Knowledge of carbohydrate consumption does not alter natural killer cell activity following an acute bout of high-intensity aerobic exercise

Abstract

Carbohydrate consumption during strenuous aerobic exercise reportedly minimizes post-exercise suppression of the innate immune system. One of the most common measurements of innate immunity is natural killer cell activity (NKCA). It is not known whether actual carbohydrate consumption or merely the knowledge of carbohydrate consumption mediates alteration in NKCA. The purpose of the present investigation was to determine if knowledge of carbohydrate beverage could result in alteration of RPE and NKCA, independent of actual carbohydrate intake. We recruited 11 male and female endurance athletes and randomly assigned them to either a correct or false knowledge of carbohydrate intake, such that in the false group, subjects were informed that they were receiving the carbohydrate beverage (CHO), but actually received a placebo (PLA) beverage. CHO and PLA beverages were matched to be similar in taste and appearance. Subjects completed 60 min of cycle ergometry (74% of VO2 peak). Venous blood samples were collected before (PRE), immediately after (POST), and 2 h after (2H) exercise and used to determine plasma glucose concentration, leukocyte total and differential counts, and NKCA. Data were statistically analyzed using a 3-factor analysis of variance (ANOVA) (p < 0.05). We did not find a significant effect of knowledge of drink type on leukocyte count, leukocyte differential, or NKCA. Drink type did not significantly alter leukocyte total, differential counts, or NKCA. There was a significant effect of exercise on NKCA. Knowledge of drink type does not alter innate immunity following exercise as assessed by leukocyte counts and NKCA.

Cognitive awareness of carbohydrate intake does not alter exercise-induced lymphocyte apoptosis

“…The rise in glucose response has been confirmed by a number of other investigations 14,22-24. We are aware of only one other deception study in which subjects have received an incorrect cognitive awareness of carbohydrate or placebo supplementation prior to exercise 25. As we have shown, cognitive awareness of drink type (whether correct or incorrect) did not have an effect on the blood glucose response.…”

“…In addition, it is likely that CHO has a different effect depending on the immune cell subset. While an overall decrease in leukocyte numbers have been reported in various CHO supplementation investigations,8,24-25 ingestion appears to affect neutrophils to a greater extent than lymphocytes. Nieman et al and Sharhag et al both found carbohydrate supplementation to reduce neutrophil count, but to have no effect on numbers of lymphocytes 8,24.…”

Short‐term resource allocation during extensive athletic competition

“…These findings include temporary increases in the pro-inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-a (TNF-a), granulocyte colony stimulating factor (GCSF), monocyte chemoattractant protein 1 (MCP-1), and other immunological factors (Nieman, 2012). Natural killer (NK) cell function and numbers increase following bouts of exercise as well (McFarlin, Hutchison, & Kueht, 2008;Shephard & Shek, 1994;Woods, Davis, Smith, & Nieman, 1999), and lysozyme, an important anti-bacterial component of innate mucosal immunity, shows a significant increase in male runners after two hours of running (Costa, Fortes, Richardson, Bilzon, & Walsh, 2012). In endurance athletes of both sexes, both leukocyte and lymphocyte counts are increased after an hour of intense exercise (McFarlin et al, 2008).…”

“…Natural killer (NK) cell function and numbers increase following bouts of exercise as well (McFarlin, Hutchison, & Kueht, 2008;Shephard & Shek, 1994;Woods, Davis, Smith, & Nieman, 1999), and lysozyme, an important anti-bacterial component of innate mucosal immunity, shows a significant increase in male runners after two hours of running (Costa, Fortes, Richardson, Bilzon, & Walsh, 2012). In endurance athletes of both sexes, both leukocyte and lymphocyte counts are increased after an hour of intense exercise (McFarlin et al, 2008). While there are some reports of declining immune measures after exercise (e.g., sIgA), these resuts could be due to a number of different parameters, including sample collection, hydration, and even environmental factors (reviewed in Bishop & Gleeson, 2009).…”

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

“…A previous study which reported that combined carbohydrate intake with 60 min and high-intensity cycling was not associated with an alteration in innate immunity. Nevertheless, previous study mentioned that the effect of exercise on NK cell activity cannot be denied 44 . Furthermore, Timmons and Bar-Or 39 showed that NK cell function is neither enhanced nor reduced following exercise in young girls, however carbohydrate intake attenuates the NK cell subsets responses to exercise in children.…”