Weight Reduction in Athletes May Adversely Affect the Phagocytic Function of Monocytes

In brief: Monocyte phagocytic function was studied in nine competitive athletes before and after a two-week weight-reduction program of calorie restriction. The phagocytic activity of monocytes before the program was higher in the athletes than in the sedentary controls, but decreased significantly after the weight-reduction program. Furthermore, plasma fibronectin concentrations and the response of lymphocytes to phytohemagglutinin decreased after the calorie restriction. These findings suggest that weight reduction by calorie restriction may adversely affect the integrity of defense mechanisms, even in healthy athletes. Thus, calorie restriction in athletes must be conducted with caution to protect them from adverse effects on their physiologic defense mechanisms.