Josely C. Koury

Zinco, estresse oxidativo e atividade física

During intense physical activity there is an increased production of reactive oxygen species that can cause muscle injury and damage to erythrocyte cell membranes, thus impairing athletic performance. In order to prevent the effects caused by oxidative stress, the organism has several antioxidant mechanisms, some of which depending on zinc. The antioxidant properties of this mineral are explained by its role in the regulation of metallothionein synthesis, in the structure of superoxide dismutase, and in the protection of sulfhydryl groups of cell membrane proteins through antagonism with pro-oxidant metals such as iron and copper. Recent studies have shown that the osmotic fragility of erythrocytes is related to the zinc function in cell membranes. Athletes generally have dietary zinc intakes inadequate to compensate for the increased sweat and urine losses to meet and the high biochemical demand. This paper reviews the biological and nutritional significance of zinc in the antioxidant protection during intense physical activity.

Brazil nuts intake improves lipid profile, oxidative stress and microvascular function in obese adolescents: a randomized controlled trial

BackgroundObesity is a chronic disease associated to an inflammatory process resulting in oxidative stress that leads to morpho-functional microvascular damage that could be improved by some dietary interventions. In this study, the intake of Brazil nuts (Bertholletia excelsa), composed of bioactive substances like selenium, α- e γ- tocopherol, folate and polyunsaturated fatty acids, have been investigated on antioxidant capacity, lipid and metabolic profiles and nutritive skin microcirculation in obese adolescents.MethodsObese female adolescents (n = 17), 15.4 ± 2.0 years and BMI of 35.6 ± 3.3 kg/m2, were randomized 1:1 in two groups with the diet supplemented either with Brazil nuts [BNG, n = 08, 15-25 g/day (equivalent to 3 to 5 units/day)] or placebo [PG (lactose), n = 09, one capsule/day] and followed for 16 weeks. Anthropometry, metabolic-lipid profiles, oxidative stress and morphological (capillary diameters) and functional [functional capillary density, red blood cell velocity (RBCV) at baseline and peak (RBCVmax) and time (TRBCVmax) to reach it during post-occlusive reactive hyperemia, after 1 min arterial occlusion] microvascular variables were assessed by nailfold videocapillaroscopy at baseline (T0) and after intervention (T1).ResultsT0 characteristics were similar between groups. At T1, BNG (intra-group variation) had increased selenium levels (p = 0.02), RBCV (p = 0.03) and RBCVmax (p = 0.03) and reduced total (TC) (p = 0.02) and LDL-cholesterol (p = 0.02). Compared to PG, Brazil nuts intake reduced TC (p = 0.003), triglycerides (p = 0.05) and LDL-ox (p = 0.02) and increased RBCV (p = 0.03).ConclusionBrazil nuts intake improved the lipid profile and microvascular function in obese adolescents, possibly due to its high level of unsaturated fatty acids and bioactive substances.Trial RegistrationClinical Trials.govNCT00937599

Effect of zinc supplementation on the antioxidant, copper, and iron status of physically active adolescents

Puberty associated with intense physical activity results in oxidation stress. Zinc supplementation may benefit antioxidant capacity although it may also affect iron and copper status. This study evaluated the effect of zinc supplementation on antioxidant, zinc and copper status of physically active male football players (13 years ± 0.4 years), divided in two groups and studied during 12 weeks: Zn‐supplemented (Zn‐SUP, 22 mg Zn d−1 as zinc gluconate, n = 21) and placebo (PLA, n = 26). At baseline, there was no significant difference in biochemical indices between the two groups. After treatment, plasma zinc and erythrocyte iron increased in both groups (p < 0.001); urinary zinc increased (p < 0.001) only in Zn‐SUP, and erythrocyte zinc decreased (p = 0.002) only in PLA. Plasma iron and copper decreased (p = 0.01 and p = 0.015, respectively) only in Zn‐SUP. Plasma ferric‐reducing ability and plasma conjugated dienes increased, and erythrocyte osmotic fragility decrease in both groups, although the latter two were significantly lower in Zn‐SUP compared to PLA (p < 0.01). In conclusion, our study indicates that the use of 22 mg d−1 of supplemental zinc during 12 week in adolescent athletes did not affect growth, improved markers of antioxidant status but reduced plasma iron and copper. Therefore, it appears that the use of zinc supplementation by healthy adolescent athletes benefits their antioxidant capacity but impairs copper and iron nutritional status. Copyright

Plasma zinc, copper, leptin, and body composition are associated in elite female judo athletes

This study evaluated levels of plasma zinc, copper, and leptin, body composition, and their relationship in nine elite female judo athletes under two different training conditions. Body composition and biochemical measurements (hematological indexes, plasma zinc, plasma copper, and plasma leptin) were analyzed 24 h after intense training and following a 5-d period without training (no-training). Plasma leptin and plasma zinc increased with no-training. Plasma zinc correlated negatively with percent fat mass (r=−0.62; r=0.05) and positively with plasma leptin (r=0.83; p=0.002) in the no-training condition Plasma copper did not change during the study and correlated positively with plasma leptin (r=0.66; p=0.05) and with percent fat mass (r=0.80; p=0.007) after training. Percent fat mass was associated negatively with plasma zinc (r=−0.62; p=0.05) in the no-training condition. Moreover percent fat mass was negatively associated with the Zn/Cu plasma ratio under both training conditions (r<−0.78, p<0.001). These results are consistent with the possible function of zinc as a lipid-mobilizing factor and of copper as a limiting factor in energy metabolism.

