Salivary IgA as a Risk Factor for Upper Respiratory Infections in Elite Professional Athletes

Mucosal immunity and upper respiratory tract infections during a 24-week competitive season in young ice hockey players

The aim of this study was to examine upper respiratory tract infections (URTI) and their associations with resting saliva and blood immune and endocrine parameters in ice hockey players. Twenty-seven participants (age 16.5 ± 0.5 years) completed the 24-week study period. The counts/concentrations of immune and endocrine markers were compared between healthy-prone athletes (≤2 episodes of URTI during the study period) and illness-prone athletes (≥3 episodes of URTI) and between the URTI state (when athletes had infections) and the healthy state (the time without URTI). There were no differences in concentration/counts of saliva and blood immune and endocrine parameters between the illness-prone and illness-free athletes. Athletes had significantly lower sIgA, sIgA1 and sIgA2 concentrations (sIgA: 119.88 ± 66.88, 144.10 ± 75.0 µg/ml; sIgA1: 90.2 ± 40.64, 108.44 ± 29.8 U; sIgA2: 67.58 ± 30.1, 80.3 ± 25.61 U, respectively) and significantly higher WBC, neutrophil, monocyte and eosinophil count values and IL-1ra concentration at the time when they had symptoms of URTI than in the period without symptoms of infections. There were no differences in salivary cortisol concentration between the period of URTI symptoms and the period without URTI symptoms. In conclusion, we observed lower concentrations of salivary immunoglobulins and higher levels of blood immune parameters during URTI in athletes, which may confirm the suppression of mucosal immunity and initiation responses to pathogenic infections by innate immunity.

Blood immune function parameters in response to combined aerobic dance exercise and honey supplementation in adult women

To date, information on the effectiveness of combined aerobic dance exercise with honey supplementation on immune function in women is lacking. The present study investigated the effects of 8 weeks of combined aerobic dance exercise and honey supplementation on blood immune function parameters in adult women. In this study, forty four healthy sedentary women (25-40 year-old) were assigned into four groups with n = 11 per group: sedentary without supplementation control (Con), honey supplementation (H), aerobic dance exercise (D) and combined aerobic dance exercise with honey supplementation (HD) groups. Aerobic dance exercise was carried out for one hour per session, three sessions per week for eight weeks. Honey drink was consumed by H and HD groups, in a dosage of 20 g of honey diluted in 300 ml of plain water, consumed 7 days a week for 8 weeks. In HD group, the participants were required to consume honey drink 30 min before performing exercise. Before and after 8 weeks of experimental period, blood samples were taken to determine the concentrations of immune parameters which include full blood counts and immunophenotyping measurements. It was found that after 8 weeks of experimental period, there were statistically significant increases in T cytotoxic (CD8) (p < 0.05) in HD group. Additionally, the percentages increase in total lymphocyte counts, T helper (CD4), and T cytotoxic (CD8) counts after 8 weeks were the highest in HD group among all the groups. As conclusion, combined aerobic dance and honey supplementation may have potential to enhance immune functions in women.

Effect of acute exercise and hypoxia on markers of systemic and mucosal immunity

Purpose

To determine how immune markers are affected by acute hypoxic exercise at the same relative intensity.

Methods

Twelve endurance-trained males (age: 28 ± 4 years, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O_2max: 63.7 ± 5.3 mL/kg/min) cycled for 75 min at 70 % of altitude-specific \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O_2max, once in normoxia (N) and once in hypobaric hypoxia equivalent to 2000 m above sea-level (H). Blood and saliva samples were collected pre-, post- and 2 h post-exercise.

Results

Participants cycled at 10.5 % lower power output in H vs. N, with no significant differences in heart rate (P = 0.10) or rating of perceived exertion (P = 0.21). Post-exercise plasma cortisol was higher in H vs. N [683 (95 % CI 576–810) nmol/l vs. 549 (469–643) nmol/l, P = 0.017]. The exercise-induced decrease in CD4:CD8 ratio was greater in H vs. N (−0.5 ± 0.2 vs. −0.3 ± 0.2, P = 0.019). There were no significant between-trial differences for adrenocorticotropic hormone, plasma cytokines, antigen-stimulated cytokine production, salivary immunoglobulin-A or lactoferrin. However, there was a main trial effect for concentration [F(11) = 5.99, P < 0.032] and secretion [F(11) = 5.01, P < 0.047] of salivary lysozyme, with this being higher in N at every time-point.

Conclusion

Whether the observed differences between H and N are of sufficient magnitude to clinically impair host defence is questionable, particularly as they are transient in nature and since other immune markers are unaffected. As such, acute hypoxic exercise likely does not pose a meaningful additional threat to immune function compared to exercise at sea level, provided that absolute workload is reduced in hypoxia so that relative exercise intensity is the same.

Severe rhinovirus pneumonia in a young woman taking performance-enhancing drugs

A 22-year-old woman presented to the emergency room of a local hospital with pleuritic chest pain. She regularly worked out and admitted to taking performance-enhancing drugs (PEDs). Clinical findings and further diagnostic work up revealed a diagnosis of perimyocarditis, and adequate therapy was initiated. During the course of the first day, the patient had to be intubated and mechanically ventilated. A diagnosis of bilateral pneumonia and acute respiratory distress syndrome (ARDS) due to an infection by rhinovirus spp was made. A smoking habit, the intense physical training and the use of PED's may have exacerbated the course of the viral pneumonia. After 12 days the patient could be extubated. The length of stay in the intensive care unit was 16 days. After hospital discharge, the patient went to a pulmonary rehabilitation facility for 2 weeks. The outcome was favourable and the patient resumed her strength and endurance training.

Salivary Hormones Response to Preparation and Pre-competitive Training of World-class Level Athletes

This study aimed to compare the response of salivary hormones of track and field athletes induced by preparation and pre-competitive training periods in an attempt to comment on the physiological effects consistent with the responses of each of the proteins measured. Salivary testosterone, cortisol, alpha-amylase, immunoglobulin A (IgA), chromogranin A, blood creatine kinase activity, and profile of mood state were assessed at rest in 24 world-class level athletes during preparation (3 times in 3 months) and pre-competitive (5 times in 5 weeks) training periods. Total mood disturbance and fatigue perception were reduced, while IgA (+61%) and creatine kinase activity (+43%) increased, and chromogranin A decreased (-27%) during pre-competitive compared to preparation period. A significant increase in salivary testosterone (+9 to +15%) and a decrease in testosterone/cortisol ratio were associated with a progressive reduction in training load during pre-competitive period (P < 0.05). None of the psycho-physiological parameters were significantly correlated to training load during the pre-competitive period. Results showed a lower adrenocortical response and autonomic activity, and an improvement of immunity status, in response to the reduction in training load and fatigue, without significant correlations of salivary hormones with training load. Our findings suggest that saliva composition is sensitive to training contents (season period) but could not be related to workload resulting from track and field athletics training.

