Uso de inquéritos alimentares na avaliação da ingestão de antioxidantes / The use of dietary survey methods for the assessment of antioxidant intake

Free radicals produced in the body can be explained by several factors and induce cell damage in case of oxidative stress. In order to fight them, there are the endogenous antioxidant defense mechanisms, or exogenous, when derived from the diet. Some vitamins and minerals, besides phenolic compounds, present antioxidant function and fight these radicals. Therefore, many studies have demonstrated an association between the consumption of food with antioxidants and health benefits. Assessing the intake of antioxidants provides intervention measures and public policy actions. Several different instruments can be used to assess this intake, but each of them should be well known in order to make the most appropriate choice. Therefore, the aim of this study is to approach the different types of diet surveys used to determine the food intake of antioxidants, as well as discuss their advantages and limitations of use. The following surveys were used to determine the intake of antioxidants: Dietary Records, 24-hour recall, Food Frequency Questionnaire, and Antioxidant Food Frequency Questionnaire. Most of the surveys meth¬ods used consider only the antioxidant micronutrients, but one of the them quantifies the total antioxidant capacity of the diet, including the phenolic compounds. The methods analyzed present advantages and disadvantages, in addition to those inherent to the instrument. Critical reflection about the choice of the method allows a better assessment of the intake of antioxidants, aiding in a more accurate food diagnosis, eventually ensuring food and nutritional security for the population through necessary public policy initiatives.

Los radicales libres producidos en el organismo pueden explicarse por varios factores y causar daños celulares en el caso de que aparezca estrés oxidativo. Para combatirlos existen los mecanismos de defensa antioxidantes endógenos o exógenos provenientes de la dieta. Algunas vitaminas y minerales, además de los compuestos fenólicos, son los responsables de la función antioxidante y de combatir los radicales. Por lo tanto, muchos estudios han asociado el consumo de alimentos ricos en antioxidantes como algo beneficioso para la salud. Para evaluar la ingesta de antioxidantes se necesitan medidas de intervención y acciones de política pública. Para evaluar la ingesta se pueden utilizar diferentes instrumentos, sin embargo, se debe conocer cada uno de ellos para hacer la elección correcta. Por lo tanto, el objetivo de este estudio es abordar los diferentes tipos de encuestas alimentarias utilizadas para determinar el consumo de antioxidantes, así como discutir las ventajas y límites de su uso. Las diferentes encuestas utilizadas para determinar el consumo de antioxidantes fueron Registro Alimentar, Recordatorio 24 horas, Cuestionario de Frecuencia Alimentaria y Cuestionario de Frecuencia Alimentaria especifico para antioxidantes. La mayoría de los análisis se hace considerando sólo micronutrientes antioxidantes, sin embargo, en uno de los métodos, se cuantifica la capacidad antioxidante total de la dieta, incluyendo los compuestos fenólicos. Las metodologías abordadas presentan ventajas e inconvenientes, además de las inherentes al instrumento. La reflexión para la elección crítica del método permite una mejor evaluación de la ingesta de antioxidantes, ayudando en la precisión del diagnóstico alimentario. Y, por último, se garantiza la seguridad alimentaria y nutricional de la población por medio de iniciativas de políticas públicas necesarias.

Os radicais livres produzidos no organismo podem ser explicados por fatores diversos e induzem a danos celulares caso ocorra estresse oxidativo. A fim de combatê-los, existem os mecanismos endógenos de defesa antioxidante ou exógenos, quando provenientes da dieta. Algumas vitaminas e minerais, além de compostos fenólicos, são responsáveis por apresentar função antioxidante e combater os radicais. Por isso, muitos estudos vêm associando o consumo de alimentos fonte de antioxidantes aos benefícios à saúde. Avaliar a ingestão de antioxidantes propicia medidas de intervenção e ações de políticas públicas. Para avaliação da ingestão, podem ser utilizados diferentes instrumentos, porém deve-se conhecer cada um deles para realizar a escolha adequada. Sendo assim, o objetivo deste estudo é abordar os diferentes tipos de inquérito alimentar utilizados para determinar a ingestão de antioxidantes, assim como discutir suas vantagens e limitação de uso. Os diferentes inquéritos utilizados para determinar a ingestão de antioxidantes foram Registro Alimentar, Recordatório 24 horas, Questionário de Frequência Alimentar e Questionário de Frequência Alimentar específico para antioxidantes. A maioria realiza análise considerando apenas os micronutrientes anti-oxidantes, porém, em um dos métodos, quantifica-se a capacidade antioxidante total da dieta, incluindo-se também os compostos fenólicos. As metodologias abordadas apresentam vantagens e desvantagens, além daquelas inerentes ao instrumento. A reflexão para a escolha crítica do método permite melhor avaliação da ingestão de antioxidantes, auxiliando no diagnóstico alimentar mais preciso. Por fim, garante a Segurança Alimentar e Nutricional da população por meio de iniciativas de políticas públicas necessárias.

