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ABSTRACT: The purpose of this study was to examine the effects of a probiotic supplement during 4 mo of spring training in men and women engaged in endurance-based physical activities on incidence of upper respiratory tract infections (URTI) and mucosal immune markers. Sixty-six highly active individuals were randomized to probiotic (n = 33) or placebo (n = 33) groups and, under double-blind procedures, received probiotic (PRO: Lactobacillus salivarius, 2 × 1010 bacterium colony-forming units) or placebo (PLA) daily for 16 wk. Resting blood and saliva samples were collected at baseline and after 8 and 16 wk. Weekly training and illness logs were kept. Fifty-four subjects completed the study (n = 27 PRO, n = 27 PLA). The proportion of subjects on PRO who experienced 1 or more wk with URTI symptoms was not different from that of those on PLA (PRO .58, PLA .59; p = .947). The number of URTI episodes was similar in the 2 groups (PRO 1.6 ± 0.3, PLA 1.4 ± 0.3; p = .710). Severity and duration of symptoms were not significantly different between treatments. Blood leukocyte, neutrophil, monocyte, and lymphocyte counts; saliva IgA; and lysozyme concentrations did not change over the course of the study and were not different on PRO compared with PLA. Regular ingestion of L. salivarius does not appear to be beneficial in reducing the frequency of URTI in an athletic cohort and does not affect blood leukocyte counts or levels of salivary antimicrobial proteins during a spring period of training and competition.
International Journal of Sport Nutrition and Exercise Metabolism 05/2012; 22(4):235-42.
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ABSTRACT: The purpose of this study was to examine sex differences in immune variables and upper respiratory tract infection (URTI) incidence in 18-35 year-old athletes engaged in endurance-based physical activity during the winter months. Eighty physically active individuals (46 males, 34 females) provided resting venous blood samples for determination of differential leukocyte counts, lymphocyte subsets and whole blood culture multi-antigen stimulated cytokine production. Timed collections of unstimulated saliva were also made for determination of saliva flow rate, immunoglobulin A (IgA) concentration and IgA secretion rate. Weekly training and illness logs were kept for the following 4 months. Training loads averaged 10 h/week of moderate-vigorous physical activity and were not different for males and females. Saliva flow rates, IgA concentration and IgA secretion rates were significantly higher in males than females (all P < 0.01). Plasma IgA, IgG and IgM concentrations and total blood leukocyte, neutrophil, monocyte and lymphocyte counts were not different between the sexes but males had higher numbers of B cells (P < 0.05) and NK cells (P < 0.001). The production of interleukins 1 beta, 2, 4, 6, 8 and 10, interferon-gamma and tumour necrosis factor-alpha in response to multi-antigen challenge were not significantly different in males and females (all P > 0.05). The average number of weeks with URTI symptoms was 1.7 +/- 2.1 (mean +/- SD) in males and 2.3 +/- 2.5 in females (P = 0.311). It is concluded that most aspects of immunity are similar in men and women in an athletic population and that the observed differences in a few immune variables are not sufficient to substantially affect URTI incidence. Sex differences in immune function among athletes probably do not need to be considered in future mixed gender studies on exercise, infection and immune function unless the focus is on mucosal immunity or NK cells.
Exercise immunology review 01/2011; 17:122-35. · 2.79 Impact Factor
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ABSTRACT: The progressive decline in strength and power with ageing leads to compromised mobility and an increased risk of falls. Angiotensin converting enzyme (ACE) I/D and alpha actinin 3 (ACTN3) R/X polymorphisms have been suggested to influence variations in skeletal muscle function and body composition. This study investigated the associations between these polymorphisms and knee extensor muscle function and muscularity in older Caucasian men. Strength was measured isometrically and isokinetically (at 30 and 240 degrees s(-1)), and the time course of the evoked twitch response recorded. A dual-energy X-ray absorptiometry scan measured thigh and whole body non-skeletal lean mass. ACE I/D and ACTN3 R/X polymorphisms were determined by polymerase chain reaction, and serum ACE activity using spectrophotometry. Whole body and thigh non-skeletal lean mass were independent of ACE and ACTN3 genotypes. Absolute and relative high velocity strength, and the time course of an evoked twitch were not associated with ACE or ACTN3 genotype. Serum ACE activity was negatively correlated with relative high velocity torque (R = -0.23, P = 0.03), and exhibited a positive trend with knee extensor isometric strength (R = 0.19, P = 0.07). ACE I/D and ACTN3 R/X polymorphisms were not associated with muscle function or muscularity phenotypes in older Caucasian men, although serum ACE activity appeared to have a small effect on muscle function.
