In keeping with this, the statistical analysis showed a significant day*group interaction (P = 0.0045). Table 4 Salivary IgA and PHA-Stimulated lymphocyte proliferation during exercise tests before and after 30 days of selleck screening library supplementation Variable Day 0 Inmunactive Placebo Day 30 Inmunactive Placebo Salivary IgA (mg · L-1)         Basal 1.87 ± 0.38 2.59 ± 1.16 2.32 ± 0.96 2.31 ± 0.61

150 min 2.43 ± 1.06 2.13 ± 0.70 1.91 ± 0.54 1.35 ± 0.45 PHA-Stimulated lymphocyte proliferation (cpm · 1000-1)     Basal 29.3 ± 3.5 35.5 ± 4.4 29.1 ± 2.1 25.9 ± 3.9 24 h 21.4 ± 3.6 35.9 ± 53.8* 34.5 ± 5.4 20.6 ± 5.1* CB-839 price values are means ± SE (n = 10). An asterisk indicates significant differences between groups at specified time point (P < 0.05). Discussion Scientific evidence from placebo-controlled trials of nutritional compounds having a positive enhancing effect on the immune function in the healthy population is scarce [32]. High-intensity

exercise has been classically associated to immune disturbances in healthy individuals [2] and thus could be considered as a model to study the efficacy of nutritional interventions in populations during periods of immune suppression [33]. Exposure to cold environments has been claimed to elicit a stress response impacting immune cell function [10], but see more evidences from controlled studies are also scarce [13]. Research on the potential for dietary nucleotides to enhance the human immune response is wide but human trials are mainly

restricted to critically ill patients [34] and to supplementation of infant formula [35]. To our knowledge, this is the first controlled study in which the efficacy of nucleotide supplementation has been evaluated in healthy individuals under multiple stressors such as strenuous exercise and cold environment. The exercise protocol was designed to elicit an immune disturbance according to previously published data [4, 36]. Subjects were instructed to perform a controlled physical work corresponding to Erastin manufacturer 90% of the VO2max for more than 20 minutes, in an exercise bout of more than 45 minutes in total. The described workload led to exhaustion as demonstrated by the maximum heart rate, lactate concentration and Borg values. On the second exercise test, Borg values were lower and HRmax and lactate concentration tended to be lower than in the previous exercise test, probably due to the effect of the training during the month of the trial. Levels of salivary IgA were unaffected by the exercise. Although falls in saliva IgA can occur during intense exercise [37–39], levels are generally unchanged with exercise lasting less than 1 h [40] and also not affected by environmental temperature [41–43], as observed in the present trial.