Organic grape juice intake improves functional capillary density and postocclusive reactive hyperemia in triathletes

OBJECTIVE The aim of this study was to evaluate the effect of organic grape juice intake on biochemical variables and microcirculatory parameters in triathlon athletes. INTRODUCTION The physiological stress that is imposed by a strenuous sport, such as a triathlon, together with an insufficient amount of antioxidants in the diet may cause oxidative imbalance and endothelial dysfunction. METHODS Ten adult male triathletes participated in this study. A venous blood sample was drawn before (baseline) and after 20 days of organic grape juice intake (300 ml/day). Serum insulin, plasma glucose and uric acid levels, the total content of polyphenols, and the erythrocyte superoxide dismutase activity were determined. The functional microcirculatory parameters (the functional capillary density, red blood cell velocity at baseline and peak levels, and time required to reach the peak red blood cell velocity during postocclusive reactive hyperemia after a one-min arterial occlusion) were evaluated using nailfold videocapillaroscopy. RESULTS Compared with baseline levels, the peak levels of serum insulin ( p = 0.02), plasma uric acid ( p = 0.04), the functional capillary density ( p = 0.003), and the red blood cell velocity (p < 0.001) increased, whereas the plasma glucose level (p,0.001), erythrocyte superoxide dismutase activity ( p = 0.04), and time required to reach red blood cell velocity during postocclusive reactive hyperemia ( p = 0.04) decreased after organic grape juice intake. CONCLUSION Our data showed that organic grape juice intake improved glucose homeostasis, antioxidant capacity, and microvascular function, which may be due to its high concentration of polyphenols. These results indicate that organic grape juice has a positive effect in endurance athletes.

Resveratrol reduces lipid peroxidation and increases sirtuin 1 expression in adult animals programed by neonatal protein restriction

Resveratrol (Res) has been associated with protective effects against oxidative stress. This study evaluated the effect of Res over lipid peroxidation, antioxidant defense, hepatic sirtuin 1 (SIRT1), which up-regulates antioxidant enzymes, and copper/zinc superoxide dismutase (Cu/Zn SOD) in adult offspring whose mothers were protein restricted during lactation. Lactating Wistar rats were divided into control (C) group, which were fed a normal diet (23% protein), and low-protein and high-carbohydrate (LPHC) group, which were fed a diet containing 8% protein. After weaning (21 days), C and LPHC offspring were fed a normal diet until they were 180 days old. At the 160th day, animals were separated into four groups as follows: control, control+Res, LPHC, and LPHC+Res. Resveratrol was given for 20 days (30  mg/kg per day by gavage). LPHC animals showed a higher total antioxidant capacity (TAC) without change in lipid peroxidation and SIRT1 expression. The treatment with Res increased TAC only in the control group without effect on lipid peroxidation and SIRT1. LPHC animals treated with Res had lower lipid peroxidation and higher protein and mRNA expression of SIRT1 without any further increase in TAC. No significant difference in liver Cu/Zn SOD expression was observed among the groups. In conclusion, maternal protein restriction during lactation programs the offspring for a higher antioxidant capacity, and these animals seem to respond to Res treatment with a lower lipid peroxidation and higher hepatic SIRT1 expression that we did not observe in the Res-treated controls. It is probable that the protective effect can be attributed to Res activating SIRT1, only in the LPHC-programmed group.

Effect of the Period of Resting in Elite Judo Athletes Hematological Indices and Copper/ Zinc-Dependent Antioxidant Capacity

The purpose of this study was to evaluate the effect of the resting period on hematological and copper-zinc-dependent antioxidant indices in Brazilian elite judo athletes (n=7). Venous blood samples were collected after 24-h and 5-d periods of resting following a competition, with an interval of 30 d between collections. Two months prior to and during the study, each athlete received an individualized adequate diet. Body composition was determined at both study periods. The following were analyzed: in whole blood, hemoglobin, hematocrit, red cell count, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, red cell distribution width, and white cell count; in plasma, zinc, copper, iron, ceruloplasmin, and total iron-binding capacity; in erythrocytes, metallothionein, copper/zinc superoxide dismutase, and osmotic fragility. Dietary intake and body composition did not affect the biochemical measurements. A significant reduction in ceruloplasmin and superoxide dismutase activity was found after 5 d compared to 24 h of resting. A significant correlation between erythrocyte metallothionein and red cell distribution width was observed after 24 h of resting (r=−0.83, p=0.02) whereas positive correlations of metallothionein with hemoglobin, red cell count, and mean corpuscular hemoglobin concentration were observed after 5 d of resting (r≥0.76, p≤0.05). Our results suggest that a longer resting period favors homeostatic adjustments in the erythrocyte population and in the copper/zinc-dependent antioxidant system in elite judo athletes.