Lipid Peroxidation, Sperm DNA Fragmentation Total Antioxidant Capacity and Semen Quality in Male Infertility.

Infertility is a major clinical problem, affecting people medically and psychosocially. Male factor plays a significant role in about 50% of infertile couples. Recent reports indicate that increasing male infertility could be due to genomic abnormalities. The etiology of sperm DNA damage is multi-factorial but compromised due to nuclear defects, protamine deficiency and oxidative stress. The present study was aimed to evaluate sperm DNA integrity and oxidative stress in infertile men. The study is prospective, comprises 96 infertile patients and 30 fertile controls. Sperm DNA integrity was assessed by flowcytometry. MDA and TAC were evaluated spectrophotometrically. The percentage of DNA Fragmentation Index and MDA were found to be significantly increased while TAC was significantly decreased in infertile men as compared to control. DFI and MDA were negatively correlated with TAC levels. Present study indicates significant increases in seminal MDA and sperm DNA damage in infertile men. Seminal MDA was significantly correlated with sperm DNA damage, TAC and standard sperm parameters. The elevated levels of seminal OS observed in these infertile patients could be responsible for poor sperm quality and sperm DNA fragmentation. Hence evaluation of DFI, MDA and TAC can be used for diagnosis, prognosis of male infertility in addition to routine semen parameters to decide the treatment strategies.

The study of lipid profile, LP (a) and electrolytes with oxidative stress, total protein and albumin in nephrotic syndrome.

Nephrotic syndrome is characterized by heavy proteinuria, hypoalbuminemia, hyperlipidemia associated with peripheral edema. Recent observation revealed that serum albumin plays an important role in the host defense mechanism as it is one of the important antioxidants. Oxidative damage by free radicals has been implicated in kidney injury, especially in nephrotic syndrome (NS). Therefore, this study was carried out to investigate oxidant and lipoprotein (a) status with protein and electrolytes in nephrotic syndrome patients. The blood samples were analyzed for quantitation of malondialdehyde as index of lipid peroxide, total antioxidant capacity, lipid profile, lipoprotein (a), electrolytes, total protein and albumin. Significantly increased levels of serum lipid peroxide, lipoprotein (a) LDL, VLDL, Tcholand decreased levels of serum total antioxidant capacity and total protein and albumin were noticed in the patients with nephrotic syndrome as compared to control subjects. Electrolytes are variable Na was increased and potassium was decreased. However, significant positive correlation in lipid peroxide with lipoprotein (a),and total protein and albumin with total antioxidant capacity were observed.

Tea and Mint Extracts Modulate the HSP70 Expression in Preeclamptic Placental Explant.

Heat shock protein 70 is a molecular chaperone which expressed during oxidative stress to protect the cell from damage. Preeclampsia is a hypertensive disorder with an oxidative stress imbalance. Antioxidant defenses appear to be depleted during preeclampsia resulting in increased oxidative stress. Various alternative medicines are employed to increase the endogenous antioxidant level during preeclampsia. The aim of the present study was to determine the modulatory effect of medicinal plants, Camellia sinensis and Mentha spicata on oxidative stress, antioxidant and thiol status using placental explant as the model system. Placental explants were cultured from the placental tissues of both normotensive and preeclamptic subjects. The lipid peroxide, total antioxidant capacity, glutathione redox ratio, HSP70 levels were measured in the placental explants with and without incubation with tea, mint and mint-tea. The addition of these three extracts increased the TAC and GRR in both placental explants with decrease in the LPO level. The expression of HSP70 also decreased more significantly in preeclamptic explants on addition of tea and mint extracts due to the restoration of cell homeostasis via maintaining the antioxidant status. In view of the above results, mint-tea may emerge as an effective antioxidant, preventing cell damage during stress condition.

Oxidative stress with homocysteine, lipoprotein (A) and lipid profile in diabetic nephropathy.

Diabetic nephropathy is the single most common disorder leading to renal diseases. Reactive oxygen species (ROS) play a major role in the development of diabetic nephropathy. Nephrotic syndrome is often manifesting in progression of diabetic nephropathy. Therefore, this study was carried out to investigate oxidant and antioxidant status in diabetic nephropathy patients. The blood samples were analyzed for quantitation of malondialdehyde as index of lipid peroxide, vitamin C, total antioxidant capacity, homocysteine, lipoprotein (a) and lipid profile. Significantly increased levels of serum total cholesterol, triglycerides, low density lipoprotein, malondialdehyde as index of lipid peroxide, lipoprotein (a), homocysteine (p<0.001) and decreased levels of serum total antioxidant capacity, total protein, albumin, high density lipoprotein & plasma vitamin C (p<0.001) were noticed in the patients with diabetic nephropathy as compared to control subjects.