Heberth de Paula

Dietary models for inducing hypercholesterolemia in rats

The present work aimed at finding a dietetical model capable of promoting the highest hypercholesterolemia without affecting the development of the rats. Sixty female Fisher rats were divided into five groups. The first one was fed a control diet; the remaining four were fed hypercholesterolemic diets with cholesterol and different contents of soybean oil, starch, casein, micronutrients and fiber and, consequently, different caloric values. After eight weeks animals were evaluated in relation to growth, fecal excretion, liver weight and fat, cholesterol and its fractions, serum biochemical parameters and sistolic pressure and compared with controls. The best result was obtained with the diet containing 25 % soybean oil, 1.0 % cholesterol, 13 % fiber and 4,538.4 Kcal/Kg, since it promoted an increase in LDL-cholesterol, a decrease in the HDL fraction and affected less the hepatic function of the animals.

Iron overload alters glucose homeostasis, causes liver steatosis, and increases serum triacylglycerols in rats

The objective of this study was to investigate the effect of iron overload with a hyperlipidemic diet on the histologic feature of hepatic tissue, the lipid and glycemic serum profiles, and the markers of oxidative damage and stress in a rat model. Twenty-four male Fischer rats, purchased from Experimental Nutrition Laboratory, Federal University of Ouro Preto, were assigned to 4 equal groups, 2 were fed a standard cholesterol-free diet (group C or control and CI or control with iron) containing 8.0% soybean oil and 2 were fed a hyperlipidemic diet (group H or hyperlipidemic and HI or hyperlipidemic with iron) containing 1.0% cholesterol and 25.0% soybean oil. A total of 50 mg of iron was administered to rats in groups CI and HI in 5 equal doses (1 every 3 weeks for a 16-week period) by intraperitoneal injections of 0.1 mL of iron dextran solution (100 g Fe(2+)/L; Sigma, St Louis, Mo). The other rats in groups C and H were treated in a similar manner but with sterile saline (0.1 mL). Irrespective of the diet, iron excess enhanced serum triacylglycerols (P < .05) and reduced serum glucose and glycated hemoglobin levels (P < .05) but did not affect serum cholesterol concentration. Histologic analysis showed steatosis in groups H and to a lesser extent in HI. No significant differences (P > .05) were observed in paraoxonase activities or in serum levels of free or total sulfhydryl radicals, malondialdehyde, or total antioxidants. The findings suggest that iron excess in the rat probably modifies lipid metabolism and, as a consequence, alters glucose homeostasis and increases the level of serum triacylglycerols but not of cholesterol.

Whey protein: composition, nutritional properties, appications in sports and benefits for human health

As proteinas do soro do leite, tambem conhecidas como whey protein, sao extraidas durante o processo de fabricacao do queijo. Possuem alto valor nutricional, contendo alto teor de aminoacidos essenciais, especialmente os de cadeia ramificada. Tambem apresentam alto teor de calcio e de peptideos bioativos do soro. Pesquisas recentes demonstram sua grande aplicabilidade no esporte, com possiveis efeitos sobre a sintese proteica muscular esqueletica, reducao da gordura corporal, assim como na modulacao da adiposidade, e melhora do desempenho fisico. Estudos envolvendo a analise de seus compostos bioativos evidenciam beneficios para a saude humana. Entre esses possiveis beneficios destacam-se seus efeitos hipotensivo, antioxidante e hipocolesterolemico. Esta revisao buscou trabalhos que trazem avaliacao das propriedades funcionais das proteinas do soro, tanto em humanos como em animais. Apesar das evidencias apresentadas, novos estudos, assim como o desenvolvimento de novos alimentos enriquecidos com as proteinas do soro, com o intuito de facilitar seu consumo por grandes grupos populacionais, sao necessarios para verificar sua real eficacia.The soluble proteins of milk, also known as whey protein, are extracted during the cheese manufacturing process. They have high nutritional value, with high levels of essential amino acids, especially branched chain amino acids. They also have a high level of calcium and whey bioactive peptides. Recent researches have shown their wide application for sports with possible effects on skeletal muscle protein synthesis, reduction of body fat, as well as adiposity modulation, and improved muscle performance. Researches involving the analysis of their bioactive compounds have also shown benefits to human health. Among these benefits, their hypotensive, antioxidant, and hypocholesterolemic effects stand out. This review has searched scientific articles that evaluate the functional properties of whey protein, both in humans and animals. Despite this evidence, new researches, as well as the development of new whey protein-enriched foods to increase their consumption by the population, are necessary to check their real effectiveness.

Effect of an aqueous extract of annatto (Bixa orellana) seeds on lipid profile and biochemical markers of renal and hepatic function in hipercholesterolemic rats

Annatto extract is a natural food color obtained fr om the outer coatings of the seeds of the Annatto t ree ( Bixa orellana L.). This is the first report in the literature that shows the relationship between the aqueous annat to extract and its influence on lipid profile in animals. Male Fisher rats were divided into three groups (n=12): C group, fed standard diet and water; H group, fed high-lipid di et and water and; HU group, with high-lipid diet an d aqueous annatto extract for 60 days. The treatment with ann atto extract in animals fed with the high-lipid die t lowered the LDL- and total cholesterol and raised the HDL-chole sterol, suggesting a hypocholesterolemic effect. Ne ither highfat diet nor aqueous annatto extract had any signif icant effect on serum levels of albumin or serum ac tivities of transaminases which suggested that no liver injury was induced.

