Multivitamin-mineral supplementation prevents lipid peroxidation during "the Marathon des Sables"

OBJECTIVE: We investigated the effect of a moderate mutivitamin and mineral supplementation containing mainly vitamin C (150.0 mg.day(-1)), vitamin E (24.0 mg.day(-1)) and beta-carotene (4.8 mg.day(-1)) prior to and during an extreme running competition -the Marathon des Sables (MDS)- that consisted of six long races in the desert. METHODS: Seventeen athletes participated in our double blind, placebo-controlled study. Blood samples were collected prior to the supplementation i.e. three weeks before the competition (D-21), two days prior to the MDS (D-2), after the third race (D3) and at the end of the competition (D7). Erythrocyte antioxidant enzyme activity (glutathione peroxidase (GPx), superoxide dismutase (SOD)), erythrocyte glutathione level (GSH), plasma non-enzymatic antioxidant status (uric acid, vitamin C, alpha-tocopherol, retinol, beta-carotene), markers of plasma lipid peroxidation (thiobarbituric reactive substances (TBARS)), reactive carbonyl derivatives (RCD) and membrane damage (creatine kinase and lactate dehydrogenase activities) were measured. RESULTS: In both groups, GSH levels, uric acid levels and membrane damage significantly increased during the competition while SOD activity significantly decreased. In Supplemented group, plasma alpha-tocopherol, beta-carotene and retinol levels significantly increased after three weeks of supplementing. In contrast to Placebo group, alpha-tocopherol, vitamin C and retinol levels were significantly affected by the competition in Supplemented group. Moreover, no increase in TBARS was observed in Supplemented group during the competition, whereas TBARS significantly increased at D3 in the placebo group. CONCLUSION: The moderate multivitamin-mineral supplementation prevented the transient increase in TBARS levels during this extreme competition.     

Nutritional and plasmatic antioxidant vitamins status of ultra endurance athletes

OBJECTIVE: The "Marathon des Sables" (MDS) is a competition known to induce oxidative stress. Antioxidant vitamins prevent exercise-induced oxidative damages. The purpose of this study was to evaluate daily intake and plasma level of the main antioxidant vitamins (alpha-tocopherol, vitamin C, beta-carotene and retinol) in 19 male athletes who participated in this competition. METHODS: Data collected before the beginning of the competition included daily dietary intake using a 7-day food record and plasma biochemical measurements (alpha-tocopherol, vitamin C, beta-carotene and retinol). RESULTS: First, total energy intake was obviously lower than the energetic intake usually observed in well-trained endurance athletes. Second, antioxidant vitamins intake was also insufficient. Indeed, the intake was lower than the French Dietary Reference Intakes (DRI) for this population in 18 subjects for vitamin E and 6 subjects for vitamin C, beta-carotene and Retinol Equivalent. As a significant relationship was found between total energy intake and the intake of vitamin E (r = 0.73; p < 0.001) and vitamin C (r = 0.78; p < 0.001), the low total energy intake contributed partially to the insufficient antioxidant vitamins intake. The dietary questionnaire analysis also revealed a low intake of vegetable oils, fruits and vegetables. However, plasma concentrations of these antioxidant vitamins were similar to the literature data observed in athletes. CONCLUSION: This study evidenced obvious insufficient energy intake in ultra endurance athletes associated with a low antioxidant vitamin intake.     

Seasonal variations of antioxidant imbalance in Cuban healthy men

OBJECTIVE: To determine the antioxidant imbalance in healthy Cuban men 2y after the end of the epidemic neuropathy (50 862 cases from 1991 to 1993) and to evaluate its change over 1 y. DESIGN: Prospective study. SETTING: La Lisa health centres (Havana, Cuba). SUBJECTS: One-hundred and ninety-nine healthy middle-aged men were selected and 106 completed the study. Subjects were studied at 3 month intervals over 1 year. INTERVENTIONS: No invervention. MAIN OUTCOME MEASURES: An assessment of dietary intake and the determination of blood lipid peroxides (TBARS), glutathione, diglutathione, glutathione peroxidase, superoxide dismutase, vitamin E, carotenoids, copper, zinc and selenium were performed at each period. RESULTS: While dietary zinc, vitamins C and E, carotenoids and fat dietary intakes and blood concentrations were low for adult men compared to international reference ranges, serum TBARS concentrations were high at every period. Some significant seasonal variations were observed. The lowest carotenoids (P < 0.002) and vitamin C(P = 0.0001) intakes, serum beta-carotene (P = 0.0001) and lutein/zeaxanthin (P < 0.05) concentrations, and the highest blood TBARS (P = 0.0001) and diglutathione (P < 0.001) concentrations were observed at the end of the rainy season (October). This period seemed to pose the greatest risk of antioxidant imbalance. CONCLUSIONS: Cuban men still represent a vulnerable population in terms of antioxidant imbalance. A national program of vegetable growing and increase in fruit and vegetable consumption is now evaluated in Cuba.     