Respiratory inflammation and infections in high-performance athletes

Upper respiratory illness is the most common reason for non-injury-related presentation to a sports medicine clinic, accounting for 35-65% of illness presentations. Recurrent or persistent respiratory illness can have a negative impact on health and performance of athletes undertaking high levels of strenuous exercise. The cause of upper respiratory symptoms (URS) in athletes can be uncertain but the majority of cases are related to common respiratory viruses, viral reactivation, allergic responses to aeroallergens and exercise-related trauma to the integrity of respiratory epithelial membranes. Bacterial respiratory infections are uncommon in athletes. Undiagnosed or inappropriately treated asthma and/or allergy are common findings in clinical assessments of elite athletes experiencing recurrent URS. High-performance athletes with recurrent episodes of URS should undergo a thorough clinical assessment to exclude underlying treatable conditions of respiratory inflammation. Identifying athletes at risk of recurrent URS is important in order to prescribe preventative clinical, training and lifestyle strategies. Monitoring secretion rates and falling concentrations of salivary IgA can identify athletes at risk of URS. Therapeutic interventions are limited by the uncertainty of the underlying cause of inflammation. Topical anti-inflammatory sprays can be beneficial for some athletes. Dietary supplementation with bovine colostrum, probiotics and selected antioxidants can reduce the incidence or severity of URS in some athletes. Preliminary studies on athletes prone to URS indicate a genetic predisposition to a pro-inflammatory response and a dysregulated anti-inflammatory cytokine response to intense exercise as a possible mechanism of respiratory inflammation. This review focuses on respiratory infections and inflammation in elite/professional athletes.

Mucosal immunity and upper respiratory tract symptoms in recreational endurance runners

The present study investigated the effects of a 12-week endurance-training intervention on salivary proteins and upper respiratory tract symptoms (URS) in 25 young men. Saliva samples of 25 recreational male endurance runners (age 34.6 years, body mass index = 23.8 kg·m(-2), peak aerobic capacity = 47.2 mL·kg(-1)·min(-1)) were collected before (PRE) and after (POST) the training intervention, in a fasting state, as well as both before and after a maximal incremental treadmill run. The training consisted of both continuous and interval training sessions, 4-6 times per week based on the polarized training approach. Participants filled in Wisconsin Upper Respiratory Symptom Survey-21 and were retrospectively divided into 2 groups according to whether they reported URS (URS group, n = 13) or not (HEALTHY group, n = 12). Basal salivary immunoglobulin A (sa-sIgA) levels were significantly higher (+70%, p < 0.05) in the HEALTHY group both at PRE and POST whereas no significant differences were observed in salivary immunoglobulin M, salivary immunoglobulin G, lysozyme, or salivary α-amylase activity (sAA). Sa-sIgA concentration at PRE significantly correlated with the number of sick-days (R = -0.755, p < 0.001) in all subjects. The incremental treadmill run acutely increased sAA significantly (p < 0.05) at PRE (200%) and POST (166%) in the HEALTHY group but not in the URS group. This study demonstrated that subjects, who experienced URS during the 12 weeks of progressive endurance training intervention, had significantly lower basal sa-sIgA levels both before and after the experimental endurance training period. In addition to sa-sIgA, acute sAA response to exercise might be a possible determinant of susceptibility to URS in endurance runners.

Exercise and the Regulation of Immune Functions

Exercise has a profound effect on the normal functioning of the immune system. It is generally accepted that prolonged periods of intensive exercise training can depress immunity, while regular moderate intensity exercise is beneficial. Single bouts of exercise evoke a striking leukocytosis and a redistribution of effector cells between the blood compartment and the lymphoid and peripheral tissues, a response that is mediated by increased hemodynamics and the release of catecholamines and glucocorticoids following the activation of the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis. Single bouts of prolonged exercise may impair T-cell, NK-cell, and neutrophil function, alter the Type I and Type II cytokine balance, and blunt immune responses to primary and recall antigens in vivo. Elite athletes frequently report symptoms associated with upper respiratory tract infections (URTI) during periods of heavy training and competition that may be due to alterations in mucosal immunity, particularly reductions in secretory immunoglobulin A. In contrast, single bouts of moderate intensity exercise are "immuno-enhancing" and have been used to effectively increase vaccine responses in "at-risk" patients. Improvements in immunity due to regular exercise of moderate intensity may be due to reductions in inflammation, maintenance of thymic mass, alterations in the composition of "older" and "younger" immune cells, enhanced immunosurveillance, and/or the amelioration of psychological stress. Indeed, exercise is a powerful behavioral intervention that has the potential to improve immune and health outcomes in the elderly, the obese, and patients living with cancer and chronic viral infections such as HIV.

Salivary SIgA responses to acute moderate-vigorous exercise in monophasic oral contraceptive users

The purpose of this study was to examine the effect of oral contraceptive (OC) use on salivary secretory immunoglobulin A (SIgA) levels at rest and in response to an acute bout of moderate-vigorous exercise during 2 phases of the 4-week OC cycle corresponding to different phases of the synthetic menstrual cycle. Ten healthy active females completed a cycling at 70% peak oxygen uptake for 45 min at 2 time points of an OC cycle: during the equivalent in time to the mid-follicular phase (day 8 ± 2) and the mid-luteal phase (day 20 ± 2). Timed unstimulated saliva samples were obtained before, immediately postexercise, and 1 h postexercise and analyzed for salivary SIgA. Salivary SIgA secretion rate was 26% (95% confidence limits (CI) 6-46) lower at postexercise compared with pre-exercise during the synthetic follicular phase (p = 0.019) but no differences were observed during the synthetic luteal trial. Saliva flow rate was 11% (95% CI, 8-30) lower at postexercise compared with pre-exercise (main effect for time; p = 0.025). In conclusion, the pattern of salivary SIgA secretion rate response to moderate-vigorous exercise varies across the early and late phases of a monophasic OC cycle, with a transient reduction in salivary SIgA responses during the synthetic follicular phase. These findings indicate that monophasic OC use should be considered when assessing mucosal immune responses to acute exercise.

