestyle factors, and were within the normal range. Sex, age, physical exercise and lower educational level were associated directly with the risk of obesity, and smoking was associated inversely with the risk of obesity. In obese smokers WC and waist-hip ratio were larger, and levels of HDL-cholesterol were lower (p < 0.05) than in obese nonsmokers. Glucemia was higher in obese persons who consumed alcohol (p < 0.05) than in obese persons who did not consume alcohol. The risk of hypercholesterolemia and high levels of LDL-cholesterol was associated only with age, and the risk of low levels of HDL-cholesterol was associated only with high WC. Conclusion: Our results provide an estimate of the prevalence of obesity in the adult population in southern Spain, and of the associated factors. Sex, age, leisure-time physical exercise and educational level appear to influence obesity. Only age and WC but not BMI were associated with a risk of dyslipidemia. No dietary associations were observed between energy or macronutrient intake and plasma lipid concentrations in overweight or obese persons.

Plasma levels of copper, manganese and selenium in an adult population in southern Spain: Influence of age, obesity and lifestyle factors

Copper, manganese and selenium are elements involved in protecting the body against oxidative stress. Determining their plasma level may contribute to assessing the health and nutritional status of populations. The aim of this study was to assess factors influencing copper, manganese and selenium plasma levels in an adult Mediterranean population and to identify groups at risk of deficiency. A cross-sectional survey was carried out in Andalusia, a region in southern Spain. Blood samples were obtained in a random subsample of 340 subjects. Food consumption was assessed by 48-h recall. Height, weight, skinfolds, waist and hip circumferences were measured. Copper, manganese and selenium were measured in plasma. Information about physical exercise, educational level, alcohol and smoking habits was obtained with a structured questionnaire. Plasma copper was found to be higher in women than among men. Hypocupraemia was found in 4.4% of the population, while 9.7% presented hypomanganesemia. Moreover, 86.5% presented plasma selenium values below 125microg/L (cutoff for optimal glutathione peroxidase activity). No association was found between plasma elements, anthropometric indices and lifestyle factors; there were tendencies, no more. Copper tended to decrease in obese and increase in sedentary, while selenium tended to decrease among smokers. Plasma Cu was positively correlated with the consumption of monounsaturated and polyunsaturated fats. Plasma Mn was directly correlated with the consumption of dairy products. Levels of Se were positively correlated with age, the consumption of fruit, vegetables, energy obtained from carbohydrates, and the consumption of fibre, and inversely correlated with the consumption of meat and sweets. Our results provide an estimate of the copper, manganese and selenium status in the adult population of southern Spain. The correlations found for Se suggest that there is a tendency for Se levels to be better maintained among the population that shows a stronger preference for the traditional diet.

Effects of high-whey-protein intake and resistance training on renal, bone and metabolic parameters in rats

Consumption of high-protein (HP) diets is postulated to exert a negative influence on bone and renal health. However, no conclusive evidence has been presented related to this issue or to the potential protective action of resistance training on HP-induced systemic effects. We examined the effects of HP diet consumption on food intake, body-weight gain, body composition, and renal, bone and metabolic parameters of rats performing resistance training. A total of ninety-six adult male Wistar rats were randomly distributed in twelve experimental groups (n 8): normal-protein (10%) or HP (45%) diets, with or without resistance training, killed for experimental periods of 1, 2 or 3 months. Diets were based on a commercial whey protein hydrolysate. Consumption of HP diets and resistance training significantly affected food intake, body weight and body composition, as well as the plasma levels of total cholesterol, HDL-cholesterol and TAG. The buffering action of resistance training on such diet-induced alterations was especially evident in the levels of plasma TAG. Consumption of HP diets led to a considerable increase in kidney weight, urinary volume and acidity, as well as in the urinary excretion of Ca, with a parallel reduction in the urinary excretion of citrate (P < 0·05). No apparent deleterious effect on bone mineral content was found. In conclusion, consumption of HP diets caused alterations in renal health status and some metabolic parameters, but did not seem to affect bone status. Resistance training had a protective action against alterations of renal health status and some metabolic parameters such as plasma TAG.

