Ana B. López-Jaén

Oxidative markers in children with severe obesity following low-calorie diets supplemented with mandarin juice

Aim:  To evaluate the effect of supplementing a hypocaloric diet with mandarin juice, a food with a high content of antioxidants (vitamin C, flavonoids and carotenoids), on biomarkers of oxidant/antioxidant status of severe obese children.

Mandarin Juice Improves the Antioxidant Status of Hypercholesterolemic Children

Background: Oxidative stress has been linked to such degenerative diseases as atherosclerosis, and it has been suggested that increased dietary intake of antioxidants may reduce its progression. Objective: To determine the effect of mandarin juice consumption on biomarkers related to oxidative stress in hypercholesterolemic children. Materials and Methods: The diet of 48 children with plasma cholesterol >200 mg/dL and low-density lipoprotein cholesterol >130 mg/dL was supplemented for 28 days with 500 mL/day of pure (100%) mandarin juice (Citrus clementina Hort. ex Tan.). The composition of the mandarin juice was analyzed, and its antioxidant antiradical activity was evaluated in vitro. Malondialdehyde, carbonyl groups, vitamins E and C, erythrocyte-reduced glutathione, and plasma lipids were measured at the onset and at the end of the supplementation period. The paired Student t test was used to compare values before and after supplementation. Results: Mandarin juice exerted a strong antioxidant effect mainly due to its high hydroxyl activity and, to a lesser extent, to its superoxide scavenger activity. At the end of the study, levels of the plasma biomarkers of oxidative stress were significantly decreased (malondialdehyde −7.4%, carbonyl groups −29.1%, P < 0.01), whereas the plasma antioxidants vitamin E and C (13.5%, P < 0.001 and 68.2%, P < 0.00001, respectively) and intraerythrocyte glutathione level (36.7%, P < 0.00001) were significantly increased. Plasma lipids and antibodies to oxidized low-density lipoproteins remained unchanged. Conclusions: Regular ingestion of mandarin juice significantly reduces plasma biomarkers of lipid and protein oxidation and enhances the antioxidant status of consumers.

Effects of alcohol-free beer on lipid profile and parameters of oxidative stress and inflammation in elderly women

OBJECTIVE We assessed the influence of alcohol-free beer on factors implicated in atherosclerosis, such as lipid profile, oxidative stress parameters, and proinflammatory cytokines, in postmenopausal women, a population particularly at risk for atherosclerotic disease. METHODS The study was carried out in 29 nuns, 58 to 73 y old, who live in a convent with a disciplined, regular, and homogeneous lifestyle. The nuns maintained their habits and diet routine, but their meals were supplemented with 500 mL/d of alcohol-free beer (0.0%) divided into two doses over a 45-d period. Lipid profile, inflammatory markers such as C-reactive protein, interleukins 1 and 6, and tumor necrosis factor-alpha, and parameters of oxidative metabolism were determined before and after the study period. RESULTS There were no differences in the levels of C-reactive protein and proinflammatory cytokines after diet supplementation. The antibody titers to oxidized low-density lipoprotein were significant lower (P < 0.05), and thiobarbituric acid-reactive substances (-18%, P < 0.001) and plasma carbonyl group content (-21%, P < 0.001) were decreased when compared with initial values. Increases in alpha-tocopherol levels (+9%, P < 0.05) and erythrocytic glutathione levels (+29%, P < 0.001) were also noted. With respect to lipid profile, only subjects with cholesterol levels higher than 240 mg/dL showed lower levels after supplementation. CONCLUSION Consumption of non-alcoholic beer produces a decrease in oxidative stress that can have a beneficial impact on cardiovascular risk; however, the circulating concentrations of inflammatory mediators involved in its pathophysiology remained unchanged.

Dried apples enriched with mandarin juice by vacuum impregnation improve antioxidant capacity and decrease inflammation in obese children.