An intensive Winter fixture schedule induces a transient fall in salivary IgA in English premier league soccer players

We examined the effects of an intensive fixture schedule on salivary IgA (SIgA) concentration in professional soccer players from the English Premier League. Salivary samples were obtained from 21 males who participated in seven games over a 30-day period during December 2013 and January 2014 (games 1-5 occurred in a 15-day period). Salivary-IgA decreased (P < 0.05) at 2 days post-game 3 (45 ± 9 μg mL(-1)), 4 (52 ± μg mL(-1)) and 5 (41 ± 10 μg mL(-1)) compared with game 1 (139 ± 25 μg mL(-1)). When the normal fixture schedule resumed (i.e. one game per week), SIgA returned towards baseline such that game 6 and 7 values were not different (P > 0.05) from game 1 (91 ± 18 and 99 ± 21 μg mL(-1), respectively). Data demonstrate for the first time that a congested winter fixture schedule induces detectable perturbations to mucosal immunity in professional soccer players.

Salivary hormones and IgA in relation to physical performance in football

Salivary biomarkers have shown to be useful to assess physiological stress in football, but their relationship with physical performance is unknown. The aims of this study were to investigate the effect of a football match on salivary cortisol, testosterone and immunoglobulin A (IgA) concentrations in elite footballers, and to examine the relationship of physical performance during the match to these biomarkers. Nine elite football players were assessed before, during and after a friendly international match. Physical performance during the match was measured by time-motion analysis, whilst salivary cortisol, testosterone and IgA were measured before and 10 min post-match. The results showed that players covered an average of 9463 ± 458 m during the match. Salivary cortisol did not change post-match. Testosterone and IgA concentrations decreased by 30.6% and 74.5%, respectively. The testosterone/cortisol (T/C) ratio decreased by 64.2% after the match. Changes in testosterone concentrations correlated (r = 0.85) with distance covered. Pre- and post-match testosterone levels correlated with post-match IgA concentrations (r = 0.8 and 0.89, respectively). These results suggest that a football match induces catabolic stress as indicated by the decreased T/C ratio. It seems that footballers with smaller decreases in testosterone levels covered more distance and decreased their immune function less.

The influence of hydration status during prolonged endurance exercise on salivary antimicrobial proteins

PURPOSE

Antimicrobial proteins (AMPs) in saliva including secretory immunoglobulin A (SIgA), lactoferrin (SLac) and lysozyme (SLys) are important in host defence against oral and respiratory infections. This study investigated the effects of hydration status on saliva AMP responses to endurance exercise.

METHODS

Using a randomized design, 10 healthy male participants (age 23 ± 4 years, [Formula: see text] 56.8 ± 6.5 ml/kg/min) completed 2 h cycling at 60 % [Formula: see text] in states of euhydration (EH) or dehydration (DH) induced by 24 h fluid restriction. Unstimulated saliva samples were collected before, during, immediately post-exercise and each hour for 3 h recovery.

RESULTS

Fluid restriction resulted in a 1.5 ± 0.5 % loss of body mass from baseline and a 4.3 ± 0.7 % loss immediately post-exercise. Pre-exercise urine osmolality was higher in DH than EH and overall, saliva flow rate was reduced in DH compared with EH (p < 0.05). Baseline SIgA secretion rates were not different between conditions; however, exercise induced a significant increase in SIgA concentration in DH (161 ± 134 to 309 ± 271 mg/L) which remained elevated throughout 3 h recovery. SLac secretion rates increased from pre- to post-exercise in both conditions which remained elevated in DH only. Overall, SLac concentrations were higher in DH than EH. Pre-exercise SLys concentrations were lower in DH compared with EH (1.6 ± 2.0 vs. 5.5 ± 6.7 mg/L). Post-exercise SLys concentrations remained elevated in DH but returned to pre-exercise levels by 1 h post-exercise in EH.

CONCLUSIONS

Exercise in DH caused a reduction in saliva flow rate yet induced greater secretion rates of SLac and higher concentrations of SIgA and SLys. Thus, DH does not impair saliva AMP responses to endurance exercise.

The effect of 14 weeks of vitamin D3 supplementation on antimicrobial peptides and proteins in athletes

Heavy training is associated with increased respiratory infection risk and antimicrobial proteins are important in defence against oral and respiratory tract infections. We examined the effect of 14 weeks of vitamin D3 supplementation (5000 IU/day) on the resting plasma cathelicidin concentration and the salivary secretion rates of secretory immunoglobulin A (SIgA), cathelicidin, lactoferrin and lysozyme in athletes during a winter training period. Blood and saliva were obtained at the start of the study from 39 healthy men who were randomly allocated to vitamin D3 supplement or placebo. Blood samples were also collected at the end of the study; saliva samples were collected after 7 and 14 weeks. Plasma total 25(OH)D concentration increased by 130% in the vitamin D3 group and decreased by 43% in the placebo group (both P = 0.001). The percentage change of plasma cathelicidin concentration in the vitamin D3 group was higher than in the placebo group (P = 0.025). Only in the vitamin D3 group, the saliva SIgA and cathelicidin secretion rates increased over time (both P = 0.03). A daily 5000 IU vitamin D3 supplement has a beneficial effect in up-regulating the expression of SIgA and cathelicidin in athletes during a winter training period, which could improve resistance to respiratory infections.

Changes in acute biochemical markers of inflammatory and structural stress in rugby union

Rugby union is a sport governed by the impacts of high force and high frequency. Analysis of physiological markers following a game can provide an understanding of the physiological response of an individual and the time course changes in response to recovery. Urine and saliva were collected from 11 elite amateur rugby players 24 h before, immediately after, and at 17, 25, 38, 62 and 86 h post-game. Myoglobin, salivary immunoglobulin A and cortisol were analysed by ELISA, whereas neopterin and total neopterin were analysed by high-performance liquid chromatography. There was a significant post-game increase of all four markers. The increases were cortisol 4-fold, myoglobin 2.85-fold, neopterin 1.75-fold and total neopterin 2.3-fold when corrected with specific gravity. All significant changes occurred post-game only, with markers returning to and remaining at baseline within 17 h. The intensity of the game caused significant changes in key physiological markers of stress. They provide an understanding of the stress experienced during a single game of rugby and the time course changes associated with player recovery. Neopterin provides a new marker of detecting an acute inflammatory response in physical exercise, while specific gravity should be considered for urine volume correction post-exercise.