Assessment of iron and zinc intake and related biochemical parameters in an adult Mediterranean population from southern Spain: influence of lifestyle factors

This study assessed factors influencing iron and zinc intake and associated biochemical parameters in an adult population from southern Spain to identify patterns of intake and groups at risk for deficiency. A cross-sectional survey was done in Andalusia (southern Spain) to study nutrient intakes in a random sample of 3421 subjects (1747 men, 1674 women, age between 25 and 60 years). Blood samples were obtained for biochemical assays in a random subsample of 354 subjects (170 men, 184 women). Food consumption was assessed by 48-h recall. In blood samples, we measured red blood cells, haemoglobin (Hb), haematocrit, total iron binding capacity (TIBC) and plasma concentration of Fe and Zn. Information about educational level, smoking habit, alcohol consumption and physical exercise was collected with a structured questionnaire. Intakes were below two thirds of the recommended dietary allowances (RDA) in 22.45% of the sample for Fe and in 56.45% for Zn. Iron deficiency [two or more abnormal values for plasma Fe, TIBC, transferrin saturation and mean cell volume (MCV)] was found in 12.7% of the sample, and iron-deficient anaemia (low values for Hb, MCV, mean cell Hb and mean corpuscular Hb concentration) was found in 2.1%. In smokers, plasma levels of Fe were higher, and MCV was lower than in nonsmokers. Plasma Zn concentrations were below the reference value in 17.8% of the persons. Age and body mass index correlated inversely with plasma Zn (P<.01). Gender, age, obesity, smoking, alcohol consumption and physical activity were associated with differences in nutrient intakes. Logistic regression analysis showed that female gender and older age were associated with the risk of low intakes of Fe and Zn.

Influence of Dietary Fat on the Lipid Composition of Perirenal Adipose Tissue in Rats

The influence of dietary fat on the composition of perirenal adipose tissue was studied in Wistar rats fed three experimental semisynthetic, isocaloric diets containing different qualities of fat (olive oil, butter and medium chain triglycerides + corn oil). Under these experimental conditions, the saturation index reflects the percentage of fatty acids supplied by each diet; this index was highest in animals fed the diet containing butter and lowest in the group in which olive oil was the dietary fat source. The amount of linoleic acid (the major component of the diunsaturation index) supplied by the diet is directly paralleled by levels of this fatty acid in perirenal adipose tissue, whereas the monounsaturation index in adipose tissues, considered an indicator of the dietary supply of monounsaturated fatty acids in the rat, failed to show a clearly proportional relationship between intake and perirenal adipose tissue levels.

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.

Improvement of the antioxidant and hypolipidaemic effects of cowpea flours (Vigna unguiculata) by fermentation: results of in vitro and in vivo experiments

BACKGROUND The antioxidant capacity and hypolipidaemic effects of Vigna unguiculata, as well as their potential improvement by different fermentation and thermal processes were studied using in vitro and in vivo methods. RESULTS Phenolic content and reducing capacity of legume acetone extract were significantly increased by different fermentation processes, and by the thermal treatment of fermented legume flours. TBARS inhibiting capacity was increased by fermentation but not by thermal treatment. A higher ability to decrease Cu(2+)/H2O2-induced electrophoretic mobility of LDL was found in fermented when compared to raw legume extracts, and a higher protective effect on short term metabolic status of HT-29 cells was found for raw and lactobacillus-fermented Vigna followed by naturally fermented Vigna extracts. Significant improvements in plasma antioxidant capacity and hepatic activity of antioxidant enzymes were observed in rats that consumed fermented legume flours when compared to the untreated legume or a casein-methionine control diet. In addition, liver weight and plasma levels of cholesterol and triglycerides were also positively affected by untreated or naturally fermented Vigna. CONCLUSION V. unguiculata has demonstrated its potential as a functional food with interesting antioxidant and lipid lowering properties, which can be further augmented by fermentation processes associated or not to thermal processing.

Body Composition in an Adult Population in Southern Spain: Influence of lifestyle Factors

The aim of the present study was to assess the body composition in an adult Mediterranean population by two methods, to identify groups at risk for obesity and lifestyle factors that might influence this risk. A cross-sectional study was carried out in Andalusia, a western Mediterranean region in southern Spain. Body composition was studied with anthropometric methods and bioelectric impedance analysis (BIA) in a random sample of 394 subjects (169 men, 225 women) between 20 and 60 years of age. When anthropometric methods were used, we found that 19.4% of the individuals had a body mass index (BMI) > or = 30 kg/m(2). In 46.2% of the men, more than 25% of the body weight consisted of fat, and in 74.1% of the women, more than 30% of the body weight consisted of fat. When BIA data were used, these values rose to 34.7% and 60.6% for men and women respectively. After controlling for sex, age correlated directly with percentage of body fat when skinfold thickness (r = 0.58) or BIA (r = 0.40) was used. In smokers, the number of cigarettes/day correlated directly with waist circumference (r = 0.76), after controlling for both age and sex. We found high percentages of obesity regardless of the indicator or method used, particularly in women. Factors such as sex, age, leisure-time physical exercise, educational level, and smoking appeared to influence obesity. The factors that made the greatest contribution to the rates of obesity and high waist-hip ratio were the age, time spent exercising, and educational level. In contrast, the risk of high body fat (as determined with both methods) was associated only with sex and age.

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).