Dietary nucleotide improves markers of immune response to strenuous exercise under a cold environment

Joan Riera,Daniel Martinez-Puig,Carlos Chetrit,Victoria Pons,Franchek Drobnic,Josep A Tur,Antoni Pons

doi:10.1186/1550-2783-10-20

Abstract

BackgroundStrenuous exercise has been classically associated to immune-suppression and consequently to an increased risk of infections, especially at the upper respiratory tract. The administration of dietary nucleotides has been demonstrated useful to maintain the immune function in situations of stress and thus could be an appropriate strategy to counteract the decline of the immune function associated to strenuous exercise. The aim of the present study was to asses the impact of a specific nucleotide formulation (Inmunactive®) on the markers of immune function of athletes after a heavy exercise bout under cold conditions.MethodsTwenty elite male taekwondo athletes were randomly divided into two groups of 10 subjects that were supplemented with placebo (P) or Inmunactive (I) at 480 mg/day during 30 days. At baseline (day 0) and after 4 wk of supplementation (day 30) each subject undertook an exhaustion exercise test using a cycloergometer. Skin temperature, core temperature, heart rate, lactate concentration and rating of perceived exertion (RPE) were recorded during the test. Blood and saliva samples were obtained before and after each exercise test for determination of blood cell concentrations, PHA-stimulated lymphocyte proliferation (PHA-LP) and salivary immunoglobulin A (SIgA).ResultsExercise tests induced neutrophilia and reduction in lymphocyte blood counts on day 0 and on day 30 in both groups. However, the I group exhibited a faster recovery from the lymphopenic response than the P group, so that lymphocyte levels were higher after 150 min (P < 0.0028). Furthermore, the lymphoproliferative response was modulated by nucleotide supplementation, since it was higher in the I group on day 30 despite an almost significant (P < 0.06) exercise-evoked decrease at baseline.ConclusionsThese findings suggest that supplementation with a nucleotide-based product for 4 weeks could counteract the impairment of immune function after heavy exercise.

Highlights

Strenuous exercise has been classically associated to immune-suppression and to an increased risk of infections, especially at the upper respiratory tract
It has been demonstrated that dietary nucleotides attenuates the fall of salivary IgA (SIgA) [24], the increase in salivary cortisol [25] and the decrease in the lymphocyte proliferative response [26] after the strenuous exercise
The subjects entered into the climatic chamber, adjusted a cycle ergometer, placed the chest Heart rate (Hr) transmitter and skin thermistors and undertook an exhaustion exercise test at work corresponding to W1 for 10 min, W2 for 20 min and W3 until fatigue in a climatic chamber adjusted at −3°C

Summary

Introduction

Strenuous exercise has been classically associated to immune-suppression and to an increased risk of infections, especially at the upper respiratory tract. The molecular mechanisms by which dietary nucleotides modulate the immune system are practically unknown, it has been demonstrated that nucleotides influence lymphocyte maturation, activation and proliferation [16,17,18]. Likewise, they affect the lymphocyte subset populations [19,20], macrophage phagocytosis [17], immunoglobulin production [18,21], and delayed hypersensitivity as well as allograft and tumour responses [15,17]. Aside from this study, there is no data available from prospective, double-blind, placebo-controlled studies, on the effects of nucleotide supplementation on the markers of immune response after strenuous exercise in a cold environment

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