beta-Carotene and canthaxanthin alter the pro-oxidation and antioxidation balance in rats fed a high-cholesterol and high-fat diet

This study investigated the effects of beta-carotene and canthaxanthin on lipid peroxidation and antioxidative enzyme activities in rats fed a high-cholesterol, high-fat diet. Wistar rats were divided into six groups. Negative control group (group NC) received a high-fat (150 g/kg) diet; cholesterol control group (group CC) received a high-cholesterol (10 g/kg), high-fat diet. The other four groups were fed a high-cholesterol, high-fat diet supplemented with crystal beta-carotene (group BC), beta-carotene beadlet (group BB), canthaxanthin beadlet (group CX) or alpha-tocopherol (group AT). Blood and livers were collected for analysis after 6 weeks of feeding. Group BB had significantly lower hepatic thiobarbituric acid reactive substance (TBARS) and conjugated diene concentrations, whereas group CX had a significantly lower plasma TBARS concentration than did group CC. In erythrocytes, glutathione peroxidase activities were significantly greater in groups BC, BB and CX than in group CC. Moreover, compared with group CC, catalase activities were significantly greater in groups BB and CX, and superoxide dismutase (SOD) activity was significantly greater in group BB. In livers, SOD activities were significantly greater in groups BC, BB and CX, and glutathione reductase activities were significantly greater in groups BB and CX than in group CC. Compared with group CC, hepatic retinol and alpha-tocopherol concentrations were significantly greater in groups BC, BB and CX, whereas plasma and hepatic cholesterol concentrations were significantly lower in group BC. These findings suggest that beta-carotene and canthaxanthin altered the pro-oxidation and antioxidation balance and suppressed cholesterol-induced oxidative stress via modulation of antioxidant system and cholesterol metabolism.     

Zinc and copper biochemical indices of antioxidant status in elite athletes of different modalities

The purpose of this study was to compare zinc and copper biochemical indices of antioxidant status and their relationship in elite athletes of different modalities: aerobic with high-impact (triathletes, n = 10 and long-distance runners, n = 12), anaerobic with high-impact (short-distance runners, n = 9), and anaerobic with low-impact (short-distance swimmers, n = 13). The influence of recent dietary intake and body composition was also evaluated. A venous blood sample was drawn 16-20 hr after competition for the following measurements: packed-cell volume and hemoglobin in blood; copper and zinc in plasma and erythrocytes; ceruloplasmin in plasma; superoxide dismutase activity and metal-lothionein in erythrocytes; and erythrocyte osmotic fragility. Zinc and copper intakes were not different in the athlete groups and did not affect the biochemical indices measured. Athletes of the long-distance high-impact aerobic modalities had higher indices of antioxidant protection (erythrocyte zinc, superoxide dismutase activity, and metallothionein) than those of the short-distance low-impact modalities, suggesting that there is adaptation of the antioxidant capacity to the specific training. Significant correlations were observed in all athletes between erythrocyte zinc, superoxide dismutase activity, and metallothionein consistent with the importance of an adequate zinc status in the response of antioxidant mechanisms to intense exercise.     

Antioxidant vitamin status in high exposure to oxidative stress in competitive athletes

