Lisa S. McAnulty

Vitamin E and Immunity after the Kona Triathlon World Championship

PURPOSE To measure the influence of vitamin E ingestion on oxidative stress and immune changes in response to the Triathlon World Championship in Kona, Hawaii. METHODS Thirty-eight triathletes received vitamin E (VitE) (800 IU x d(-1) alpha-tocopherol) or placebo (Pla) capsules in randomized, double-blind fashion for 2 months before the race event. Blood, urine, and saliva samples were collected the day before the race, 5-10 min postrace, and 1.5 h postrace. RESULTS Race times did not differ between VitE (N = 19, 721 +/- 24 min) and Pla groups (N = 17, 719 +/- 27 min, P = 0.959), and both groups maintained an intensity of approximately 80% maximum heart rate during the bike and run portions. Plasma alpha-tocopherol was approximately 75% higher in the VitE versus Pla group prerace (24.1 +/- 1.1 and 13.8 +/- 1.1 micromol x L(-1), P < 0.001, respectively) and postrace. Plasma F2-isoprostanes increased 181% versus 97% postrace in the VitE versus Pla groups (P = 0.044). IL-6 was 89% higher (166 +/- 28 and 88 +/- 13 pg x mL(-1), respectively, P = 0.016), IL-1ra was 107% higher (4848 +/- 1203 and 2341 +/- 790 pg x mL(-1), respectively, P = 0.057), and IL-8 was 41% higher postrace in the VitE versus Pla groups (26.0 +/- 3.6 and 18.4 +/- 2.4 pg x mL(-1), respectively, P = 0.094). CONCLUSION These data indicate that vitamin E (800 IU x d(-1) for 2 months) compared with placebo ingestion before a competitive triathlon race event promotes lipid peroxidation and inflammation during exercise.

Quercetin ingestion does not alter cytokine changes in athletes competing in the Western States Endurance Run.

The purpose of this study was to measure the influence of quercetin on plasma cytokines, leukocyte cytokine mRNA, and related variables in ultramarathoners competing in the 160-km Western States Endurance Run (WSER). Sixty-three runners were randomized to quercetin and placebo groups and under double-blinded methods ingested 1000 mg/day quercetin for 3 weeks before the WSER. Thirty-nine of the 63 subjects (n = 18 for quercetin, n = 21 for placebo) finished the race and provided blood samples the morning before the race and 15-30 min postrace. Significant prerace to postrace WSER increases were measured for nine proinflammatory and anti-inflammatory plasma cytokines, cortisol (quercetin = 94%, placebo = 96%), serum C-reactive protein (CRP) (mean +/- SE absolute increase, quercetin = 31.8 +/- 4.2, placebo = 38.2 +/- 5.0 mg/L), and creatine kinase (CK) (quercetin = 21,575 +/- 3,977, placebo = 19,455 +/- 3,969 U/L), with no significant group differences. Interleukin-6 (IL-6) mRNA did not change post-WSER, with a significant decrease measured for leukocyte IL-8 mRNA (0.21 +/- 0.03-fold and 0.25 +/- 0.04-fold change from rest, quercetin and placebo, respectively) and significant increases for IL-1Ra mRNA (1.43 +/- 0.18-fold and 1.40 +/- 0.16-fold change, quercetin and placebo, respectively) and IL-10 mRNA (12.9 +/- 3.9-fold and 17.2 +/- 6.1-fold change, quercetin and placebo, respectively), with no significant differences between groups. In conclusion, quercetin ingestion (1 g/day) by ultramarathon athletes for 3 weeks before a competitive 160-km race significantly increased plasma quercetin levels but failed to attenuate muscle damage, inflammation, increases in plasma cytokine and hormone levels, and alterations in leukocyte cytokine mRNA expression.