Salivary IgA response and upper respiratory tract infection symptoms during a 21-week competitive season in young soccer players

Sports training and competition are significant sources of stress, especially for young athletes. It is well known that physiological and psychological stressors induce neuroendocrine responses that could modulate immune system function. However, to date, little is known about the immune responses of young soccer players during a competitive season. Therefore, this study examined the effects of a 21-week competitive season divided into preseason, competitive season, and detraining on salivary immunoglobulin A (SIgA), upper respiratory tract infection (URTI) symptoms, and salivary cortisol in preadolescent male soccer players. Thirty-four young soccer players agreed to participate, and 26 (12.9 ± 0.2 years) completed the entire study. The investigation period was structured as follows: a 12-week preparatory training phase (preseason training), a 7-week competitive and a 2-week detraining phase. Resting saliva samples were taken to determine cortisol and SIgA responses. The players were required to complete a weekly log during the entire investigation reporting every sign or symptoms consistent with URTI. A significant increase in SIgA secretion rate and a decrease in URTI symptoms were observed after the 2-week detraining period (p < 0.05). No change was observed for cortisol during the study. These results indicate that training and competition demands affect the mucosal immune responses of young athletes. In addition, a short-prophylactic period (2-week detraining period) after a competitive period may attenuate mucosal immunosuppression related to URTI symptoms. Sport coaches should monitor markers of mucosal immune function to minimize illness that ultimately might lead to a decrease in performance.

Prematch salivary secretory immunoglobulin a in soccer players from the 2014 World Cup qualifying campaign

PURPOSE

To monitor resting salivary secretory immunoglobulin A (SIgA) levels in international soccer players during the short-term training period that precedes international match play.

METHODS

In a repeated-measure design, saliva samples were obtained from 13 outfield soccer players who participated in the training camps preceding 7 games (5 home and 2 away) of the 2014 FIFA World Cup qualifying campaign. Samples were obtained daily for 4 d preceding each game (and analyzed for SIgA using the IPRO oral-fluid-collection system) at match day minus 1 (MD-1), minus 2 (MD-2), minus 3 (MD-3), and minus 4 (MD-4).

RESULTS

SIgA displayed a progressive decline (P = .01) during the 4-d training period (MD-4, 365 ± 127 μg/mL; MD-3, 348 ± 154 μg/mL; MD-2, 290 ± 138 μg/mL; MD-1, 256 ± 90 μg/mL) such that MD-1 values were significantly lower (P = .01) than both MD-4 and MD-3. The 95% confidence intervals for the differences between MD-1 and MD-4 were -191 to -26 and between MD-1 and MD-3 were -155 to -28.

CONCLUSIONS

Data demonstrate that a short-term soccer-training camp in preparation for international competition induces detectable perturbations to mucosal immunity. Future studies should monitor SIgA (as a practical and noninvasive measure of immunity) alongside internal and external measures of training load in an attempt to strategically individualize training and nutritional strategies that may support optimal preparation for high-level competition.

Immunological effects of massage after exercise: A systematic review

OBJECTIVE

The objective of this review was to determine whether immune parameters can be modulated by massage after intense physical activity.

METHODS

A search was conducted in Pub Med Medline, PEDro, and Cochrane databases, using the key words: "massage", "myofascial release", "acupressure", "recovery", and "warm up" combined with "exercise", "exercise-induced muscle damage", "sport", "immunology", and lymphocytes" independently. Only controlled studies published between 1970 and 2012 were selected, with no restrictions regarding publication language. The CONSORT Declaration was applied to assess the quality of the selected studies.

RESULTS

The initial search identified 739 publications in the databases, of which only 5 met the review inclusion criteria. A positive relationship between immunological recovery and post-exercise massage was reported by some of these studies but not by others.

CONCLUSION

There is preliminary evidence that massage may modulate immune parameters when applied after exercise, but more research is needed to confirm this possibility.

Changes in salivary hormones, immunoglobulin A, and C-reactive protein in response to ultra-endurance exercises

The aim of the study was to determine the influence of the exercise duration on the changes in salivary stress markers in response to ultra-endurance exercises. The study was developed in 2 ultra-endurance exercise tests: the Ultra-trail Serra de Tramuntana (UTST), a 104 km ultra-marathon competition (n = 64) and the 25 km Cabrera Open Water Race (COWR) (n = 43). Participants in the COWR completed the 25 km at a constant pace of 3 km/h (3K group) or 2.5 km /h (2.5K group). Saliva samples were taken before and after the exercises. Salivary flow rate as well as cortisol, testosterone, C-reactive protein (CRP), and immunoglobulin A (IgA) levels were measured. Salivary flow rate decreased after the UTST but increased after the COWR. The UTST induced significant increases in cortisol and CRP levels and decreases in testosterone and IgA levels. Furthermore, a negative correlation was found between the time the athletes took to complete the exercise and the changes in salivary cortisol. After the COWR, higher increases in salivary cortisol levels were observed in the 3K group than in the 2.5K group. A significant effect of exercise decreasing testosterone and IgA levels was observed in both groups. No changes in the CRP levels were observed during the COWR. In conclusion, shorter times to complete the ultra-endurance exercise were associated with higher increases in cortisol. However, no relationships were found between the time to complete the exercises and the changes in testosterone, CRP, and IgA levels.

URI in athletes: are mucosal immunity and cytokine responses key risk factors?

Infection incidence among athletes is highest during periods of intensified training and competition and after strenuous long-distance events. Which aspects of depressed immune function are responsible for this increased infection risk are not known, but our hypothesis is that lower salivary immunoglobulin A (IgA) secretion and a higher antiinflammatory cytokine response to antigen exposure are key determinants of infection risk.