Arbeitsphysiologie 05/2010; 109(2):269-77. · 2.15 Impact Factor
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ABSTRACT: The angiotensin-converting enzyme (ACE) I/D and α-actinin 3 (ACTN3) R/X polymorphisms have been suggested to influence variations in skeletal muscle function. This study investigated the association between ACE I/D and ACTN3 R/X polymorphisms and muscle strength and contractile properties in young UK Caucasian men. Measurements of the knee extensor muscles were taken from 79 recreationally active but non-strength-trained males on two occasions. Isometric knee extensor strength was measured using a conventional strength-testing chair. Maximal twitches were electrically evoked by percutaneous stimulation to assess time-to-peak tension, half-relaxation time and peak rate of force development. The torque–velocity relationship was measured at four angular velocities (0, 30, 90 and 240 deg s−1) using isokinetic dynamometry, and the relative torque at high velocity was calculated (torque at 240 deg s−1 as a percentage of that at 30 deg s−1). The ACE I/D and ACTN3 R/X polymorphisms were genotyped from whole blood by polymerase chain reaction. Serum ACE activity was assayed from serum using automated spectrophotometry. Physical characteristics were independent of either genotype. Absolute and relative high-velocity torque were not influenced by ACE or ACTN3 genotypes. Isometric strength and the time course of a maximal twitch were independent of ACE and ACTN3 genotypes. Serum ACE activity was significantly dependent on ACE genotype (P < 0.001), but was not associated with any measure of functional or contractile properties. Knee extensor functional and contractile properties, including high-velocity strength, were not influenced by ACE and ACTN3 polymorphisms in a cohort of UK Caucasian males. Any influence of these individual polymorphisms on human skeletal muscle does not appear to be of sufficient magnitude to influence function in free-living UK Caucasian men.
Experimental physiology 12/2008; 94(1):81 - 89. · 3.17 Impact Factor
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ABSTRACT: The angiotensin-converting enzyme (ACE) I/D and alpha-actinin 3 (ACTN3) R/X polymorphisms have been suggested to influence variations in skeletal muscle function. This study investigated the association between ACE I/D and ACTN3 R/X polymorphisms and muscle strength and contractile properties in young UK Caucasian men. Measurements of the knee extensor muscles were taken from 79 recreationally active but non-strength-trained males on two occasions. Isometric knee extensor strength was measured using a conventional strength-testing chair. Maximal twitches were electrically evoked by percutaneous stimulation to assess time-to-peak tension, half-relaxation time and peak rate of force development. The torque-velocity relationship was measured at four angular velocities (0, 30, 90 and 240 deg s(-1)) using isokinetic dynamometry, and the relative torque at high velocity was calculated (torque at 240 deg s(-1) as a percentage of that at 30 deg s(-1)). The ACE I/D and ACTN3 R/X polymorphisms were genotyped from whole blood by polymerase chain reaction. Serum ACE activity was assayed from serum using automated spectrophotometry. Physical characteristics were independent of either genotype. Absolute and relative high-velocity torque were not influenced by ACE or ACTN3 genotypes. Isometric strength and the time course of a maximal twitch were independent of ACE and ACTN3 genotypes. Serum ACE activity was significantly dependent on ACE genotype (P < 0.001), but was not associated with any measure of functional or contractile properties. Knee extensor functional and contractile properties, including high-velocity strength, were not influenced by ACE and ACTN3 polymorphisms in a cohort of UK Caucasian males. Any influence of these individual polymorphisms on human skeletal muscle does not appear to be of sufficient magnitude to influence function in free-living UK Caucasian men.
Experimental physiology 08/2008; 94(1):81-9. · 3.17 Impact Factor