Evaluation of Biological and Biochemical Quality of Whey Protein

Nutritional and biochemical properties of noncommercial whey protein have been described since 1950. However, comparisons between commercial whey protein for human consumption and casein are rarely found. The aim of this study was to compare biological quality of a commercial whey protein with casein and its effect on biochemical parameters of rats. Thirty-two weanling Fisher rats were divided into three groups and given the following diets: casein group, standard diet (AOAC); whey protein group, modified AOAC diet with whey protein instead of casein; and casein:whey group, modified AOAC diet with 70%:30% casein:whey. A protein-free group was used for determination of endogenous nitrogen losses. Net protein ratio, protein efficiency ratio, and true digestibility were determined, and blood was collected for biochemical analysis. When compared with casein, whey protein showed significant differences for all biological parameters evaluated, as well as for albumin, total protein, total cholesterol, and glucose concentrations. Replacing 30% of casein with whey protein did not affect these parameters. A positive relation among whey protein, high-density lipoprotein-cholesterol, and paraoxonase activity was found. Hepatic or renal dysfunctions were not observed. In conclusion, in comparison with casein, commercial whey protein had higher values of biological parameters, and biochemical evaluation revealed it improved glycemic homeostasis, lipid status, and paraoxonase activity in rats.

Influência das proteínas do soro sobre enzimas hepáticas, perfil lipídico e formação óssea de ratos hipercolesterolêmicos

OBJECTIVE: The aim of this study was to assess the effect of whey protein consumption on the lipid, hepatic and renal metabolism, bone formation and antioxidant defense system of rats given a hypercholesterolemic diet. METHODS: A total of 32 adult Fisher rats were divided into 4 groups: C group, standard diet; H group, hypercholesterolemic diet; WP group, standard diet with whey protein; WPH group, hypercholesterolemic diet with whey protein. Food ingestion and weight gain were monitored weekly. After 8 weeks, blood was collected for biochemical analysis and the rats were killed. The statistical tests analysis of variance and Tukeys test were performed. RESULTS: Whey protein did not lower serum cholesterol significantly and increased serum triglycerides in hypercholesterolemic rats. However, whey protein decreased the activity of aspartate aminotransferase and alkaline phosphatase, as well as serum creatinine. The assessed antioxidant defenses were not affected. Diets containing whey protein generated heavier, thicker and longer bones than casein diets. CONCLUSION: Whey proteins did not have a significant hypocholesterolemic effect in rats. On the other hand, they significantly prevented changes in liver and kidney functions brought about by hypercholesterolemic diets. Data also suggest that whey proteins benefit bone formation when compared with casein diets.

Biological evaluation of a nutritional supplement prepared with QPM Maize cultivar BR 473 and other traditional food items

Quality Protein Maize (QPM) cultivar BR 473 was emp loyed, together with soybean flour, brown sugar, ba nana meal and oat meal, for the preparation of a nutriti onal supplement.. 21-day old male Fisher rats were fed diets containing the supplement as a protein source, both with and without soybean flour; casein diets with 10 or 7% protein served as respective controls. Protein Effi ciency Ratio (PER), Net Protein Utilization (NPU), Net Protein Retention (NPR) and Digestibility were determined. Blood biochemical parameters (glucose, cholesterol, urea, hemoglobin, albumin and total protein) were also me asured in the animals and showed that all were in g ood health condition at the end of the experiment. The obtaine d results for PER, NPU and NPR indicated that the s prepared with QPM maize cultivar BR 473 was a good protein source, especially when soybean flour was a dded.

Estudo dos determinantes clínicos e epidemiológicos das concentrações de sódio e potássio no colostro de nutrizes hipertensas e normotensas

Abstract This study aimed to determine whether mater-nal hypertension and other clinical and epi-demiological determinants have an impact on sodium and potassium levels in the 48-hour colostrum of breastfeeding mothers. The study included 105 randomly selected breastfeeding mothers, of whom 72 (68.8%) had normal blood pressure and 33 (31.4%) were hypertensive. Co-lostrum was collected in-hospital in the morn-ing, and sodium and potassium concentrations were measured using a flame photometer. When sodium and potassium concentrations were compared to the variables age, parity, family history of hypertension, gestational age, birth weight, and socioeconomic factors, colostrum potassium level was associated with maternal age. Average sodium and potassium levels in 48-hour colostrum non-hypertensive and hyper-tensive breastfeeding mothers showed no signif-icant differences. Thus, breastfeeding by hyper-tensive mothers probably does not increase the risk of their children developing hypertension in adulthood.Colostrum; Hypertension; Sodium; Potassium