Oral intake of heat-killed Lactobacillus plantarum L-137 decreases the incidence of upper respiratory tract infection in healthy subjects with high levels of psychological stress

The immunomodulatory effects of live or non-viable lactic acid bacteria have been extensively investigated. We reported that oral intake of heat-killed Lactobacillus plantarum L-137 (HK L-137) augmented innate and acquired immunity in mice and human subjects. To examine the effects of HK L-137 intake on upper respiratory tract infection (URTI) symptoms and immune functions in human subjects, a randomised, double-blind, placebo-controlled, parallel study was conducted in subjects with high psychological stress levels. A total of seventy-eight healthy subjects (thirty-three men and forty-five women; mean age 50·6 years) with scores of >41 on eighteen-item subscales of psychological distress in the Brief Job Stress Questionnaire were randomly assigned to receive a tablet containing HK L-137 (10 mg) or a placebo tablet daily for 12 weeks. The URTI symptoms were rated once daily on the validated twenty-one-item Wisconsin Upper Respiratory Symptom Survey-21. Immune functions, such as concanavalin A-induced proliferation and percentages of interferon (IFN)-γ- and IL-4-producing CD4 T cells of peripheral blood mononuclear cells (PBMC), and serum IFN-β concentrations were measured every 4 weeks. URTI incidence was significantly lower in the HK L-137 group than in the control group. URTI incidence, duration and severity, and duration of medication showed significant negative correlations with duration of HK L-137 intake. The percentage change from baseline of concanavalin A-induced proliferation of PBMC was significantly greater in the HK L-137 group than in the control group. These findings suggest that daily HK L-137 intake can decrease URTI incidence in healthy subjects, possibly through augmentation of immune functions.

Salivary IL-21 and IgA responses to a competitive match in elite basketball players

Athletes engaged in strenuous training might experience transient immune suppression that could lead to greater incidence of upper respiratory tract infections (URTI). Since interleukin 21 (IL-21) stimulates immunoglobulin A (IgA) secreting cells and a low level of this immunoglobulin is associated with increased incidence of URTI, the aim of the present study was to investigate the effect of a basketball match on salivary cortisol (sC), salivary IL-21 (sIL-21) and salivary IgA (sIgA) levels. Twenty male basketball players participated in an official game in two teams (10 players in each team). The saliva samples were collected before the warm-up and approximately 10-15 min after the end of the match and were analysed by ELISA methods. sC concentration increased significantly after the match while sIL-21 level was reduced (p < 0.05). In opposition to the study's hypothesis, sIgA level did not change in response to the match. The present findings suggest that a basketball match is sufficiently stressful to elevate sC concentration and attenuates the sIL-21 output without compromising the sIgA level. It is reasonable to speculate that the stability of sIgA acute responses to the match, despite the decrement in sIL-21, indicates that other mechanisms rather than IL-21 stimulating B cell proliferation/differentiation might modulate IgA concentration and secretion rate.

Training load, immune system, upper respiratory symptoms and performance in well-trained cyclists throughout a competitive season

This study aimed to evaluate the leukocyte subset counts, serum immunoglobulin A, performance and upper respiratory symptoms (URS), as well as their interrelationships, of well-trained cyclists for a 29-week training season using monitored loads. The season was divided into three phases: preparatory (nine weeks), first competitive phase (nine weeks) and second competitive phase (11 weeks). The sample consisted of eight well-trained cyclists, aged 18 ± 2 years. Immunological parameters and performance were evaluated during weeks 1 (baseline), 10 (early first competitive phase), 19 (early second competitive phase) and 29 (end of the second competitive phase). The training loads (volume x rating of perceived exertion) were monitored daily while the monitoring of URS was performed every 15 days using the WURSS-44 questionnaire. The data were analyzed using a one-way ANOVA and a Pearson correlation test with the significance level set at p ≤ 0.05. No significant differences were found for training load, leukocyte subset counts or serum immunoglobulin A among the three phases. However, serum immunoglobulin A was 50.9% below the control group values. URS were significantly higher during the preparatory period, and there were significant correlations between URS and training load (strain) in the preparatory period (r = 0.72, p = 0.032) and second competitive phase (r = 0.73, p = 0.036). In conclusion, indicators of training load without a significant change throughout the season did not significantly affect immune parameters measured; however, the increase of strain can cause an increase of upper respiratory symptoms throughout the season, but without loss of performance.

Monitoring internal training load and mucosal immune responses in futsal athletes

The purpose of this study was to examine the changes in salivary immunoglobulin A (SIgA), cortisol, and upper respiratory tract infection (URTI) and their relationships with training loads (TLs) during a 4-week period of intensive training during the competitive season in elite Brazilian futsal players. Twelve athletes (age: 19 ± 1 years; height: 180 ± 4 cm; and body mass: 73 ± 7 kg) participated in the study. The training program included tactical, technical, specific conditioning and strength training, and competition matches. Training load was quantified using the session rating of perceived exertion. Salivary immunoglobulin A, salivary cortisol and symptoms of URTIs were assessed weekly. A significant decrease in weekly TL was observed for week 4 (tapering) compared with that of other weeks (p < 0.05). No significant differences were observed for cortisol and SIgA during the study (p > 0.05). There was a significant decrease in URTI symptom severity during week 4 as compared with that of weeks 1 and 2 (p < 0.05), with a significant correlation between weekly TL and URTI severity and weekly TL during week 4 (rs = 0.75; p < 0.05). The present findings suggest that futsal athletes are more susceptible to high URTI symptom severity in the periods of higher training. Therefore, the reduction in TLs before competitions is an appropriate strategy to minimize URTI symptoms ensuring the athlete's ability to train and compete.

Monitoring immune modulation by nutrition in the general population: identifying and substantiating effects on human health

Optimal functioning of the immune system is crucial to human health, and nutrition is one of the major exogenous factors modulating different aspects of immune function. Currently, no single marker is available to predict the effect of a dietary intervention on different aspects of immune function. To provide further guidance on the assessment and interpretation of the modulation of immune functions due to nutrition in the general population, International Life Sciences Institute Europe commissioned a group of experts from academia, government and the food industry to prepare a guidance document. A draft of this paper was refined at a workshop involving additional experts. First, the expert group defined criteria to evaluate the usefulness of immune function markers. Over seventy-five markers were scored within the context of three distinct immune system functions: defence against pathogens; avoidance or mitigation of allergy; control of low-grade (metabolic) inflammation. The most useful markers were subsequently classified depending on whether they by themselves signify clinical relevance and/or involvement of immune function. Next, five theoretical scenarios were drafted describing potential changes in the values of markers compared with a relevant reference range. Finally, all elements were combined, providing a framework to aid the design and interpretation of studies assessing the effects of nutrition on immune function. This stepwise approach offers a clear rationale for selecting markers for future trials and provides a framework for the interpretation of outcomes. A similar stepwise approach may also be useful to rationalise the selection and interpretation of markers for other physiological processes critical to the maintenance of health and well-being.

