Obesity has been reported to impair immune functions and lead to low-grade long-term inflammation; however, studies that have investigated the impact of weight loss on these among the young and slightly obese are limited. Thus, we investigated the effect of a 12-week weight management program with behavioral modifications on cell-mediated immune functions and inflammatory responses in young obese participants. Our hypothesis was that weight loss would result in improved immune functions and decreased inflammatory responses. Sixty-four participants (45 obese and 19 normal weight) finished the program. Obese (body mass index ≥25) participants took part in 5 group education and 6 individual counseling sessions. Normal-weight (body mass index 18.5-23) participants only attended 6 individual sessions. The goal for the obese was to lose 0.5 kg/wk by reducing their intake by 300 to 500 kcal/d and increasing their physical activity. Program participation resulted in a modest but significant decrease in weight (2.7 ± 0.4 kg, P < .001) and lipopolysaccharide-stimulated interleukin-1β production (from 0.85 ± 0.07 to 0.67 ± 0.07 ng/mL, P < .05) in the obese. In the obese group, increase in phytohemagglutinin-stimulated interleukin-10 production, a TH2 and anti-inflammatory cytokine, approached significance after program participation (from 6181 ± 475 to 6970 ± 632 pg/mL, P = .06). No significant changes in proliferative responses to the optimal concentration of concanavalin A or phytohemagglutinin were observed in the obese after program participation. Collectively, modest weight loss did not change the cell-mediated immune functions significantly but did attenuate the inflammatory response in young and otherwise healthy obese adults.
Keywords: Cell-mediated immune response; Inflammatory response; Obesity; Weight loss.
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