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Nitrate-rich beetroot juice offsets salivary acidity following carbohydrate ingestion before and after endurance exercise in healthy male runners.
Burleigh, MC, Sculthorpe, N, Henriquez, FL, Easton, C
PloS one. 2020;(12):e0243755
Abstract
There have been recent calls for strategies to improve oral health in athletes. High carbohydrate diets, exercise induced dehydration and transient perturbations to immune function combine to increase oral disease risk in this group. We tested whether a single dose of nitrate (NO3-) would offset the reduction in salivary pH following carbohydrate ingestion before and after an exercise bout designed to cause mild dehydration. Eleven trained male runners ([Formula: see text] 53 ± 9 ml∙kg-1∙min-1, age 30 ± 7 years) completed a randomised placebo-controlled study comprising four experimental trials. Participants ingested the following fluids one hour before each trial: (a) 140 ml of water (negative-control), (b) 140 ml of water (positive-control), (c) 140 ml of NO3- rich beetroot juice (~12.4 mmol NO3-) (NO3- trial) or (d) 140 ml NO3- depleted beetroot juice (placebo-trial). During the negative-control trial, participants ingested 795 ml of water in three equal aliquots: before, during, and after 90 min of submaximal running. In the other trials they received 795 ml of carbohydrate supplements in the same fashion. Venous blood was collected before and after the exercise bout and saliva was sampled before and repeatedly over the 20 min following carbohydrate or water ingestion. As expected, nitrite (NO2-) and NO3- were higher in plasma and saliva during the NO3- trial than all other trials (all P<0.001). Compared to the negative-control, salivary-pH was significantly reduced following the ingestion of carbohydrate in the positive-control and placebo trials (both P <0.05). Salivary-pH was similar between the negative-control and NO3- trials before and after exercise despite ingestion of carbohydrate in the NO3- trial (both P≥0.221). Ingesting NO3- attenuates the expected reduction in salivary-pH following carbohydrate supplements and exercise-induced dehydration. NO3- should be considered by athletes as a novel nutritional strategy to reduce the risk of developing acidity related oral health conditions.
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Salivary immunity and lower respiratory tract infections in non-elite marathon runners.
Cantó, E, Roca, E, Perea, L, Rodrigo-Troyano, A, Suarez-Cuartin, G, Giner, J, Feliu, A, Soria, JM, Nescolarde, L, Vidal, S, et al
PloS one. 2018;(11):e0206059
Abstract
RATIONALE Respiratory infections are common after strenuous exercise, when salivary immunity may be altered. We aim to investigate changes in salivary immunity after a marathon and its relationship with lower respiratory tract infections (LRTI) in healthy non-elite marathon runners. METHODS Forty seven healthy marathon runners (28 males and 19 females) who completed the 42.195 km of the 2016 Barcelona marathon were studied. Saliva and blood samples were collected the day before the marathon and two days after the end of the race. Salivary IgA, antimicrobial proteins (lactoferrin, lysozyme) and chemokines (Groα, Groβ, MCP-1) were determined using ELISA kits in saliva supernatant. Blood biochemistry and haemogram were analyzed in all participants. The presence of LRTI was considered in those runners who reported infectious lower respiratory tract symptoms during a minimum of 3 consecutive days in the 2 weeks after the race. RESULTS Eight participants (17%) presented a LRTI during the 2 weeks of follow-up. Higher lysozyme levels were detected after the race in runners with LRTI when compared with those without infection. A decrease in salivary lysozyme, Groα and Groβ levels after the race were observed in those runners who did not develop a LRTI when compared to basal levels. Salivary Groα levels correlated with basophil blood counts, and salivary lysozyme levels correlated with leukocyte blood counts. CONCLUSIONS LRTI are common after a marathon race in non-elite healthy runners. Changes in salivary antimicrobial proteins and chemokines are related to the presence of LRTI and correlate with systemic defense cells, which suggest an important role of salivary immunity in the development of LRTI in non-elite marathon runners.
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Sublingual nucleotides prolong run time to exhaustion in young physically active men.
Ostojic, SM, Idrizovic, K, Stojanovic, MD
Nutrients. 2013;(11):4776-85
Abstract
Although dietary nucleotides have been determined to be required for normal immune function, there is limited direct interventional evidence confirming performance-enhancing effects of sublingual nucleotides in humans. A double-blind, placebo-controlled, randomized trial was conducted to evaluate the effect of sublingual nucleotides (50 mg/day) administered for 14 days in thirty young healthy physically active males, on endurance performance and immune responses. Fasting white blood cell count, natural killer cells (NKC) number, NKC cytotoxic activity, and serum immunoglobulin (IgA, IgM, IgG), and time to exhaustion, peak rate of perceived exertion, peak heart rate, and peak running speed during the exercise test were measured at baseline (day 0) and post-intervention (day 14). Time to exhaustion, as well as serum immunoglobulin A and NKC cytotoxic activity, were significantly higher at day 14 (p < 0.05) in participants supplemented with nucleotides compared with those who consumed placebo. No significant differences in other parameters were observed between groups at post-intervention. No volunteers withdrew before the end of the study nor reported any vexatious side effects of supplementation. The results of the present study suggest that sublingual nucleotides may provide pertinent benefit as both an ergogenic and immunostimulatory additive in active males.