Comparison of salivary IgA secretion rate collected by the aspiration method and swab method

Salivary immunoglobulin A (IgA) is used as an immunity marker, as saliva can be easily collected, noninvasively with little stress. However, several saliva collection methods can be used. Our comparison between samples collected using different methods demonstrated that the salivary IgA secretion rate in samples collected using an aspiration method was significantly correlated with that in samples collected using a swab method. Moreover, the significant circadian variation in salivary IgA secretion rate in the aspirated saliva suggested that the aspiration method does not suppress salivary IgA secretion rate variability compared with the swab method. Therefore, the aspiration method should be considered as the preferable saliva collection method.

Resposta imuno-endócrina associada à partida de futsal

O objetivo do estudo foi analisar o efeito de uma partida simulada de futsal sobre as concentrações salivares de cortisol (Cs) e imunoglobulina A (SIgA) em jogadores de elite. Amostras de saliva foram coletadas antes e após a partida e analisadas, posteriormente, pelo método de ELISA. A carga interna de treinamento foi avaliada através do método da Percepção Subjetiva de Esforço da sessão. Através da análise do tamanho do efeito (TE), foi constatado aumento grande (TE=1,07) do Cs e diminuição grande (TE=-1,36) da SIgA do momento pré para o pós-partida. Foi observada correlação significante (r=0,66) entre a carga interna de treinamento e a resposta do Cs. Os resultados do presente estudo indicam que uma partida simulada de futsal pode modular a resposta imuno-endócrina. A adoção de estratégias para monitorar as respostas imuno-endócrinas, em associação a utilização de instrumentos psicométricos, pode auxiliar o planejamento e o ajuste das cargas de treinamento.

Prevention, diagnosis, and treatment of the overtraining syndrome: joint consensus statement of the European College of Sport Science and the American College of Sports Medicine

Successful training not only must involve overload but also must avoid the combination of excessive overload plus inadequate recovery. Athletes can experience short-term performance decrement without severe psychological or lasting other negative symptoms. This functional overreaching will eventually lead to an improvement in performance after recovery. When athletes do not sufficiently respect the balance between training and recovery, nonfunctional overreaching (NFOR) can occur. The distinction between NFOR and overtraining syndrome (OTS) is very difficult and will depend on the clinical outcome and exclusion diagnosis. The athlete will often show the same clinical, hormonal, and other signs and symptoms. A keyword in the recognition of OTS might be "prolonged maladaptation" not only of the athlete but also of several biological, neurochemical, and hormonal regulation mechanisms. It is generally thought that symptoms of OTS, such as fatigue, performance decline, and mood disturbances, are more severe than those of NFOR. However, there is no scientific evidence to either confirm or refute this suggestion. One approach to understanding the etiology of OTS involves the exclusion of organic diseases or infections and factors such as dietary caloric restriction (negative energy balance) and insufficient carbohydrate and/or protein intake, iron deficiency, magnesium deficiency, allergies, and others together with identification of initiating events or triggers. In this article, we provide the recent status of possible markers for the detection of OTS. Currently, several markers (hormones, performance tests, psychological tests, and biochemical and immune markers) are used, but none of them meet all the criteria to make their use generally accepted.

Salivary antimicrobial protein responses during multistage ultramarathon competition conducted in hot environmental conditions

Prolonged strenuous exercise is commonly reported to depress oral-respiratory immune status and increase the incidence of upper respiratory symptoms. This novel investigation aimed to determine the salivary antimicrobial responses and hydration status of ultraendurance runners (n = 23) during a 230-km multistage ultramarathon conducted in hot ambient conditions (32-40 °C). Body mass was measured and unstimulated saliva and venous blood samples were taken before and after each stage of the ultramarathon. Ad libitum fluid intake was permitted throughout each race day. Upper respiratory symptoms were monitored during and until 4 weeks after race completion. Samples were analyzed for salivary immunoglobulin A (IgA), lysozyme, α-amylase, and cortisol, as well as for plasma and saliva osmolality. Mean exercise-induced body mass loss over the 5 stages ranged from 1.3% to 2.4%. Overall mean pre- and post-stage plasma osmolality measurements in the ultraendurance runners were 279 ± 14 mOsmol·kg(-1) and 293 ± 15 mOsmol·kg(-1), respectively. Decreases in saliva flow rate (overall change 22%) and post-stage increases in saliva osmolality (36%) were observed in the ultraendurance runners during the ultramarathon. Reduced salivary IgA (32%) (p < 0.001 vs. pre-stage salivary IgA), enhanced salivary α-amylase (187%) (p < 0.001 vs. pre-stage salivary α-amylase), and no change in salivary lysozyme secretion rates were observed in the ultraendurance runners throughout the ultramarathon. Only 1 ultraendurance runner reported upper respiratory symptoms during and 1 month after competition. Observed depressions in salivary IgA secretion rates were offset by favourable increases in salivary α-amylase and unchanged lysozyme responses in the majority of runners during the competition. Ensuring euhydration throughout a multistage ultramarathon competition in the heat may play a role in protecting the upper respiratory tract.

Stimulating whole saliva affects the response of antimicrobial proteins to exercise

This study investigated the salivary secretion rates of antimicrobial proteins in response to prolonged, exhaustive exercise in both stimulated (STIM) and unstimulated (UNSTIM) saliva flow sample methods. Twenty-four trained men cycled for 2.5 h at 60% V̇O₂max and then to exhaustion at 75% V̇O₂max. Timed collections of whole saliva were made before exercise, mid-exercise, at the end of the moderate exercise bout and post-exhaustive exercise. After each UNSTIM collection, a STIM sample was collected following chewing flavored gum for 1 min. Saliva was analysed for lysozyme, α-amylase and salivary immunoglobulin A (s-IgA), and secretion rates were calculated. Saliva flow was 156% higher in STIM compared with UNSTIM (P < 0.001) and decreased with exercise in STIM only (P < 0.001). Exercise increased lysozyme and α-amylase levels and secretion rates were 144% higher and 152% higher in STIM compared with UNSTIM for lysozyme and α-amylase, respectively (all P < 0.001). S-IgA concentration (P < 0.05) and secretion rate (P < 0.001) increased with exercise but were both lower in STIM compared with UNSTIM (P < 0.001). In conclusion, a STIM saliva flow collection during exercise by chewing flavored gum increased the quantity of saliva and the secretion of lysozyme and α-amylase, but had a limited impact on the secretion of s-IgA.