Chronic quercetin ingestion and exercise-induced oxidative damage and inflammation

Quercetin is a flavonoid compound that has been demonstrated to be a potent antioxidant in vitro. The objective of this study was to evaluate if quercetin ingestion would increase plasma antioxidant measures and attenuate increases in exercise-induced oxidative damage. Forty athletes were recruited and randomized to quercetin or placebo. Subjects consumed 1000 mg quercetin or placebo each day for 6 weeks before and during 3 d of cycling at 57% work maximum for 3 h. Blood was collected before and immediately after exercise each day, and analyzed for F2-isoprostanes, nitrite, ferric-reducing ability of plasma, trolox equivalent antioxidant capacity, and C-reactive protein. Statistical analyses involved a 2 (treatment) x 6 (times) repeated measures analysis of variance to test main effects. F2-isoprostanes, nitrite, ferric-reducing ability of plasma, trolox equivalent antioxidant capacity, and C-reactive protein were significantly elevated as a result of exercise, but no group effects were found. Despite previous data demonstrating potent antioxidant actions of quercetin in vitro, this study indicates that this effect is absent in vivo and that chronic quercetin ingestion does not exert protection from exercise-induced oxidative stress and inflammation.

Effect of daily fruit ingestion on angiotensin converting enzyme activity, blood pressure, and oxidative stress in chronic smokers

Objective: This study examined whether, daily fruit (blueberries) consumption (250 g) for three weeks or acute fruit ingestion (250 g) would attenuate angiotensin converting enzyme (ACE) activity and reduce oxidative stress in chronic cigarette smokers. Methods: Twenty subjects were recruited and randomized into fruit or control groups. Blood samples and blood pressure were obtained at baseline and then pre and one hour post when subjects returned to the lab three weeks later. To examine acute effects, the fruit group immediately ingested 250 g of blueberries after returning and at least one hour prior to the post blood draw. Plasma samples were analyzed for ACE activity, F2- isoprostanes and lipid hydroperoxides (LH) as measures of oxidative stress, and ferric reducing ability of plasma (FRAP) as a measure of antioxidant potential. A 2 (treatment) × 3 (time) repeated measures ANOVA was used for statistical analysis. If interaction was significant, then Students t-tests were used to further examine this relationship. For these comparisons, a Bonferroni adjustment was made with statistical significance set at P < 0.025. Results: The pattern of change between treatments was not significant for any variable except LH (P < 0.001). Conclusion: This study indicates that LH are significantly reduced by daily fruit consumption, but not affected by acute ingestion. This finding could be one way in which fruit consumption contributes to prevention of cardiovascular disease.

Effect of blueberry ingestion on natural killer cell counts, oxidative stress, and inflammation prior to and after 2.5 h of running.

Blueberries are rich in antioxidants known as anthocyanins, which may exhibit significant health benefits. Strenous exercise is known to acutely generate oxidative stress and an inflammatory state, and serves as an on-demand model to test antioxidant and anti-inflammatory compounds. The purpose of this study was to examine whether 250 g of blueberries per day for 6 weeks and 375 g given 1 h prior to 2.5 h of running at ∼72% maximal oxygen consumption counters oxidative stress, inflammation, and immune changes. Twenty-five well-trained subjects were recruited and randomized into blueberry (BB) (N = 13) or control (CON) (N = 12) groups. Blood, muscle, and urine samples were obtained pre-exercise and immediately postexercise, and blood and urine 1 h postexercise. Blood was examined for F₂-isoprostanes for oxidative stress, cortisol, cytokines, homocysteine, leukocytes, T-cell function, natural killer (NK), and lymphocyte cell counts for inflammation and immune system activation, and ferric reducing ability of plasma for antioxidant capacity. Muscle biopsies were examined for glycogen and NFkB expression to evaluate stress and inflammation. Urine was tested for modification of DNA (8-OHDG) and RNA (5-OHMU) as markers of nucleic acid oxidation. A 2 (treatment) × 3 (time) repeated measures ANOVA was used for statistical analysis. Increases in F₂-isoprostanes and 5-OHMU were significantly less in BB and plasma IL-10 and NK cell counts were significantly greater in BB vs. CON. Changes in all other markers did not differ. This study indicates that daily blueberry consumption for 6 weeks increases NK cell counts, and acute ingestion reduces oxidative stress and increases anti-inflammatory cytokines.

Effect of n-3 fatty acids and antioxidants on oxidative stress after exercise.

