Nutrition and Athlete Immune Health: New Perspectives on an Old Paradigm.

Respiratory and gastrointestinal infections limit an athlete's availability to train and compete. To better understand how sick an athlete will become when they have an infection, a paradigm recently adopted from ecological immunology is presented that includes the concepts of immune resistance (the ability to destroy microbes) and immune tolerance (the ability to dampen defence yet control infection at a non-damaging level). This affords a new theoretical perspective on how nutrition may influence athlete immune health; paving the way for focused research efforts on tolerogenic nutritional supplements to reduce the infection burden in athletes. Looking through this new lens clarifies why nutritional supplements targeted at improving immune resistance in athletes show limited benefits: evidence supporting the old paradigm of immune suppression in athletes is lacking. Indeed, there is limited evidence that the dietary practices of athletes suppress immunity, e.g. low-energy availability and train- or sleep-low carbohydrate. It goes without saying, irrespective of the dietary preference (omnivorous, vegetarian), that athletes are recommended to follow a balanced diet to avoid a frank deficiency of a nutrient required for proper immune function. The new theoretical perspective provided sharpens the focus on tolerogenic nutritional supplements shown to reduce the infection burden in athletes, e.g. probiotics, vitamin C and vitamin D. Further research should demonstrate the benefits of candidate tolerogenic supplements to reduce infection in athletes; without blunting training adaptations and without side effects

Effects of protein–carbohydrate supplementation on immunity and resistance training outcomes: a double-blind, randomized, controlled clinical trial

Purpose: To examine the impact of ingesting hydrolyzed beef protein, whey protein, and carbohydrate on resistance training outcomes, body composition, muscle thickness, blood indices of health and salivary human neutrophil peptides (HNP1-3), as reference of humoral immunity followed an 8-week resistance training program in college athletes. Methods: Twenty-seven recreationally physically active males and females (n = 9 per treatment) were randomly assigned to one of the three groups: hydrolyzed beef protein, whey protein, or non-protein isoenergetic carbohydrate. Treatment consisted of ingesting 20 g of supplement, mixed with orange juice, once a day immediately post-workout or before breakfast on non-training days. Measurements were performed pre- and post-intervention on total load (kg) lifted at the first and last workout, body composition (via plethysmography) vastus medialis thickness (mm) (via ultrasonography), and blood indices of health. Salivary HNP1-3 were determined before and after performing the first and last workout. Results: Salivary concentration and secretion rates of the HNP1-3 decreased in the beef condition only from pre-first-workout (1.90 ± 0.83 μg/mL; 2.95 ± 2.83 μg/min, respectively) to pre-last-workout (0.92 ± 0.63 μg/mL, p = 0.025, d = 1.03; 0.76 ± 0.74 μg/min, p = 0.049, d = 0.95), and post-last-workout (0.95 ± 0.60 μg/mL, p = 0.032, d = 1.00; 0.59 ± 0.52 μg/min, p = 0.027, d = 1.02). No other significant differences between groups were observed. Conclusions: Supplementation with a carbohydrate–protein beverage may support resistance training outcomes in a comparable way as the ingestion of only carbohydrate. Furthermore, the ingestion of 20 g of hydrolyzed beef protein resulted in a decreased level and secretion rates of the HNP1-3 from baseline with no negative effect on blood indices of health

Tear Lactoferrin and Lysozyme as Clinically Relevant Biomarkers of Mucosal Immune Competence

Tears have attracted interest as a minimally-invasive biological fluid from which to assess biomarkers. Lactoferrin (Lf) and lysozyme (Lys) are abundant in the tear fluid and have antimicrobial properties. Since the eye is a portal for infection transmission, assessment of immune status at the ocular surface may be clinically relevant. Therefore, the aim of this series of studies was to investigate the tear fluid antimicrobial proteins (AMPs) Lf and Lys as biomarkers of mucosal immune status. To be considered biomarkers of interest, we would expect tear AMPs to respond to stressors known to perturb immunity but be robust to confounding variables, and to be lower in participants with heightened risk or incidence of illness. We investigated the relationship between tear AMPs and upper respiratory tract infection (URTI; study 1) as well as the response of tear AMPs to prolonged treadmill exercise (study 2) and dehydration (study 3). Study 1 was a prospective cohort study conducted during the common cold season whereas studies 2 and 3 used repeated-measures crossover designs. In study 1, tear Lys concentration (C) as well as tear AMP secretion rates (SRs) were lower in individuals who reported pathogen-confirmed URTI (n = 9) throughout the observation period than in healthy, pathogen-free controls (n = 17; Lys-C, P = 0.002, d = 0.85; Lys-SR, P < 0.001, d = 1.00; Lf-SR, P = 0.018, d = 0.66). Tear AMP secretion rates were also lower in contact lens wearers. In study 2, tear AMP SRs were 42-49% lower at 30 min-1 h post-exercise vs. pre-exercise (P < 0.001, d = 0.80-0.93). Finally, in study 3, tear AMPs were not influenced by dehydration, although tear AMP concentrations (but not secretion rates) displayed diurnal variation. We conclude that Lf and Lys have potential as biomarkers of mucosal immune competence; in particular, whether these markers are lower in infection-prone individuals warrants further investigation