Effects of Ramadan fasting on serum immunoglobulin G and M, and salivary immunoglobulin A concentrations

OBJECTIVE

To investigate the effects of Ramadan fasting on serum concentrations of immunoglobulin (Ig)G and IgM, and salivary IgA concentrations.

METHODS

Blood and saliva samples were collected one week before and during the last week of Ramadan from healthy male volunteers. Albumin, total lymphocyte count, electrolytes, and IgG and IgM concentrations were determined in serum; salivary IgA concentrations were measured. Anthropometric measurements were also recorded.

RESULTS

Samples were collected from 35 subjects (mean age 35.86 years, range 20-59 years). Weight, body mass index, albumin levels and the nutritional risk index decreased significantly during Ramadan fasting compared with before fasting. In addition, Na(+) and Cl(-) electrolyte levels were significantly decreased during Ramadan. Serum IgG concentrations decreased significantly during Ramadan compared with before fasting, but were still within the normal range. Salivary IgA concentrations also decreased significantly, whereas serum IgM levels did not change. Lymphocyte numbers increased significantly, but there was no correlation between Ig levels and lymphocyte count.

CONCLUSION

Ramadan fasting did not result in severe immunological disturbances.

Alternative investigations for irritable bowel syndrome

BACKGROUND AND AIM

Alternative and complementary medical practitioners have long advocated alternative treatments for irritable bowel syndrome. A more recent development has been the use of alternative investigations by these practitioners and, in the era of internet advertising, directly by patients themselves. The aim of the present study was to examine the alternative investigations that are advocated for the assessment of gastrointestinal disease and that are available through mainstream laboratories in Australia.

METHODS

A comprehensive literature review was undertaken for each investigation, which was then evaluated on the basis of ACCE criteria for diagnostic tests. The ACCE criteria consider the analytical and clinical validity, clinical utility and ethical implications of the test.

RESULTS

Serum immunoglobulin G (IgG) to food antigens, salivary IgA, intestinal permeability, fecal short-chain fatty acids and fecal microbial analysis were identified as readily available. None of the investigations satisfied the ACCE criteria. The tests were deficient in one or more areas of analytical validity, clinical application, validity and ethical usage standards.

CONCLUSION

Alternative investigations lack reliability and direct clinical applications, and should not be recommended for the investigation of gastrointestinal symptoms.

Salivary cortisol and immunoglobulin A responses to simulated and official Jiu-Jitsu matches

The aim of this study was to compare the salivary cortisol (sC) and the salivary immunoglobulin A (sIgA) responses to simulated and official Brazilian Jiu-Jitsu (BJJ) matches. Saliva samples were collected from 9 male BJJ athletes before (pre) and after (post) 2 simulated matches (SMs) and 2 official matches (OMs) performed during 2 different competitions. Salivary cortisol and sIgA concentrations (absolute concentration of sIgA [sIgAabs] and the secretion rate of sIgA [sIgArate]) were measured by an enzyme-linked immunosorbent assay. For sC, there was an effect of condition (SM vs. OM) (p < 0.05) and a time effect (pre and post) (p < 0.05). The sC was lower during SMs as compared with that during OMs and lower at premeasurement when compared with postmeasurement. No changes were observed for sIgA measurements. In summary, both SMs and official BJJ matches can increase sC levels. Moreover, the higher sC resting levels, observed before OMs, suggest that psychological factors associated with high physical-physiological demands from official BJJ competitions maximize stress hormone responses. In addition, the present findings suggest that the acute effect of BJJ matches on mucosal immunity is minimal, and it seems unlikely that changes in cortisol play a major role in the alterations in sIgA levels in response to BJJ matches. The findings of this study suggest that the use of sC can provide valuable information for coaches regarding athletes' responses to competition. In addition, psychological strategies should be implemented before events, to improve the manner in which BJJ athletes cope with the stress inherent to official matches.

Resting salivary levels of IgA and cortisol are significantly affected during intensive resistance training periods in elite male weightlifters

The aim of this study was to investigate the cumulative effects of intensive resistance training on salivary immunoglobulin A (SIgA) and cortisol responses in elite male weightlifters. Eleven elite male Taiwanese weightlifters were trained through 3 training stages before a national weightlifting competition, and this was followed by a 2-week recovery stage. Resting saliva samples were collected once in each of the 4 stages. Salivary concentrations of total protein (TP), SIgA, lactoferrin, and cortisol were measured. The results showed that (a) salivary TP concentrations were not significantly affected; (b) resting levels of SIgA, the ratio of SIgA to TP (SIgA/TP), cortisol, and the ratio of cortisol to TP (cortisol/TP) were significantly higher in the training stages than in the recovery stage; (c) a positive correlation was revealed between the ratios of SIgA/TP and cortisol/TP; and (d) the resting salivary lactoferrin concentrations and the ratio of lactoferrin to TP (lactoferrin/TP) were significantly lower in stage 1 than in the recovery stage. The findings in this study suggest that prolonged, intensive resistance training exerts cumulative effects on SIgA and cortisol responses in elite weightlifters.

Effect of exercise on the level of immunoglobulin a in saliva

The aim of this paper is to describe the structure, production and function of secretory immunoglobulin A (sIgA) as well as changes of its concentration caused by exercise of various intensity and duration. Immunoglobulin A is the main class of antibodies present in the body secreted fluids such as saliva, tears or mucus from the intestines. It is generally recognized that IgA, due to its dominance in the immune system of mucous membranes, is the first line of defence against harmful environmental factors. The secretion and composition of saliva depends on the activity of the sympathetic and parasympathetic nervous systems. Physical activity, stimulating the autonomous nervous system, may reduce the amount of saliva and/or inhibit its secretion. The relationship between physical activity and the suppression of the immune system is not fully understood, but it is known that moderate intensity exercise can improve immune defences, while extreme effort can reduce them by creating an increased risk of upper respiratory tract inflammation (URTI). In athletes, the lowest risk of upper tract infection was connected with the case of moderate intensity exercise. It is now believed that the relationship between exercise volume and the risk of URTI has the shape of the letter "J". This means that both too little and too much physical activity may increase the risk of upper respiratory tract infection. Training optimization and correct balance between exercise and rest periods may reduce the risk of adverse changes in the immune system and decrease the frequency of URTI.