PURPOSE n-3 fatty acids are known to exert multiple beneficial effects including anti-inflammatory actions that may diminish oxidative stress. Supplementation with antioxidant vitamins has been proposed to counteract oxidative stress and improve antioxidant status. Therefore, this project investigated the effects of daily supplementation in 48 trained cyclists over 6 wk and during 3 d of continuous exercise on F2-isoprostanes (oxidative stress), plasma n-3 fatty acids, and antioxidant status (oxygen radical absorption capacity and ferric-reducing antioxidant potential). METHODS Cyclists were randomized into n-3 fatty acids (N3) (n = 11) (2000 mg of eicosapentaenoic acid and 400 mg of docosahexaenoic acid), a vitamin-mineral (VM) complex (n = 12) emphasizing vitamins C (2000 mg), E (800 IU), A (3000 IU), and selenium (200 microg), a VM and n-3 fatty acid combination (VN3) (n = 13), or placebo (P) (n = 12). Blood was collected at baseline and preexercise and postexercise. A 4 x 3 repeated-measures ANOVA was performed to test main effects. RESULTS After exercise, F2-isoprostanes were higher in N3 (treatment effect P = 0.014). Eicosapentaenoic acid and docosahexaenoic acid plasma values were higher after supplementation (interaction effect P = 0.001 and 0.006, respectively) in both n-3 supplemented groups. Oxygen radical absorption capacity declined similarly among all groups after exercise. Ferric-reducing antioxidant potential exhibited significant interaction (P = 0.045) and significantly increased after exercise in VN3 and VM (P < 0.01). CONCLUSIONS This study indicates that supplementation with n-3 fatty acids alone significantly increases F2-isoprostanes after exhaustive exercise. Lastly, antioxidant supplementation augments plasma antioxidant status and modestly attenuates but does not prevent the significant n-3 fatty acid associated increase in F2-isoprostanes postexercise.

Influence of Carbohydrate Ingestion on Oxidative Stress and Plasma Antioxidant Potential Following a 3 h Run

Concentrations of reactive oxygen species (ROS) increase during exercise secondary to increased oxygen uptake, xanthine oxidase activity, and immune system activation. Carbohydrate compared to placebo beverage ingestion is associated with an attenuated cortisol and catecholamine response. Catecholamines can undergo autooxidation to form ROS. We hypothesized that during intense exercise, ingestion of carbohydrate compared to placebo would diminish oxidative stress. Sixteen experienced marathoners ran on treadmills for 3 h at ∼70% VO2max on two occasions while receiving carbohydrate or placebo beverages (1 l/h, double-blinded) in a randomized, counterbalanced order. Blood samples were collected before and immediately after exercise, snap frozen in liquid nitrogen, and stored at -80°C until analysis. Plasma samples were analyzed for F2-isoprostanes (FIP) and lipid hydroperoxides (ROOH) as measures for lipid peroxidation, ferric reducing ability of plasma (FRAP) as a measure of plasma antioxidant potential and for cortisol. The pattern of change in cortisol was significantly different between carbohydrate and placebo conditions (P=0.024), with post-exercise levels higher in the placebo condition. Under both carbohydrate and placebo conditions, significant increases in FIP, ROOH, and FRAP were measured, but the pattern of increase was not different (FIP, interaction effect, P=0.472; ROOH, P=0.572; FRAP, P=0.668). Despite an attenuation in the cortisol response, carbohydrate compared to placebo ingestion does not counter the increase in oxidative stress or modulate plasma antioxidant potential in athletes running 3 h at 70% VO2max.