We conducted a cross-sectional study in 118 well-trained athletes to investigate 'high exposure' to sub-deficient antioxidant status, and consequently to oxidative damage, in relation to estimated daily energy expenditure (EE) and dietary antioxidant intake. Subjects completed 7 d food and activity records. Blood samples were obtained on day 8. Of the athletes 81, 60 and 43% had intakes of vitamins E, C and beta-carotene below two-thirds of the French RDA respectively, which is adjusted for EE (FRDAa). The deficit in vitamin E intake was positively correlated with EE (r 0.51, P<0.0001). All the athletes had normal plasma vitamins E and C and 14% had marginal plasma beta-carotene. Plasma thiobarbituric acid-reactive substances (TBARS) did not increase with increased EE. As evidenced by ANOVA, EE-induced vitamin C intakes increased and consequently led to increased plasma ascorbic acid concentrations. In male athletes, plasma total carotenoids were negatively correlated with plasma TBARS concentrations (r -0.31, P<0.006). The relationship between vitamin C intakes and plasma concentrations was logarithmic (r 0.59, P< 0.0001). To summarize, it is not clear whether vitamin E requirements are overestimated with reference to EE in the FRDAa. Daily requirements for vitamin C do not exceed 200 mg. Our present results could be interpreted as meaning that carotenoids play a protective role as exogenous antioxidants. Carotenoid intakes in athletes must be considered carefully.     

Influence of habitual diet on antioxidant status: a study in a population of vegetarians and omnivores

BACKGROUND: Antioxidant status can be used as a biomarker to assess chronic disease risk and diet can modulate antioxidant defence. OBJECTIVE: To examine effects of vegetarian diet and variations in the habitual intakes of foods and nutrients on blood antioxidants. SUBJECTS AND SETTING: Thirty-one vegetarians (including six vegans) and 58 omnivores, non-smokers, in Northern Ireland. DESIGN: A diet history method was used to assess habitual diet. Antioxidant vitamins, carotenoids, uric acid, zinc- and ferric-reducing ability of plasma (FRAP) were measured in fasting plasma and activities of glutathione peroxidase (GPX), superoxide dismutase (SOD) and glutathione S-transferase (GST) and level of reduced glutathione (GSH) were measured in erythrocytes. RESULTS: Vegetarians had approximately 15% higher levels of plasma carotenoids compared with omnivores, including lutein (P< or =0.05), alpha-cryptoxanthin P< or =0.05), lycopene (NS), alpha-carotene (NS) and beta-carotene (NS). The levels/activities of all other antioxidants measured were similar between vegetarians and omnivores. Total intake of fruits, vegetables and fruit juices was positively associated with plasma levels of several carotenoids and vitamin C. Intake of vegetables was positively associated with plasma lutein, alpha-cryptoxanthin, alpha-carotene and beta-carotene, whereas intake of fruits was positively associated with plasma beta-cryptoxanthin. Intake of tea and wine was positively associated with FRAP value, whereas intake of herbal tea associated positively with plasma vitamin C. Intakes of meat and fish were positively associated with plasma uric acid and FRAP value. CONCLUSIONS: The overall antioxidant status was similar between vegetarians and omnivores. Good correlations were found between intakes of carotenoids and their respective status in blood.     

Antioxidant status in children with juvenile rheumatoid arthritis (JRA) living in Cairo, Egypt

The aim of this study was to examine both enzymatic and non-enzymatic antioxidant status in a select group of children with juvenile rheumatoid arthritis (JRA), living in Cairo, Egypt. The plasma concentrations of albumin, ceruloplasmin, vitamin C, vitamin E as well as erythrocyte superoxide dismutase and whole blood glutathione peroxidase activities were all significantly decreased in the presence of JRA compared to those without JRA. Unlike these antioxidant factors, vitamin A and its carrier (e.g. retinol binding protein), which have very little or no antioxidant property, remained unaffected by JRA. These results suggest that the children with JRA are subject to oxidative stress.     

Antioxidant status in children with juvenile rheumatoid arthritis (JRA) living in Cairo,Egypt

The aim of this study was to examine both enzymatic and non-enzymatic antioxidant status in a select group of children with juvenile rheumatoid arthritis (JRA), living in Cairo, Egypt. The plasma concentrations of albumin, ceruloplasmin, vitamin C, vitamin E as well as erythrocyte superoxide dismutase and whole blood glutathione peroxidase activities were all significantly decreased in the presence of JRA compared to those without JRA. Unlike these antioxidant factors, vitamin A and its carrier (e.g. retinol binding protein), which have very little or no antioxidant property, remained unaffected by JRA. These results suggest that the children with JRA are subject to oxidative stress.     