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Effects of oral supplementation with cystine and theanine on the immune function of athletes in endurance exercise: randomized, double-blind, placebo-controlled trial.
Murakami, S, Kurihara, S, Koikawa, N, Nakamura, A, Aoki, K, Yosigi, H, Sawaki, K, Ohtani, M
Bioscience, biotechnology, and biochemistry. 2009;(4):817-21
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Abstract
Athletes become increasingly susceptible to infection with intense training that results in immune suppression. The immune state was investigated after administering cystine/theanine (CT), which has been reported to have an immune reinforcement effect, to athletes before training involving a prolonged period of intense exercise. Fifteen long-distance runners were each allocated to the CT or placebo group, and the test food was ingested for 10 d prior to the start of training. Clinical examinations were performed before and after the training. The results indicate a significant increase in the high-sensitivity C-reactive protein (hs-CRP) and neutrophil count in the blood, as well as a decreasing tendency for lymphocytes in the placebo group, but not the CT group. These observations suggest that the ingestion of CT contributed to suppressing the change in inflammatory response, prevented a decrease in the immune function, and prevented infection and reduced symptoms when infected associated with continuous intense exercise.
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Influence of vitamin C supplementation on oxidative and immune changes after an ultramarathon.
Nieman, DC, Henson, DA, McAnulty, SR, McAnulty, L, Swick, NS, Utter, AC, Vinci, DM, Opiela, SJ, Morrow, JD
Journal of applied physiology (Bethesda, Md. : 1985). 2002;(5):1970-7
Abstract
The purpose of this randomized study was to measure the influence of vitamin C (n = 15 runners) compared with placebo (n = 13 runners) supplementation on oxidative and immune changes in runners competing in an ultramarathon race. During the 7-day period before the race and on race day, subjects ingested in randomized, double-blind fashion 1,500 mg/day vitamin C or placebo. On race day, blood samples were collected 1 h before race, after 32 km of running, and then again immediately after race. Subjects in both groups maintained an intensity of approximately 75% maximal heart rate throughout the ultramarathon race and ran a mean of 69 km (range: 48-80 km) in 9.8 h (range: 5-12 h). Plasma ascorbic acid was markedly higher in the vitamin C compared with placebo group prerace and rose more strongly in the vitamin C group during the race (postrace: 3.21 +/- 0.29 and 1.28 +/- 0.12 microg/100 microl, respectively, P < 0.001). No significant group or interaction effects were measured for lipid hydroperoxide, F2-isoprostane, immune cell counts, plasma interleukin (IL)-6, IL-10, IL-1-receptor antagonist, or IL-8 concentrations, or mitogen-stimulated lymphocyte proliferation and IL-2 and IFN-gamma production. These data indicate that vitamin C supplementation in carbohydrate-fed runners does not serve as a countermeasure to oxidative and immune changes during or after a competitive ultramarathon race.
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Marathon running transiently increases c-Jun NH2-terminal kinase and p38 activities in human skeletal muscle.
Boppart, MD, Asp, S, Wojtaszewski, JF, Fielding, RA, Mohr, T, Goodyear, LJ
The Journal of physiology. 2000;(Pt 3):663-9
Abstract
We examined the pattern of activation and deactivation of the stress-activated protein kinase signalling molecules c-Jun NH2-terminal kinase (JNK) and p38 kinase in skeletal muscle in response to prolonged strenuous running exercise in human subjects. Male subjects (n = 14; age 32 +/- 2 years; VO2,max 60 +/- 2 ml kg-1 min-1) completed a 42.2 km marathon (mean race time 3 h 35 min). Muscle biopsies were obtained 10 days prior to the marathon, immediately following the race, and 1, 3 and 5 days after the race. The activation of JNK and p38, including both p38alpha and p38gamma, was measured with immune complex assays. The phosphorylation state of p38 (alpha and gamma) and the upstream regulators of JNK and p38, mitogen-activated protein kinase kinase 4 (MKK4) and mitogen-activated protein kinase kinase 6 (MKK6), were assessed using phosphospecific antibodies. JNK activity increased 7-fold over basal level immediately post-exercise, but decreased back to basal levels 1, 3 and 5 days after the exercise. p38gamma phosphorylation (4-fold) and activity (1.5-fold) increased immediately post-exercise and returned to basal levels at 1, 3 and 5 days following exercise. In contrast, p38alpha phosphorylation and activity did not change over the time course studied. MKK4 and MKK6 phosphorylation increased and decreased in a trend similar to that observed with JNK activity and p38gamma phosphorylation. Prolonged running exercise did not affect JNK, p38alpha, or p38gamma protein expression in the days following the race. This study demonstrates that both JNK and p38 intracellular signalling cascades are robustly, yet transiently increased following prolonged running exercise. The differential activation of the p38 isoforms with exercise in human skeletal muscle indicates that these proteins may have distinct functions in vivo.