Bovine colostrum supplementation and upper respiratory symptoms during exercise training: a systematic review and meta-analysis of randomised controlled trials

Abstract Background Bovine colostrum is proposed as a nutritional countermeasure to the risk of upper respiratory symptoms (URS) during exercise training. The aim of this systematic review and meta-analysis was to estimate the size of the effect of bovine colostrum supplementation on URS. Methods Databases (CDSR, CENTRAL, Cinahl, ClinicalTrials.gov, Current Controlled Trials, DARE, EMBASE, Medline, PROSPERO and Web of Science) of published, unpublished and ongoing studies were searched for randomised controlled trials of healthy adults (≥18 years), evaluating the effect of oral bovine colostrum supplementation compared to a concurrent control group on URS. Results Five trials (152 participants) met the inclusion criteria, all of which involved individuals involved in regular exercise training. Over an 8–12 week follow-up period, bovine colostrum supplementation when compared to placebo significantly reduced the incidence rate of URS days (rate ratio 0.56, 95 % confidence intervals 0.43 to 0.72, P value < 0.001) and URS episodes (0.62, 0.40 to 0.99, P value = 0.04) by 44 and 38 % respectively. There were limited data and considerable variation in results of included studies for duration of URS episodes hence a meta-analysis of this outcome was deemed inappropriate. The risk of bias assessment in this review was hindered by poor reporting practices of included studies. Due to incomplete reporting of study methods, four of the five studies were judged to have a moderate or high risk of overall bias. Our findings must be interpreted in relation to quantity and quality of the available evidence. Conclusions The present systematic review and meta-analysis provides evidence that bovine colostrum supplementation may be effective in preventing the incidence of URS days and episodes in adults engaged in exercise training. The fact that the majority of included studies did not report significant effects on URS outcomes mitigates concerns about publication bias. The point estimates of the random-effects meta-analyses are greater than the smallest clinically important difference, but the low precision of the individual study estimates means the evidence presented in this review needs to be followed up with an appropriately designed and adequately powered, randomised control trial

Seed systems smallholder farmers use

Seed can be an important entry point for promoting productivity, nutrition and resilience among smallholder farmers. While investments have primarily focused on strengthening the formal sector, this article documents the degree to which the informal sector remains the core for seed acquisition, especially in Africa. Conclusions drawn from a uniquely comprehensive data set, 9660 observations across six countries and covering 40 crops, show that farmers access 90.2 % of their seed from informal systems with 50.9 % of that deriving from local markets. Further, 55 % of seed is paid for by cash, indicating that smallholders are already making important investments in this arena. Targeted interventions are proposed for rendering formal and informal seed sector more smallholder-responsive and for scaling up positive impacts

Post-exercise Hot Water Immersion Elicits Heat Acclimation Adaptations That Are Retained for at Least Two Weeks

Heat acclimation by post-exercise hot water immersion (HWI) on six consecutive days reduces thermal strain and improves exercise performance during heat stress. However, the retention of adaptations by this method remains unknown. Typically, adaptations to short-term, exercise-heat-acclimation ( 0.05). As such, the reduction in thermal strain during exercise-heat stress appears likely due to the reduction in resting T re evident at POST, WK 1, and WK 2. In summary, 6 days of post-exercise HWI is an effective, practical and accessible heat acclimation strategy that induces adaptations, which are retained for at least 2 weeks. Therefore, post-exercise HWI can be completed during an athlete's pre-taper phase and does not suffer from the same practical limitations as short-term, exercise-heat-acclimation

Consensus Statement Immunonutrition and Exercise.