Antioxidant effect of diphenyl diselenide on oxidative damage induced by smoke in rats: involvement of glutathione

In the present study, the involvement of glutathione system in the restorative effect of diphenyl diselenide (PhSe)(2) on damage induced by cigarette smoke was investigated. Rat pups were progressively exposed to four, five, and six cigarettes for exposure periods of 15 min during their first, second, and third weeks of life. Thiobarbituric acid reactive species (TBARS) levels, components of the enzymatic antioxidant defenses (superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST) activities), and non-enzymatic antioxidant defenses (vitamin C and non-protein thiol (NPSH) levels) were examined in lungs of pups. The results demonstrated an increase in lipid peroxidation and the alteration in non-enzymatic and enzymatic antioxidant defenses induced by cigarette smoke exposure in lung of pups. Administration of (PhSe)(2) (0.5mg/kg) restored TBARS levels and antioxidant defenses in lungs of rat pups exposed to cigarette smoke. (PhSe)(2) treatment increased NPSH levels and GST activity per se in lungs of rat pups. Together these results indicate that (PhSe)(2) restored oxidative damage induced by cigarette smoke exposure in lungs of rat pups. The glutathione system is involved in antioxidant effect of this compound.     

Green tea extract only affects markers of oxidative status postprandially: lasting antioxidant effect of flavonoid-free diet

Epidemiological studies suggest that foods rich in flavonoids might reduce the risk of cardiovascular disease and cancer. The objective of the present study was to investigate the effect of green tea extract (GTE) used as a food antioxidant on markers of oxidative status after dietary depletion of flavonoids and catechins. The study was designed as a 2 x 3 weeks blinded human cross-over intervention study (eight smokers, eight non-smokers) with GTE corresponding to a daily intake of 18.6 mg catechins/d. The GTE was incorporated into meat patties and consumed with a strictly controlled diet otherwise low in flavonoids. GTE intervention increased plasma antioxidant capacity from 1.35 to 1.56 (P<0.02) in postprandially collected plasma, most prominently in smokers. The intervention did not significantly affect markers in fasting blood samples, including plasma or haemoglobin protein oxidation, plasma oxidation lagtime, or activities of the erythrocyte superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase. Neither were fasting plasma triacylglycerol, cholesterol, alpha-tocopherol, retinol, beta-carotene, or ascorbic acid affected by intervention. Urinary 8-oxo-deoxyguanosine excretion was also unaffected. Catechins from the extract were excreted into urine with a half-life of less than 2 h in accordance with the short-term effects on plasma antioxidant capacity. Since no long-term effects of GTE were observed, the study essentially served as a fruit and vegetables depletion study. The overall effect of the 10-week period without dietary fruits and vegetables was a decrease in oxidative damage to DNA, blood proteins, and plasma lipids, concomitantly with marked changes in antioxidative defence.     

Effects of beta-carotene and retinyl palmitate on corn oil-induced superoxide dismutase and catalase in rats

The present study was undertaken to determine the effects of beta-carotene on corn oil-induced superoxide dismutase and catalase. Six groups of male Buffalo rats were fed the following diets for 6 wk: a control diet containing recommended levels of beta-carotene and retinyl palmitate, a retinol diet containing 10 times the recommended level of retinyl palmitate, and a beta-carotene diet containing 10 times the recommended levels of beta-carotene and adequate levels of retinyl palmitate. Each vitamin combination was fed with either 5% (wt/wt) corn oil (low fat) or 20% corn oil (high fat). Plasma total beta-carotene levels were highest in the beta-carotene groups. Levels varied inversely with the level of fat in the control group and directly with fat in the beta-carotene group. Transport of beta-carotene appeared to parallel that of cholesterol in that 36 and 35%, respectively, were associated with the low density lipoprotein fraction. Accumulation of beta-carotene in the liver was apparent from the observation that levels in liver were much higher than those in plasma. Superoxide dismutase activity was much lower in the beta-carotene groups than in the retinol groups, irrespective of level of fat, and catalase activity was also lower in the beta-carotene group, but it was in proportion to the level of fat. These findings suggest that beta-carotene functions as an antioxidant in vivo.     