β-Glucan, Immune Function, and Upper Respiratory Tract Infections in Athletes

PURPOSE This study investigated the effects of oat beta-glucan (BG) supplementation on chronic resting immunity, exercise-induced changes in immune function, and self-reported upper respiratory tract infection (URTI) incidence in human endurance athletes. METHODS Trained male cyclists were randomized to BG (N = 19) or placebo (P; N = 17) groups and under double-blind procedures received BG (5.6 g x d(-1)) or P beverage supplements for 2 wk before, during, and 1 d after a 3-d period in which subjects cycled for 3 h x d(-1) at approximately 57% maximal watts. URTI symptoms were monitored during BG supplementation and for 2 wk afterward. Blood samples were collected before and after 2 wk of supplementation (both samples, 8:00 a.m.), immediately after the 3-h exercise bout on day 3 (6:00 p.m.), and 14 h after exercise (8:00 a.m.) and were assayed for natural killer cell activity (NKCA), polymorphonuclear respiratory burst activity (PMN-RBA), phytohemagglutinin-stimulated lymphocyte proliferation (PHA-LP), plasma interleukin 6 (IL-6), IL-10, IL-1 receptor agonist (IL-1ra), and IL-8, and blood leukocyte IL-10, IL-8, and IL-1ra mRNA expression. RESULTS Chronic resting levels and exercise-induced changes in NKCA, PMN-RBA, PHA-LP, plasma cytokines, and blood leukocyte cytokine mRNA did not differ significantly between BG and P groups. URTI incidence during the 2-wk postexercise period did not differ significantly between groups. CONCLUSIONS An 18-d period of BG versus P ingestion did not alter chronic resting or exercise-induced changes in immune function or URTI incidence in cyclists during the 2-wk period after an intensified exercise.

Effect of resistance exercise and carbohydrate ingestion on oxidative stress

Some research studies have produced data indicating that resistance exercise induces oxidative stress, despite minimal increases in VO2. These studies have primarily relied on oxidative stress markers with low sensitivity and debatable reliability. However, F2-isoprostanes as measured by gas chromatography mass spectrometry are considered to be a reliable and precise indicator of oxidative stress. Carbohydrate ingestion during exercise is associated with reduced levels of stress hormones, which may influence oxidative stress and plasma antioxidant potential. Therefore, the purpose of this study was to investigate the influence of carbohydrate ingestion during resistance training on F2-isoprostanes and plasma antioxidant potential. Thirty strength-trained subjects were randomized to carbohydrate (CHO) or placebo (PLA) groups that lifted weights for 2 h. Subjects received 10 ml kg− 1 h− 1 CHO (6%) or PLA beverages during the exercise. Blood and vastus lateralis muscle biopsy samples were collected before and after exercise and analyzed for cortisol as a marker of general stress, F2-isoprostanes as a measure of oxidative stress, and ferric reducing ability of plasma (FRAP) as a measure of antioxidant potential, and for muscle glycogen, respectively. Decreases in muscle glycogen content did not differ between CHO and PLA. Cortisol and FRAP increased significantly in CHO and PLA (P = 0.008 and 0.044, respectively), but the pattern of change was not different between groups. F2-isoprostanes were unaffected by exercise. These results indicate that exhaustive resistance exercise and carbohydrate ingestion have no effect on oxidative stress or plasma antioxidant potential in trained subjects.

Six weeks daily ingestion of whole blueberry powder increases natural killer cell counts and reduces arterial stiffness in sedentary males and females

Evidence suggests that berries contain bioactive compounds, which reduce certain cancers and hypertension. Our hypothesis was that daily blueberry (BB) consumption would increase natural killer (NK) cells and plasma redox capacity and reduce blood pressure, augmentation index (AIx), central pulse wave velocity, and aortic systolic pressures (ASPs). Twenty-five men and postmenopausal women aged 18 to 50 years were recruited and randomized to BB (n, 13) or placebo groups (n, 12). Participants were provided with BB (equivalent to 250 g berries) or placebo powders each day for 6 weeks. Blood pressure, vascular performance testing, and blood samples were taken at baseline (presupplementation). Participants returned after 6 weeks and repeated all procedures. Presupplementation to postsupplementation comparisons for the main effects of treatment, time, and treatment-time interaction were made using a 2 (treatment) × 2 (times) repeated-measures analysis of variance for all vascular measures, redox status, and NK cell counts. Anthropometric measures were compared using t tests. Body mass, composition, and overall blood pressures were not affected in either group. Overall, AIx and ASPs were decreased in BB (treatment effect, P = .024 and P = .046, respectively). Plasma redox was not affected. Absolute NK cells were increased in BB (time, P = .001 and interaction, P = .012). Subjects (n, 9) with prehypertensive pressures (≥120/80 mm Hg, respectively) were examined as a subset using t tests and exhibited significant reductions in diastolic pressure (P = .038) from presupplementation to postsupplementation in BB. We conclude that BB ingestion for 6 weeks increases NK cells and reduces AIx, ASP, and diastolic pressures in sedentary males and females.