In this consensus statement on immunonutrition and exercise, a panel of knowledgeable contributors from across the globe provides a consensus of updated science, including the background, the aspects for which a consensus actually exists, the controversies and, when possible, suggested directions for future research

Anxiety and perceived psychological stress play an important role in the immune response after exercise

There are common pathways by which psychological stress and exercise stress alter immunity. However, it remains unknown whether psychological stress plays a role in the in vivo immune response to exercise. We examined the relationship between anxiety and perceived psychological stress reported before exercise and in vivo immunity after exercise using skin sensitisation with Diphenylcyclopropenone (DPCP). In a randomised design, sixty four, thoroughly familiarised, males completed widely used psychological instruments to assess state-anxiety and perceived psychological stress before exercise, and ran either 30 minutes at 60% (30MI) or 80% (30HI) V . O2peak, 120 minutes at 60% (120MI) V . O2peak or rested (CON) before DPCP sensitisation. Cutaneous recall to DPCP was measured as the dermal thickening response to a low-dose series DPCP challenge 4-weeks after sensitisation. After accounting for exercise (R2 = 0.20; P < 0.01), multiple-regression showed that pre-exercise state-anxiety (STAI-S; DeltaR2 = 0.19; P < 0.01) and perceived psychological stress (DeltaR2 = 0.13; P < 0.05) were moderately associated with the DPCP response after exercise. The STAI-S scores before exercise were considered low-to-moderate in these familiarised individuals (median split; mean STAI-S of low 25 and moderate 34). Further examination showed that the DPCP response after exercise (30MI, 30HI or 120MI) was 62% lower in those reporting low vs. moderate state-anxiety before exercise (mean difference in dermal thickening: -2.6 mm; 95% CI: -0.8 to -4.4 mm; P < 0.01). As such, the results indicate a beneficial effect of moderate (vs. low) state-anxiety and perceived psychological stress on in vivo immunity after exercise. Moreover, correlations were of comparable strength for the relationship between physiological stress (heart rate training impulse) and the summed dermal response to DPCP (r = -0.37; 95% CI: -0.05 to -0.62; P = 0.01), and state-anxiety and the summed dermal response to DPCP (r = 0.39; 95% CI: 0.08 to 0.63; P < 0.01). In conclusion, state-anxiety and perceived psychological stress levels before exercise play animportant role in determining the strength of the in vivo immune response after exercise. These findings indicate a similar strength relationship for the level of state-anxiety prior to exercise and the level of physiological stress during exercise with the in vivo immune response after exercise. Future research is required to investigate exercise-immune responses in athletes, military personnel and others in physically demanding occupations experiencing higher levels of psychological stress than those reported in this study e.g. related to important competition, military operations and major life events. Nevertheless, the present findings support the recommendation that exercise scientists should account for anxiety and psychological stress when examining the immune response to exercise

Physical and immunological aspects of exercise in chronic diseases.

Physical inactivity and sedentary lifestyles are believed to be independent risk factors for the occurrence of numerous diseases, including, obesity, Type 2 diabetes, metabolic syndrome, cardiovascular disease, cancer and mental health, all leading to substantial morbidity and/or premature death. It has been found that regular exercise, is associated with better quality of life and health outcomes, and reduces the risk of cardiovascular disease and cancer. Here, we review the effects regular exercise has on mental health and well-being, on the immune system and in cancer, cardiovascular disease, autoimmunity and metabolic syndrome. Is exercise the new immunotherapy to treat diseases

Diversity of Zoanthids (Anthozoa: Hexacorallia) on Hawaiian Seamounts: Description of the Hawaiian Gold Coral and Additional Zoanthids

The Hawaiian gold coral has a history of exploitation from the deep slopes and seamounts of the Hawaiian Islands as one of the precious corals commercialised in the jewellery industry. Due to its peculiar characteristic of building a scleroproteic skeleton, this zoanthid has been referred as Gerardia sp. (a junior synonym of Savalia Nardo, 1844) but never formally described or examined by taxonomists despite its commercial interest. While collection of Hawaiian gold coral is now regulated, globally seamounts habitats are increasingly threatened by a variety of anthropogenic impacts. However, impact assessment studies and conservation measures cannot be taken without consistent knowledge of the biodiversity of such environments. Recently, multiple samples of octocoral-associated zoanthids were collected from the deep slopes of the islands and seamounts of the Hawaiian Archipelago. The molecular and morphological examination of these zoanthids revealed the presence of at least five different species including the gold coral. Among these only the gold coral appeared to create its own skeleton, two other species are simply using the octocoral as substrate, and the situation is not clear for the final two species. Phylogenetically, all these species appear related to zoanthids of the genus Savalia as well as to the octocoral-associated zoanthid Corallizoanthus tsukaharai, suggesting a common ancestor to all octocoral-associated zoanthids. The diversity of zoanthids described or observed during this study is comparable to levels of diversity found in shallow water tropical coral reefs. Such unexpected species diversity is symptomatic of the lack of biological exploration and taxonomic studies of the diversity of seamount hexacorals