Increased plasma fatty acid concentrations after respiratory exacerbations are associated with elevated oxidative stress in cystic fibrosis patients

BACKGROUND: Oxidative stress and depleted antioxidant defenses occur in stable cystic fibrosis patients. During acute infection, the balance between oxidants and antioxidants may be further disturbed. OBJECTIVE: We examined the oxidative stress during acute infection in cystic fibrosis patients by measuring 8-iso-prostaglandin F(2 alpha) (8-iso-PGF(2 alpha)) and antioxidant defenses in relation to dietary intake, fatty acid status, immune function, and clinical status. DESIGN: Plasma concentrations of total 8-iso-PGF(2 alpha), vitamins E and C, beta-carotene, zinc, selenium, and copper; plasma fatty acid compositions; erythrocyte glutathione concentrations; glutathione peroxidase and superoxide dismutase activity; sputum glutathione and 8-iso-PGF(2 alpha) concentrations; lung function; clinical symptoms; and dietary intake were measured in 15 cystic fibrosis patients before and after 10-14 d of intravenous antibiotic treatment for a pulmonary exacerbation. RESULTS: After treatment, respiratory status improved (percentage of forced expiratory volume in 1 s: 60 +/- 6% at baseline compared with 74 +/- 7% after treatment, P = 0.01), quality of well-being improved (P = 0.001), and total plasma 8-iso-PGF(2 alpha) concentrations increased from 469 nmol/L at baseline (interquartile range: 373-554 nmol/L) to 565 nmol/L after treatment (interquartile range: 429-689 nmol/L; P = 0.008). Total energy, fat, carbohydrate, and protein intakes per kilogram body weight also increased; however, dietary antioxidant intake was unchanged. Plasma fatty acid concentrations increased after treatment, strongly correlating with plasma 8-iso-PGF(2 alpha) concentrations (r = 0.768, P = 0.001). There were no significant changes in white cell counts or plasma concentrations of vitamins E and C or beta-carotene. Erythrocyte glutathione peroxidase activity was reduced after treatment, whereas there was no significant change in superoxide dismutase activity. CONCLUSIONS: Oxidative stress increased after treatment for pulmonary exacerbations and was strongly linked to increased concentrations of plasma fatty acids. Although intravenous antibiotic therapy and physiotherapy improved lung function within 10-14 d of treatment, the biochemical effects of oxidation continued further. Thus, antioxidant intervention during treatment for and recovery from acute infection in cystic fibrosis should be considered.     

Naringin supplementation lowers plasma lipids and enhances erythrocyte antioxidant enzyme activities in hypercholesterolemic subjects

BACKGROUND AND AIMS: Preliminary studies have shown that naringin has a potent lipid-lowering effect and antioxidant capacity in high-cholesterol diet fed animals. Accordingly, the present study was conducted to investigate the effect of naringin on hypercholesterolemic subjects. METHODS: A hypercholesterolemic group (n=30) and healthy control group (n=30) were established based on the plasma cholesterol levels in the subjects, then all subjects received naringin (400mg/capsule/day) with regular meals for a period of 8 weeks. RESULTS: In the hypercholesterolemic subjects, naringin supplementation was found to lower the plasma total cholesterol by 14% and low-density lipoprotein cholesterol concentrations by 17%, while the plasma triglyceride and high-density lipoprotein cholesterol concentrations remained unaffected. The apolipoprotein B levels in the hypercholesterolemic subjects were significantly lowered after naringin treatment, yet no change was observed in the apolipoprotein A-1 levels. The erythrocyte superoxide dismutase and catalase activities in the hypercholesterolemic group were significantly increased, whereas the glutathione peroxidase activity and plasma TBARS levels were not different from the baseline measurements. Meanwhile, naringin supplementation had no affect on plasma lipids, apolipoproteins, and TBARS levels or antioxidant enzyme activities in the control group. CONCLUSIONS: Therefore, these data suggest that naringin may play an important role in lowering plasma cholesterol and regulating the antioxidant capacity in hypercholesterolemic subjects.     

Antioxidant status and cancer mortality in China.

Sex-specific mortality rates for selected cancer sites (including oesophagus, stomach, liver, lung, colorectum, breast and cervix) and a variety of biochemical indicators of antioxidant status, enzyme activity and oxidative stress (including plasma levels of beta-carotene, alpha-tocopherol, ascorbic acid, selenium, glutathione peroxidase, catalase, superoxide dismutase, iron, copper, zinc, total cholesterol and lipid peroxide) were examined in an ecological study of 65 mostly rural counties in the People's Republic of China. The wide range of both mortality rates and biochemical values and the measurement of a comprehensive set of biochemical indicators permitted both simple correlational and multivariate analyses of the joint and relative effects of each factor on site-specific cancer mortality. Plasma levels of dietary antioxidants were consistently negatively correlated with cancer mortality rates. Ascorbic acid was most strongly negatively associated with most cancers and selenium with oesophageal and stomach cancers. beta-carotene was found to have a protective effect independent of retinol, particularly for stomach cancer.     