Physical exercise is associated with better fat mass distribution and lower insulin resistance in spinal cord injured individuals

Abstract Objectives The aim of the study was to compare total and regional body composition and their relationship with glucose homeostasis in physically active and non-active individuals with cervical spinal cord injury (c-SCI). Methods Individuals with lesion level between C5–C7 were divided into two groups: physically active (PA; n = 14; who practiced physical exercise for at least 3 months, three times per week or more, minimum of 150 minutes/week): and non-physically active (N-PA n = 8). Total fat mass (t-FM) and regional fat mass (r-FM) were assessed by dual energy X-ray absorptiometry. Fasting plasma insulin (FPI) was determined by enzyme-linked immunosorbent assay. Results PA group present lower (P < 0.01) total fat mass (t-FM), % and kg, regional fat mass (r-FM), % and kg, FPI levels and HOMA index, while they had higher (P < 0.001) total free fat mass (t-FFM), %, and regional free fat mass (r-FFM), %, compared to the N-PA group. In the N-PA group, FPI and HOMA index were negatively (P < 0.05) correlated with FFM% (r = −0.71, −0.69, respectively) and positively correlated to trunk-FM (r = 0.71, 0.69, respectively) and trunk-FM:t-FM (kg) ratio (r = 0.83, 0.79, respectively). Conclusion Physical exercise is associated with lower t-FM, r-FM, and insulin resistance, which could contribute to the decrease of the risk of cardiovascular and metabolic conditions in individuals with c-SCI.

Serum Levels of Long-Chain Polyunsaturated Fatty Acids in Patients With Periodontal Disease

BACKGROUND Long-chain polyunsaturated fatty acids omega-3 and omega-6 (LC-PUFA n-3 and n-6) can function as important inflammatory modulators and also have a strong effect in the proresolving inflammatory processes. The aim of the authors is to analyze the serum levels of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and arachidonic acid (AA) in patients with generalized chronic periodontitis (GCP) and compare these results with serum levels of patients with gingivitis only. METHODS Twenty-one patients with untreated GCP (mean age: 46.0 ± 8.8 years) and 16 patients with gingivitis only (mean age: 31.5 ± 7.5 years) were investigated. The clinical examination included probing depth (PD), clinical attachment level, bleeding on probing, and plaque index. Blood samples were analyzed for the presence of DHA, EPA, DPA, and AA using gas chromatography. RESULTS Significantly higher levels of DHA, DPA, EPA, and AA were observed in patients with GCP when compared with patients with gingivitis (P = 0.007, P = 0.004, P = 0.033, and P = 0.001, respectively). The differences were still significant even after the adjustments for age and sex. The PD showed a significant positive correlation with DHA (r = 0.5; P = 0.003), DPA (r = 0.6; P <0.001), and AA (r = 0.6; P <0.001). CONCLUSION The present findings suggest that serum levels of LC-PUFA n-3 and n-6 may be affected by the severity of periodontal disease.

Phase Angle and Bioelectrical Impedance Vectors in Adolescent and Adult Male Athletes

The aim of the current study was to assess phase angle (PA) and bioelectrical impedance vectors (BIVA) in adolescent (n = 105, 12-19 y) and adult (n = 90, 20-50 y) male athletes practicing varied sports modalities. Bioelectrical impedance analysis (BIA) was performed with a single-frequency tetrapolar impedance analyzer after the athletes had fasted overnight for 8 h. PA and BIVA were determined from BIA data. PA presented correlations (P < .01) with body-mass index (r = .58) in all athletes and also with age in adolescent (r = .63) and adult (r = -.27) athletes. Compared with adults, adolescent athletes presented lower PA and higher frequency of PA below the 5th percentile of a reference population (P < .001). The adolescents with low PA were mostly football and basketball players. The BIVA confidence ellipses of adult and adolescent athletes were different (P < .001) between them and from their respective reference populations and were closer than those of adult and adolescent nonathletes. About 80% of the athletes were in the 95th percentile of BIVA tolerance ellipses and in quadrants consistent with adequate body cell mass and total body water. The adolescent athletes outside the 95th percentile ellipse were all football and basketball players who showed indications of decreased water retention and body cell mass and of increased water retention, respectively. PA and BIVA ellipses showed that the intense training routine of the athletes changed functional and hydration parameters and that the magnitude of these changes in adolescents may depend on the sport modality practiced.