BACKGROUND A favorable effect over development of degenerative diseases is derived of an adecuate intake of fruit and vegetables, mainly due to their antioxidant compounds OBJECTIVES The goal of this study was to test the effect in vivo over oxidant status and inflammation in obese children of a novel food product made of dried apples enriched with mandarin juice by vacuum impregnation. METHODS A four-week intervention study was conducted in 41 obese children (> 2 standard deviation score-body mass index). Participants were instructed to follow their usual diet supplemented with 40 g/day of the developed product. Anthropometric parameters were determined including body mass index, waist circumference and estimations of body fat percentage using bioelectrical impedance. Dietary intake was assessed by questionnaire. Metabolic risk factors (blood pressure, lipid profile, glucose and insulin resistance) were recorded. To determine oxidant status, plasma total antioxidant capacity and 8-hydroxydeoxyguanosine, as marker of oxidative damage to DNA, were investigated. High-sensitive C-reactive protein, tumor necrosis factor-α, and interleukins 6 and 1-α were measured as inflammatory markers. Measurements were collected at baseline and at the end of the intervention period. RESULTS Significant improvement in systolic blood pressure and lipid profile after intervention period was noted. A significant increase in the antioxidant capacity of plasma (ABTS and FRAP assays) and reductions in DNA oxidative damage and inflammatory markers were also found. CONCLUSION Overall, adding the product to the diet contributes to ameliorate oxidant and inflammatory status in obese children and several risk factors for atherosclerosis.

Dried apple enriched with mandarin juice counteracts tamoxifen-induced oxidative stress in rats.

Abstract The effect of a product made of dehydrated apples enriched with mandarin juice by vacuum impregnation on markers of oxidative stress (plasma antioxidant capacity, carbonyl groups (CGs), 8-hydroxydeoxyguanosine (8OHdG) and α-tocopherol) was tested in rats. Six groups of animals were studied: one group was fed a standard diet; two groups were supplemented with dehydrated apple either impregnated or not with mandarin juice throughout 28 days; and three groups (one unsupplemented and two supplemented) were additionally treated with tamoxifen (TAM) for 21 days used for induction of oxidative stress. The rats treated with TAM showed an increase in aminotransferases, CGs and 8OHdG. All of these effects were significantly decreased in the animals after apple snack consumption; the addition of mandarin juice into the apple mainly accounts for increased levels of α-tocopherol in plasma and liver. These findings suggest that the food product have a protective action against oxidative stress induced by TAM in rats.

Free radicals: A review

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are normally produced in aerobic organisms. Free radicals play a physiological role being necessary for cellular functioning because redox reactions are the basis for numerous biochemical pathways as well as cellular chemistry, biosynthesis of macromolecules and metabolic regulation. They can able to act as second messengers, producing the stimulation of cell proliferation and being mediators for the activation of cells. However, ROS and RNS can also lead to unwanted oxidation reactions when accumulate and if they are in high amounts they can produce toxic effects. The organism must confront and control the presence of both pro-oxidants and antioxidants continuously. The balance between these is tightly regulated and extremely important for maintaining vital cellular and biochemical functions. Although the exposure of the organism to ROS is extremely high from exogenous sources, the exposure to endogenous sources is much more important and extensive. The dual nature of these species with their beneficial and deleterious characteristics implies the complexities of their specific functioning at a biological site.

Antioxidants: A review

Oxidative stress is defined as an imbalance between free radical production and antioxidant defense in favor of the first. Free radicals can exert negative effects on biomolecules and metabolic reactions that results in cellular damage which may be involved in aging processes and degenerative pathologies. To limit the harmful effects of free radicals, the organism has developed a series of antioxidant defense systems in order to protect themselves. These systems give to the free radicals elimi- nation or its transformation into stable molecules. The antioxidant defense system consists on cellular enzymatic antioxidants such as superoxide dismutase, catalase and glutathione peroxidase and non-enzymatic antioxidants either endogenous (gluta- thione) or exogenous (vitamin E, vitamin C, flavonoids, carotenoids) between others.