Concentrations of tocopherols and carotenoids in maternal and cord blood plasma.

OBJECTIVES: To determine the levels of tocopherols, retinol and carotenoids in maternal and umbilical cord blood plasma and to investigate the relationships between them. DESIGN: Venous blood plasma concentrations of alpha, gamma and delta-tocopherol, retinol, lutein, lycopene, zeaxanthin, beta-cryptoxanthin, alpha and beta-carotene were determined by HPLC in healthy pregnant women and in pair-matched umbilical cords. Plasma levels of triglycerides and cholesterol were also measured. SUBJECTS: Sixty-six women, between 10 and 20 weeks gestation, were recruited randomly during their first antenatal appointment. From this group, 40 pair-matched umbilical cord blood samples were obtained. RESULTS: Tocopherols, retinol, carotenoids and lipids were present in significantly higher (P < 0.001) concentrations in maternal plasma than in cord plasma. There was a significant correlation (r = 0.45, P < 0.005) between maternal and cord levels of gamma-tocopherol, but not of alpha-tocopherol, retinol or carotenoids. Tocopherols and carotenoids were significantly correlated with each other (P < 0.05) in maternal and cord plasma. CONCLUSIONS: Plasma levels of tocopherols, carotenoids and lipids are substantially lower at birth than in adulthood. There is a clear relationship between gamma-tocopherol levels in maternal and cord plasma. The importance of gamma-tocopherol in human nutrition should be further investigated. There are no significant relationships between plasma alpha-tocopherol and carotenoids in pregnant mothers and cords. More research is needed to elucidate the maternal-foetal transfer of tocopherols and carotenoids, and to examine the impact of maternal antioxidant nutrient status on neonatal antioxidant capacity. It is important to determine if a low level of tocopherols and carotenoids at birth is a normal stage of human development or indicative of deficiency.     

Classic dengue fever affects levels of circulating antioxidants

OBJECTIVE: We studied alterations of circulating antioxidant nutrients in patients with classic dengue fever in the tropical lowlands of Guatemala. METHODS: In nine patients with dengue fever and 12 healthy Guatemalan control subjects, we assessed plasma concentrations of retinol, alpha-tocopherol, beta-carotene, glutathione, taurine, thiobarbituric acid-reactive species, and total antioxidant status. Control subjects were assessed twice within 48 h to account for day-to-day variations. Febrile patients with dengue fever were examined on the day of admission to the hospital, at discharge after defervescence (approximately 5 d after admission), and 7 d thereafter. RESULTS: In patients with dengue fever, increases in plasma concentrations of retinol and beta-carotene were seen, whereas decreases were observed for glutathione and total antioxidant status. As compared with the reference group, patients with dengue fever had lower retinol concentrations in the acute phase of the disease and lower glutathione concentrations 7 d after discharge. Further, thiobarbituric acid-reactive species levels were higher in the dengue fever patients as analyzed by unpaired t test. CONCLUSION: Using dengue fever as a model for the metabolic response to an acute, self-limited tropical viral infection, the present findings suggest slight turbulence of the antioxidant system that may be a response to or a consequence of the viral inflammatory process.     

Response of blood cell antioxidant enzyme defences to antioxidant diet supplementation and to intense exercise

Summary Background Exhaustive exercise induces oxidative stress. The cellular antioxidant defence systems have demonstrated great adaptation to chronic exercise. Aim To establish the influence of the antioxidant diet supplementation on the erythrocyte and lymphocyte antioxidant enzyme activities in athletes at basal and post–exercise levels. Methods Fifteen amateur trained male athletes were randomly distributed in two groups: control and antioxidant supplemented (90 days’ diet supplementation with 500 mg/day vitamin E and 30 mg/day β–carotene, and the last 15 days also with 1 g/day vitamin C). The study was double blind. Maximal and submaximal exercise tests were performed after three months of diet supplementation. The study was developed during the training and competition season. Results The sportsmen of the supplemented group presented significantly higher plasmatic final levels of vitamin C, vitamin E and β–carotene. Erythrocyte glutathione reductase activity significantly decreased in the placebo group but was maintained in the supplemented group after the three months studied. The erythrocyte superoxide dismutase activity increased after the training/competition period in the placebo group. Lymphocyte catalase and glutathione peroxidase activities increased significantly in the supplemented group after the supplementation period but were maintained in the placebo group. No effects of the antioxidant supplementation were observed in the erythrocyte antioxidant enzyme response to the exercise tests. The antioxidant supplementation induced a better adaptation of lymphocyte catalase after submaximal test. Conclusions Lymphocytes showed higher sensibility to antioxidant supplementation, improving the response of antioxidant enzymes to training and to acute exercise. In erythrocytes the training adaptations were more important than the antioxidant supplementation effects.     