Fecal lactic acid bacteria increased in adolescents randomized to whole-grain but not refined-grain foods, whereas inflammatory cytokine production decreased equally with both interventions

The intake of whole-grain (WG) foods by adolescents is reported to be approximately one-third the recommended intake of 48 g/d. This 6-wk randomized interventional study determined the effect of replacing grains within the diet with refined-grain (RG; n = 42) or WG (n = 41) foods/d on gastrointestinal and immune health in adolescents (aged 12.7 ± 0.1 y). A variety of grain-based foods were delivered weekly to participants and their families. Participants were encouraged to eat 3 different kinds of study foods (e.g., bread, cereals, snacks)/d with goals of 0 g/d (RG) and 80 g/d (WG). Stool samples were obtained during the prebaseline and final weeks to measure bifidobacteria and lactic acid bacteria (LAB) using qPCR. Stool frequency was recorded daily. Blood was drawn at baseline and at final visits for immune markers. Across groups, total-grain intake increased by one serving. The intake of WG was similar at baseline (18 ± 3 g) between groups but increased to 60 ± 5 g in the WG group and decreased to 4 ± 1 g in the RG group. Fecal bifidobacteria increased from baseline with both interventions, but LAB increased (P < 0.05) from baseline [2.4 ± 0.2 log(10) genome equivalents (eq)] to wk 6 (3.0 ± 0.2 log(10) genome eq) in the WG group but not in the RG group (baseline: 2.9 ± 0.2 log(10) genome eq; wk 6: 3.0 ± 0.1 log(10) genome eq). There was no difference in stool frequency, serum antioxidant potential, or in vitro LPS-stimulated mononuclear cell production of inflammatory cytokines between groups. However, across both groups the number of daily stools tended to increase (P = 0.08) by 0.0034 stools/g WG or by 0.2 stools with 60 g WG, mean antioxidant potential increased by 58%, and mean production of TNF-α, IL-1β, and IL-6 decreased by 24, 22, and 42%, respectively, between baseline and wk 6. Overall, incorporating either WG or RG foods increased serum antioxidant concentrations and decreased inflammatory cytokine production; however, WG study foods had more of an effect on aspects of gastrointestinal health.

Effects on secretory IgA levels in small intestine of mice that underwent moderate exercise training followed by a bout of strenuous swimming exercise

Intestinal homeostasis effectors, secretory IgA (SIgA) and polymeric immunoglobulin receptor (pIgR), have been evaluated in proximal and distal small intestine with moderate-exercise training but not with strenuous exercise or a combination of these two protocols. Therefore, two groups of mice (n=6-8) were submitted to strenuous exercise, one with and one without previous training. The control group had no exercise protocol. Assessment was made of intestinal SIgA and plasma adrenal hormones (by immunoenzymatic assay), alpha-chain and pIgR proteins in intestinal mucosa (by Western blot), lamina propria IgA plasma-cells (by cytofluorometry), mRNA expression (by real-time PCR) for pIgR, alpha- and J-chains in liver and intestinal mucosa, and pro- and anti-inflammatory cytokines in mucosa samples. Compared to other exercise protocols, training plus strenuous exercise elicited: (1) higher levels of SIgA and pIgR in the proximal intestine (probably by hepatobiliary contribution); (2) higher levels of SIgA in the distal segment; (3) lower mRNA expression of some SIgA- and most pro-inflammatory pIgR-producing cytokines. SIgA and pIgR in both segments were derived from an existing pool of their corresponding producing cells. The apparent decreased translation of mRNA transcripts underlies lower levels of SIgA and pIgR in distal than proximal small intestine. There was no significant difference in the relatively high adrenal hormone levels found in both exercised groups. Further study is required about the effects of training plus strenuous exercise on pool-derived SIgA levels and mRNA expression of pro-inflammatory pIgR-producing cytokines. These results could have important implications for intestinal disorders involving inflammation and infection.

Mucosal immune function comparison between amenorrheic and eumenorrheic distance runners

This study examined the effects of amenorrhea on mucosal immune function and susceptibility to upper respiratory tract infection (URTI) in elite female distance runners. Based on their menstrual cycles during the prior year, 21 elite, collegiate, female distance runners were designated as eumenorrheic runners (ERs; n = 8; 19.9 ± 0.8 years) or amenorrheic runners (ARs; n n = 13; 20.0 ± 0.3 years). Resting saliva and blood samples were collected in the morning. The secretory immunoglobulin A (SIgA) concentration was measured using enzyme-linked immunosorbent assay. The SIgA secretion rate was calculated. Serum 17β-estradiol concentrations and serum progesterone concentrations were measured using radioimmunoassay. Subjects reported the appearance of URTI symptoms (sore throat, headache, runny nose, coughing, or fever), if any, during the prior month. The serum estradiol concentration and salivary SIgA secretion rate were significantly lower for ARs than for ERs (p < 0.05). Serum progesterone concentration was not significantly different between groups. Higher frequencies of headache, runny nose, coughing, and fever were observed in ARs than in ERs. Results show that athletic amenorrhea with low estrogen might accelerate downregulation of mucosal immune function in athletes and enhance susceptibility to infection.

New insights into the impact of the intestinal microbiota on health and disease: a symposium report

The present report summarises key insights from a recent symposium focusing on the impact of the intestinal microbiota on health and disease. A more appropriate definition of health was proposed since health maintenance is a dynamic process better assessed in terms of ability to adapt to stress and maintain physiological homeostasis. Biomarkers specifically for health are needed; use of challenge models and subjects with suboptimal health or specific disease risk were advised. The complexity of interactions between external factors, the intestinal epithelium, intestinal microbiota, the immune system and health was exemplified by describing the effects of antibiotics, the Western diet and non-digestible carbohydrates on the microbiota. The association of certain bacteria with different states of health or disease was acknowledged but also that is not always clear whether this is a cause or effect. Recent identification of three robust faecal metagenome clusters may advance this understanding. It was speculated that knowledge of the intestinal microbiota profile may eventually help in the diagnosis of health risks and choice of therapy. It was agreed that beneficial manipulation of the commensal microbiota can improve health outcome. For this purpose, three areas were reviewed. Firstly, research into probiotics as vaccine adjuvants was considered useful for substantiation of immune function claims. Secondly, positive results with certain probiotics and synbiotics for colorectal cancer are emerging, mostly fromin vitroand animal studies. Finally, studies in endurance athletes have shown strain-specific probiotic benefit in terms of maintenance of immune function and, for certain strains, reduction of episodes of respiratory and/or gastrointestinal tract infections.