Preventive action of green tea from changes in the liver antioxidant abilities of different aged rats intoxicated with ethanol

OBJECTIVE: The present study investigated the influence of green tea as a source of water-soluble antioxidants on the liver antioxidant potential of different aged rats chronically intoxicated with ethanol. METHODS: Rats (2, 12, and 24 mo old) were fed for 5 wk on a control or an ethanol Lieber-DeCarli diet with and without green tea (7 g/L). The activity and level of enzymatic and non-enzymatic antioxidants and the level of markers of protein and lipid oxidation in the liver of rats were examined. RESULTS: The activities of superoxide dismutase and catalase and levels of vitamins C, E, A, and beta-carotene were significantly decreased, whereas activities of glutathione peroxidase and glutathione reductase and the level of reduced glutathione significantly increased during aging. The ethanol diet caused a significant decrease in activity of antioxidant enzymes and in the level of non-enzymatic antioxidants tested. Administration of green tea to ethanol-treated rats of different ages partly normalized the activity of enzymes and the level of non-enzymatic antioxidants. Changes in antioxidant ability observed during aging were accompanied by increased levels of markers of lipid and protein modifications that also were intensified by ethanol. Green tea caused a decrease in lipid and protein oxidation in aged and ethanol-treated rats. The protective effect of green tea was confirmed by the significantly lower activity of biomarkers of liver damage (alanine and aspartate aminotransferases) in the serum of rats that received green tea with ethanol compared with rats from the control ethanol group. CONCLUSIONS: The use of green tea appears to be beneficial to rat liver by decreasing oxidative stress caused by ethanol and/or aging.     

Retinol, carotenoids, and tocopherols in the milk of lactating adolescents and relationships with plasma concentrations

OBJECTIVE: We determined the concentrations of retinol, carotenoids, and tocopherols in breast milk of adolescents and evaluated their associations with plasma levels and with maternal characteristics (period of lactation, body mass index, age of menarche, and years postmenarche). METHODS: This was a single cross-sectional survey of retinol, carotenoid, and tocopherol composition of milk and plasma of lactating adolescent mothers (n = 72; 30-120 d postpartum) attending public daycare clinics in Rio de Janeiro, Brazil. Milk and plasma components were analyzed by high-performance liquid chromatography. RESULTS: Nutrient concentrations (micromoles per liter, mean +/- SE) in plasma and milk were, respectively, retinol 2.1 +/- 0.5 and 0.62 +/- 0.44, beta-carotene 0.18 +/- 0.19 and 0.016 +/- 0.017, alpha-carotene 0.05 +/- 0.04 and 0.0035 +/- 0.002, lutein plus zeaxanthin 0.15 +/- 0.11 and 0.025 +/- 0.024, lycopene 0.1 +/- 0.11 and 0.016 +/- 0.025, alpha-tocopherol 10.8 +/- 5.3 and 2.7 +/- 1.8, gamma-tocopherol 2.6 +/- 2.3 and 0.37 +/- 0.15. The milk/plasma molar ratios of retinol and tocopherols were two times higher than those of carotenoids. Significant correlations (P < 0.001) between milk and plasma nutrient levels were observed for beta-carotene (r = 0.41), alpha-carotene (r = 0.60), and lutein plus zeaxanthin (r = 0.57), but not for lycopene, retinol, and tocopherols. Nutrient concentrations in plasma and in milk were not associated with the maternal characteristics investigated. CONCLUSION: Concentrations of the nutrients studied, especially retinol and alpha-tocopherol, in mature milk of lactating adolescents were, in general, lower than in milk of adult lactating women. Milk concentrations were associated with plasma concentrations only for beta-carotene, alpha-carotene, and lutein plus zeaxanthin.